General description
PCA9959 is a daisy-chain SPI-compatible 4-wire serial bus controlled 24-channel
constant preset current LED driver, optimized for dimming and blinking 63 mA Red/
Green/Blue/Amber (RGBA) LEDs.
Each LED output has its own 6-bit resolution (64 steps) preset current configuration, with
an absolute accuracy of ±8 %.
PCA9959 supports up to four groups of LED gradation control, with each LED channel
assigned to one of the groups. For each group, PCA9959 supports 64-grid brightness
control, with the time duration of each grid adjustable from 2.5 μs to 1 ms. Each LED
output can be off or on, set at its individual preset current value within each grid. Once
gradation control is enabled, PCA9959 automatically changes each LED preset current
with the setup from grid0 to grid63; once finished, it can hold grid63 or repeat from grid0
as configured.
PCA9959 operates with a supply voltage range of 2.7 V to 5.5 V and the constant preset
current sink LED outputs allow up to 5.5 V for the LED supply.
This device has built-in open short load and overtemperature detection circuitry. The
error information from the corresponding register can be read via the 4-wire serial bus.
Additionally, a thermal shutdown feature protects the device when internal junction
temperature exceeds the limit allowed for the process.
The PCA9959 device is designed to use a 4-wire read/write serial bus with higher data
clock frequency (up to 10 MHz).
The OE pin can be used as a synchronization signal to switch on/off several PCA9959
devices at the same time.

Features and benefits
• 24 LED drivers, each output programmable at:
– Off
– On
– 6 bits programmable LED brightness
– Programmable LED output delay to reduce EMI and surge currents
• Gradation control for all channels
– Each channel can assign to one of four gradation control groups
– 64 grids for gradation control for each channel
– Programmable grid duration time
– Four preset current options for each channel during gradation control
• 24 constant preset current output channels can sink up to 63 mA, and tolerate up to
5.5 V when OFF
• Output preset current adjusted through an external resistor (REXT input)
• Output preset current accuracy
– ±8 % absolute accuracy with 60 mA output current
– ±6.5 % absolute accuracy with 30 mA output current
– Maximum ±5 % channel to channel variation
– Maximum ±7 % device to device variation
• Open/short load/overtemperature detection mode to detect individual LED errors
• 4-wire serial bus interface with 10 MHz data clock rate
• Active LOW Output Enable (OE) input pin
• Internal power-on reset
• No glitch on LEDn outputs on power-up
• Low standby preset current
• Operating power supply voltage (VDD) range of 2.7 V to 5.5 V
• 5.5 V tolerant inputs on non-LED pins
• -40 °C to +85 °C operation
• Latch-up performance exceeds 100 mA per JESD 78, Class II
• ESD protection exceeds 2 kV HBM per JESD22-A114
– 2000 V Human-Body Model (A114-A)
– 1000 V Charged-Device Model (C101)
• Available in HVQFN40 package