INTERSIL EL5325AIRZ

EL5325A
®
Data Sheet
12-Channel TFT-LCD Reference Voltage
Generator with External Shutdown
The EL5325A with external shutdown
is designed to produce the reference
voltages required in TFT-LCD
applications. Each output is programmed to the required
voltage with 10 bits of resolution. Reference pins determine
the high and low voltages of the output range, which are
capable of swinging to either supply rail. Programming of
each output is performed using the 3-wire, SPI compatible
interface.
A number of EL5325A can be stacked for applications
requiring more than 12 outputs. The reference inputs can be
tied to the rails, enabling each part to output the full voltage
range, or alternatively, they can be connected to external
resistors to split the output range and enable finer
resolutions of the outputs.
The EL5325A has 12 outputs and is available in a 28-pin
TSSOP package. They are specified for operation over the
full -40°C to +85°C temperature range.
Ordering Information
PART
NUMBER
PACKAGE
TAPE &
REEL
PKG.
DWG. #
EL5325AIRZ
(Note)
28-Pin TSSOP
(Pb-Free)
-
MDP0044
EL5325AIRZ-T7
(Note)
28-Pin TSSOP
(Pb-Free)
7”
MDP0044
EL5325AIRZ-T13
(Note)
28-Pin TSSOP
(Pb-Free)
13”
MDP0044
NOTE: Intersil Pb-Free products employ special Pb-free material
sets; molding compounds/die attach materials and 100% matte tin
plate termination finish, which is compatible with both SnPb and Pbfree soldering operations. Intersil Pb-Free products are MSL
classified at Pb-free peak reflow temperatures that meet or exceed
the Pb-free requirements of IPC/JEDEC J Std-020B.
1
April 28, 2004
FN7447
Features
• 12-channel reference outputs
• Accuracy of ±1%
• Supply voltage of 5V to 16.5V
• Digital supply 3.3V to 5V
• Low supply current of 10mA
• Rail-to-rail capability
• Internal thermal protection
• External shutdown
• Pb-free available
Applications
• TFT-LCD drive circuits
• Reference voltage generators
Pinout
EL5325A
(28-PIN TSSOP)
TOP VIEW
ENA 1
28 OUTA
SDI 2
27 OUTB
SCLK 3
26 OUTC
SDO 4
25 GND
EXT_OSC 5
24 OUTD
VS 6
23 OUTE
SHDN 7
22 OUTF
VSD 8
21 OUTG
REFH 9
20 OUTH
REFL 10
19 OUTI
VS 11
18 GND
GND 12
17 OUTJ
CAP 13
16 OUTK
NC 14
15 OUTL
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2004. All Rights Reserved. Elantec is a registered trademark of Elantec Semiconductor, Inc.
All other trademarks mentioned are the property of their respective owners.
EL5325A
Absolute Maximum Ratings (TA = 25°C)
Supply Voltage between VS & GND . . . . . . 4.5V (min) to 18V (max)
Supply Voltage between VSD & GND . 3V (min) to VS and 7V (max)
Maximum Continuous Output Current . . . . . . . . . . . . . . . . . . . 30mA
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Curves
Maximum Die Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . +125°C
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C
Ambient Operating Temperature . . . . . . . . . . . . . . . .-40°C to +85°C
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typ values are for information purposes only. Unless otherwise noted, all tests are
at the specified temperature and are pulsed tests, therefore: TJ = TC = TA
Electrical Specifications
VS = 15V, VSD = 5V, VREFH = 13V, VREFL = 2V, RL = 1.5kΩ and CL = 200pF to 0V, TA = 25°C, unless otherwise
specified.
