PCA9922_11 Datasheet, PDF (1/27 Pages) NXP Semiconductors – 8-channel constant current LED driver with output error detection

PCA9922
8-channel constant current LED driver with output error
detection
Rev. 2 — 6 April 2011
Product data sheet
1. General description
The PCA9922 is an 8-channel constant current LED driver designed for LED signage and
display applications. The output current is adjustable from 15 mA to 60 mA controlled by
an external series resistor. The outputs are controlled via a serial interface with a
maximum clock frequency of 25 MHz to allow for the system requirement of high volume
data transmission. Each of the 8 channel outputs has edge rate control to limit the change
in current when the outputs are enabled or disabled.
The device has built-in circuitry for detecting LED open-circuit and output short to ground.
After signaling the specified error detect sequence on the input control lines, error status
can be read out of the device via the serial data out.
The device is designed such that it may be cascaded with other similar devices. The SDO
pin contains the output of the shift register which may be used for cascading to the SDI pin
of the next device in the series. SDO changes state on the falling edge of CLK. SDI
captures data on the rising edge of CLK.
The PCA9922 is a pin-to-pin functionally equivalent 5 V alternative (exception: error data
is inverted; see Section 7.2.1, Section 7.2.2 and Section 7.2.7) for the ST2221A and
STP08CDC596.
The PCA9922 is available in DIP16, TSSOP16 and HVQFN20 packages and is specified
over the −40 °C to +85 °C industrial temperature range.
2. Features and benefits
„ 25 MHz serial interface
„ 3.3 V to 5.5 V operation
„ 8 LED low side constant current outputs
„ Global control for the 8 LED outputs variable between 15 mA to 60 mA
„ 15 mA to 60 mA maximum current for all 8 output channels set by an external resistor
„ Constant current matching at 25 °C, V_DD = 5.0 V
„ Bit-to-bit: ±6 %
„ Chip-to-chip: ±10 %
„ Gradual turn-on/turn-off output to limit EMI
„ Error detection mode for line open, output short to ground, LED open and LED short
„ −40 °C to +85 °C operation
„ ESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per
JESD22-A115, and 1000 V CDM per JESD22-C101
„ Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA