PHILIPS PCA9620H

PCA9620
Universal LCD driver for low multiplex rates
Rev. 1 — 9 December 2010
Product data sheet
1. General description
The PCA9620 is a peripheral device which interfaces to almost any Liquid Crystal Display
(LCD)1 with low multiplex rates. It generates the drive signals for any static or multiplexed
LCD containing up to eight backplanes, 60 segments, and up to 480 elements. The
PCA9620 is compatible with most microprocessors or microcontrollers and communicates
via a two-line bidirectional I2C-bus. Communication overheads are minimized using a
display RAM with auto-incremented addressing and display memory switching. The
PCA9620 features an internal charge pump with internal capacitors for on-chip generation
of the LCD driving voltages.
AEC Q100 grade 2 compliant for automotive applications.
2. Features and benefits
„ Low power consumption
„ Extended operating temperature range from −40 °C to +105 °C
„ 60 segments and 8 backplanes allowing to drive:
‹ up to 60 7-segment alphanumeric characters
‹ up to 30 14-segment alphanumeric characters
‹ any graphics of up to 480 elements
„ 480 bit RAM for display data storage
„ Selectable backplane drive configuration: static, 2, 4, 6, or 8 backplane multiplexing
„ Programmable internal charge pump for on-chip LCD voltage generation up to
3 × VDD2
„ 400 kHz I2C-bus interface
„ Selectable linear temperature compensation of VLCD
„ Selectable display bias configuration
„ Wide range for digital and analog power supply: from 2.5 V to 5.5 V
„ Wide LCD supply range: from 2.5 V for low threshold LCDs and up to 9.0 V for high
threshold (automobile) twisted nematic LCDs
„ Display memory bank switching in static, duplex, and quadruplex drive modes
„ Programmable frame frequency in steps of 10 Hz in the range of 60 Hz to 300 Hz;
factory calibrated with a tolerance of ±15 % covering the whole temperature and
voltage range
„ Selectable inversion scheme for LCD driving waveforms: frame or line inversion
„ Integrated temperature sensor with temperature readout
„ On chip calibration of internal oscillator frequency and VLCD
1.
The definition of the abbreviations and acronyms used in this data sheet can be found in Section 15 on page 65.
PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
3. Ordering information
Table 1.
Ordering information
Type number
Package
PCA9620H
Name
Description
Version
LQFP80
plastic low profile quad flat package; 80 leads;
body 12 × 12 × 1.4 mm
SOT315-1
4. Marking
Table 2.
Marking codes
Type number
Marking code
PCA9620H
PCA9620H/Q900
5. Block diagram
VLCD
S0 to S59
BP0 to BP7
60
VDD2
BACKPLANE
OUTPUTS
DISPLAY SEGMENT OUTPUTS
LCD
VOLTAGE
SELECTOR
CHARGE
PUMP(1)
(VOLTAGE
MULTIPLIER)
DISPLAY REGISTER
DISPLAY
CONTROL
OUTPUT BANK SELECT
LCD BIAS
GENERATOR
VSS
DISPLAY RAM
CLK
SCL
SDA
TEMPERATURE
SENSOR
CLOCK SELECT
AND TIMING
OSCILLATOR
POWER-ON
RESET
INPUT
FILTERS
PCA9620
COMMAND
DECODER
WRITE DATA
CONTROL
DATA POINTER,
AUTO INCREMENT
I2C-BUS
CONTROLLER
013aaa246
A0
A1
VDD1
T1 T2 T3
(1) The charge pump can generate a maximum output voltage of 3 × VDD2.
Fig 1.
Block diagram of PCA9620
PCA9620
Product data sheet
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
6. Pinning information
61 S0
62 S1
63 S2
64 S3
65 S4
66 S5
67 S6
68 S7
69 S8
70 S9
71 S10
72 S11
73 S12
74 S13
75 S14
76 S15
77 S16
78 S17
79 S18
80 S19
6.1 Pinning
S20
1
60 SDA
S21
2
59 SCL
S22
3
58 A1
S23
4
57 A0
S24
5
56 CLK
S25
6
55 T3
S26
7
54 T2
S27
8
53 T1
S28
9
52 VSS
S29 10
51 VDD1
PCA9620
S30 11
50 VDD2
S59 40
S58 39
S57 38
S56 37
S55 36
S54 35
S53 34
S52 33
S51 32
S50 31
S49 30
41 BP0
S48 29
42 BP1
S39 20
S47 28
43 BP2
S38 19
S46 27
44 BP3
S37 18
S45 26
45 BP4
S36 17
S44 25
46 BP5
S35 16
S43 24
47 BP6
S34 15
S42 23
48 BP7
S33 14
S41 22
49 VLCD
S32 13
S40 21
S31 12
013aaa244
Top view. For mechanical details, see Figure 57 on page 61.
Fig 2. Pin configuration for LQFP80 (PCA9620H)
PCA9620
Product data sheet
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
6.2 Pin description
Table 3.
Pin
Type
Description
S0 to S59
61 to 80 and
1 to 40
output
LCD segment
BP0 to BP7
41 to 48
output
LCD backplane
VLCD
49
supply/output[1] LCD supply voltage
VDD2
50
supply
supply voltage 2 (charge pump)
VDD1
51
supply
supply voltage 1 (analog and digital)
VSS
52
supply
ground supply voltage
T1 to T3
53 to 55
input
test pins; must be tied to VSS in applications
CLK
56
input/output
internal oscillator output, external oscillator input
A0, A1
57, 58
input
I2C-bus slave address selection bit
SCL
59
input
I2C-bus serial clock
SDA
60
input/output
I2C-bus serial data
[1]
PCA9620
Product data sheet
Pin description
Symbol
When the internal VLCD generation is used, this pin drives the VLCD voltage. In this case pin VLCD
is an output. When the external supply is requested then pin VLCD is an input and VLCD can be
supplied to it. In this case the internal charge pump must be disabled (see Table 8 on page 7).
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Rev. 1 — 9 December 2010
© NXP B.V. 2010. All rights reserved.
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
7. Functional description
The PCA9620 is a versatile peripheral device designed to interface any microprocessor or
microcontroller to a wide variety of LCDs. It can directly drive any static or multiplexed
LCD containing up to 480 elements.
7.1 Commands of PCA9620
The PCA9620 is controlled by 22 commands, which are defined in Table 4. Any other
combinations of operation code bits that are not mentioned in this document may lead to
undesired operation modes of PCA9620.
Table 4.
Commands of PCA9620
Command name
initialize
Bits
Reference
7
6
5
4
3
2
1
0
0
0
1
1
1
0
1
0
Section 7.1.1
OTP-refresh
1
1
0
1
0
0
0
0
Section 7.1.2
oscillator-ctrl
1
1
0
0
1
1
COE
OSC
Section 7.1.3
charge-pump-ctrl
1
1
0
0
0
0
CPE
CPC
Section 7.1.4
temp-msr-ctrl
1
1
0
0
1
0
TCE
TME
Section 7.1.5
temp-comp-SLA
0
0
0
1
1
SLA[2:0]
temp-comp-SLB
0
0
1
0
0
SLB[2:0]
temp-comp-SLC
0
0
1
0
1
SLC[2:0]
temp-comp-SLD
0
0
1
1
0
SLD[2:0]
Table 29
set-VPR-MSB
0
1
0
0
VPR[7:4]
set-VPR-LSB
0
1
0
1
VPR[3:0]
Section 7.1.6
display-enable
0
0
1
1
1
0
set-MUX-mode
0
0
0
0
0
M[2:0]
set-bias-mode
1
1
0
0
0
1
load-data-pointer
1
0
P[5:0]
frame-frequency
0
1
1
F[4:0]
input-bank-select
0
0
0
0
1
IB[2:0]
output-bank-select
0
0
0
1
0
OB[2:0]
write-RAM-data
B[7:0]
Section 7.1.13
temp-read
TD[7:0]
Section 7.1.14,
Section 7.4.7
invmode_CPF_ctrl
1
1
0
1
0
1
LF
CPF
Section 7.1.15
temp-filter
1
1
0
1
0
0
1
TFE
Section 7.1.16
0
E
Section 7.1.7
Section 7.1.8
B[1:0]
Section 7.1.9
Section 7.1.10
Section 7.1.11
Section 7.1.12.1
7.1.1 Command: initialize
This command generates a chip wide reset which resets all command values to their
default values (see Table 25 on page 15). It must be sent to the PCA9620 after power-on.
After this command is sent, it is possible to send additional commands without the need to
re-initialize the interface. Reset takes 100 ns to complete.
For further information see Section 7.3 on page 14.
PCA9620
Product data sheet
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
Table 5.
Initialize - initialize command bit description
Bit
Symbol
Value
Description
7 to 0
-
00111010
fixed value
7.1.2 Command: OTP-refresh
During production and testing of the device, each IC is calibrated in order to achieve the
specified accuracy of VLCD, the frame frequency, and the temperature measurement. This
calibration is performed on EPROM cells called One Time Programmable (OTP) cells.
These cells are being read by the device at power-on, after a reset, and every time when
the initialize command or the OTP-refresh command is sent. This command will take
approximately 10 ms to finish.
Table 6.
OTP-refresh - OTP-refresh command bit description
Bit
Symbol
Value
Description
7 to 0
-
11010000
fixed value
7.1.3 Command: oscillator-ctrl
The oscillator-ctrl command switches between internal and external oscillator and enables
or disables pin CLK.
Table 7.
Oscillator-ctrl - oscillator control command bit description
For further information, see Section 7.5 on page 38.
Bit
Symbol
Value
Description
7 to 2
-
110011
fixed value
1
COE
0
[1]
PCA9620
Product data sheet
control pin CLK
0[1]
clock signal not available on pin CLK;
pin CLK is in 3-state and may be left floating
1
clock signal available on pin CLK
OSC
oscillator source
0[1]
internal oscillator running
1
external oscillator used;
pin CLK becomes an input
Default value.
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
7.1.4 Command: charge-pump-ctrl
The charge-pump-ctrl command enables or disables the internal VLCD generation and
controls the charge pump voltage multiplier setting.
Table 8.
Charge-pump-ctrl - charge pump control command bit description
Bit
Symbol
Value
Description
7 to 2
-
110000
fixed value
1
CPE
0
[1]
charge pump switch
0[1]
charge pump disabled;
no internal VLCD generation;
external supply of VLCD
1
charge pump enabled
CPC
charge pump voltage multiplier setting
0[1]
VLCD = 2 × VDD2
1
VLCD = 3 × VDD2
Default value.
7.1.5 Command: temp-msr-ctrl
The temp-msr-ctrl command enables or disables the temperature measurement block and
the temperature compensation of VLCD.
Table 9.
Temp-msr-ctrl - temperature measurement control command bit description
For further information, see Section 7.4.8 on page 36.
Bit
Symbol
Value
Description
7 to 2
-
110010
fixed value
1
TCE
temperature compensation switch
0
no temperature compensation of VLCD
possible
1[1]
0
temperature compensation of VLCD possible
TME
temperature measurement switch
0
temperature measurement disabled;
1[1]
temperature measurement enabled;
no temperature readout possible
temperature readout possible
[1]
Default value.
7.1.6 Command: set-VPR-MSB and set-VPR-LSB
With these two instructions it is possible to set the target VLCD voltage for the internal
charge pump, see Section 7.4.3 on page 31.
Table 10.
Bit
Symbol
Value
Description
7 to 4
-
0100
fixed value
VPR[7:4]
0000[1]
3 to 0
[1]
PCA9620
Product data sheet
Set-VPR-MSB - set VPR MSB command bit description
to 1111 the four most significant bits of VPR[7:0]
Default value.
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
Table 11.
Set-VPR-LSB - set VPR LSB command bit description
Bit
Symbol
Value
Description
7 to 4
-
0101
fixed value
VPR[3:0]
0000[1]
3 to 0
[1]
to 1111 the four least significant bits of VPR[7:0]
Default value.
7.1.7 Command: display-enable
Table 12.
Display-enable - display enable command bit description
Bit
Symbol
Value
Description
7 to 1
-
0011100
fixed value
0
E
0[1]
display disabled;
backplane and segment outputs are internally
connected to VSS
1
display enabled
[1]
Default value.
7.1.8 Command: set-MUX-mode
Table 13.
Set-MUX-mode - set multiplex drive mode command bit description
Bit
Symbol
Value
Description
7 to 3
-
00000
fixed value
2 to 0
M[2:0]
000[1], 011,
110, 111
1:8 multiplex drive mode: 8 backplanes
001
static drive mode: 1 backplane
010
1:2 multiplex drive mode: 2 backplanes
100
1:4 multiplex drive mode: 4 backplanes
101
1:6 multiplex drive mode: 6 backplanes
[1]
Default value.
7.1.9 Command: set-bias-mode
Table 14.
Set-bias-mode - set bias mode command bit description
Bit
Symbol
Value
Description
7 to 2
-
110001
fixed value
B[1:0]
00[1],
1⁄
4
bias
11
1⁄
3
bias
10
1⁄
2
bias
1 to 0
[1]
01
Default value.
7.1.10 Command: load-data-pointer
The load-data-pointer command defines one of the 60 display RAM addresses where the
following display data will be sent to. For further information, see Section 7.9.1 on
page 41.
PCA9620
Product data sheet
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
Table 15.
Load-data-pointer - load data pointer command bit description
Bit
Symbol
Value
Description
7 to 6
-
10
fixed value
5 to 0
P[5:0]
000000 to
111111
6-bit binary value of 0 to 59
7.1.11 Command: frame-frequency
With the frame-frequency command the frame frequency and the output clock frequency
can be configured.
Table 16.
Bit
Symbol
Value
Description
7 to 5
-
011
fixed value
4 to 0
F[4:0]
see Table 17
nominal frame frequency (Hz)
Table 17.
Product data sheet
Frame frequency values
F[4:0]
Nominal frame
frequency, ffr (Hz)[1]
Resultant oscillator
frequency, fosc (Hz)
Duty cycle (%)[2]
00000
60
2880
20 : 80
00001
70
3360
7 : 93
00010
80
3840
47 : 53
00011
91
4368
40 : 60
00100
100
4800
33 : 67
00101
109
5232
27 : 73
00110
120
5760
20 : 80
00111
129.7
6226
13 : 87
01000
141.2
6778
5 : 95
01001
150
7200
50 : 50
01010
160
7680
47 : 53
01011
171.4
8227
43 : 57
01100
177.8
8534
41 : 59
01101
192
9216
36 : 64
01110[3]
200
9600
33 : 67
01111
208.7
10018
30 : 70
10000
218.2
10474
27 : 73
10001
228.6
10973
23 : 77
10010
240
11520
20 : 80
10011
252.6
12125
16 : 84
10100, 10101
266.7
12802
10 : 90
10110, 10111
282.4
13555
5 : 95
11000 to 11111
300
14400
50 : 50
[1]
PCA9620
Frame frequency - frame frequency and output clock frequency command bit
description
Nominal frame frequency calculated for the default clock frequency of 9600 Hz.
[2]
Duty cycle definition: % HIGH-level time : % LOW-level time.
[3]
Default value.
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
7.1.12 Bank select commands
For multiplex drive modes 1:4, 1:2 and static drive mode, it is possible to write data to one
area of the RAM whilst displaying from another. These areas are named as RAM banks.
Input and output banks can be set independently from one another with the
input-bank-select and the output-bank-select command. For further information see
Section 7.9.2 on page 46.
7.1.12.1
Command: input-bank-select
Input-bank-select - input bank select command bit description[1]
Table 18.
7.1.12.2
Bit
Symbol
Value
Description
7 to 3
-
00001
fixed value
2 to 0
IB[2:0]
Product data sheet
static drive mode
1:2 drive mode
1:4 drive mode
000[2]
bank 0: RAM-row 0
001
bank 1: RAM-row 1
bank 0: RAM-rows 0
and 1
bank 0: RAM-rows 0,
1, 2, and 3
010
bank 2: RAM-row 2
011
bank 3: RAM-row 3
100
bank 4: RAM-row 4
101
bank 5: RAM-row 5
110
bank 6: RAM-row 6
111
bank 7: RAM-row 7
[1]
Not applicable for multiplex drive mode 1:6 and 1:8.
[2]
Default value.
bank 2: RAM-rows 2
and 3
bank 4: RAM-rows 4
and 5
bank 4: RAM-rows 4,
5, 6, and 7
bank 6: RAM-rows 6
and 7
Command: output-bank-select
Output-bank-select - output bank select command bit description[1]
Table 19.
PCA9620
selects RAM bank to write to
Bit
Symbol
Value
Description
7 to 3
-
00010
fixed value
2 to 0
OB[2:0]
selects RAM bank to read from to the LCD
static drive mode
1:2 drive mode
1:4 drive mode
000[2]
bank 0: RAM-row 0
001
bank 1: RAM-row 1
bank 0: RAM-rows 0
and 1
bank 0: RAM-rows 0,
1, 2, and 3
010
bank 2: RAM-row 2
011
bank 3: RAM-row 3
100
bank 4: RAM-row 4
101
bank 5: RAM-row 5
110
bank 6: RAM-row 6
111
bank 7: RAM-row 7
[1]
Not applicable for multiplex drive mode 1:6 and 1:8.
[2]
Default value.
bank 2: RAM-rows 2
and 3
bank 4: RAM-rows 4
and 5
bank 6: RAM-rows 6
and 7
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Rev. 1 — 9 December 2010
bank 4: RAM-rows 4,
5, 6, and 7
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
7.1.13 Command: write-RAM-data
The write-RAM-data command writes data byte-wise to the RAM. After Power-On Reset
(POR) the RAM content is random and should be brought to a defined status by clearing it
(setting it logic 0).
Write-RAM-data - write RAM data command bit description[1]
Table 20.
Bit
Symbol
Value
Description
7 to 0
B[7:0]
00000000 to
11111111
writing data byte-wise to RAM
[1]
For this command bit RS of the control byte has to be set logic 1 (see Table 33 on page 52).
More information about the display RAM can be found in Section 7.9 on page 40.
7.1.14 Command: temp-read
The temp-read command allows reading out the temperature values measured by the
internal temperature sensor.
Table 21. Temp-read - temperature readout command bit description[1]
For further information, see Table 9 on page 7 and Section 7.4.7 on page 35.
Bit
Symbol
Value
Description
7 to 0
TD[7:0]
00000000 to
11111111
readout representing the digital temperature
[1]
For this command bit R/W of the I2C-bus slave address byte has to be set logic 1 (see Table 32 on
page 51).
7.1.15 Command: invmode_CPF_ctrl
The invmode_CPF_ctrl command allows changing the drive scheme inversion mode and
the charge pump frequency.
The waveforms used to drive LCD displays inherently produce a DC voltage across the
display cell. The PCA9620 will compensate for the DC voltage by inverting the waveforms
on alternate frames or alternate lines. The choice of compensation method is determined
with the LF bit.
Table 22.
Bit
Symbol
Value
Description
7 to 2
-
110101
fixed value
1
LF
0
[1]
PCA9620
Product data sheet
Invmode_CPF_ctrl - inversion mode and charge pump frequency prescaler
command bit description
set inversion mode
0[1]
line inversion mode
1
frame inversion mode
CPF
set charge pump oscillator frequency
0[1]
fosc(cp) ~ 1 MHz
1
fosc(cp) ~ 500 kHz
Default value.
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
In frame inversion mode the DC value is compensated across two frames and not within
one frame. Changing the inversion mode to frame inversion reduces the power
consumption, therefore it is useful when power consumption is a key point in the
application.
Frame inversion may not be suitable for all applications. The RMS voltage across a
segment is better defined, however since the switching frequency is reduced there is
possibility for flicker to occur.
The waveforms of Figure 15 on page 23 to Figure 21 on page 29 are showing line
inversion mode. Figure 22 on page 30 shows one example of frame inversion.
7.1.16 Command: temp-filter
Table 23.
Temp-filter - digital temperature filter command bit description
Bit
Symbol
Value
Description
7 to 1
-
1101001
fixed value
0
TFE
[1]
digital temperature filter switch
0[1]
digital temperature filter disabled;
the unfiltered digital value of TD[7:0] is
immediately available for the readout and
VLCD compensation, see Section 7.4.7 on
page 35
1
digital temperature filter enabled
Default value.
7.2 Possible display configurations
The PCA9620 is a versatile peripheral device designed to interface between any
microprocessor or microcontroller to a wide variety of LCD segment or dot matrix displays
(see Figure 3). It can directly drive any static or multiplexed LCD containing up to eight
backplanes and up to 60 segments.
The display configurations possible with the PCA9620 depend on the number of active
backplane outputs required; a selection of possible display configurations is given in
Table 24.
PCA9620
Product data sheet
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
dot matrix
7-segment with dot
14-segment with dot and accent
013aaa312
Fig 3.
Example of displays suitable for PCA9620
Table 24.
Selection of possible display configurations
Number of
Backplanes
Icons
Digits/Characters
7-segment
14-segment
Dot matrix/
Elements
8
480
60
30
480 dots (8 × 60)
6
320
45
22
360 dots (6 × 60)
4
240
30
15
240 dots (4 × 60)
2
120
15
7
120 dots (2 × 60)
1
60
7
3
60 dots (1 × 60)
All of the display configurations in Table 24 can be implemented in the typical systems
shown in Figure 4 (internal VLCD) and in Figure 5 (external VLCD).
VDD2
VDD1
R≤
tr
2Cb
VDD1
HOST
PROCESSOR/
MICROCONTROLLER
VDD2
VLCD
60 segment drives
SDA
LCD PANEL
(up to 480
elements)
SCL PCA9620
8 backplanes
A0
A1
CLK
VSS
013aaa247
n.c.
VSS
VDD1 from 2.5 V to 5.5 V and VDD2 from 2.5 V to 5.5 V.
Fig 4.
PCA9620
Product data sheet
Typical system configuration when using the internal VLCD generation
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
VLCD
VDD1
R≤
tr
2Cb
VDD1
VDD2
VLCD
60 segment drives
SDA
HOST
PROCESSOR/
MICROCONTROLLER
LCD PANEL
(up to 480
elements)
SCL PCA9620
8 backplanes
A0
A1
CLK
VSS
013aaa248
n.c.
VSS
VDD1 from 2.5 V to 5.5 V, VDD2 from 2.5 V to 5.5 V and VLCD from 2.5 V to 9.0 V.
Fig 5.
Typical system configuration when using an external VLCD
The host microprocessor or microcontroller maintains the 2 line I2C-bus communication
channel with the PCA9620. The appropriate biasing voltages for the multiplexed LCD
waveforms are generated internally. The only other connections required to complete the
system are the power supplies (VDD1, VDD2, VSS, VLCD), the external capacitors, and the
LCD panel selected for the application.
The minimum recommended values for external capacitors on VDD1, VDD2, and VLCD are
nominal 100 nF. When using bigger capacitors, especially on the VLCD, the generated
ripple will be consequently smaller, however it will take longer for the internal charge pump
to first reach the target VLCD voltage.
In the case that VDD1 and VDD2 are connected externally, the capacitors on VDD1 and VDD2
can be replaced by a single capacitor with a minimum value of 200 nF.
Remark: In the case of insufficient decoupling, ripple of VDD1 and VDD2 will create
additional VLCD ripple. The ripple on VLCD can be reduced by making the VSS connection
as low-ohmic as possible. Excessive ripple on VLCD may give rise to flicker on the display.
7.3 Start-up and shut-down
7.3.1 Power-On Reset (POR)
At power-on the PCA9620 resets to starting conditions as follows:
1. All backplane outputs are set to VSS.
2. All segment outputs are set to VSS.
3. Selected drive mode is: 1:8 with 1⁄4 bias.
4. Input and output bank selectors are reset.
5. The I2C-bus interface is initialized.
6. The data pointer is cleared (set logic 0).
7. The Internal oscillator is running; no clock signal is available on pin CLK; pin CLK is in
3-state.
8. Temperature measurement is enabled.
PCA9620
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PCA9620
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9. Temperature filter is disabled.
10. The internal VLCD voltage generation is disabled. The charge pump is switched off.
11. The VLCD temperature compensation is enabled.
12. The display is disabled.
Remark: Do not transfer data on the I2C-bus for at least 1 ms after a power-on to allow
the reset action to complete.
The first command sent to the device after the power-on event must be the initialize
command (see Section 7.1.1 on page 5).
After Power-On Reset (POR) and before enabling the display, the RAM content should be
brought to a defined status
• by clearing it (setting it all logic 0) or
• by writing meaningful content (e.g. a graphic)
otherwise unwanted display artifacts may appear on the display.
Table 25. Reset states
Bits labeled - are undefined at power-on.
Command name
PCA9620
Product data sheet
Bits
7
6
5
4
3
2
1
0
initialize
0
0
1
1
1
0
1
0
OTP-refresh
1
1
0
1
0
0
0
0
oscillator-ctrl
1
1
0
0
1
1
0
0
charge-pump-ctrl
1
1
0
0
0
0
0
0
temp-msr-ctrl
1
1
0
0
1
0
1
1
temp-comp-SLA
0
0
0
1
1
0
0
0
temp-comp-SLB
0
0
1
0
0
0
0
0
temp-comp-SLC
0
0
1
0
1
0
0
0
temp-comp-SLD
0
0
1
1
0
0
0
0
set-VPR-MSB
0
1
0
0
0
0
0
0
set-VPR-LSB
0
1
0
1
0
0
0
0
display-enable
0
0
1
1
1
0
0
0
set-MUX-mode
0
0
0
0
0
0
0
0
set-bias-mode
1
1
0
0
0
1
0
0
load-data-pointer
1
0
0
0
0
0
0
0
frame-frequency
0
1
1
0
1
1
1
0
input-bank-select
0
0
0
0
1
0
0
0
output-bank-select
0
0
0
1
0
0
0
0
write-RAM-data
-
-
-
-
-
-
-
-
temp-read
0
1
0
0
0
0
0
0
invmode_CPF_ctrl
1
1
0
1
0
1
0
0
temp-filter
1
1
0
1
0
0
1
0
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Universal LCD driver for low multiplex rates
7.3.2 Recommended start-up sequences
This chapter describes how to proceed with the initialization of the chip in different
application modes.
START
Power-on
VDD1 and
VDD2 at the
same time
Set VPR
register to
desired VLCD
value
Set
multiplication
factor for
charge pump
and enable it
Wait 1 ms
Initialize
command
Initiate an
OTP-refresh
Wait till
VLCD reaches
programmed
value(1)
Write RAM
content to be
displayed and
enable the
display(2)
STOP
013aaa249
(1) This time depends on the external capacitor on pin VLCD. For a capacitor of 100 nF a delay of 5 ms
to 15 ms is expected.
When using the internal VLCD generation, the display must not be enabled before the generation of
VLCD with the internal charge pump is completed, otherwise unwanted display artifacts may appear
on the display.
(2) RAM data may be written before or during the ramp-up of VLCD.
Fig 6.
PCA9620
Product data sheet
Recommended start-up sequence when using the internal charge pump and the
internal clock signal
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START
Initiate an
OTP-refresh
Power-on
VDD1, VDD2,
and VLCD
at the
same time
Write RAM
content to be
displayed and
enable the
display
Wait 1 ms
STOP
Initialize
command
013aaa250
Fig 7.
Recommended start-up sequence when using an external supplied VLCD and the
internal clock signal
START
Power-on
VDD1 and
VDD2 at the
same time
Apply external
clock signal
to pin CLK;
set OSC bit
logic 1(1)
Wait till
VLCD reaches
programmed
value(2)
(1)
Wait 1 ms
Set VPR
register to
desired VLCD
value
Initialize
command
Initiate an
OTP-refresh
Set
multiplication
factor for
charge pump
and enable it
Write RAM
content to be
displayed and
enable the
display(3)
STOP
013aaa251
(1) The external clock signal can be applied after the generation of the VLCD voltage as well.
(2) This time depends on the external capacitor on pin VLCD. For a capacitor of 100 nF a delay of 5 ms
to 15 ms is expected.
(3) RAM data may be written before or during the ramp-up of VLCD.
Fig 8.
PCA9620
Product data sheet
Recommended start-up sequence when using the internal charge pump and an
external clock signal
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PCA9620
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Universal LCD driver for low multiplex rates
START
Power-on
VDD1, VDD2,
and VLCD
at the
same time
Apply external
clock signal
to pin CLK;
set OSC bit
logic 1
Wait 1 ms
Write RAM
content to be
displayed and
enable the
display
Initialize
command
STOP
Initiate an
OTP-refresh
Fig 9.
013aaa252
Recommended start-up sequence when using an external supplied VLCD and an
external clock signal
7.3.3 Recommended power-down sequences
With the following sequences the PCA9620 can be set to a state of minimum power
consumption, called power-down mode.
