Data Sheet

PCA9550
2-bit I2C-bus LED driver with programmable blink rates
Rev. 05 — 13 October 2008
Product data sheet
1. General description
The PCA9550 LED blinker blinks LEDs in I2C-bus and SMBus applications where it is
necessary to limit bus traffic or free up the I2C master's (MCU, MPU, DSP, chip set, etc.)
timer. The uniqueness of this device is the internal oscillator with two programmable blink
rates. To blink LEDs using normal I/O expanders like the PCF8574 or PCA9554, the bus
master must send repeated commands to turn the LED on and off. This greatly increases
the amount of traffic on the I2C-bus and uses up one of the master's timers. The PCA9550
LED blinker instead requires only the initial set-up command to program BLINK RATE 1
and BLINK RATE 2 (i.e., the frequency and duty cycle). From then on, only one command
from the bus master is required to turn each individual open-drain output ON, OFF, or to
cycle at BLINK RATE 1 or BLINK RATE 2. Maximum output sink current is 25 mA per bit
and 50 mA per package.
Any bits not used for controlling the LEDs can be used for General Purpose parallel
Input/Output (GPIO) expansion.
The active LOW hardware reset pin (RESET) and Power-On Reset (POR) initializes the
registers to their default state, all zeroes, causing the bits to be set HIGH (LED off).
One hardware address pin on the PCA9550 allows two devices to operate on the same
bus.
2. Features
n 2 LED drivers (on, off, flashing at a programmable rate)
n 2 selectable, fully programmable blink rates (frequency and duty cycle) between
0.172 Hz and 44 Hz (5.82 seconds and 0.023 second)
n Input/output not used as LED drivers can be used as regular GPIOs
n Internal oscillator requires no external components
n I2C-bus interface logic compatible with SMBus
n Internal power-on reset
n Noise filter on SCL/SDA inputs
n Active LOW reset input
n 2 open-drain outputs directly drive LEDs to 25 mA
n Controlled edge rates to minimize ground bounce
n No glitch on power-up
n Supports hot insertion
n Low standby current
n Operating power supply voltage range of 2.3 V to 5.5 V
n 0 kHz to 400 kHz clock frequency
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
n ESD protection exceeds 2000 V HBM per JESD22-A114, 150 V MM per
JESD22-A115 and 1000 V CDM per JESD22-C101
n Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
n Packages offered: SO8, TSSOP8 (MSOP8), HVSON8
3. Ordering information
Table 1.
Ordering information
Type number
Package
Name
Description
Version
PCA9550D
SO8
plastic small outline package; 8 leads; body width 3.9 mm
SOT96-1
PCA9550DP
TSSOP8[1]
plastic thin shrink small outline package; 8 leads; body width 3 mm
SOT505-1
PCA9550TK
HVSON8
plastic thermal enhanced very thin small outline package; no leads; 8 terminals; SOT908-1
body 3 × 3 × 0.85 mm
[1]
Also known as MSOP8.
3.1 Ordering options
Table 2.
Ordering options
Type number
Topside mark
Temperature range
PCA9550D
PCA9550
Tamb = −40 °C to +85 °C
PCA9550DP
9550
Tamb = −40 °C to +85 °C
PCA9550TK
9550
Tamb = −40 °C to +85 °C
4. Block diagram
A0
PCA9550
SCL
SDA
INPUT
REGISTER
INPUT
FILTERS
I2C-BUS
CONTROL
LED SELECT (LS0)
REGISTER
0
VDD
RESET
1
POWER-ON
RESET
OSCILLATOR
VSS
PRESCALER 0
REGISTER
PWM0
REGISTER
BLINK0
PRESCALER 1
REGISTER
PWM1
REGISTER
BLINK1
LEDn
002aad241
Only one I/O shown for clarity.
Fig 1.
Block diagram of PCA9550
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
2 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
5. Pinning information
5.1 Pinning
A0
1
8
VDD
LED0
2
7
SDA
LED1
3
6
SCL
VSS
4
5
RESET
PCA9550D
A0
1
8
VDD
LED0
2
7
SDA
6
SCL
5
RESET
LED1
3
VSS
4
PCA9550DP
002aad239
002aad238
Fig 2.
Pin configuration for SO8
Fig 3.
Pin configuration for TSSOP8
terminal 1
index area
A0
1
LED0
2
8
VDD
7
SDA
PCA9550TK
LED1
3
6
SCL
VSS
4
5
RESET
002aad240
Transparent top view
Fig 4.