PARAMETER
DESCRIPTION
CONDITIONS
MIN
TYP
MAX
UNIT
10.2
12.5
mA
0.17
0.35
mA
50
150
mV
SUPPLY
IS
Supply Current
ISD
Digital Supply Current
No load
ANALOG
VOL
Output Swing Low
Sinking 5mA (VREFH = 15V, VREFL = 0)
VOH
Output Swing High
Sourcing 5mA (VREFH = 15V, VREFL = 0)
ISC
Short Circuit Current
PSRR
Power Supply Rejection Ratio
14.85
14.95
V
RL = 10Ω
100
140
mA
VS+ is moved from 14V to 16V
45
65
dB
tD
Program to Out Delay
4
ms
VAC
Accuracy referred to the ideal value
Code = 512
20
mV
∆VMIS
Channel to Channel Mismatch
Code = 512
2
mV
VDROOP
Droop Voltage
1
2
mV/ms
0.5
1.5
mV/mA
1.3
1.6
V
RINH
Input Resistance @ VREFH, VREFL
REG
Load Regulation
IOUT = 5mA step
32
kΩ
CAP
Band Gap
By pass with 0.1µF
1
Logic 1 Input Voltage
VSD = 5V
4
V
VSD = 3.3V
2
V
DIGITAL
VIH
FCLK
Clock Frequency
VIL
Logic 0 Input Voltage
VSD = 3.3V/5V
5
MHz
1
V
tS
Setup Time
20
ns
tH
Hold Time
20
ns
tLC
Load to Clock Time
20
ns
tCE
Clock to Load Line
20
ns
tDCO
Clock to Out Delay Time
10
ns
RSDIN
SDIN Input Resistance
1
GΩ
TPULSE
Minimum Pulse Width for EXT_OSC Signal
5
µs
Duty Cycle
Duty Cycle for EXT_OSC Signal
50
%
INL
Integral Nonlinearity Error
1.3
LSB
DNL
Differential Nonlinearity Error
0.5
LSB
F_OSC
Internal Refresh Oscillator Frequency
21
kHz
VIH_SHDN
SHDN Voltage Input High
IIH_SHDN
SHDN Current Input High
2
Negative edge of SCLK
OSC_Select = 0
2
SHDN = 2V
V
100
µA
EL5325A
Pin Descriptions
EL5325A
PIN NAME
PIN TYPE
PIN FUNCTION
1
ENA
Logic Input
Chip select, low enables data input to logic
2
SDI
Logic Input
Serial data input
3
SCLK
Logic Input
Serial data clock
4
SDO
Logic Output
Serial data output
5
EXT_OSC
Logic Input/Output
6, 11
VS+
Analog Power
7
SHDN
Logic Input
8
VSD
Digital Power
9
REFH
Analog Reference Input
High reference voltage
10
REFL
Analog Reference Input
Low reference voltage
12
GND
Ground
13
CAP
Analog Bypass Pin
14
NC
17
OUTJ
Analog Output
Channel J programmable output voltage
19
OUTI
Analog Output
Channel I programmable output voltage
20
OUTH
Analog Output
Channel H programmable output voltage
21
OUTG
Analog Output
Channel G programmable output voltage
22
OUTF
Analog Output
Channel F programmable output voltage
23
OUTE
Analog Output
Channel E programmable output voltage
24
OUTD
Analog Output
Channel D programmable output voltage
26
OUTC
Analog Output
Channel C programmable output voltage
27
OUTB
Analog Output
Channel B programmable output voltage
28
OUTA
Analog Output
Channel A programmable output voltage
15
OUTL
Analog Output
Channel L programmable output voltage
16
OUTK
Analog Output
Channel K programmable output voltage
18, 25
GND
Power
External oscillator input or internal oscillator output
Positive supply voltage for analog circuits
Chip shutdown: float enables chip, high > 2V disables chip
Positive power supply for digital circuits (3.3V - 5V)
Ground
Decoupling capacitor for internal reference generator, 0.1µF
Not connected
3
Ground
EL5325A
0.3
VS=15V, VSD=5V, VREFH=13V, VREFL=2V
REFH=13V, REFL=2V
1.5
0.2
1
0.1
INL (LSB)
DIFFERENTIAL NONLINEARITY (LSB)
Typical Performance Curves
0
-0.1
0
-0.5
-0.2
-0.3
10
0.5
-1
210
410
610
810
1010
0
200
400
600
800
1000
1200
CODE
INPUT CODE
FIGURE 1. DIFFERENTIAL NONLINEARITY vs CODE
FIGURE 2. INTEGRAL NONLINEARITY ERROR
VS=VREFH=15V
M=400ns/DIV
VS=VREFH=15V
M=400ns/DIV
0mA
5mA/DIV
5mA
0mA
5mA
CL=1nF
RS=20Ω
CL=4.7nF
RS=20Ω
5V
200mV/DIV
CL=1nF
RS=20Ω
CL=4.7nF
RS=20Ω
CL=180pF
CL=180pF
FIGURE 3. TRANSIENT LOAD REGULATION (SOURCING)
FIGURE 4. TRANSIENT LOAD REGULATION (SINKING)