START
Disable display by setting
bit E logic 0
Stop generation of VLCD
by setting bit
CPE logic 0
Disable temperature measurement by
setting bit
TME logic 0
STOP
013aaa253
Fig 10. Recommended power-down sequence for minimum power-down current when
using the internal charge pump and the internal clock signal
PCA9620
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PCA9620
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Universal LCD driver for low multiplex rates
START
Disable display by setting
bit E logic 0
Disable temperature measurement by
setting bit
TME logic 0
STOP
013aaa254
Fig 11. Recommended power-down sequence when using an external supplied VLCD and
the internal clock signal
START
Disable display by setting
bit E logic 0
Stop generation of VLCD
by setting bit
CPE logic 0
Disable temperature measurement by
setting bit
TME logic 0
Bring pin CLK
to 3-state by
setting bit
OSC and bit
COE logic 0
External
clock may
be switched
off
STOP
013aaa255
Fig 12. Recommended power-down sequence when using the internal charge pump and
an external clock signal
PCA9620
Product data sheet
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PCA9620
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Universal LCD driver for low multiplex rates
START
Disable display by setting
bit E logic 0
Disable temperature measurement by
setting bit
TME logic 0
Bring pin CLK
to 3-state by
setting bit
OSC and bit
COE logic 0
External
clock may
be switched
off
STOP
013aaa256
Fig 13. Recommended power-down sequence when using an external supplied VLCD and
an external clock signal
Remark: It is necessary to run the power-down sequence before removing the supplies.
Depending on the application, care must be taken that no other signals are present at the
chip input or output pins when removing the supplies (please refer to Section 9 on
page 53). Otherwise this may cause unwanted display artifacts. In case of uncontrolled
removal of supply voltages the PCA9620 will not be damaged.
Remark: Static voltages across the liquid crystal display can build up when the external
LCD supply voltage (VLCD) is on while the IC supply voltage (VDD1 or VDD2) is off, or vice
versa. This may cause unwanted display artifacts. To avoid such artifacts, external VLCD,
VDD1, and VDD2 must be applied or removed together.
Remark: A clock signal must always be supplied to the device when the device is active;
removing the clock may freeze the LCD in a DC state, which is not suitable for the liquid
crystal. It is recommended to first disable the display and afterwards to remove the clock
signal.
7.4 LCD voltage
7.4.1 LCD voltage selector
The LCD voltage selector co-ordinates the multiplexing of the LCD in accordance with the
selected LCD drive configuration. The operation of the voltage selector is controlled by the
set-bias-mode command (see Table 14 on page 8) and the set-MUX-mode command
(see Table 13 on page 8).
Intermediate LCD biasing voltages are obtained from an internal voltage divider. The
biasing configurations that apply to the preferred modes of operation, together with the
biasing characteristics as functions of VLCD and the resulting discrimination ratios (D), are
given in Table 26.
Discrimination is a term which is defined as the ratio of the on and off RMS voltage across
a segment. It can be thought of as a measurement of contrast.
PCA9620
Product data sheet
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Universal LCD driver for low multiplex rates
Table 26.
LCD drive modes: summary of characteristics
LCD drive
mode
Number of:
Backplanes Levels
LCD bias
configuration
V off ( RMS )
----------------------V LCD
V on ( RMS )
---------------------V LCD
VLCD[2]
V on ( RMS )
D = ----------------------- [1]
V off ( RMS )
static
1
2
static
0
1
∞
Von(RMS)
1:2 multiplex
2
3
1⁄
2
0.354
0.791
2.236
2.828 × Voff(RMS)
1:2 multiplex
2
4
1⁄
3
0.333
0.745
2.236
3.0 × Voff(RMS)
5
1⁄
4
0.395
0.729
1.845
2.529 × Voff(RMS)
4
3
1⁄
2
0.433
0.661
1.527
2.309 × Voff(RMS)
4
4
1⁄
3
0.333
0.577
1.732
3.0 × Voff(RMS)
5
1⁄
4
0.331
0.545
1.646
3.024 × Voff(RMS)
3
1⁄
2
0.456
0.612
1.341
2.191 × Voff(RMS)
1:2
multiplex[3]
1:4
multiplex[3]
1:4 multiplex
1:4
multiplex[3]
1:6
multiplex[3]
2
4
6
1:6 multiplex
6
4
1⁄
3
0.333
0.509
1.527
3.0 × Voff(RMS)
1:6 multiplex
6
5
1⁄
4
0.306
0.467
1.527
3.266 × Voff(RMS)
3
1⁄
2
0.467
0.586
1.254
2.138 × Voff(RMS)
4
1⁄
3
0.333
0.471
1.414
3.0 × Voff(RMS)
5
1⁄
4
0.293
0.424
1.447
3.411 × Voff(RMS)
1:8
multiplex[3]
1:8
multiplex[3]
1:8 multiplex
8
8
8
[1]
Determined from Equation 3.
[2]
Determined from Equation 2.
[3]
In this examples the discrimination factor and hence the contrast ratios are smaller. The advantage of these LCD drive modes is a
power saving from a reduction of the LCD voltage VLCD.
A practical value for VLCD is determined by equating Voff(RMS) with a defined LCD
threshold voltage (Vth), typically when the LCD exhibits approximately 10 % contrast. In
the static drive mode a suitable choice is VLCD > 3Vth.
1
Bias is calculated by ------------- , where the values for a are
1+a
a = 1 for 1⁄2 bias
a = 2 for 1⁄3 bias
a = 3 for 1⁄4 bias
The RMS on-state voltage (Von(RMS)) for the LCD is calculated with Equation 1:
V on ( RMS ) =
V LCD
a 2 + 2a + n
-----------------------------2
n × (1 + a)
(1)
where VLCD is the resultant voltage at the LCD segment and where the values for n are
n = 1 for static mode
n = 2 for 1:2 multiplex
n = 4 for 1:4 multiplex
n = 6 for 1:6 multiplex
n = 8 for 1:8 multiplex
The RMS off-state voltage (Voff(RMS)) for the LCD is calculated with Equation 2:
PCA9620
Product data sheet
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PCA9620
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Universal LCD driver for low multiplex rates
V off ( RMS ) =
V LCD
a 2 – 2a + n
-----------------------------2
n × (1 + a)
(2)
Discrimination is the ratio of Von(RMS) to Voff(RMS) and is determined from Equation 3:
V on ( RMS )
--------------------- =
V off ( RMS )
2
(a + 1) + (n – 1)
-------------------------------------------2
(a – 1) + (n – 1)
(3)
It should be noted that VLCD is sometimes referred as the LCD operating voltage.
7.4.1.1
Electro-optical performance
Suitable values for Von(RMS) and Voff(RMS) are dependant on the LCD liquid used. The
RMS voltage, at which a pixel will be switched on or off, determine the transmissibility of
the pixel.
For any given liquid, there are two threshold values defined. One point is at 10 % relative
transmission (at Vlow) and the other at 90 % relative transmission (at Vhigh), see Figure 14.
For a good contrast performance, the following rules should be followed:
V on ( RMS ) ≥ V high
(4)
V off ( RMS ) ≤ V low
(5)
Von(RMS) and Voff(RMS) are properties of the display driver and are affected by the selection
of a, n (see Equation 1 to Equation 3) and the VLCD voltage.
Vlow and Vhigh are properties of the LCD liquid and can be provided by the module
manufacturer.
It is important to match the module properties to those of the driver in order to achieve
optimum performance.
100 %
Relative Transmission
90 %
10 %
Vlow
OFF
SEGMENT
Vhigh
GREY
SEGMENT
VRMS [V]
ON
SEGMENT
001aam358
Fig 14. Electro-optical characteristic: relative transmission curve of the liquid
PCA9620
Product data sheet
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7.4.2 LCD drive mode waveforms
7.4.2.1
Static drive mode
The static LCD drive mode is used when a single backplane is provided in the LCD.
Tfr
LCD segments
VLCD
BP0
VSS
state 1
(on)
VLCD
state 2
(off)
Sn
VSS
VLCD
Sn+1
VSS
(a) Waveforms at driver.
VLCD
state 1
0V
−VLCD
VLCD
state 2
0V
−VLCD
(b) Resultant waveforms
at LCD segment.
013aaa207
Vstate1(t) = VSn(t) − VBP0(t).
Vstate2(t) = V(Sn + 1)(t) − VBP0(t).
Von(RMS)(t) = VLCD. Voff(RMS)(t) = 0 V.
Fig 15. Static drive mode waveforms (line inversion mode)
PCA9620
Product data sheet
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PCA9620
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Universal LCD driver for low multiplex rates
7.4.2.2
1:2 Multiplex drive mode
When two backplanes are provided in the LCD, the 1:2 multiplex mode applies. The
PCA9620 allows the use of 1⁄2 bias or 1⁄3 bias in this mode as shown in Figure 16 and
Figure 17.
Tfr
VLCD
BP0
LCD segments
VLCD/2
VSS
state 1
VLCD
BP1
state 2
VLCD/2
VSS
VLCD
Sn
VSS
VLCD
Sn+1
VSS
(a) Waveforms at driver.
VLCD
VLCD/2
state 1
0V
−VLCD/2
−VLCD
VLCD
VLCD/2
state 2
0V
−VLCD/2
−VLCD
(b) Resultant waveforms
at LCD segment.
013aaa208
Vstate1(t) = VSn(t) − VBP0(t).
Vstate2(t) = VSn(t) − VBP1(t).
Von(RMS)(t) = 0.791VLCD. Voff(RMS)(t) = 0.354VLCD.
Fig 16. Waveforms for the 1:2 multiplex drive mode with 1⁄2 bias (line inversion mode)
PCA9620
Product data sheet
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PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
Tfr
BP0
BP1
Sn
Sn+1
VLCD
2VLCD/3
LCD segments
VLCD/3
VSS
state 1
VLCD
2VLCD/3
state 2
VLCD/3
VSS
VLCD
2VLCD/3
VLCD/3
VSS
VLCD
2VLCD/3
VLCD/3
VSS
(a) Waveforms at driver.
VLCD
2VLCD/3
VLCD/3
state 1
0V
−VLCD/3
−2VLCD/3
−VLCD
VLCD
2VLCD/3
VLCD/3
state 2
0V
−VLCD/3
−2VLCD/3
−VLCD
(b) Resultant waveforms
at LCD segment.
013aaa209
Vstate1(t) = VSn(t) − VBP0(t).
Vstate2(t) = VSn(t) − VBP1(t).
Von(RMS)(t) = 0.745VLCD. Voff(RMS)(t) = 0.333VLCD.
Fig 17. Waveforms for the 1:2 multiplex drive mode with 1⁄3 bias (line inversion mode)
PCA9620
Product data sheet
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PCA9620
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Universal LCD driver for low multiplex rates
7.4.2.3
1:4 Multiplex drive mode
When four backplanes are provided in the LCD, the 1:4 multiplex drive mode applies, as
shown in Figure 18.
Tfr
BP0
VLCD
2VLCD/3
VLCD/3
VSS
BP1
VLCD
2VLCD/3
VLCD/3
VSS
BP2
VLCD
2VLCD/3
VLCD/3
VSS
BP3
VLCD
2VLCD/3
VLCD/3
VSS
Sn
VLCD
2VLCD/3
VLCD/3
VSS
Sn+1
VLCD
2VLCD/3
VLCD/3
VSS
Sn+2
VLCD
2VLCD/3
VLCD/3
VSS
Sn+3
VLCD
2VLCD/3
VLCD/3
VSS
state 1
VLCD
2VLCD/3
VLCD/3
0V
−VLCD/3
−2VLCD/3
−VLCD
state 2
VLCD
2VLCD/3
VLCD/3
0V
−VLCD/3
−2VLCD/3
−VLCD
LCD segments
state 1
state 2
(a) Waveforms at driver.
(b) Resultant waveforms
at LCD segment.
013aaa211
Vstate1(t) = VSn(t) − VBP0(t).
Vstate2(t) = VSn(t) − VBP1(t).
Von(RMS)(t) = 0.577VLCD. Voff(RMS)(t) = 0.333VLCD.
Fig 18. Waveforms for the 1:4 multiplex drive mode with 1⁄3 bias (line inversion mode)
PCA9620
Product data sheet
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PCA9620
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Universal LCD driver for low multiplex rates
7.4.2.4
1:6 Multiplex drive mode
When six backplanes are provided in the LCD, the 1:6 multiplex drive mode applies. The
PCA9620 allows the use of 1⁄3 bias or 1⁄4 bias in this mode as shown in Figure 19 and
Figure 20.
Tfr
BP0
VLCD
2VLCD / 3
VLCD / 3
VSS
BP1
VLCD
2VLCD / 3
VLCD / 3
VSS
BP2
VLCD
2VLCD / 3
VLCD / 3
VSS
BP3
VLCD
2VLCD / 3
VLCD / 3
VSS
BP4
VLCD
2VLCD / 3
VLCD / 3
VSS
BP5
VLCD
2VLCD / 3
VLCD / 3
VSS
Sn
VLCD
2VLCD / 3
VLCD / 3
VSS
Sn + 1
VLCD
2VLCD / 3
VLCD / 3
VSS
LCD segments
state 1
state 2
VLCD
2VLCD / 3
state 1
VLCD / 3
VSS
−VLCD / 3
−2VLCD / 3
−VLCD
state 2
VLCD
2VLCD / 3
VLCD / 3
VSS
−VLCD / 3
−2VLCD / 3
−VLCD
001aal399
Vstate1(t) = VSn(t) − VBP0(t). Vstate2(t) = VSn(t) − VBP1(t).
Von(RMS)(t) = 0.509VLCD. Voff(RMS)(t) = 0.333VLCD.
Fig 19. Waveforms for 1:6 multiplex drive mode with 1⁄3 bias (line inversion mode)
PCA9620
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PCA9620
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Universal LCD driver for low multiplex rates
Tfr
LCD segments
VLCD
3VLCD / 4
state 1
state 2
BP0
VLCD / 4
VSS
VLCD
3VLCD / 4
BP1
VLCD / 4
VSS
VLCD
3VLCD / 4
BP2
VLCD / 4
VSS
VLCD
3VLCD / 4
BP3
VLCD / 4
VSS
VLCD
3VLCD / 4
BP4
VLCD / 4
VSS
VLCD
3VLCD / 4
BP5
VLCD / 4
VSS
VLCD
Sn
VLCD / 2
VSS
VLCD
Sn + 1
VLCD / 2
VSS
VLCD
3VLCD / 4
state 1
VLCD / 4
VSS
−VLCD / 4
−3VLCD / 4
−VLCD
VLCD
3VLCD / 4
VLCD / 2
VLCD / 4
VSS
state 2
−VLCD / 4
−VLCD / 2
−3VLCD / 4
−VLCD
001aal400
Vstate1(t) = VSn(t) − VBP0(t). Vstate2(t) = VSn(t) − VBP1(t).