Pin configuration for HVSON8
5.2 Pin description
Table 3.
Pin description
Symbol
Pin
Description
A0
1
address input 0
LED0
2
LED driver 0
LED1
3
LED driver 1
VSS
4
supply ground
RESET
5
active LOW reset input
SCL
6
serial clock line
SDA
7
serial data line
VDD
8
supply voltage
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
3 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
6. Functional description
Refer to Figure 1 “Block diagram of PCA9550”.
6.1 Device address
Following a START condition, the bus master must output the address of the slave it is
accessing. The address of the PCA9550 is shown in Figure 5. To conserve power, no
internal pull-up resistor is incorporated on the hardware selectable address pin and it must
be pulled HIGH or LOW.
slave address
1
1
0
0
0
fixed
0
A0 R/W
hardware
selectable
002aad242
Fig 5.
PCA9550 slave address
The last bit of the address byte defines the operation to be performed. When set to logic 1
a read is selected, while a logic 0 selects a write operation.
6.2 Control register
Following the successful acknowledgement of the slave address, the bus master will send
a byte to the PCA9550, which will be stored in the Control register.
0
0
0
AI
Auto-Increment flag
0
B2
B1
B0
register address
002aad243
Reset state: 00h
Fig 6.
Control register
The lowest 3 bits are used as a pointer to determine which register will be accessed.
If the Auto-Increment (AI) flag is set, the three low order bits of the Control register are
automatically incremented after a read or write. This allows the user to program the
registers sequentially. The contents of these bits will rollover to ‘000’ after the last register
is accessed.
When the Auto-Increment flag is set (AI = 1) and a read sequence is initiated, the
sequence must start by reading a register different from the input register
(B2 B1 B0 ≠ 000).
Only the 3 least significant bits are affected by the AI flag. Unused bits must be
programmed with zeroes.
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
4 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
6.2.1 Control register definition
Table 4.
Register summary
B2
B1
B0
Register name
Access
Description
0
0
0
INPUT
read only
input register
0
0
1
PSC0
read/write
frequency prescaler 0
0
1
0
PWM0
read/write
PWM register 0
0
1
1
PSC1
read/write
frequency prescaler 1
1
0
0
PWM1
read/write
PWM register 1
1
0
1
LS0
read/write
LED selector
6.3 Register descriptions
6.3.1 INPUT - Input register
The INPUT register reflects the state of the device pins. Writes to this register will be
acknowledged but will have no effect.
Table 5.
Bit
INPUT - Input register description
7
6
5
Symbol
Default
4
3
2
not used
0
0
0
0
0
0
1
0
LED1
LED0
X
X
Remark: The default value ‘X’ is determined by the externally applied logic level (normally
logic 1) when used for directly driving LED with pull-up to VDD.
6.3.2 PSC0 - Frequency Prescaler 0
PSC0 is used to program the period of the PWM output.
The period of BLINK0 = (PSC0 + 1) / 44.
Table 6.
Bit
PSC0 - Frequency Prescaler 0 register description
7
6
5
4
3
2
1
0
Symbol
PSC0[7]
PSC0[6]
PSC0[5]
PSC0[4]
PSC0[3]
PSC0[2]
PSC0[1]
PSC0[0]
Default
1
1
1
1
1
1
1
1
6.3.3 PWM0 - Pulse Width Modulation 0
The PWM0 register determines the duty cycle of BLINK0. The outputs are LOW (LED off)
when the count is less than the value in PWM0 and HIGH when it is greater. If PWM0 is
programmed with 00h, then the PWM0 output is always LOW.
The duty cycle of BLINK0 = (256 − PWM0) / 256.
Table 7.
Bit
PWM0 - Pulse Width Modulation 0 register description
7
6
5
4
3
2
1
0
Symbol
PWM0
[7]
PWM0
[6]
PWM0
[5]
PWM0
[4]
PWM0
[3]
PWM0
[2]
PWM0
[1]
PWM0
[0]
Default
1
0
0
0
0
0
0
0
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
5 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
6.3.4 PSC1 - Frequency Prescaler 1
PSC1 is used to program the period of the PWM output.
The period of BLINK1 = (PSC1 + 1) / 44.
Table 8.
Bit
PSC1 - Frequency Prescaler 1 register description
7
6
5
4
3
2
1
0
Symbol
PSC1[7]
PSC1[6]
PSC1[5]
PSC1[4]
PSC1[3]
PSC1[2]
PSC1[1]
PSC1[0]
Default
1
1
1
1
1
1
1
1
6.3.5 PWM1 - Pulse Width Modulation 1
The PWM1 register determines the duty cycle of BLINK1. The outputs are LOW (LED off)
when the count is less than the value in PWM1 and HIGH when it is greater. If PWM1 is
programmed with 00h, then the PWM1 output is always LOW.