M=400µs/DIV
M=400µs/DIV
5V
SCLK
SCLK
SDA
SDA
0V
5V
0V
10V
5V
0V
OUTPUT
OUTPUT
FIGURE 5. LARGE SIGNAL RESPONSE (RISING FROM 0V
TO 8V)
4
FIGURE 6. LARGE SIGNAL RESPONSE (FALLING FROM 8V
TO 0V)
EL5325A
Typical Performance Curves (Continued)
M=400µs/DIV
M=400µs/DIV
5V
0V
SCLK
SCLK
SDA
SDA
5V
0V
OUTPUT
OUTPUT
200mV
0V
FIGURE 7. SMALL SIGNAL RESPONSE (RISING FROM 0V
TO 200mV)
0.9
FIGURE 8. SMALL SIGNAL RESPONSE (FALLING FROM
200mV TO 0V)
JEDEC JESD51-3 LOW EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
1.4
833mW
0.7
θ
0.6
JA
=
TS
S
12
0.5
POWER DISSIPATION (W)
POWER DISSIPATION (W)
0.8
0.4
O
P2
0° 8
C/
W
0.3
0.2
0.1
0
0
25
75 85
50
100
125
JEDEC JESD51-7 HIGH EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
1.333W
1.2
θ
0.8
SO
P2
75
8
°C
/W
0.6
0.4
0.2
0
0
AMBIENT TEMPERATURE (°C)
FIGURE 9. POWER DISSIPATION vs AMBIENT
TEMPERATURE
TS
JA
=
1
25
50
75 85
100
125
AMBIENT TEMPERATURE (°C)
FIGURE 10. POWER DISSIPATION vs AMBIENT
TEMPERATURE
General Description
Digital Interface
The EL5325A provides a versatile method of providing the
reference voltages that are used in setting the transfer
characteristics of LCD display panels. The V/T
(Voltage/Transmission) curve of the LCD panel requires that
a correction is applied to make it linear; however, if the panel
is to be used in more than one application, the final curve
may differ for different applications. By using the EL5325A,
the V/T curve can be changed to optimize its characteristics
according to the required application of the display product.
Each of the eight reference voltage outputs can be set with a
10-bit resolution. These outputs can be driven to within
50mV of the power rails of the EL5325A. As all of the output
buffers are identical, it is also possible to use the EL5325A
for applications other than LCDs where multiple voltage
references are required that can be set to 10 bit accuracy.
The EL5325A uses a simple 3-wire SPI compliant digital
interface to program the outputs. The EL5325A can support
the clock rate up to 5MHz.
5
Serial Interface
The EL5325A is programmed through a three-wire serial
interface. The start and stop conditions are defined by the
ENA signal. While the ENA is low, the data on the SDI (serial
data input) pin is shifted into the 16-bit shift register on the
positive edge of the SCLK (serial clock) signal. The MSB (bit
15) is loaded first and the LSB (bit 0) is loaded last (see
Table 1). After the full 16-bit data has been loaded, the ENA
is pulled high and the addressed output channel is updated.
The SCLK is disabled internally when the ENA is high. The
SCLK must be low before the ENA is pulled low.
EL5325A
To facilitate the system designs that use multiple EL5325A
chips, a buffered serial output of the shift register (SDO pin)
is available. Data appears on the SDO pin at the 16th falling
SCLK edge after being applied to the SDI pin.
TABLE 1. CONTROL BITS LOGIC TABLE
To control the multiple EL5325A chips from a single threewire serial port, just connect the ENA pins and the SCLK
pins together, connect the SDO pin to the SDI pin on the
next chip. While the ENA is held low, the 16m-bit data is
loaded to the SDI input of the first chip. The first 16-bit data
will go to the last chip and the last 16-bit data will go to the
first chip. While the ENA is held high, all addressed outputs
will be updated simultaneously.
The Serial Timing Diagram and parameters table show the
timing requirements for three-wire signals.