Von(RMS)(t) = 0.467VLCD. Voff(RMS)(t) = 0.306VLCD.
Fig 20. Waveforms for 1:6 multiplex drive mode with 1⁄4 bias (line inversion mode)
PCA9620
Product data sheet
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7.4.2.5
1:8 Multiplex drive mode
Tfr
VLCD
3VLCD / 4
LCD segments
state 1
state 2
BP0
VLCD / 4
VSS
VLCD
3VLCD / 4
BP1
VLCD / 4
VSS
VLCD
3VLCD / 4
BP2
VLCD / 4
VSS
VLCD
3VLCD / 4
BP3
VLCD / 4
VSS
VLCD
3VLCD / 4
BP4
3LCD / 4
VSS
VLCD
3VLCD / 4
BP5
VLCD / 4
VSS
VLCD
3VLCD / 4
BP6
VLCD / 4
VSS
VLCD
3VLCD / 4
BP7
VLCD / 4
VSS
VLCD
Sn
VLCD / 2
VSS
VLCD
Sn + 1
VLCD / 2
VSS
VLCD
3VLCD / 4
state 1
VLCD / 4
VSS
−VLCD / 4
−3VLCD / 4
−VLCD
state 2
VLCD
3VLCD / 4
VLCD / 2
VLCD / 4
VSS
−VLCD / 4
−VLCD / 2
−3VLCD / 4
−VLCD
001aal398
Vstate1(t) = VSn(t) − VBP0(t). Vstate2(t) = VSn(t) − VBP1(t). Von(RMS)(t) = 0.424VLCD. Voff(RMS)(t) = 0.293VLCD.
Fig 21. Waveforms for 1:8 multiplex drive mode with 1⁄4 bias (line inversion mode)
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VLCD
3/4 VLCD
Tfr
frame n
Tfr
frame n+1
LCD segments
state 1
BP0
state 2
1/4 VLCD
VSS
VLCD
3/4 VLCD
BP1
1/4 VLCD
VSS
VLCD
3/4 VLCD
BP2
1/4 VLCD
VSS
VLCD
3/4 VLCD
BP3
1/4 VLCD
VSS
VLCD
3/4 VLCD
BP4
1/4 VLCD
VSS
VLCD
3/4 VLCD
BP5
1/4 VLCD
VSS
VLCD
3/4 VLCD
BP6
1/4 VLCD
VSS
VLCD
3/4 VLCD
BP7
1/4 VLCD
VSS
VLCD
Sn
1/2 VLCD
VSS
VLCD
Sn + 1
1/2 VLCD
VSS
state 1
VLCD
3/4 VLCD
1/2 VLCD
1/4 VLCD
VSS
1/4 VLCD
1/2 VLCD
3/4 VLCD
VLCD
state 2
VLCD
3/4 VLCD
1/2 VLCD
1/4 VLCD
VSS
1/4 VLCD
1/2 VLCD
3/4 VLCD
VLCD
001aam359
Vstate1(t) = VSn(t) − VBP0(t). Vstate2(t) = VSn(t) − VBP1(t). Von(RMS)(t) = 0.424VLCD. Voff(RMS)(t) = 0.293VLCD.
Fig 22. Waveforms for 1:8 multiplex drive mode with 1⁄4 bias (frame inversion mode)
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When eight backplanes are provided in the LCD, the 1:8 multiplex drive mode applies, as
shown in Figure 21 and Figure 22.
7.4.3 VLCD generation
VLCD can be generated and controlled on the chip by using software commands. When
the internal charge pump is used, the programmed VLCD is available on pin VLCD. The
charge pump generates a VLCD of up to 3 × VDD2.
The charge pump can be enabled or disabled with the CPE bit (see Table 8 on page 7).
With bit CPC the charge pump multiplier setting can be configured.
The final value of VLCD is a combination of the programmed VPR[7:0] value and the output
of the temperature compensation block, VT[7:0]. The system is shown in Figure 23.
SLA
SLB
SLC
SLD
0 OFFSET
TEMPERATURE
READOUT
8
8
TD
−40
0
+20
+50
+80
TEMPERATURE
n
VPR[7:0]
m
8
VLCD
013aaa257
Fig 23. VLCD generation including temperature compensation
In Equation 6 the main parameters are the programmed digital value term and the
compensated temperature term.
V LCD = [ VPR [ 7:0 ] + VT [ 7:0 ] ] × n + m
(6)
1. VPR[7:0] is the binary value of the programmed voltage.
2. VT[7:0] is the binary value of the temperature compensated voltage. Its value comes
from the temperature compensation block and is a two’s complement which has the
value 0h at 20 °C.
3. m and n are fixed values (see Table 27).
Table 27.
Symbol
Parameters of VLCD generation
Value
Unit
m
3
V
n
0.03
V
Figure 24 shows how VLCD changes with the programmed value of VPR[7:0].
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It has to be taken into account that the charge pump has to be configured (via bit CPC)
properly to obtain the desired voltage range. For example, if VDD2 = 3.0 V and CPC is set
to 2 × VDD2 (logic 0) then the maximum theoretical value that the charge pump can reach
is VLCD = 6.0 V. But in reality, lower values will be reached due to internal resistances, see
Section 7.4.5. So, if the requested value for VLCD = 7.0 V then the charge pump has to be
configured with CPC set to 3 × VDD2 (logic 1).
V LCD
(2)
9V
n
(1)
VDD2
m
00
01
02
03
04
05
06
........................
C7
C8
C9 CA
...
FC
FD
FE
FF
VPR[7:0]
013aaa258
(1) If VDD2 > 3.0 V then VPR[7:0] must be set so that VLCD > VDD2.
(2) Automatic limitation for VLCD > 9.0 V.
Fig 24. VLCD programming of PCA9620 (assuming VT[7:0] = 0h)
Programmable range of VPR[7:0] is from 0h to FFh. This would allow to achieve
VLCD > 9.0 V, but the PCA9620 has a built-in automatic limitation of VLCD at 9.0 V.
In case that VDD2 is higher than 3.0 V, then it is important that VPR[7:0] is set to a value
such that the resultant VLCD (including the temperature correction of VT[7:0]) is higher
than VDD2.
7.4.4 External VLCD supply
VLCD can be directly supplied to the VLCD pin. In this case the internal charge pump must
not be enabled otherwise a high current may occur on pin VDD2 and pin VLCD. When VLCD
is supplied externally, no internal temperature compensation occurs on this voltage even if
bit TCE is set logic 1 (see Section 7.4.8 on page 36). The VLCD voltage which is supplied
externally will be available at the segments and backplanes of the device through the
chosen bias system. Also programming the VPR[7:0] bit field has no effect on the VLCD
which is externally supplied.
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7.4.5 Charge pump driving capability
Figure 25 illustrates the main factor determining how much current the charge pump can
deliver.
Regulated desired VLCD
This supplies the segments
and backplanes
Theoretical VLCD value
VLCD = 2 × VDD2 or
VLCD = 3 × VDD2
Output Resistance
Ro(cp)
013aaa259
Fig 25. Charge pump model (used to characterize the driving strength)
The output resistance of the charge pump is specified in Table 35 on page 55. With these
values it can be calculated how much current the charge pump can drive under certain
conditions.
Example: Assuming the user would like to have the normal operation point at 25 °C with
VLCD = 7.0 V and VDD2 = 5.0 V and the charge pump is set to 2 × VDD2. Then the
theoretical value of VLCD is 10.0 V and the desired one is 7.0 V. The difference between
the theoretical maximum value and desired one is 3.0 V. The charge pump resistance is
nominally 0.85 kΩ. Equation 7 shows the possible current that the charge pump could
deliver:
I load = ΔV LCD ⁄ R o ( cp )
(7)
For this example we get: I load = 3.0 V ⁄ 0.85 kΩ = 3.5 mA
In cases where no extreme driving capability is needed, a command is available for
decreasing the charge pump frequency (see Table 22 on page 11) and thus reducing the
total current consumption. If the charge pump frequency is halved, then the driving
capability is halved as well, whereas the output resistance doubles.
7.4.6 Charge pump frequency settings and power efficiency
The PCA9620 offers the possibility to use different frequency settings for the charge
pump. Bit CPF controls the frequency at which the charge pump is running (see Table 22
on page 11). This frequency has a direct influence on the current consumption of the IC
but also on the charge pump driving capability. Using a lower charge pump frequency
decreases the current consumption and the driving capability.
The power efficiency of the charge pump determines in certain applications which
frequency settings to choose for the CPF bit. In the example shown in Figure 26, the
current consumption was measured with the charge pump set to 2 × VDD2 and with
VDD2 = 3.0 V and VPR[7:0] set to maximum to obtain the maximum possible VLCD with this
setup, which is close to 6.0 V. The current load on pin VLCD determines the output power
delivered by the IC:
P o = I load × V LCD
(8)
The current consumption on pin VDD2 determines the input power taken by the IC:
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P i = I DD2 × V DD2
(9)
The ratio between these two numbers determines the charge pump power efficiency:
ηp = Po ⁄ Pi
(10)
001aan027
90
ηp
(%)
7
VLCD
(V)
70
5
(3)
(4)
(1)
(2)
50
3
30
0
200
400
600
1
1000
800
Iload (μA)
Charge pump set to 2 × VDD2; VDD2 = 3 V.
(1) ηp, full charge pump frequency.
(2) ηp, half charge pump frequency.
(3) VLCD, full frequency.
(4) VLCD, half frequency.
Fig 26. Power efficiency of the charge pump
Loading the charge pump with higher currents decreases the output voltage. This
decrease is determined by the charge pump driving capability, respectively by the output
resistance of the charge pump (see Table 35 on page 55).
The power efficiency calculation is only valid when the charge pump is running at its
maximum peak frequency and regulates the generated VLCD voltage with full speed. In
this case, the ripple on the VLCD voltage equals the internal charge pump frequency.
Approximately, this could also be calculated with the parameter of the output resistance of
the charge pump (see Table 35 on page 55), the load current, and the voltage needed to
be provided by using Equation 7 on page 33. This value of Iload is close to the value of the
load current needed for the application.
If the application runs with VDD2 = 3.0 V, the load currents are up to 400 μA
(DC measured), and the VLCD generated voltages are up to 5.0 V, then - concerning
power efficiency - it would be the best to have a charge pump frequency set to half
frequency.
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In case it is desired to change the charge pump frequency, it is recommended to make a
graph like Figure 26 and understand what the application requirements are. This would
basically imply to find out what would be the maximum VLCD requirements and what would
be the maximum load currents required. Then it can be decided which is the best setting
of bit CPF.
Tuning the charge pump frequency might be a difficult task to do and requires good
knowledge of the application in which the IC is being used; therefore, NXP recommends
to keep the CPF bit set logic 0 to have the maximum charge pump frequency, thus having
the maximum driving strength.
7.4.7 Temperature readout
The PCA9620 has a built-in temperature sensor which provides a 8 bit digital value,
TD[7:0], of the ambient temperature. This value can be read through the I2C interface (see
Figure 49 on page 52). The actual temperature is determined from TD[7:0] using
Equation 11:
T (°C) = 0.9375 × TD [ 7:0 ] – 40
(11)
The measurement needs about 5 ms to complete and is repeated periodically as soon as
bit TME is set logic 1 (see Table 9 on page 7). The time between measurements is linked
to the system clock and hence varies with changes in the chosen frame frequency, see
Table 28.
Table 28.
Temperature measurement update rate
Selected frame frequency
Temperature measurement update rate
60 Hz
3.3 s
200 Hz
1s
300 Hz
0.67 s
Due to the nature of a temperature sensor, oscillations on the VLCD may occur. To avoid
this, a filter has been implemented in PCA9620. The system is shown in Figure 27.
TEMPERATURE
MEASUREMENT
BLOCK
TD[7:0]
unfiltered
DIGITAL
TEMPERATURE
FILTER
TD[7:0]
filtered
To the readout register
via I2C-bus and to
the VLCD compensation
block
enabled or disabled
by bit TFE
013aaa260
Fig 27. Temperature measurement block with digital temperature filter
Like any other filtering, the digital temperature filter (see Figure 27) introduces a certain
delay in the measurement of temperature. This behavior is illustrated in Figure 28.
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001aal393
50
16
ΔT
(°C)(3)
T
(°C)
40
12
30
8
(1)
(2)
20
4
(3)
10
0
−4
160
0
0
40
80
120
t (s)
(1) Environment temperature, T1 (°C).
(2) Measured temperature, T2 (°C).
(3) Temperature deviation, ΔT = T2 − T1.
Fig 28. Temperature measurement delay
This delay may cause undesired effects at start-up when the environment temperature
may be different than the reset value of the PCA9620 which is 20 °C. In this case it takes
up to 30 s till the correct measured temperature value will be available. A control bit, TFE,
is implemented to enable or disable the digital temperature filter. This bit is set logic 0 by
default which means that the filter is disabled and the unfiltered environment temperature
value is available to calculate the desired VLCD.
7.4.8 Temperature compensation of VLCD
Due to the temperature dependency of the liquid crystal viscosity the LCD controlling
voltage VLCD might have to be adjusted at different temperatures to maintain optimal
contrast. The temperature behavior of the liquid comes from the LCD manufacturer. The
slope has to be set to compensate for the liquid behavior. Internal temperature
compensation may be enabled via bit TCE.
The ambient temperature range is split up into four equally sized regions and a different
temperature coefficient can be applied to each (see Figure 29). Each coefficient can be
selected from a choice of eight different slopes. Each one of these coefficients (see
Table 29) may be independently selected via the temp-comp-SLA to temp-comp-SLD
commands (see Table 4 on page 5).
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Table 29.
Temperature coefficients
SLA[2:0] to SLD[2:0] value
Corresponding slope factor
(mV/°C)
Temperature coefficients
MA, MB, MC, MD[1]
000[2]
0
0.00
001
−4
−0.125
010
−8
−0.25
011
−16
−0.5
100
−40
−1.25
101
+4
0.125
110
+8
0.25
111
+16
0.5
[1]
The relationship between the temperature coefficients MA to MD and the slope factor is derived from the
0.9375
0.03
slope
1000
following equation: Mx = ---------------- × -------------- .
