900,000+ datasheet pdf search and download

Datasheet4U offers most rated semiconductors data sheet pdf




NXP Semiconductors Electronic Components Datasheet

PCA9957 Datasheet

24-channel SPI serial bus 32mA/5.5V constant current LED driver

No Preview Available !

PCA9957
24-channel SPI serial bus 32 mA/5.5 V constant current LED
driver
Rev. 1 — 24 October 2019
Product data sheet
1. General description
The PCA9957 is a daisy-chain SPI-compatible 4-wire serial bus controlled 24-channel
constant current LED driver optimized for dimming and blinking 32 mA
Red/Green/Blue/Amber (RGBA) LEDs.
Each LED output has its own 8-bit resolution (256 steps) fixed frequency individual PWM
controller that operates at 31.25 kHz with a duty cycle that is adjustable from 0 % to
100 % to allow the LED to be set to a specific brightness value. An additional 8-bit
resolution (256 steps) group PWM controller has both a fixed frequency of 122 Hz and an
adjustable frequency between 15 Hz to once every 16.8 seconds with a duty cycle that is
adjustable from 0 % to 99.6 % that is used to either dim or blink all LEDs with the same
value.
Each LED output can be off, on (no PWM control), set at its individual PWM controller
value or at both individual and group PWM controller values. The PCA9957 operates with
a supply voltage range of 2.7 V to 5.5 V and the constant current sink LED outputs allow
up to 5 V for the LED supply. The output peak current is adjustable with an 8-bit linear
DAC from 125 A to 31.875 mA with REXT = 2 k.
Gradation control for all current sources is achieved via the 4-wire serial bus interface and
allows user to ramp current automatically without MCU intervention. 8-bit DACs are
available to adjust brightness levels for each LED current source. There are six selectable
gradation control groups and each group has four independent registers to control
ramp-up and ramp-down rate, step time, hold ON/OFF time and final hold ON output
current. Two gradation operation modes are available for each group: single shot mode
(output pattern once) and continuous mode (output pattern repeat). Each channel can be
set to either gradation mode or normal mode and assigned to any one of these six
gradation control groups.
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 PCA9957 device is designed to use 4-wire read/write serial bus with higher data clock
frequency (up to 10 MHz).
The active LOW output enable input pin (OE) blinks all the LED outputs and can be used
to externally PWM the outputs, which is useful when multiple devices need to be dimmed
or blinked together without using software control.


NXP Semiconductors Electronic Components Datasheet

PCA9957 Datasheet

24-channel SPI serial bus 32mA/5.5V constant current LED driver

No Preview Available !

NXP Semiconductors
PCA9957
24-channel SPI serial bus 32 mA/5.5 V constant current LED driver
2. Features and benefits
24 LED drivers. Each output programmable at:
Off
On
8 bits programmable LED brightness
8 bits programmable group dimming/blinking mixed with individual LED brightness
Programmable LED output delay to reduce EMI and surge currents
Gradation control for all channels
Each channel can be assigned to one of six gradation control groups
Programmable gradation time and rate for ramp-up and/or ramp-down operations
Programmable step time (6-bit) from 0.5 ms (minimum) to 512 ms (maximum)
Programmable hold-on time after ramp-up and hold-off time after ramp-down (3-bit)
from 0 s to 6 s
Programmable final ramp-up and hold-on current
Programmable brightness current output adjustment, either linear or exponential
curve
24 constant current output channels can sink up to 32 mA, and tolerate up to 5.5 V
when OFF
Output current adjusted through an external resistor (REXT input)
Output current accuracy
6.5 % absolute accuracy with 30 mA output current
Maximum ±4 % channel to channel variation
Maximum ±6 % 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
256-step (8-bit) linear programmable brightness per LED output varying from fully off
(default) to maximum brightness fully ON using a 31.25 kHz PWM signal
256-step group brightness control allows general dimming (using a 122 Hz PWM
signal) from fully off to maximum brightness (default)
256-step group blinking with frequency programmable from 15 Hz to 16.8 s and duty
cycle from 0 % to 99.6 %
Active LOW Output Enable (OE) input pin allows for hardware blinking and dimming of
the LEDs
8 MHz internal oscillator requires no external components
Internal power-on reset
No glitch on LEDn outputs on power-up
Low standby 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 Human-Body Model (A114-A)
1 kV Charged-Device Model (C101)
PCA9957
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 24 October 2019
© NXP B.V. 2019. All rights reserved.
2 of 56


Part Number PCA9957
Description 24-channel SPI serial bus 32mA/5.5V constant current LED driver
Maker NXP
PDF Download

PCA9957 Datasheet PDF






Similar Datasheet

1 PCA9952 16-channel constant current LED driver
NXP
2 PCA9952-Q900 16-channel constant current LED driver
NXP
3 PCA9952Q900 16-channel constant current LED driver
NXP
4 PCA9955 16-channel constant current LED driver
NXP
5 PCA9955-Q900 16-channel constant current LED driver
NXP
6 PCA9955A 16-channel Fm+ I2C-bus 57 mA/20 V constant current LED driver
NXP
7 PCA9955Q900 16-channel constant current LED driver
NXP
8 PCA9956B LED driver
NXP
9 PCA9957 24-channel SPI serial bus 32mA/5.5V constant current LED driver
NXP





Part Number Start With

0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F    G    H    I    J    K    L    M    N    O    P    Q    R    S    T    U    V    W    X    Y    Z



Site map

Webmaste! click here

Contact us

Buy Components

Privacy Policy