The serial data has a minimum length of 16 bits, the MSB
(most significant bit) is the first bit in the signal. The bits are
allocated to the following functions (also refer to the Control
Bits Logic Table)
• Bit 15 is always set to a zero
• Bit 14 controls the source of the clock, see the next
section for details
• Bits 13 through 10 select the channel to be written to,
these are binary coded with channel A = 0, and channel
H=7
• The 10-bit data is on bits 9 through 0. Some examples of
data words are shown in the table of Serial Programming
Examples
BIT
NAME
DESCRIPTION
B15
Test
B14
Oscillator
B13
A3
Channel Address
B12
A2
Channel Address
B11
A1
Channel Address
B10
A0
Channel Address
B9
D9
Data
B8
D8
Data
B7
D7
Data
B6
D6
Data
B5
D5
Data
B4
D4
Data
B3
D3
Data
B2
D2
Data
B1
D1
Data
B0
D0
Data
Always 0
0 = Internal, 1 = External
Serial Timing Diagram
ENA
tHE
tSE
T
tr
tf
tHE
tSE
SCLK
tSD
tHD
B15
SDI
tw
B14
B13
B12-B2
B1
B0
t
MSB
6
Load MSB first, LSB last
LSB
EL5325A
TABLE 2. SERIAL TIMING PARAMETERS
PARAMETER
RECOMMENDED OPERATING RANGE
DESCRIPTION
T
≥200ns
Clock Period
tr/tf
0.05 * T
Clock Rise/Fall Time
tHE
≥10ns
ENA Hold Time
tSE
≥10ns
ENA Setup Time
tHD
≥10ns
Data Hold Time
tSD
≥10ns
Data Setup Time
tW
0.50 * T
Clock Pulse Width
TABLE 3. SERIAL PROGRAMMING EXAMPLES
CONTROL
CHANNEL ADDRESS
DATA
C1
C0
A3
A2
A1
A0
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Internal Oscillator, Channel A, Value = 0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
Internal Oscillator, Channel A, Value = 1023
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
Internal Oscillator, Channel A, Value = 512
0
0
0
0
1
1
1
0
0
0
0
0
0
0
0
1‘t
Internal Oscillator, Channel C, Value = 513
0
0
0
1
1
1
0
0
0
0
0
1
1
1
1
1
Internal Oscillator, Channel H, Value = 31
0
1
0
1
1
1
0
0
0
0
0
1
1
1
1
1
External Oscillator, Channel H, Value = 31
CONDITION
Analog Section
CLOCK OSCILLATOR
TRANSFER FUNCTION
The EL5325A requires an internal clock or external clock to
refresh its outputs. The outputs are refreshed at the falling OSC
clock edges. The output refreshed switches open at the rising
edges of the OSC clock. The driving load shouldn’t be changed
at the rising edges of the OSC clock. Otherwise, it will generate
a voltage error at the outputs. This clock may be input or output
via the clock pin labeled OSC. The internal clock is provided by
an internal oscillator running at approximately 21kHz and can
be output to the OSC pin. In a 2 chip system, if the driving loads
are stable, one chip may be programmed to use the internal
oscillator; then the OSC pin will output the clock from the
internal oscillator. The second chip may have the OSC pin
connected to this clock source.
The transfer function is:
data
V OUT ( IDEAL ) = V REFL + ------------- × ( V REFH - V REFL )
1024
where data is the decimal value of the 10-bit data binary
input code.
The output voltages from the EL5325A will be derived from
the reference voltages present at the VREFL and VREFH
pins. The impedance between those two pins is about 32kΩ.
Care should be taken that the system design holds these two
reference voltages within the limits of the power rails of the
EL5325A. GND < VREFH ≤ VS and GND ≤ VREFL ≤ VREFH.
In some LCD applications that require more than 12
channels, the system can be designed such that one
EL5325A will provide the Gamma correction voltages that
are more positive than the VCOM potential. The second
EL5325A can provide the Gamma correction voltage more
negative than the VCOM potential. The Application Drawing
shows a system connected in this way.
7
For transient load application, the external clock Mode
should be used to ensure all functions are synchronized
together. The positive edge of the external clock to the OSC
pin should be timed to avoid the transient load effect. The
Application Drawing shows the LCD H rate signal used, here
the positive clock edge is timed to avoid the transient load of
the column driver circuits.
After power on, the chip will start with the internal oscillator
mode. At this time, the OSC pin will be in a high impedance
condition to prevent contention. By setting B14 to high, the
chip is on external clock mode. Setting B14 to low, the chip is
on internal clock mode.
EL5325A
Block Diagram
REFERENCE HIGH
OUTA
OUTB
OUTJ
EIGHT
CHANNEL
MEMORY
VOLTAGE
SOURCES
OUTK
OUTL
REFERENCE LOW
REFERENCE DECOUPLE
CLK
SDI
SDO
CONTROL IF
LOAD
FILTER
EXT_OSC
CHANNEL OUTPUTS
POWER DISSIPATION AND THERMAL SHUTDOWN
Each of the channel outputs has a rail-to-rail buffer. This
enables all channels to have the capability to drive to within
50mV of the power rails, (see Electrical Characteristics for
details).
With the 30mA maximum continues output drive capability
for each channel, it is possible to exceed the 125°C absolute
maximum junction temperature. Therefore, it is important to
calculate the maximum junction temperature for the
application to determine if load conditions need to be
modified for the part to remain in the safe operation.
When driving large capacitive loads, a series resistor should
be placed in series with the output. (Usually between 5Ω and
50Ω).