The duty cycle of BLINK1 = (256 − PWM1) / 256.
Table 9.
Bit
PWM1 - Pulse Width Modulation 1 register description
7
6
5
4
3
2
1
0
Symbol
PWM1
[7]
PWM1
[6]
PWM1
[5]
PWM1
[4]
PWM1
[3]
PWM1
[2]
PWM1
[1]
PWM1
[0]
Default
1
0
0
0
0
0
0
0
1
0
6.3.6 LS0 - LED selector
The LS0 LED select register determines the source of the LED data.
00 = output is set LOW (LED on)
01 = output is set high-impedance (LED off; default)
10 = output blinks at PWM0 rate
11 = output blinks at PWM1 rate
Table 10.
Bit
LS0 - LED selector register description
7
6
Symbol
Default
5
4
LS0[7:4]
1
1
2
LED1
1
1
PCA9550_5
Product data sheet
3
0
LED0
1
0
1
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
6 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
6.4 Pins used as GPIOs
LED pins not used to control LEDs can be used as General Purpose Input/Outputs
(GPIOs).
For use as input, set LEDn to high-impedance (01) and then read the pin state via the
Input register.
For use as output, connect external pull-up resistor to the pin and size it according to the
DC recommended operating characteristics. LEDn output pin is HIGH when the output is
programmed as high-impedance, and LOW when the output is programmed LOW through
the LED selector register (LS0). The output can be pulse-width controlled when PWM0 or
PWM1 are used.
6.5 Power-on reset
When power is applied to VDD, an internal Power-On Reset (POR) holds the PCA9550 in
a reset condition until VDD has reached VPOR. At that point, the reset condition is released
and the PCA9550 registers are initialized to their default states, all the outputs in the
OFF state. Thereafter, VDD must be lowered below 0.2 V to reset the device.
6.6 External RESET
A reset can be accomplished by holding the RESET pin LOW for a minimum of tw(rst). The
PCA9550 registers and I2C-bus state machine will be held in their default states until the
RESET input is once again HIGH.
This input requires a pull-up resistor to VDD if no active connection is used.
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
7 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
7. Characteristics of the I2C-bus
The I2C-bus is for 2-way, 2-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.
7.1 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 control signals (see Figure 7).
SDA
SCL
data line
stable;
data valid
Fig 7.
change
of data
allowed
mba607
Bit transfer
7.1.1 START and STOP conditions
Both data and clock lines remain HIGH when the bus is not busy. A HIGH-to-LOW
transition of the data line while the clock is HIGH is defined as the START condition (S).
A LOW-to-HIGH transition of the data line while the clock is HIGH is defined as the STOP
condition (P) (see Figure 8).
SDA
SDA
SCL
SCL
S
P
START condition
STOP condition
mba608
Fig 8.
Definition of START and STOP conditions
7.2 System configuration
A device generating a message is a ‘transmitter’; a device receiving is the ‘receiver’. The
device that controls the message is the ‘master’ and the devices which are controlled by
the master are the ‘slaves’ (see Figure 9).
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
8 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
SDA
SCL
MASTER
TRANSMITTER/
RECEIVER
SLAVE
RECEIVER
SLAVE
TRANSMITTER/
RECEIVER
MASTER
TRANSMITTER
MASTER
TRANSMITTER/
RECEIVER
I2C-BUS
MULTIPLEXER
SLAVE
002aaa966
Fig 9.
System configuration
7.3 Acknowledge
The number of data bytes transferred between the START and the STOP conditions from
transmitter to receiver is not limited. Each byte of eight bits is followed by one
acknowledge bit. The acknowledge bit is a HIGH level put on the bus by the transmitter,
whereas the master generates an extra acknowledge related clock pulse.
A slave receiver which is addressed must generate an acknowledge after the reception of
each byte. Also a master must generate an acknowledge after the reception of each byte
that has been clocked out of the slave transmitter. The device that acknowledges has to
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 account.