[2]
Default value.
The slope factors imply a linear correction, however the implementation is set in steps of
30 mV (parameter n in Table 27 on page 31).
SLA
SLB
SLC
SLD
TD[7:0]
0h
40h
20h
7Fh
60h
VLCD with temperature
compensation (V)
zero offset
at 20 °C
MA
−40
MB
−10
MC
20
MD
50
79
Temperature (°C)
013aaa261
Fig 29. Example of segmented temperature coefficients
Remark: After reset, VLCD is fixed because the VPR[7:0] bit field is reset logic 0. The
value of VT[7:0] is generated by the reset value of TD[7:0] (40h, representing 20 °C).
Temperature compensation is implemented by adding an offset VT[7:0] to the VPR[7:0]
value. VT[7:0] is a two’s complement number that equals 0h at 20 °C. The final result for
VLCD calculation is an 8-bit positive number (see Equation 6 on page 31).
Remark: Care must be taken that the ranges of VPR[7:0] and VT[7:0] don’t cause clipping
and hence undesired results. The device will not permit overflow or underflow and will
clamp results to either end of the range.
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The Voffset(LCD) value can be calculated with the equations given in Table 30:
V offset ( LCD ) = m × V T
Table 30.
(12)
Calculation of the temperature compensated voltage VT
Temperature range
TD[7:0]
Offset equation for VT
T ≤ −40 °C
0h
V T = – 32 × MA – 32 × MB
−40 °C ≤ T ≤ −10 °C
0h to 20h
V T = ( TD [ 7:0 ] – 32 ) × MA – 32 × MB
−10 °C < T ≤ 20 °C
21h to 40h
V T = ( TD [ 7:0 ] ( – 64 ) ) × MB
20 °C < T ≤ 50 °C
41h to 60h
V T = ( TD [ 7:0 ] – 64 ) × MC
50 °C < T < 80 °C
61h to 7Eh
V T = ( TD [ 7:0 ] – 96 ) × MD + 32 × MC
80 °C ≤ T
7Fh[1]
V T = 31 × MD + 32 × MC
[1]
No temperature compensation is possible above 80 °C. Above this value, the system maintains the
compensation value from 80 °C.
Example: Assumed that Tamb = −8 °C; TD[7:0] = 22h; MB = −0.5:
V offset ( LCD ) = m × V T = m × ( TD[7:0] – 64 ) × MB = 30mV × ( ( 34 – 64 ) × – 0.5 ) =
30mV × – 30 × – 0.5 = 450mV
The VT[7:0] term is calculated using the digital temperature value TD[7:0] which is
provided by the temperature measurement block (Section 7.4.7). Therefore the accuracy
of the temperature measurement block (Tacc, see Table 35 on page 55) will be directly
translated to the LCD voltage deviation ΔVLCD.
Since VT[7:0] = f[T,slope] and Tacc = ±6 °C then ΔV T = T acc × slope , where slope has one
of the possible values specified in Table 29. This term will be added to the total LCD
voltage deviation ΔVoffset(LCD)tot over the temperature range. So the total VLCD offset will
be: ΔV offset ( LCD )tot = ΔV LCD + ΔV T .
7.5 Oscillator
The internal logic and LCD drive signals of the PCA9620 are timed by a frequency fclk
which either is the built-in oscillator frequency fosc or equals an external clock frequency.
7.5.1 Internal oscillator
When the internal oscillator is used, it is possible to make the clock signal available on pin
CLK by using the oscillator-ctrl command (see Table 7 on page 6). If this is not intended,
pin CLK should be left open. At power-on the signal at pin CLK is disabled and pin CLK is
in 3-state.
The duty cycle of the output clock provided on the CLK pin is not always 50 : 50. Table 17
on page 9 shows the expected duty cycle for each of the chosen frame frequencies.
7.5.2 External clock
In applications where an external clock needs to be applied to the PCA9620, bit OSC (see
Table 7 on page 6) must be set logic 1. In this case pin CLK becomes an input.
The CLK signal is a signal that is fed into the VDD1 domain so it must have an amplitude
equal to the VDD1 voltage supplied to the chip and be referenced to VSS.
The clock frequency (fclk) determines the LCD frame frequency ffr.
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Remark: In case that a external clock is used then this clock signal must always be
supplied to the device; removing the clock may freeze the LCD in a DC state, which is not
suitable for the liquid crystal. Removal of the clock is possible when following the correct
procedures. See Figure 12 on page 19 and Figure 13 on page 20.
7.5.3 Timing and frame frequency
The timing of the PCA9620 organizes the internal data flow of the device. This includes
the transfer of display data from the display RAM to the display segment outputs. The
timing also generates the LCD frame frequency which it derives as an integer division of
the clock frequency. The frame frequency is a fixed division of the internal clock or of the
frequency applied to pin CLK when an external clock is used:
f clk
f fr = ------48
(13)
When the internal clock is used, the clock and frame frequency can be programmed by
software such that the nominal frame frequency can be chosen in steps of 10 Hz in the
range of 60 Hz to 300 Hz (see Table 17 on page 9). Furthermore the nominal frame
frequency is factory-calibrated with an accuracy of ±15 %.
When the internal clock is enabled at pin CLK by using bit COE, the duty ratio of the clock
may change when choosing different values for the frame frequency prescaler. Table 17
on page 9 shows the different output duty ratios for each frame frequency prescaler
setting.
7.6 Backplane outputs
The LCD drive section includes eight backplane outputs: BP0 to BP7. The backplane
output signals are generated based on the selected LCD multiplex drive mode.
Table 31 describes which outputs are active for each of the multiplex drive modes and
what signal is generated.
Table 31.
Multiplex
drive
mode
Output pin
1:8
BP0
Product data sheet
BP0
BP1
BP2
BP3
BP4
BP5
BP6
BP7
BP1
BP2
BP3
BP4
BP5
BP6
BP7
BP1[1]
Signal
1:6
BP0
BP1
BP2
BP3
BP4
BP5
BP0[1]
1:4
BP0
BP1
BP2
BP3
BP0[1]
BP1[1]
BP2[1]
BP3[1]
BP1[1]
BP0[1]
BP1[1]
BP0[1]
BP1[1]
BP0[1]
BP0[1]
BP0[1]
BP0[1]
BP0[1]
1:2
BP0
BP1
BP0[1]
static
BP0
BP0[1]
BP0[1]
[1]
PCA9620
Mapping of output pins and corresponding output signals with respect to the
multiplex driving mode
These pins may optionally be connected to the display to improve drive strength. Connect only with the
corresponding output pin carrying the same signal. If not required they can be left open-circuit.
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7.7 Segment outputs
The LCD drive section includes 60 segment outputs (S0 to S59) which must be connected
directly to the LCD. The segment output signals are generated based on the multiplexed
backplane signals and with data resident in the display register. When less than
60 segment outputs are required, the unused segment outputs must be left open-circuit.
7.8 Display register
The display register holds the display data while the corresponding multiplex signals are
generated.
7.9 Display RAM
The display RAM is a static 60 × 8-bit RAM which stores LCD data. Logic 1 in the RAM bit
map indicates the on-state of the corresponding LCD element; similarly, logic 0 indicates
the off-state.
There is a one-to-one correspondence between
• the bits in the RAM bitmap and the LCD elements
• the RAM columns and the segment outputs
• the RAM rows and the backplane outputs.
The display RAM bit map, Figure 30, shows row 0 to row 7 which correspond with the
backplane outputs BP0 to BP7, and column 0 to column 59 which correspond with the
segment outputs S0 to S59. In multiplexed LCD applications the data of each row of the
display RAM is time-multiplexed with the corresponding backplane (row 0 with BP0, row 1
with BP1 and so on).
When display data is transmitted to the PCA9620 the display bytes received are stored in
the display RAM in accordance with the selected LCD multiplex drive mode. The data is
stored as it arrives and does not wait for the acknowledge cycle as with the commands.
Depending on the current multiplex drive mode, data is stored singularly, in pairs,
quadruples, sextuples or bytes.
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columns
display RAM columns/segment outputs (S)
static drive mode
0
1
2
3
4
55
56 57 58 59
0
bank 0
1
bank 1
2
bank 2
3
bank 3
4
bank 4
5
bank 5
6
bank 6
7
bank 7
multiplex 1:2 drive mode
0
1
2
3
4
55
56 57 58 59
0
bank 0
1
2
rows
bank 2
display RAM rows/
backplane outputs
(BP)
3
4
bank 4
5
6
bank 6
7
0
multiplex 1:4 drive mode
1
2
3
4
55
56 57 58 59
0
1
bank 0
2
3
4
5
bank 4
6
7
013aaa262
The display RAM bitmap shows the direct relationship between the display RAM column and the
segment outputs, between the bits in a RAM row and the backplane outputs, and between the
RAM rows and banks.
Fig 30. Display RAM bitmap
7.9.1 Data pointer
The addressing mechanism for the display RAM is realized using the data pointer. This
allows the loading of an individual display data byte, or a series of display data bytes into
any location of the display RAM. The sequence commences with the initialization of the
data pointer by the load-data-pointer command. Following this command, an arriving data
byte is stored starting at the display RAM address indicated by the data pointer.
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Universal LCD driver for low multiplex rates
The data pointer is automatically incremented in accordance with the chosen LCD
multiplex drive mode configuration. That is, after each byte is stored, the contents of the
data pointer are incremented
•
•
•
•
•
by eight (static drive mode)
by four (1:2 multiplex drive mode)
by two (1:4 multiplex drive mode)
by one or two (1:6 multiplex drive mode), see Figure 37 on page 45
by one (1:8 multiplex drive mode)
If the data pointer reaches the end of the RAM row it is automatically wrapped around to
address 0. This means that it can be continuously written to or read from the display RAM.
The data pointer should always be set to an address where the remaining RAM is divisible
by eight because odd bits will be discarded (see Figure 32). This behavior is actually only
shown in static drive mode because of the fact that the 60 RAM cells can’t be divided by
eight without remainder.
If an I2C-bus data access is terminated early then the state of the data pointer is unknown.
The data pointer must then be re-written prior to further RAM accesses.
7.9.1.1
RAM filling in static drive mode
In the static drive mode the eight transmitted data bits are placed in eight successive
display RAM columns in row 0 (see Figure 31).
columns
display RAM columns/segment outputs (S)
rows
0
1
2
3
4
5
6
7
55 56 57 58 59
display RAM rows/
0 b7 b6 b5 b4 b3 b2 b1 b0
backplane outputs
(BP)
b7 b6 b5 b4 b3 b2 b1 b0
MSB
LSB
transmitted data byte
013aaa263
Fig 31. Display RAM filling order in static drive mode
In order to fill the whole RAM row, 8 bytes must be sent to the PCA9620, but the last 4 bits
from the last byte are discarded, and the data pointer is wrapped around to column 0 to
start a possible RAM content update (see Figure 32).
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Universal LCD driver for low multiplex rates
data pointer
0
1
2
3
4
5
6
48 49 50 51 52 53 54 55 56 57 58 59
7
0 a7 a6 a5 a4 a3 a2 a1 a0
f7 f6 f5 f4 f3 f2 f1 f0 g7 g6 g5 g4 g3 g2 g1 g0
discarded
display RAM
wrap around
013aaa287
Fig 32. Discarded bits and data pointer wrap around at the end of data transmission
7.9.1.2
RAM filling in 1:2 multiplex drive mode
In the 1:2 multiplex drive mode the eight transmitted data bits are placed in four
successive display RAM columns of two rows (see Figure 33).
columns
display RAM columns/segment outputs (S)
rows
0
1
2
3
4
5
6
7
55 56 57 58 59
display RAM rows/ 0 b7 b5 b3 b1
backplane outputs 1 b6 b4 b2 b0
(BP)
LSB
b7 b6 b5 b4 b3 b2 b1 b0
MSB
transmitted data byte
013aaa264
Fig 33. Display RAM filling order in 1:2 multiplex drive mode
In order to fill the whole two RAM rows 15 bytes need to be sent to the PCA9620. After the
last byte sent the data pointer is wrapped around to column 0 to start a possible RAM
content update (see Figure 34). Even if a data byte is transmitted during the wrapping of
the data pointer, then all the bits in the byte will be written correctly.
data pointer
0
1
2
3
4
5
6
7
55 56 57 58 59
0 b1
display RAM
1 b0
b7 b5 b3
b6 b4 b2
wrap around
013aaa288
Fig 34. Data pointer wrap around in 1:2 multiplex drive mode
7.9.1.3
RAM filling in 1:4 multiplex drive mode
In the 1:4 multiplex drive mode the eight transmitted data bits are placed in two
successive display RAM columns of four rows (see Figure 35).
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columns
display RAM columns/segment outputs (S)
0 1 2
0 b7 b3
1 b6 b2
rows
3
4
5
6
7
55 56 57 58 59
2 b5 b1
display RAM rows/
backplane outputs
(BP)
3 b4 b0
b7 b6 b5 b4 b3 b2 b1 b0
MSB
LSB
transmitted data byte
013aaa265
Fig 35. Display RAM filling order in 1:4 multiplex drive mode
In order to fill the whole four RAM rows 30 bytes need to be sent to the PCA9620. After
the last byte sent, the data pointer is wrapped around to column 0 to start a possible RAM
content update (see Figure 36). Even if a data byte is transmitted during the wrapping of
the data pointer, all the bits in the byte will be written correctly.
columns
display RAM columns/segment outputs (S)
data pointer
display RAM
0 1
0 b3
1 b2
2
3
4
5
6
7
55 56 57 58 59
b7
b6
2 b1
b5
3 b0
b4
wrap around
013aaa289
Fig 36. Data pointer wrap around in 1:4 multiplex drive mode
7.9.1.4
RAM filling in 1:6 multiplex drive mode
In the 1:6 multiplex drive mode the RAM is organized in six rows and 60 columns. The
eight transmitted data bits are placed in such a way, that a column is filled up (see
Figure 37).