Each of the channels is updated on a continuous cycle, the
time for the new data to appear at a specific output will
depend on the exact timing relationship of the incoming data
to this cycle.
The best-case scenario is when the data has just been
captured and then passed on to the output stage
immediately; this can be as short as 48µs. In the worst-case
scenario this will be 576µs when the data has just missed
the cycle.
When a large change in output voltage is required, the
change will occur in 2V steps, thus the requisite number of
timing cycles will be added to the overall update time. This
means that a large change of 16V can take between 4.6ms
to 5.2ms depending on the absolute timing relative to the
update cycle.
8
The maximum power dissipation allowed in a package is
determined according to:
T JMAX - T AMAX
P DMAX = -------------------------------------------Θ JA
where:
• TJMAX = Maximum junction temperature
• TAMAX = Maximum ambient temperature
• θJA = Thermal resistance of the package
• PDMAX = Maximum power dissipation in the package
The maximum power dissipation actually produced by the IC
is the total quiescent supply current times the total power
supply voltage and plus the power in the IC due to the loads.
P DMAX = V S × I S + Σ [ ( V S - V OUT i ) × I LOAD i ]
EL5325A
when sourcing, and:
External Shutdown
P DMAX = V S × I S + Σ ( V OUT i × I LOAD i )
The EL5325A also has an external shutdown to enable and
disable the part. The SHDN pin should never be driven low.
Rather, to enable the part, the SHDN pin must be left open
(float). To disable, the SHDN pin must be driven HI (>2V).
WIth this feature, the EL5325A can be forced to shut down,
regardless of any other conditions. A simple open collector
driver is adequate to control the enable and disable function:
when sinking.
Where:
• i = 1 to total 12
• VS = Supply voltage
VSD
• IS = Quiescent current
• VOUTi = Output voltage of the i channel
• ILOADi = Load current of the i channel
By setting the two PDMAX equations equal to each other, we
can solve for the RLOADs to avoid the device overheat. The
package power dissipation curves provide a convenient way
to see if the device will overheat.
The EL5325A has an internal thermal shutdown circuitry that
prevents overheating of the part. When the junction
temperature goes up to about 150°C, the part will be
disabled. When the junction temperature drops down to
about 120°C, the part will be enabled. With this feature, any
short circuit at the outputs will enable the thermal shutdown
circuitry to disable the part.
POWER SUPPLY BYPASSING AND PRINTED CIRCUIT
BOARD LAYOUT
Good printed circuit board layout is necessary for optimum
performance. A low impedance and clean analog ground
plane should be used for the EL5325A. The traces from the
two ground pins to the ground plane must be very short. The
thermal pad of the EL5325A should be connected to the
analog ground plane. Lead length should be as short as
possible and all power supply pins must be well bypassed. A
0.1µF ceramic capacitor must be place very close to the VS,
VREFH, VREFL, and CAP pins. A 4.7µF local bypass
tantalum capacitor should be placed to the VS, VREFH, and
VREFL pins.
APPLICATION USING THE EL5325A
In the first application drawing, the schematic shows the
interconnect of a pair of EL5325A chips connected to give
12 gamma corrected voltages above the VCOM voltage, and
12 gamma corrected voltages below the VCOM voltage.
9
R1
100K
R2
100K
SHDN
Q1
PNP
EL5325A
SHDN
EL5325A
Application Drawing
+10V
HIGH REFERENCE
VOLTAGE
REFH
OUTA
VS
OUTB
0.1µF
+12V
COLUMN
(SOURCE)
DRIVER
0.1µF
+5V
MICROCONTROLLER
VSD
OUTC
0.1µF
OUTD
LCD
TIMING
CONTROLLER
SDI
SCK
ENA
SDO
HORIZONTAL RATE
OUTE
OSC
CAP
OUTF
0.1µF
OUTK
REFL
GND
OUTL
EL5325A
MIDDLE REFERENCE
+5.5V
+12V
REFH
OSC
OUTA
VS
OUTB
0.1µF
+5V
VSD
OUTC
0.1µF
OUTD
SDI
SCK
ENA
CAP
+1V
0.1µF
LOW REFERENCE
VOLTAGE
OUTE
OUTF
REFL
0.1µF
OUTK
GND
OUTL
EL5325A
10
LCD PANEL
EL5325A
TSSOP Package Outline Drawing
NOTE: The package drawing shown here may not be the latest version. To check the latest revision, please refer to the Intersil
website at <http://www.intersil.com/design/packages/index.asp>
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Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
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11