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.
data output
by transmitter
not acknowledge
data output
by receiver
acknowledge
SCL from master
1
S
START
condition
2
8
9
clock pulse for
acknowledgement
002aaa987
Fig 10. Acknowledgement on the I2C-bus
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
9 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
7.4 Bus transactions
SCL
1
2
3
4
5
6
7
8
9
slave address
1
SDA S
1
0
0
0
data to register
command byte
0 A0 0
START condition
A
R/W
0
0
0
AI
0 B2 B1 B0 A
DATA 1
A
acknowledge
from slave
acknowledge
from slave
acknowledge
from slave
write to register
tv(Q)
data out from port
DATA 1 VALID
002aad268
Fig 11. Write to register
slave address
SDA S
1
1
0
0
0
command byte
0 A0 0
START condition
0
A
0
1
1
0
AI
0
0
0 A0 1
(repeated)
START condition
0 B2 B1 B0 A
(cont.)
acknowledge
from slave
R/W
acknowledge
from slave
slave address
(cont.) S
0
data from register
DATA (first byte)
A
Auto-Increment
register address
if AI = 1
R/W
acknowledge
from slave
data from register
DATA (last byte)
A
acknowledge
from master
NA P
STOP
condition
no acknowledge
from master
at this moment master-transmitter becomes master-receiver
and slave-receiver becomes slave-transmitter
002aad269
Fig 12. Read from register
no acknowledge
from master
slave address
SDA S
1
1
0
0
0
START condition
data from port
data from port
0 A0 1
R/W
A
A
DATA 1
DATA 4
acknowledge
from master
acknowledge
from slave
NA P
STOP
condition
read from
port
th(D)
data into
port
DATA 1
tsu(D)
DATA 2
DATA 3
DATA 4
002aad270
Remark: This figure assumes the command byte has previously been programmed with 00h.
Fig 13. Read input port register
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
10 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
8. Application design-in information
5V
5V
10 kΩ
10 kΩ
10 kΩ
VDD
I2C-BUS/SMBus
MASTER
SDA
SDA
LED0
SCL
SCL
LED1
PCA9550
RESET
A0
VSS
002aad271
Fig 14. Typical application
8.1 Minimizing IDD when the I/Os are used to control LEDs
When the I/Os are used to control LEDs, they are normally connected to VDD through a
resistor as shown in Figure 14. Since the LED acts as a diode, when the LED is off the
I/O VI is about 1.2 V less than VDD. The supply current, IDD, increases as VI becomes
lower than VDD.
Designs needing to minimize current consumption, such as battery power applications,
should consider maintaining the I/O pins greater than or equal to VDD when the LED is off.
Figure 15 shows a high value resistor in parallel with the LED. Figure 16 shows VDD less
than the LED supply voltage by at least 1.2 V. Both of these methods maintain the I/O VI
at or above VDD and prevents additional supply current consumption when the LED is off.
VDD
VDD
LED
100 kΩ
LEDn
VDD
5V
LED
LEDn
002aac189
Fig 15. High value resistor in parallel with
the LED
PCA9550_5
Product data sheet
3.3 V
002aac190
Fig 16. Device supplied by a lower voltage
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
11 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
8.2 Programming example
The following example will show how to set LED0 to blink at 1 Hz at a 50 % duty cycle.
LED1 will be set to blink at 4 Hz and at a 25 % duty cycle.
Table 11.
Programming PCA9550
I2C-bus
Program sequence
START
S
PCA9550 address with A0 = LOW
C0h
PSC0 subaddress + Auto-Increment
11h
Set prescaler PSC0 to achieve a period of 1 second:
2Bh
PSC0 + 1
Blink period = 1 = -----------------------44
PSC0 = 43
Set PWM0 duty cycle to 50 %:
80h
256 – PWM0
-------------------------------- = 0.5
256
PWM0 = 128
Set prescaler PSC1 to achieve a period of 0.25 seconds:
0Ah
PSC1 + 1
Blink period = 0.25 = -----------------------44
PSC1 = 10
Set PWM1 output duty cycle to 25 %:
C0h
256 – PWM1
-------------------------------- = 0.25
256
PWM1 = 192
Set LED0 to PWM0, and set LED1 to blink at PWM1
0Eh
STOP
P
9. Limiting values
Table 12. Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol
Parameter
VDD
Conditions
Min
Max
Unit
supply voltage
−0.5
+6.0
V
VI/O
voltage on an input/output pin
VSS − 0.5
5.5
V
IO(LEDn)
output current on pin LEDn
-
±25
mA
ISS
ground supply current
-
50
mA
Ptot
total power dissipation
-
400
mW
Tstg
storage temperature
−65
+150
°C
Tamb
ambient temperature
−40
+85
°C
operating
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
12 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
10. Static characteristics
Table 13. Static characteristics
VDD = 2.3 V to 5.5 V; VSS = 0 V; Tamb = −40 °C to +85 °C; unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ[1]
Max
Unit
Supplies
VDD
supply voltage
2.3
-
5.5
V
IDD
supply current
operating mode; VDD = 5.5 V; no load;
VI = VDD or VSS; fSCL = 100 kHz
-
350
500
µA
Istb
standby current
Standby mode; VDD = 5.5 V; no load;
VI = VDD or VSS; fSCL = 0 kHz
-
1.9
3.0
µA
VPOR
power-on reset voltage
no load; VI = VDD or VSS
1.4
1.7
2.2
V
−0.5
-
+0.3VDD
V
[2]
Input SCL; input/output SDA
VIL
LOW-level input voltage
VIH
HIGH-level input voltage
0.7VDD
-
5.5
V
IOL
LOW-level output current
VOL = 0.4 V
3
6.5
-
mA
IL
leakage current
VI = VDD = VSS
−1
-
+1
µA
Ci
input capacitance
VI = VSS
-
3.7
5
pF
I/Os
VIL
LOW-level input voltage
−0.5
-
+0.8
V
VIH
HIGH-level input voltage
2.0
-
5.5
V
IOL
LOW-level output current
VOL = 0.4 V
VDD = 2.3 V
[3]
6
9
-
mA
VDD = 3.0 V
[3]
8
11
-
mA
VDD = 5.0 V
[3]
10
14
-
mA
VDD = 2.3 V
[3]
11
14
-
mA
VDD = 3.0 V
[3]
14
18
-
mA
VDD = 5.0 V
[3]
17
24
-
mA
−1
-
+1
µA
-
2.1
5
pF
VOL = 0.7 V
ILI
input leakage current
Cio
input/output capacitance
VDD = 3.6 V; VI = 0 V or VDD
Select inputs A0; RESET
VIL
LOW-level input voltage
−0.5
-
+0.8
V
VIH
HIGH-level input voltage
2.0
-
5.5
V
ILI
input leakage current
−1
-
+1
µA
Ci
input capacitance
-
2.3
5
pF
VI = VSS
[1]
Typical limits at VDD = 3.3 V, Tamb = 25 °C.
[2]
VDD must be lowered to 0.2 V in order to reset part.
[3]
Each I/O must be externally limited to a maximum of 25 mA and the device must be limited to a maximum current of 50 mA.
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
13 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
20 %
002aac191
(1)
percent
variation
20 %
002aac192
(1)
percent
variation
0%
0%
(2)
−20 %
(3)
(2)
−20 %
(3)
−40 %
−40
−20
0
20
40
60
100
Tamb (°C)
80
−40 %
−40
−20
(1) maximum
(1) maximum
(2) average
(2) average
(3) minimum
(3) minimum
Fig 17. Typical frequency variation over process at
VDD = 2.3 V to 3.0 V
20
40
60
100
80
Tamb (°C)
Fig 18. Typical frequency variation over process at
VDD = 3.0 V to 5.5 V
PCA9550_5
Product data sheet
0
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
14 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
11. Dynamic characteristics
Table 14.
Dynamic characteristics
Symbol
Parameter
Conditions
Standard-mode
I2C-bus
Min
Max
Fast-mode I2C-bus
Min
Max
Unit
fSCL
SCL clock frequency
0
100
0
400
tBUF
bus free time between a STOP and
START condition
4.7
-
1.3
-
µs
tHD;STA
hold time (repeated) START condition
4.0
-
0.6
-
µs
tSU;STA
set-up time for a repeated START
condition
4.7
-
0.6
-
µs
tSU;STO
set-up time for STOP condition
4.0
-
0.6
-
µs
tHD;DAT
data hold time
tVD;ACK
data valid acknowledge time
tVD;DAT
data valid time
kHz
0
-
0
-
ns
[1]
-
600
-
600
ns
LOW-level
[2]
-
600
-
600
ns
HIGH-level
[2]
-
1500
-
600
ns
tSU;DAT
data set-up time
250
-
100
-
ns
tLOW
LOW period of the SCL clock
4.7
-
1.3
-
µs
tHIGH
HIGH period of the SCL clock
4.0
-
0.6
-
µs
20 +
0.1Cb[3]
300
ns
20 +
0.1Cb[3]
300
ns
rise time of both SDA and SCL signals
tr
-
1000
tf
fall time of both SDA and SCL signals
-
300
tSP
pulse width of spikes that must be
suppressed by the input filter
-
50
-
50
ns
tv(Q)
data output valid time
-
200
-
200
ns
tsu(D)
data input set-up time
100
-
100
-
ns
th(D)
data input hold time
1
-
1
-
µs
tw(rst)
reset pulse width
6
-
6
-
ns
trec(rst)
reset recovery time
0
-
0
-
ns
trst
reset time
400
-
400
-
ns
Port timing
Reset
[4][5]
[1]
tVD;ACK = time for Acknowledgement signal from SCL LOW to SDA (out) LOW.
[2]
tVD;DAT = minimum time for SDA data output to be valid following SCL LOW.
[3]
Cb = total capacitance of one bus line in pF.
[4]
Resetting the device while actively communicating on the bus may cause glitches or errant STOP conditions.
[5]
Upon reset, the full delay will be the sum of trst and the RC time constant of the SDA bus.
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
15 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
ACK or read cycle
START
SCL
SDA
30 %
trst
RESET
50 %
50 %
trec(rst)
50 %
tw(rst)
trst
LEDn
50 %
LED off
002aac193
Fig 19. Definition of RESET timing
SDA
tr
tBUF
tf
tHD;STA
tSP
tLOW
SCL
tHD;STA
P
S
tSU;STA
tHD;DAT
tHIGH
tSU;DAT
Sr
tSU;STO
P
002aaa986
Fig 20. Definition of timing
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
16 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
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
tVD;ACK
tVD;DAT
tHD;DAT
tSU;STO
002aab175
Rise and fall times refer to VIL and VIH.
Fig 21. I2C-bus timing diagram
12. Test information
VDD
PULSE
GENERATOR
VI
VO
RL
500 Ω
VDD
open
VSS
DUT
RT
CL
50 pF
002aab880
RL = load resistor for LEDn. RL for SDA and SCL > 1 kΩ (3 mA or less current).
CL = load capacitance includes jig and probe capacitance.
RT = termination resistance should be equal to the output impedance Zo of the pulse generators.
Fig 22. Test circuitry for switching times
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
17 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
13. Package outline
SO8: plastic small outline package; 8 leads; body width 3.9 mm
SOT96-1
D
E
A
X
c
y
HE
v M A
Z
5
8
Q
A2
A
(A 3)
A1
pin 1 index
θ
Lp
1
L
4
e
detail X
w M
bp
0
2.5
5 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D (1)
E (2)
e
HE
L
Lp
Q
v
w
y
Z (1)
mm
1.75
0.25
0.10
1.45
1.25
0.25
0.49
0.36
0.25
0.19
5.0
4.8
4.0
3.8
1.27
6.2
5.8
1.05
1.0
0.4
0.7
0.6
0.25
0.25
0.1
0.7
0.3
inches
0.069
0.010 0.057
0.004 0.049
0.01
0.019 0.0100
0.014 0.0075
0.20
0.19
0.16
0.15
0.05
0.01
0.01
0.004
0.028
0.012
0.244
0.039 0.028
0.041
0.228
0.016 0.024
θ
8o
o
0
Notes
1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included.
2. Plastic or metal protrusions of 0.25 mm (0.01 inch) maximum per side are not included.
REFERENCES
OUTLINE
VERSION
IEC
JEDEC
SOT96-1
076E03
MS-012
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
99-12-27
03-02-18
Fig 23. Package outline SOT96-1 (SO8)
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
18 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
TSSOP8: plastic thin shrink small outline package; 8 leads; body width 3 mm
D
E
SOT505-1
A
X
c
y
HE
v M A
Z
5
8
A2
pin 1 index
(A3)
A1
A
θ
Lp
L
1
4
detail X
e
w M
bp
0
2.5
5 mm
scale
DIMENSIONS (mm are the original dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D(1)
E(2)
e
HE
L
Lp
v
w
y
Z(1)
θ
mm
1.1
0.15
0.05
0.95
0.80
0.25
0.45
0.25
0.28
0.15
3.1
2.9
3.1
2.9
0.65
5.1
4.7
0.94
0.7
0.4
0.1
0.1
0.1
0.70
0.35
6°
0°
Notes
1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.
2. Plastic or metal protrusions of 0.25 mm maximum per side are not included.
OUTLINE
VERSION
REFERENCES
IEC
JEDEC
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
99-04-09
03-02-18
SOT505-1
Fig 24. Package outline SOT505-1 (TSSOP8)
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
19 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
HVSON8: plastic thermal enhanced very thin small outline package; no leads;
8 terminals; body 3 x 3 x 0.85 mm
SOT908-1
0
1
2 mm
scale
X
B
D
A
E
A
A1
c
detail X
terminal 1
index area
e1
terminal 1
index area
e
v
w
b
1
4
M
M
C
C A B
C
y1 C
y
L
exposed tie bar (4×)
Eh
exposed tie bar (4×)
8
5
Dh
DIMENSIONS (mm are the original dimensions)
UNIT
A(1)
max.
