PCA9551 Philips Semiconductors, PCA9551 Datasheet - Page 10

• Manufacturer Part Number: PCA9551
• Description: 8-bit I2C LED driver with programmable blink rates
• Manufacturer: Philips Semiconductors

Philips Semiconductors
APPLICATION DATA
Minimizing I
When the I/Os are used to control LEDs, they are normally connected to V
diode, when the LED is off the I/O V
specified as I
Designs needing to minimize current consumption, such as battery power applications, should consider maintaining the I/O pins greater than or
equal to V
voltage by at least 1.2 V. Both of these methods maintain the I/O V
the LED is off.
2004 Oct 01
8-bit I
Figure 14. High value resistor in parallel with the LED
Note: LED0 to LED5 are used as LED drivers
I
DD
2
C/SMBus MASTER
LED6 and LED7 are used as regular GPIOs.
2
when the LED is off. Figure 14 shows a high value resistor in parallel with the LED. Figure 15 shows V
C LED driver with programmable blink rates
DD
5 V
DD
in the DC characteristics table.
when the I/O is used to control LEDs
V
DD
LEDx
SDA
SCL
LED
10 k
IN
is about 1.2 V less than V
100 k
10 k
V
DD
10 k
Figure 13. Typical application
RESET
A2
A1
A0
V
SW02086
SDA
SCL
SS
DD
PCA9551
IN
. The supply current, I
V
DD
at or above V
10
LED0
LED1
LED2
LED3
LED4
LED5
LED6
LED7
DD
through a resistor as shown in Figure 13. Since the LED acts as a
DD
Figure 15. Device supplied by a lower voltage
and prevents additional supply current consumption when
DD
, increases as V
V
3.3 V
5 V
DD
LEDx
IN
becomes lower than V
LED
DD
5 V
less than the LED supply
PCA9551
GPIO
Product data sheet
SW00899
DD
SW02087
and is