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Universal LCD driver for low multiplex rates
columns
display RAM columns/segment outputs (S)
data pointer
incrementation
0
1
2
3
4
5
6
7
55 56 57 58 59
0 a7 a1 b3 c5
rows
1 a6 a0 b2 c4
2 a5 b7 b1 c3
display RAM rows/
backplane outputs
(BP)
3 a4 b6 b0 c2
4 a3 b5 c7 c1
5 a2 b4 c6 c0
LSB
MSB
a7 a6 a5 a4 a3 a2 a1 a0
b7 b6 b5 b4 b3 b2 b1 b0
c7 c6 c5 c4 c3 c2 c1 c0
transmitted data bytes
013aaa266
Fig 37. Display RAM filling order in 1:6 multiplex drive mode
The remaining bits are wrapped up into the next column. In order to fill the whole RAM
addresses 45 bytes need to be sent to the PCA9620. After the last byte sent the data
pointer is wrapped around to column 0 to start a possible RAM content update (see
Figure 38). Even if a data byte is transmitted during the wrapping of the data pointer, all
the bits in the byte will be written correctly.
data pointer
display RAM
0
1
2
3
4
5
6
7
55 56 57 58 59
0 b3 c5
a7 a1
1 b2 c4
a6 a0
2 b1 c3
a5 b7
3 b0 c2
a4 b6
4 c7 c1
a3 b5
5 c6 c0
a2 b4
wrap around
013aaa290
Fig 38. Data pointer wrap around in 1:6 multiplex drive mode
7.9.1.5
RAM filling in 1:8 multiplex drive mode
In the 1:8 multiplex drive mode the eight transmitted data bits are placed into eight rows of
one display RAM column (see Figure 39).
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Universal LCD driver for low multiplex rates
columns
transmitted data byte
display RAM columns/segment outputs (S)
MSB
LSB
b7 b6 b5 b4 b3 b2 b1 b0
0
1
2
3
4
5
6
7
55 56 57 58 59
0 b7
1 b6
rows
2 b5
3 b4
display RAM rows/
backplane outputs
(BP)
4 b3
5 b2
6 b1
7 b0
013aaa267
Fig 39. Display RAM filling order in 1:8 multiplex drive mode
In order to fill the whole RAM addresses 60 bytes need to be sent to the PCA9620. After
the last byte sent the data pointer is wrapped around to column 0 to start a possible RAM
content update (see Figure 40). In this case there is no situation possible where a
transmitted data byte can be written over the RAM boundary.
data pointer
display RAM
0
1
2
3
4
5
6
7
55 56 57 58 59
0 b7
a7
1 b6
a6
2 b5
a5
3 b4
a4
4 b3
a3
5 b2
a2
6 b1
a1
7 b0
a0
wrap around
013aaa291
Fig 40. Data pointer wrap around in 1:8 multiplex drive mode
7.9.2 Bank selection
A RAM bank can be thought of as a collection of RAM rows. The PCA9620 includes a
RAM bank switching feature in the static, 1:2, and 1:4 multiplex drive modes.
The RAM bank switching gives the provision for preparing display information in an
alternative bank and to be able to switch to it once it is complete. Input and output banks
can be set independently from one another with the input-bank-select and the
output-bank-select commands; Figure 41 shows the concept.
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INPUT-BANK-SELECT COMMAND
CONTROLS THE INPUT DATA PATH
OUTPUT-BANK-SELECT COMMAND
CONTROLS THE OUTPUT DATA PATH
BANK 0
MICROCONTROLLER
RAM
DISPLAY
BANK 4
013aaa422
Fig 41. Example of bank selection in 1:4 multiplex mode
In Figure 41 an example is shown for 1:4 multiplex drive mode where the displayed data is
read from the first four rows of the memory (bank 0), while the transmitted data is stored in
the second four rows of the memory (bank 4) which is currently not accessed for the
reading. Therefore different content can be loaded into the first and second four RAM
rows which will be immediately displayed on the LCD by switching it with the
output-bank-select command (see Figure 42).
columns
display RAM columns/segment outputs (S)
0
1
2
3
4
5
6
7
55 56 57 58 59
0
1
rows
to the LCD
2
display RAM rows/
backplane outputs
(BP)
output RAM bank
3
4
5
to the RAM
6
7
input RAM bank
013aaa424
Fig 42. Example of the input-bank-select and the output-bank-select command with
multiplex drive mode 1:4
7.9.2.1
Input-bank-select
The input-bank-select command (see Table 18 on page 10) loads display data into the
display RAM in accordance with the selected LCD drive configuration.
• In static drive mode, an individual content can be stored in each RAM bank (bank 0 to
bank 7 which corresponds to row 0 to row 7).
• In 1:2 multiplex drive mode, individual content for RAM bank 0 (row 0 and row 1),
RAM bank 2 (row 2 and row 3), RAM bank 4 (row 4 and 5) and RAM bank 6 (row 6
and row 7) can be stored.
• In 1:4 multiplex drive mode individual content can be stored in RAM bank 0 (row 0 to
row 3) and RAM bank 4 (row 4 to row 7).
The input-bank-select command works independently to the output-bank-select.
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7.9.2.2
Output-bank-select
The output-bank-select command (see Table 19 on page 10) selects the display RAM
transferring it to the display register in accordance with the selected LCD drive
configuration.
• In the static drive mode it is possible to request the content of RAM bank 1 (row 1) to
RAM bank 7 (row 7) for display instead of the default RAM bank 0 (row 0).
• In 1:2 multiplex drive mode, the content of RAM bank 2 (row 2 and row 3) or of RAM
bank 4 (row 4 and row 5) or of RAM bank 6 (row 6 and row 7) may be selected
instead of the default RAM bank 0 (row 0 and row 1).
• In 1:4 multiplex drive mode, the content of RAM bank 4 (row 4, 5, 6, and 7) may be
selected instead of RAM bank 0 (row 0, 1, 2, and 3).
The output-bank-select command works independently to the input-bank-select.
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Universal LCD driver for low multiplex rates
8. I2C-bus interface characteristics
The I2C-bus is for bidirectional, two-line communication between different ICs or modules.
The two lines are a Serial DAta line (SDA) and a Serial CLock line (SCL). Both lines must
be connected to a positive supply via a pull-up resistor when connected to the output
stages of a device. Data transfer may be initiated only when the bus is not busy.
8.1 Bit transfer
One data bit is transferred during each clock pulse. The data on the SDA line must remain
stable during the HIGH period of the clock pulse as changes in the data line at this time
will be interpreted as a control signal (see Figure 43).
SDA
SCL
data line
stable;
data valid
change
of data
allowed
mba607
Fig 43. Bit transfer
8.2 START and STOP conditions
Both data and clock lines remain HIGH when the bus is not busy.
A HIGH-to-LOW change of the data line, while the clock is HIGH is defined as the START
condition (S).
A LOW-to-HIGH change of the data line while the clock is HIGH is defined as the STOP
condition (P).
The START and STOP conditions are shown in Figure 44.
SDA
SDA
SCL
SCL
S
P
START condition
STOP condition
mbc622
Fig 44. Definition of START and STOP conditions
8.3 System configuration
A device generating a message is a transmitter; a device receiving a message is the
receiver. The device that controls the message is the master; and the devices which are
controlled by the master are the slaves. The system configuration is shown in Figure 45.
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MASTER
TRANSMITTER/
RECEIVER
SLAVE
TRANSMITTER/
RECEIVER
SLAVE
RECEIVER
MASTER
TRANSMITTER
MASTER
TRANSMITTER/
RECEIVER
SDA
SCL
mga807
Fig 45. System configuration
8.4 Acknowledge
The number of data bytes transferred between the START and STOP conditions from
transmitter to receiver is unlimited. Each byte of eight bits is followed by an acknowledge
cycle.
• A slave receiver which is addressed must generate an acknowledge after the
reception of each byte.
• Also a master receiver must generate an acknowledge after the reception of each
byte that has been clocked out of the slave transmitter.
• The device that acknowledges must pull-down the SDA line during the acknowledge
clock pulse, so that the SDA line is stable LOW during the HIGH period of the
acknowledge related clock pulse (set-up and hold times must be taken into
consideration).
• A master receiver must signal an end of data to the transmitter by not generating an
acknowledge on the last byte that has been clocked out of the slave. In this event the
transmitter must leave the data line HIGH to enable the master to generate a STOP
condition.
Acknowledgement on the I2C-bus is shown in Figure 46.
data output
by transmitter
not acknowledge
data output
by receiver
acknowledge
SCL from
master
1
2
8
9
S
START
condition
clock pulse for
acknowledgement
mbc602
Fig 46. Acknowledgement on the I2C-bus
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8.5 I2C-bus controller
The PCA9620 acts as an I2C-bus slave receiver. It does not initiate I2C-bus transfers or
transmit data to an I2C-bus master receiver. The only data output from PCA9620 are the
acknowledge signals and the temperature readout byte of the selected device.
8.6 Input filters
To enhance noise immunity in electrically adverse environments, RC low-pass filters are
provided on the SDA and SCL lines.
8.7 I2C-bus slave address
Device selection depends on the I2C-bus slave address.
Four different I2C-bus slave addresses can be used to address the PCA9620 (see
Table 32).
Table 32.
I2C slave address
Slave address
Bit
7
6
5
4
3
2
1
MSB
slave address
0
0
LSB
1
1
1
0
A1
A0
R/W
The least significant bit of the slave address byte is bit R/W. Bit 1 and bit 2 of the slave
address are defined by connecting the inputs A0 and A1 to either VSS (logic 0) or VDD
(logic 1). Therefore, four instances of PCA9620 can be distinguished on the same
I2C-bus.
8.8 I2C-bus protocol
R/W = 0
slave address
control byte
A A
C R
S 0 1 1 1 0
0 A
1 0
O S
RAM/command byte
M
A S
B
L
S P
B
EXAMPLES
a) transmit two bytes of RAM data
S 0 1 1 1 0 A A 0 A 0 1
1 0
A
RAM DATA
A
A
COMMAND
A 0 0
A
COMMAND
A P
A
COMMAND
A 0 1
A
RAM DATA
A
RAM DATA
A P
b) transmit two command bytes
S 0 1 1 1 0
A A
0 A 1 0
1 0
c) transmit one command byte and two RAM date bytes
S 0 1 1 1 0
A A
0 A 1 0
1 0
RAM DATA
A P
013aaa293
Fig 47. I2C-bus protocol write mode
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Universal LCD driver for low multiplex rates
The I2C-bus protocol is shown in Figure 47. The sequence is initiated with a START
condition (S) from the I2C-bus master which is followed by one of the four PCA9620 slave
addresses available. All PCA9620’s with the corresponding A1 and A0 level acknowledge
in parallel to the slave address, but all PCA9620 with the alternative A1 and A0 levels
ignore the whole I2C-bus transfer.
After acknowledgement, a control byte follows which defines if the next byte is RAM or
command information. The control byte also defines if the next byte is a control byte or
further RAM or command data.
Table 33.
Control byte description
Bit
Symbol
7
CO
6
Value
Description
continue bit
0
last control byte
1
control bytes continue
RS
register selection
0
command register
1
5 to 0
-
data register
-
not relevant
MSB
7
6
5
4
CO RS
3
2
1
LSB
0
not relevant
mgl753
Fig 48. Control byte format
In this way it is possible to configure the device and then fill the display RAM with little
overhead.
The display bytes are stored in the display RAM at the address specified by the data
pointer.
The acknowledgement after each byte is made only by the (A0 and A1) addressed
PCA9620. After the last display byte, the I2C-bus master issues a STOP condition (P).
Alternatively a START may be issued to RESTART an I2C-bus access.
In case that a temperature readout (byte TD[7:0]) is made the R/W bit must be logic 1 and
then the next data byte following is provided by the PCA9620 as shown in Figure 49.
R/W = 1
slave address
S 0 1 1 1 0
temperature
readout byte
M
A A
1 A S
1 0
B
acknowledge
from PCA9620
L
S A P
B
acknowledge
from master
013aaa294
Fig 49. I2C-bus protocol read mode
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9. Internal circuitry
VDD1
A0, A1, T1,
T2, CLK
T3, VLCD, SDA,
SCL, VDD1, VDD2
VSS
VLCD
VSS
BP0 to BP7,
S0 to S59
VSS
013aaa295
Fig 50. Device protection diagram
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10. Limiting values
CAUTION
Static voltages across the liquid crystal display can build up when the LCD supply voltage
(VLCD) is on while the IC supply voltage (VDD) is off, or vice versa. This may cause unwanted
display artifacts. To avoid such artifacts, VLCD and VDD must be applied or removed together.
Table 34. Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol
Parameter
Conditions
Min
Max
Unit
VDD1
supply voltage 1
analog and digital
−0.5
+6.5
V
VDD2
supply voltage 2
charge pump
−0.5
+6.5
V
IDD1
supply current 1
analog and digital
−50
+50
mA
IDD2
supply current 2
charge pump
−50
+50
mA
VLCD
LCD supply voltage
−0.5
+10
V
IDD(LCD)
LCD supply current
−50
+50
mA
Vi
input voltage
−0.5
+6.5
V
II
input current
−10
+10
mA
VO
output voltage
on pins S0 to S59,
BP0 to BP7
−0.5
+10
V
on pins SDA, CLK
−0.5
+6.5
V
IO
output current
−10
+10
mA
ISS
ground supply current
−50
+50
mA
Ptot
total power dissipation
-
400
mW
P/out
power dissipation per
output
-
100
mW
VESD
electrostatic discharge
voltage
HBM
[1]
-
±4000
V
CDM
[2]
-
±1500
V
latch-up current
[3]
-
100
mA
Tstg
storage temperature
[4]
−65
+150
°C
Tamb
ambient temperature
−40
+105
°C
Ilu
[1]
PCA9620
Product data sheet
on pins CLK,
SDA, SCL, A0,
A1, T1, T2, T3
operating device
Pass level; Human Body Model (HBM), according to Ref. 6 “JESD22-A114”.
[2]
Pass level; Charged-Device Model (CDM), according to Ref. 7 “JESD22-C101”.
[3]
Pass level; latch-up testing according to Ref. 8 “JESD78” at maximum ambient temperature (Tamb(max)).
[4]
According to the NXP store and transport requirements (see Ref. 10 “NX3-00092”) the devices have to be
stored at a temperature of +8 °C to +45 °C and a humidity of 25 % to 75 %. For long term storage products
divergent conditions are described in that document.