A1
b
c
D(1)
Dh
E(1)
Eh
e
e1
L
v
w
y
y1
mm
1
0.05
0.00
0.3
0.2
0.2
3.1
2.9
2.25
1.95
3.1
2.9
1.65
1.35
0.5
1.5
0.5
0.3
0.1
0.05
0.05
0.1
Note
1. Plastic or metal protrusions of 0.075 mm maximum per side are not included.
OUTLINE
VERSION
SOT908-1
REFERENCES
IEC
JEDEC
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
05-09-26
05-10-05
MO-229
Fig 25. Package outline SOT908-1 (HVSON8)
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
20 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
14. Handling information
Inputs and outputs are protected against electrostatic discharge in normal handling.
However, to be completely safe you must take normal precautions appropriate to handling
integrated circuits.
15. 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”.
15.1 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.
15.2 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
15.3 Wave soldering
Key characteristics in wave soldering are:
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
21 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
• 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
15.4 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 26) 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 15 and 16
Table 15.
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 16.
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 26.
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
22 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
maximum peak temperature
= MSL limit, damage level
temperature
minimum peak temperature
= minimum soldering temperature
peak
temperature
time
001aac844
MSL: Moisture Sensitivity Level
Fig 26. Temperature profiles for large and small components
For further information on temperature profiles, refer to Application Note AN10365
“Surface mount reflow soldering description”.
16. Abbreviations
Table 17.
Abbreviations
Acronym
Description
AI
Auto-Increment
CDM
Charged Device Model
DSP
Digital Signal Processor
DUT
Device Under Test
ESD
ElectroStatic Discharge
GPIO
General Purpose Input/Output
HBM
Human Body Model
I2C-bus
Inter IC bus
I/O
Input/Output
IC
Integrated Circuit
LED
Light Emitting Diode
MCU
MicroController Unit
MM
Machine Model
MPU
MicroProcessor Unit
POR
Power-On Reset
PWM
Pulse Width Modulation
RC
Resistor-Capacitor network
SMBus
System Management Bus
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
23 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
17. Revision history
Table 18.
Revision history
Document ID
Release date
Data sheet status
Change notice
PCA9550_5
20081013
Product data sheet
-
Modifications:
Supersedes
PCA9550_4
•
Section 8.1 “Minimizing IDD when the I/Os are used to control LEDs”,
paragraph,
3rd sentence changed from “The supply current, IDD, increases as VI becomes lower than
VDD and is specified as ∆IDD in Table 13 “Static characteristics”.” to “The supply current, IDD,
increases as VI becomes lower than VDD.”
•
•
Table 13 “Static characteristics”, sub-section “Supplies”: removed ∆IDD characteristic
1st
Table 13 “Static characteristics”, sub-section “I/Os”, symbol IOL, LOW-level output current:
– condition VOL = 0.4 V; VDD = 2.3 V: changed Min value from “9 mA” to “6 mA”;
changed Typ value from “-” to “9 mA”
– condition VOL = 0.4 V; VDD = 3.0 V: changed Min value from “11 mA” to “8 mA”;
changed Typ value from “-” to “11 mA”
– condition VOL = 0.4 V; VDD = 5.0 V: changed Min value from “14 mA” to “10 mA”;
changed Typ value from “-” to “14 mA”
– condition VOL = 0.7 V; VDD = 2.3 V: changed Min value from “14 mA” to “11 mA”;
changed Typ value from “-” to “14 mA”
– condition VOL = 0.7 V; VDD = 3.0 V: changed Min value from “18 mA” to “14 mA”;
changed Typ value from “-” to “18 mA”
– condition VOL = 0.7 V; VDD = 5.0 V: changed Min value from “24 mA” to “17 mA”;
changed Typ value from “-” to “24 mA”
•
updated soldering information
PCA9550_4
20080107
Product data sheet
-
PCA9550_3
PCA9550_3
(9397 750 13719)
20041001
Product data sheet
-
PCA9550_2
PCA9550_2
(9397 750 11461)
20030502
Product data
ECN 853-2396 29859 of PCA9550_1
24 Apr 2003
PCA9550_1
(9397 750 10857)
20021213
Product data
ECN 853-2396 29264 of 09 Dec 2002
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
24 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
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.
18.3 Disclaimers
General — 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.
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 — NXP Semiconductors products are not designed,
authorized or warranted to be 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.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) may cause permanent
damage to the device. Limiting values are stress ratings only and operation of
the device at these or any other conditions above those given in the
Characteristics sections of this document is not implied. Exposure to limiting
values for extended periods may affect device reliability.
Terms and conditions of 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, including those pertaining to warranty,
intellectual property rights infringement and limitation of liability, unless
explicitly otherwise agreed to in writing by NXP Semiconductors. In case of
any inconsistency or conflict between information in this document and such
terms and conditions, the latter will prevail.
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.
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]
PCA9550_5
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 05 — 13 October 2008
25 of 26
PCA9550
NXP Semiconductors
2-bit I2C-bus LED driver with programmable blink rates
20. Contents
1
2
3
3.1
4
5
5.1
5.2
6
6.1
6.2
6.2.1
6.3
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
6.3.6
6.4
6.5
6.6
7
7.1
7.1.1
7.2
7.3
7.4
8
8.1
8.2
9
10
11
12
13
14
15
15.1
15.2
15.3
15.4
16
17
General description . . . . . . . . . . . . . . . . . . . . . . 1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Ordering information . . . . . . . . . . . . . . . . . . . . . 2
Ordering options . . . . . . . . . . . . . . . . . . . . . . . . 2
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Pinning information . . . . . . . . . . . . . . . . . . . . . . 3
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 3
Functional description . . . . . . . . . . . . . . . . . . . 4
Device address . . . . . . . . . . . . . . . . . . . . . . . . . 4
Control register . . . . . . . . . . . . . . . . . . . . . . . . . 4
Control register definition . . . . . . . . . . . . . . . . . 5
Register descriptions . . . . . . . . . . . . . . . . . . . . 5
INPUT - Input register. . . . . . . . . . . . . . . . . . . . 5
PSC0 - Frequency Prescaler 0 . . . . . . . . . . . . . 5
PWM0 - Pulse Width Modulation 0 . . . . . . . . . . 5
PSC1 - Frequency Prescaler 1 . . . . . . . . . . . . . 6
PWM1 - Pulse Width Modulation 1 . . . . . . . . . . 6
LS0 - LED selector . . . . . . . . . . . . . . . . . . . . . . 6
Pins used as GPIOs . . . . . . . . . . . . . . . . . . . . . 7
Power-on reset . . . . . . . . . . . . . . . . . . . . . . . . . 7
External RESET . . . . . . . . . . . . . . . . . . . . . . . . 7
Characteristics of the I2C-bus. . . . . . . . . . . . . . 8
Bit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
START and STOP conditions . . . . . . . . . . . . . . 8
System configuration . . . . . . . . . . . . . . . . . . . . 8
Acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Bus transactions . . . . . . . . . . . . . . . . . . . . . . . 10
Application design-in information . . . . . . . . . 11
Minimizing IDD when the I/Os are used
to control LEDs . . . . . . . . . . . . . . . . . . . . . . . . 11
Programming example . . . . . . . . . . . . . . . . . . 12
Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 12
Static characteristics. . . . . . . . . . . . . . . . . . . . 13
Dynamic characteristics . . . . . . . . . . . . . . . . . 15
Test information . . . . . . . . . . . . . . . . . . . . . . . . 17
Package outline . . . . . . . . . . . . . . . . . . . . . . . . 18
Handling information. . . . . . . . . . . . . . . . . . . . 21
Soldering of SMD packages . . . . . . . . . . . . . . 21
Introduction to soldering . . . . . . . . . . . . . . . . . 21
Wave and reflow soldering . . . . . . . . . . . . . . . 21
Wave soldering . . . . . . . . . . . . . . . . . . . . . . . . 21
Reflow soldering . . . . . . . . . . . . . . . . . . . . . . . 22
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Revision history . . . . . . . . . . . . . . . . . . . . . . . . 24
18
18.1
18.2
18.3
18.4
19
20
Legal information . . . . . . . . . . . . . . . . . . . . . .
Data sheet status . . . . . . . . . . . . . . . . . . . . . .
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disclaimers. . . . . . . . . . . . . . . . . . . . . . . . . . .
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . .
Contact information . . . . . . . . . . . . . . . . . . . .
Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
25
25
25
25
25
26
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. 2008.
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: 13 October 2008
Document identifier: PCA9550_5
Similar pages