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11. Static characteristics
Table 35. Static characteristics
VDD1 = 2.5 V to 5.5 V; VDD2 = 2.5 V to 5.5 V; VSS = 0 V; VLCD = 2.5 V to 9.0 V; Tamb = −40 °C to +105 °C; unless otherwise
specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
2.5
-
5.5
V
2.5
-
5.5
V
2.5
-
9.0
V
Tamb = −40 °C to −10 °C
−100
-
+100
mV
Tamb = −10 °C to +70 °C
−70
-
+70
mV
Supplies
VDD1
supply voltage 1
VDD2
supply voltage 2
VDD2 ≥ VDD1
LCD supply voltage
VLCD ≥ VDD2
[1]
VLCD = 5.0 V to 9.0 V
[2]
VLCD
ΔVLCD
LCD voltage variation
Tamb = +70 °C to +105 °C
−100
-
+100
mV
-
1.0
3.0
μA
200
μA
IDD(pd)
power-down mode supply on pin VDD1
current
[3][4]
IDD1
supply current 1
[4][5]
-
100
IDD2
supply current 2
charge pump off; external VLCD
[4][5]
-
0.5
3.0
μA
charge pump on; internal VLCD
[4][6]
-
250
550
μA
external VLCD
[4][7]
-
125
250
μA
[3][4]
-
12
35
μA
IDD(LCD)
LCD supply current
fosc = 9.6 kHz
ILCD(pd)
power-down LCD current
external VLCD
RO
output resistance
of charge pump (driving capabilities)
Tacc
temperature accuracy
charge pump set to 2 × VDD2;
Iload = 3 mA (on pin VLCD)
[8]
0.2
0.85
1.6
kΩ
charge pump set to 3 × VDD2;
Iload = 2 mA (on pin VLCD)
[9]
2.0
3.2
4.5
kΩ
Tamb = −40 °C to +105 °C
−6
-
+6
°C
Tamb = 27 °C
−4
-
+4
°C
readout temperature error;
VDD1 = 5.0 V
Logic
VSS − 0.5 -
VDD + 0.5 V
on pins CLK, A1, A0
-
0.3VDD
V
on pins CLK, A1, A0
0.7VDD
-
-
V
−0.5
-
VDD + 0.5 V
HIGH-level output voltage on pin CLK
0.8VDD
-
-
V
VOL
LOW-level output voltage
-
-
0.2VDD
V
IOH
HIGH-level output current output source current;
VOH = 4.6 V; VDD = 5 V; on pin CLK
1
-
-
mA
IOL
LOW-level output current
1
-
-
mA
VPOR
power-on reset voltage
[10]
-
-
1.6
V
IL
leakage current
[11]
-
0
-
μA
VI
input voltage
VIL
LOW-level input voltage
VIH
HIGH-level input voltage
VO
output voltage
VOH
PCA9620
Product data sheet
on pin CLK
output sink current;
VOL = 0.4 V; VDD = 5 V; on pin CLK
Vi = VDD or VSS; on pins CLK, A1,
A0, T1, T2, T3
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Table 35. Static characteristics …continued
VDD1 = 2.5 V to 5.5 V; VDD2 = 2.5 V to 5.5 V; VSS = 0 V; VLCD = 2.5 V to 9.0 V; Tamb = −40 °C to +105 °C; unless otherwise
specified.
Symbol
I2C-bus;
Parameter
Conditions
Min
Typ
Max
Unit
pins SDA and SCL
VI
input voltage
VSS − 0.5 -
5.5
V
VIL
LOW-level input voltage
pins SCL, SDA
-
-
0.3VDD
V
VIH
HIGH-level input voltage
pins SCL, SDA
0.7VDD
-
-
V
VO
output voltage
pins SCL, SDA
−0.5
-
5.5
V
IOL
LOW-level output current
VOL = 0.4 V; VDD = 5 V; on pin SDA
3
-
-
mA
IL
leakage current
VI = VDD or VSS
[11]
-
0
-
μA
output voltage variation
on pins BP0 to BP7
[12]
−15
-
+15
mV
on pins S0 to S59
[13]
−15
-
+15
mV
VLCD = 7 V; on pins BP0 to BP7
[14]
0.3
0.8
1.5
kΩ
VLCD = 7 V; on pins S0 to S59
[14]
0.6
1.5
3
kΩ
LCD outputs
ΔVO
output resistance
RO
[1]
When supplying external VLCD it must be VLCD ≥ VDD2. Also when using the internal charge pump to generate a certain VLCD, VPR[7:0]
must be set to a value that the voltage is higher than VDD2 (see Section 7.4.3 on page 31).
[2]
Calibrated at testing stage with VDD1 = VDD2 = 5.0 V. VLCD temperature compensation is disabled.
[3]
Display is disabled; I2C-bus inactive; temperature measurement disabled.
[4]
The typical value is defined at VDD1 = VDD2 = 5.0 V, VLCD = 7.0 V and 30 °C.
[5]
Temperature measurement enabled; 1:8 multiplex drive mode; 1⁄4 bias; display enabled; LCD outputs are open circuit; RAM is all written
with logic 1; inputs at VSS or VDD; internal clock with the default prescale factor; I2C-bus inactive.
[6]
VDD2 = 5.0 V; charge pump set to 2 × VDD2; VPR[7:0] set for VLCD = 7.0 V; 1:8 multiplex drive mode; 1⁄4 bias; temperature measurement
enabled; display enabled; LCD outputs are open circuit; RAM is all written with logic 1; inputs at VSS or VDD; external clock with 50 %
duty factor; I2C-bus inactive.
[7]
External supplied VLCD = 7.0 V; 1:8 multiplex drive mode; 1⁄4 bias; temperature measurement enabled; display enabled; LCD outputs
are open circuit; RAM is all written with logic 1; inputs at VSS or VDD; external clock with 50 % duty factor; I2C-bus inactive.
[8]
VDD2 = 5.0 V; charge pump set to 2 × VDD2; VPR[7:0] set for VLCD = 9.0 V; display disabled; CPF (see Table 22 on page 11) set logic 0.
[9]
VDD2 = 4.0 V; charge pump set to 3 × VDD2; VPR[7:0] set for VLCD = 9.0 V; display disabled; CPF (see Table 22 on page 11) set logic 0.
[10] If VDD1 > VPOR then no reset occurs.
[11] In case of an ESD event, the value may increase slightly.
[12] Variation between any 2 backplanes on a given voltage level; static measured.
[13] Variation between any 2 segments on a given voltage level; static measured.
[14] Outputs measured one at a time.
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001aan026
8.3
VLCD
(V)
(3)
7.8
7.3
(1)
6.8
6.3
(2)
5.8
−50
0
50
100
150
temperature (°C)
(1) VPR[7:0] = 85h.
(2) VPR[7:0] = 64h.
(3) VPR[7:0] = A4h.
Temperature compensation disabled.
Fig 51. Typical VLCD with respect to temperature
001aan023
120
IDD1
(μA)
100
80
60
−40
0
40
80
120
temperature (°C)
VDD1 = 5.0 V.
Fig 52. Typical IDD1 with respect to temperature
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001aan024
300
IDD2
(μA)
260
220
180
140
100
−40
0
40
80
120
temperature (°C)
Charge pump set to 2 × VDD2; VLCD = 7.0 V; VDD1 = VDD2 = 5.0 V.
Fig 53. Typical IDD2 with respect to temperature
001aan025
140
ILCD
(μA)
120
100
80
−40
0
40
80
120
temperature (°C)
VLCD = 7.0 V, external supplied; VDD1 = VDD2 = 5.0 V; display enabled, but no display attached.
Fig 54. Typical ILCD with respect to temperature
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12. Dynamic characteristics
Table 36. Dynamic characteristics
VDD1 = 2.5 V to 5.5 V; VDD2 = 2.5 V to 5.5 V; VSS = 0 V; VLCD = 2.5 V to 9.0 V; Tamb = −40 °C to +105 °C; unless otherwise
specified.
Symbol
Parameter
fosc
oscillator frequency
fclk(ext)
external clock frequency
tclk(H)
HIGH-level clock time
tclk(L)
LOW-level clock time
Conditions
on pin CLK; see Table 17 on
page 9
[1][2]
external clock source used
Min
Typ
Max
Unit
8160
9600
11040
Hz
450
-
14500
Hz
33
-
-
μs
33
-
-
μs
Timing characteristics: I2C-bus[3]
fSCL
SCL frequency
-
-
400
kHz
tBUF
bus free time between a
STOP and START condition
1.3
-
-
μs
tHD;STA
hold time (repeated) START
condition
0.6
-
-
μs
tSU;STA
set-up time for a repeated
START condition
0.6
-
-
μs
tVD;DAT
data valid time
[4]
-
-
0.9
μs
tVD;ACK
data valid acknowledge time
[5]
-
-
0.9
μs
tLOW
LOW period of the SCL clock
1.3
-
-
μs
tHIGH
HIGH period of the SCL clock
0.6
-
-
μs
tf
fall time
of both SDA and SCL signals
-
-
0.3
μs
tr
rise time
of both SDA and SCL signals
-
-
0.3
μs
Cb
capacitive load for each bus
line
-
-
400
pF
tSU;DAT
data set-up time
100
-
-
ns
tHD;DAT
data hold time
0
-
-
ns
tSU;STO
set-up time for STOP
condition
0.6
-
-
μs
tw(spike)
spike pulse width
-
-
50
ns
[1]
Internal calibration made with OTP so that the maximum variation is ±15 % over whole temperature and voltage range. The typical fosc
generates a typical frame frequency of 200 Hz when the default frequency division factor is used (see Section 7.5.3 on page 39).
[2]
The typical value is defined at VDD1 = VDD2 = 5.0 V and 30 °C.
[3]
All timing values are valid within the operating supply voltage and ambient temperature range and are referenced to VIL and VIH with an
input voltage swing of VSS to VDD.
[4]
tVD;DAT = minimum time for valid SDA output following SCL LOW.
[5]
tVD;ACK = time for acknowledgement signal from SCL LOW to SDA output LOW.
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1/fclk
tclk(H)
tclk(L)
0.7 VDD
CLK
0.3 VDD
013aaa296
Fig 55. Driver timing waveforms
protocol
START
condition
(S)
tSU;STA
bit 7
MSB
(A7)
tLOW
bit 6
(A6)
tHIGH
bit 0
(R/W)
acknowledge
(A)
STOP
condition
(P)
1/f
SCL
SCL
tBUF
tr
tf
SDA
tHD;STA
tSU;DAT
tHD;DAT
tVD;DAT
tVD;ACK
tSU;STO
013aaa417
Fig 56. I2C-bus timing waveforms
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13. Package outline
LQFP80: plastic low profile quad flat package; 80 leads; body 12 x 12 x 1.4 mm
SOT315-1
c
y
X
A
60
41
40 Z E
61
e
E HE
A A2
(A 3)
A1
w M
θ
bp
Lp
L
pin 1 index
80
21
detail X
20
1
ZD
e
v M A
w M
bp
D
B
HD
v M B
0
5
10 mm
scale
DIMENSIONS (mm are the original dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D (1)
E (1)
e
mm
1.6
0.16
0.04
1.5
1.3
0.25
0.27
0.13
0.18
0.12
12.1
11.9
12.1
11.9
0.5
HD
HE
14.15 14.15
13.85 13.85
L
Lp
v
w
y
1
0.75
0.30
0.2
0.15
0.1
Z D (1) Z E (1)
θ
1.45
1.05
7
o
0
1.45
1.05
o
Note
1. Plastic or metal protrusions of 0.25 mm maximum per side are not included.
REFERENCES
OUTLINE
VERSION
IEC
JEDEC
SOT315-1
136E15
MS-026
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
00-01-19
03-02-25
Fig 57. Package outline SOT315-1 (LQFP80)
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14. Soldering of SMD packages
This text provides a very brief insight into a complex technology. A more in-depth account
of soldering ICs can be found in Application Note AN10365 “Surface mount reflow
soldering description”.
14.1 Introduction to soldering
Soldering is one of the most common methods through which packages are attached to
Printed Circuit Boards (PCBs), to form electrical circuits. The soldered joint provides both
the mechanical and the electrical connection. There is no single soldering method that is
ideal for all IC packages. Wave soldering is often preferred when through-hole and
Surface Mount Devices (SMDs) are mixed on one printed wiring board; however, it is not
suitable for fine pitch SMDs. Reflow soldering is ideal for the small pitches and high
densities that come with increased miniaturization.
14.2 Wave and reflow soldering
Wave soldering is a joining technology in which the joints are made by solder coming from
a standing wave of liquid solder. The wave soldering process is suitable for the following:
• Through-hole components
• Leaded or leadless SMDs, which are glued to the surface of the printed circuit board
Not all SMDs can be wave soldered. Packages with solder balls, and some leadless
packages which have solder lands underneath the body, cannot be wave soldered. Also,
leaded SMDs with leads having a pitch smaller than ~0.6 mm cannot be wave soldered,
due to an increased probability of bridging.
The reflow soldering process involves applying solder paste to a board, followed by
component placement and exposure to a temperature profile. Leaded packages,
packages with solder balls, and leadless packages are all reflow solderable.
Key characteristics in both wave and reflow soldering are:
•
•
•
•
•
•
Board specifications, including the board finish, solder masks and vias
Package footprints, including solder thieves and orientation
The moisture sensitivity level of the packages
Package placement
Inspection and repair
Lead-free soldering versus SnPb soldering
14.3 Wave soldering
Key characteristics in wave soldering are:
• Process issues, such as application of adhesive and flux, clinching of leads, board
transport, the solder wave parameters, and the time during which components are
exposed to the wave
• Solder bath specifications, including temperature and impurities
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14.4 Reflow soldering
Key characteristics in reflow soldering are:
• Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to
higher minimum peak temperatures (see Figure 58) than a SnPb process, thus
reducing the process window
• Solder paste printing issues including smearing, release, and adjusting the process
window for a mix of large and small components on one board
• Reflow temperature profile; this profile includes preheat, reflow (in which the board is
heated to the peak temperature) and cooling down. It is imperative that the peak
temperature is high enough for the solder to make reliable solder joints (a solder paste
characteristic). In addition, the peak temperature must be low enough that the
packages and/or boards are not damaged. The peak temperature of the package
depends on package thickness and volume and is classified in accordance with
Table 37 and 38
Table 37.
SnPb eutectic process (from J-STD-020C)
Package thickness (mm)
Package reflow temperature (°C)
Volume (mm3)
< 350
≥ 350
< 2.5
235
220
≥ 2.5
220
220
Table 38.
Lead-free process (from J-STD-020C)
Package thickness (mm)
Package reflow temperature (°C)
Volume (mm3)
< 350
350 to 2000
> 2000
< 1.6
260
260
260
1.6 to 2.5
260
250
245
> 2.5
250
245
245
Moisture sensitivity precautions, as indicated on the packing, must be respected at all
times.
Studies have shown that small packages reach higher temperatures during reflow
soldering, see Figure 58.
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temperature
maximum peak temperature
= MSL limit, damage level
minimum peak temperature
= minimum soldering temperature
peak
temperature
time
001aac844
MSL: Moisture Sensitivity Level
Fig 58. Temperature profiles for large and small components
For further information on temperature profiles, refer to Application Note AN10365
“Surface mount reflow soldering description”.
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15. Abbreviations
Table 39.
PCA9620
Product data sheet
Abbreviations
Acronym
Description
AEC
Automotive Electronics Council
CDM
Charged-Device Model
DC
Direct Current
EPROM
Erasable Programmable Read-Only Memory
ESD
ElectroStatic Discharge
HBM
Human Body Model
I2C
Inter-Integrated Circuit bus
IC
Integrated Circuit
LCD
Liquid Crystal Display
LSB
Least Significant Bit
MSB
Most Significant Bit
MSL
Moisture Sensitivity Level
MUX
Multiplexer
OTP
One Time Programmable
PCB
Printed-Circuit Board
POR
Power-On Reset
RC
Resistance-Capacitance
RAM
Random Access Memory
RMS
Root Mean Square
SCL
Serial CLock line
SDA
Serial DAta line
SMD
Surface Mount Device
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16. References
[1]
AN10365 — Surface mount reflow soldering description
[2]
AN10853 — ESD and EMC sensitivity of IC
[3]
IEC 60134 — Rating systems for electronic tubes and valves and analogous
semiconductor devices
[4]
IEC 61340-5 — Protection of electronic devices from electrostatic phenomena
[5]
IPC/JEDEC J-STD-020D — Moisture/Reflow Sensitivity Classification for
Nonhermetic Solid State Surface Mount Devices
[6]
JESD22-A114 — Electrostatic Discharge (ESD) Sensitivity Testing Human Body
Model (HBM)
[7]
JESD22-C101 — Field-Induced Charged-Device Model Test Method for
Electrostatic-Discharge-Withstand Thresholds of Microelectronic Components
[8]
JESD78 — IC Latch-Up Test
[9]
JESD625-A — Requirements for Handling Electrostatic-Discharge-Sensitive
(ESDS) Devices
[10] NX3-00092 — NXP store and transport requirements
[11] SNV-FA-01-02 — Marking Formats Integrated Circuits
[12] UM10204 — I2C-bus specification and user manual
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17. Revision history
Table 40.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
PCA9620 v.1
20101209
Product data sheet
-
-
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18. Legal information
18.1 Data sheet status
Document status[1][2]
Product status[3]
Definition
Objective [short] data sheet
Development
This document contains data from the objective specification for product development.
Preliminary [short] data sheet
Qualification
This document contains data from the preliminary specification.
Product [short] data sheet
Production
This document contains the product specification.
[1]
Please consult the most recently issued document before initiating or completing a design.
[2]
The term ‘short data sheet’ is explained in section “Definitions”.
[3]
The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status
information is available on the Internet at URL http://www.nxp.com.
18.2 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences of
use of such information.
Short data sheet — A short data sheet is an extract from a full data sheet
with the same product type number(s) and title. A short data sheet is intended
for quick reference only and should not be relied upon to contain detailed and
full information. For detailed and full information see the relevant full data
sheet, which is available on request via the local NXP Semiconductors sales
office. In case of any inconsistency or conflict with the short data sheet, the
full data sheet shall prevail.
Product specification — The information and data provided in a Product
data sheet shall define the specification of the product as agreed between
NXP Semiconductors and its customer, unless NXP Semiconductors and
customer have explicitly agreed otherwise in writing. In no event however,
shall an agreement be valid in which the NXP Semiconductors product is
deemed to offer functions and qualities beyond those described in the
Product data sheet.
18.3 Disclaimers
Limited warranty and liability — Information in this document is believed to
be accurate and reliable. However, NXP Semiconductors does not give any
representations or warranties, expressed or implied, as to the accuracy or
completeness of such information and shall have no liability for the
consequences of use of such information.
In no event shall NXP Semiconductors be liable for any indirect, incidental,
punitive, special or consequential damages (including - without limitation - lost
profits, lost savings, business interruption, costs related to the removal or
replacement of any products or rework charges) whether or not such
damages are based on tort (including negligence), warranty, breach of
contract or any other legal theory.
Notwithstanding any damages that customer might incur for any reason
whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards
customer for the products described herein shall be limited in accordance
with the Terms and conditions of commercial sale of NXP Semiconductors.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
Suitability for use in automotive applications — This NXP
Semiconductors product has been qualified for use in automotive
applications. The product is not designed, authorized or warranted to be
PCA9620
Product data sheet
suitable for use in medical, military, aircraft, space or life support equipment,
nor in applications where failure or malfunction of an NXP Semiconductors
product can reasonably be expected to result in personal injury, death or
severe property or environmental damage. NXP Semiconductors accepts no
liability for inclusion and/or use of NXP Semiconductors products in such
equipment or applications and therefore such inclusion and/or use is at the
customer’s own risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Customers are responsible for the design and operation of their applications
and products using NXP Semiconductors products, and NXP Semiconductors
accepts no liability for any assistance with applications or customer product
design. It is customer’s sole responsibility to determine whether the NXP
Semiconductors product is suitable and fit for the customer’s applications and
products planned, as well as for the planned application and use of
customer’s third party customer(s). Customers should provide appropriate
design and operating safeguards to minimize the risks associated with their
applications and products.
NXP Semiconductors does not accept any liability related to any default,
damage, costs or problem which is based on any weakness or default in the
customer’s applications or products, or the application or use by customer’s
third party customer(s). Customer is responsible for doing all necessary
testing for the customer’s applications and products using NXP
Semiconductors products in order to avoid a default of the applications and
the products or of the application or use by customer’s third party
customer(s). NXP does not accept any liability in this respect.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) will cause permanent
damage to the device. Limiting values are stress ratings only and (proper)
operation of the device at these or any other conditions above those given in
the Recommended operating conditions section (if present) or the
Characteristics sections of this document is not warranted. Constant or
repeated exposure to limiting values will permanently and irreversibly affect
the quality and reliability of the device.
Terms and conditions of commercial sale — NXP Semiconductors
products are sold subject to the general terms and conditions of commercial
sale, as published at http://www.nxp.com/profile/terms, unless otherwise
agreed in a valid written individual agreement. In case an individual
agreement is concluded only the terms and conditions of the respective
agreement shall apply. NXP Semiconductors hereby expressly objects to
applying the customer’s general terms and conditions with regard to the
purchase of NXP Semiconductors products by customer.
No offer to sell or license — Nothing in this document may be interpreted or
construed as an offer to sell products that is open for acceptance or the grant,
conveyance or implication of any license under any copyrights, patents or
other industrial or intellectual property rights.
All information provided in this document is subject to legal disclaimers.
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Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from national authorities.
18.4 Trademarks
Notice: All referenced brands, product names, service names and trademarks
are the property of their respective owners.
I2C-bus — logo is a trademark of NXP B.V.
19. Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
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20. Contents
1
General description . . . . . . . . . . . . . . . . . . . . . . 1
2
Features and benefits . . . . . . . . . . . . . . . . . . . . 1
3
Ordering information . . . . . . . . . . . . . . . . . . . . . 2
4
Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
5
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 2
6
Pinning information . . . . . . . . . . . . . . . . . . . . . . 3
6.1
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
6.2
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 4
7
Functional description . . . . . . . . . . . . . . . . . . . 5
7.1
Commands of PCA9620 . . . . . . . . . . . . . . . . . . 5
7.1.1
Command: initialize . . . . . . . . . . . . . . . . . . . . . 5
7.1.2
Command: OTP-refresh . . . . . . . . . . . . . . . . . . 6
7.1.3
Command: oscillator-ctrl . . . . . . . . . . . . . . . . . . 6
7.1.4
Command: charge-pump-ctrl . . . . . . . . . . . . . . 7
7.1.5
Command: temp-msr-ctrl . . . . . . . . . . . . . . . . . 7
7.1.6
Command: set-VPR-MSB and set-VPR-LSB . . 7
7.1.7
Command: display-enable . . . . . . . . . . . . . . . . 8
7.1.8
Command: set-MUX-mode . . . . . . . . . . . . . . . . 8
7.1.9
Command: set-bias-mode . . . . . . . . . . . . . . . . 8
7.1.10
Command: load-data-pointer . . . . . . . . . . . . . . 8
7.1.11
Command: frame-frequency . . . . . . . . . . . . . . . 9
7.1.12
Bank select commands . . . . . . . . . . . . . . . . . 10
7.1.12.1 Command: input-bank-select . . . . . . . . . . . . . 10
7.1.12.2 Command: output-bank-select . . . . . . . . . . . . 10
7.1.13
Command: write-RAM-data . . . . . . . . . . . . . . 11
7.1.14
Command: temp-read. . . . . . . . . . . . . . . . . . . 11
7.1.15
Command: invmode_CPF_ctrl . . . . . . . . . . . . 11
7.1.16
Command: temp-filter . . . . . . . . . . . . . . . . . . . 12
7.2
Possible display configurations . . . . . . . . . . . 12
7.3
Start-up and shut-down. . . . . . . . . . . . . . . . . . 14
7.3.1
Power-On Reset (POR) . . . . . . . . . . . . . . . . . 14
7.3.2
Recommended start-up sequences . . . . . . . . 16
7.3.3
Recommended power-down sequences . . . . 18
7.4
LCD voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7.4.1
LCD voltage selector . . . . . . . . . . . . . . . . . . . 20
7.4.1.1
Electro-optical performance . . . . . . . . . . . . . . 22
7.4.2
LCD drive mode waveforms . . . . . . . . . . . . . . 23
7.4.2.1
Static drive mode . . . . . . . . . . . . . . . . . . . . . . 23
7.4.2.2
1:2 Multiplex drive mode. . . . . . . . . . . . . . . . . 24
7.4.2.3
1:4 Multiplex drive mode. . . . . . . . . . . . . . . . . 26
7.4.2.4
1:6 Multiplex drive mode. . . . . . . . . . . . . . . . . 27
7.4.2.5
1:8 Multiplex drive mode. . . . . . . . . . . . . . . . . 29
7.4.3
VLCD generation . . . . . . . . . . . . . . . . . . . . . . . 31
7.4.4
External VLCD supply . . . . . . . . . . . . . . . . . . . 32
7.4.5
Charge pump driving capability . . . . . . . . . . . 33
7.4.6
Charge pump frequency settings and power
efficiency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.4.7
7.4.8
7.5
7.5.1
7.5.2
7.5.3
7.6
7.7
7.8
7.9
7.9.1
7.9.1.1
7.9.1.2
7.9.1.3
7.9.1.4
7.9.1.5
7.9.2
7.9.2.1
7.9.2.2
8
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
9
10
11
12
13
14
14.1
14.2
14.3
14.4
15
16
17
18
18.1
18.2
18.3
18.4
Temperature readout . . . . . . . . . . . . . . . . . . .
Temperature compensation of VLCD . . . . . . . .
Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Internal oscillator . . . . . . . . . . . . . . . . . . . . . .
External clock. . . . . . . . . . . . . . . . . . . . . . . . .
Timing and frame frequency . . . . . . . . . . . . .
Backplane outputs . . . . . . . . . . . . . . . . . . . . .
Segment outputs . . . . . . . . . . . . . . . . . . . . . .
Display register . . . . . . . . . . . . . . . . . . . . . . .
Display RAM . . . . . . . . . . . . . . . . . . . . . . . . .
Data pointer . . . . . . . . . . . . . . . . . . . . . . . . . .
RAM filling in static drive mode . . . . . . . . . . .
RAM filling in 1:2 multiplex drive mode . . . . .
RAM filling in 1:4 multiplex drive mode . . . . .
RAM filling in 1:6 multiplex drive mode . . . . .
RAM filling in 1:8 multiplex drive mode . . . . .
Bank selection . . . . . . . . . . . . . . . . . . . . . . . .
Input-bank-select . . . . . . . . . . . . . . . . . . . . . .
Output-bank-select. . . . . . . . . . . . . . . . . . . . .
I2C-bus interface characteristics . . . . . . . . . .
Bit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . .
START and STOP conditions. . . . . . . . . . . . .
System configuration . . . . . . . . . . . . . . . . . . .
Acknowledge . . . . . . . . . . . . . . . . . . . . . . . . .
I2C-bus controller . . . . . . . . . . . . . . . . . . . . . .
Input filters . . . . . . . . . . . . . . . . . . . . . . . . . . .
I2C-bus slave address . . . . . . . . . . . . . . . . . .
I2C-bus protocol . . . . . . . . . . . . . . . . . . . . . . .
Internal circuitry . . . . . . . . . . . . . . . . . . . . . . .
Limiting values . . . . . . . . . . . . . . . . . . . . . . . .
Static characteristics . . . . . . . . . . . . . . . . . . .
Dynamic characteristics. . . . . . . . . . . . . . . . .
Package outline. . . . . . . . . . . . . . . . . . . . . . . .
Soldering of SMD packages . . . . . . . . . . . . . .
Introduction to soldering. . . . . . . . . . . . . . . . .
Wave and reflow soldering. . . . . . . . . . . . . . .
Wave soldering . . . . . . . . . . . . . . . . . . . . . . .
Reflow soldering . . . . . . . . . . . . . . . . . . . . . .
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . .
References. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Revision history . . . . . . . . . . . . . . . . . . . . . . .
Legal information . . . . . . . . . . . . . . . . . . . . . .
Data sheet status . . . . . . . . . . . . . . . . . . . . . .
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . .
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . .
35
36
38
38
38
39
39
40
40
40
41
42
43
43
44
45
46
47
48
49
49
49
49
50
51
51
51
51
53
54
55
59
61
62
62
62
62
63
65
66
67
68
68
68
68
69
continued >>
PCA9620
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 9 December 2010
© NXP B.V. 2010. All rights reserved.
70 of 71
PCA9620
NXP Semiconductors
Universal LCD driver for low multiplex rates
19
20
Contact information. . . . . . . . . . . . . . . . . . . . . 69
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.
© NXP B.V. 2010.
All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
Date of release: 9 December 2010
Document identifier: PCA9620