PCA9634
8-bit Fm+ I
2
C-bus LED driver
Rev. 04 — 5 January 2007
Product data sheet
1. General description
The PCA9634 is an I
2
C-bus controlled 8-bit LED driver optimized for
Red/Green/Blue/Amber (RGBA) color mixing applications. Each LED output has its own
8-bit resolution (256 steps) fixed frequency Individual PWM controller that operates at
97 kHz with a duty cycle that is adjustable from 0 % to 99.6 % 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 190 Hz and an adjustable frequency between
24 Hz to once every 10.73 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 LED output driver is
programmed to be either open-drain with a 25 mA current sink capability at 5 V or
totem-pole with a 25 mA sink, 10 mA source capability at 5 V. The PCA9634 operates with
a supply voltage range of 2.3 V to 5.5 V and the outputs are 5.5 V tolerant. LEDs can be
directly connected to the LED output (up to 25 mA, 5.5 V) or controlled with external
drivers and a minimum amount of discrete components for larger current or higher voltage
LEDs.
The PCA9634 is one of the first LED controller devices in a new Fast-mode Plus (Fm+)
family. Fm+ devices offer higher frequency (up to 1 MHz) and more densely populated bus
operation (up to 4000 pF).
The active LOW Output Enable input pin (OE) allows asynchronous control of the LED
outputs and can be used to set all the outputs to a defined I
2
C-bus programmable logic
state. The OE can also be used to externally PWM the outputs, which is useful when
multiple devices need to be dimmed or blinked together using software control.
Software programmable LED Group and three Sub Call I
2
C-bus addresses allow all or
defined groups of PCA9634 devices to respond to a common I
2
C-bus address, allowing
for example, all red LEDs to be turned on or off at the same time or marquee chasing
effect, thus minimizing I
2
C-bus commands. Seven hardware address pins allow up to
126 devices on the same bus.
The Software Reset (SWRST) Call allows the master to perform a reset of the PCA9634
through the I
2
C-bus, identical to the Power-On Reset (POR) that initializes the registers to
their default state causing the outputs to be set HIGH (LED off). This allows an easy and
quick way to reconfigure all device registers to the same condition.
NXP Semiconductors
PCA9634
8-bit Fm+ I
2
C-bus LED driver
2. Features
I
8 LED drivers. Each output programmable at:
N
Off
N
On
N
Programmable LED brightness
N
Programmable group dimming/blinking mixed with individual LED brightness
I
1 MHz Fast-mode Plus compatible I
2
C-bus interface with 30 mA high drive capability
on SDA output for driving high capacitive buses
I
256-step (8-bit) linear programmable brightness per LED output varying from fully off
(default) to maximum brightness using a 97 kHz PWM signal
I
256-step group brightness control allows general dimming (using a 190 Hz PWM
signal) from fully off to maximum brightness (default)
I
256-step group blinking with frequency programmable from 24 Hz to 10.73 s and duty
cycle from 0 % to 99.6 %
I
Eight totem-pole outputs (sink 25 mA and source 10 mA at 5 V) with software
programmable open-drain LED outputs selection (default at totem-pole). No input
function.
I
Output state change programmable on the Acknowledge or the STOP Command to
update outputs byte-by-byte or all at the same time (default to ‘Change on STOP’).
I
Active LOW Output Enable (OE) input pin. LED outputs programmable to ‘1’, ‘0’ or
‘high-impedance’ (default at power-up) when OE is HIGH, thus allowing hardware
blinking and dimming of the LEDs.
I
7 hardware address pins allow 126 devices to be connected to the same I
2
C-bus
I
4 software programmable I
2
C-bus addresses (one LED Group Call address and three
LED Sub Call addresses) allow groups of devices to be addressed at the same time in
any combination (for example, one register used for ‘All Call’ so that all the PCA9634s
on the I
2
C-bus can be addressed at the same time and the second register used for
three different addresses so that
1
⁄
3
of all devices on the bus can be addressed at the
same time in a group). Software enable and disable for I
2
C-bus address.
I
Software Reset feature (SWRST Call) allows the device to be reset through the
I
2
C-bus
I
Up to 126 possible hardware adjustable individual I
2
C-bus addresses per device so
that each device can be programmed individually.
I
25 MHz internal oscillator requires no external components
I
Internal power-on reset
I
Noise filter on SDA/SCL inputs
I
Edge rate control on outputs
I
No glitch on power-up
I
Supports hot insertion
I
Low standby current
I
Operating power supply voltage range of 2.3 V to 5.5 V
I
5.5 V tolerant inputs
I
−40 °C
to +85
°C
operation
I
ESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per
JESD22-A115, and 1000 V CDM per JESD22-C101
I
Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
PCA9634_4
© NXP B.V. 2007. All rights reserved.
Product data sheet
Rev. 04 — 5 January 2007
2 of 37
NXP Semiconductors
PCA9634
8-bit Fm+ I
2
C-bus LED driver
I
Packages offered: SO20, TSSOP20, HVQFN20
3. Applications
I
I
I
I
I
RGB or RGBA LED drivers
LED status information
LED displays
LCD backlights
Keypad backlights for cellular phones or handheld devices
4. Ordering information
Table 1.
Ordering information
Topside
mark
Package
Name
TSSOP20
HVQFN20
Description
plastic small outline package; 20 leads; body width 7.5 mm
plastic thin shrink small outline package; 20 leads;
body width 4.4 mm
Version
SOT163-1
SOT360-1
Type number
PCA9634D
PCA9634PW
PCA9634BS
PCA9634D SO20
PCA9634
9634
plastic thermal enhanced very thin quad flat package; no leads; SOT662-1
20 terminals; body 5
×
5
×
0.85 mm
PCA9634_4
© NXP B.V. 2007. All rights reserved.
Product data sheet
Rev. 04 — 5 January 2007
3 of 37
NXP Semiconductors
PCA9634
8-bit Fm+ I
2
C-bus LED driver
5. Block diagram
A0
A1
A2
A3
A4
A5
A6
PCA9634
SCL
SDA
I
2
C-BUS
CONTROL
V
DD
V
SS
LED
STATE
SELECT
REGISTER
PWM
REGISTER X
BRIGHTNESS
CONTROL
POWER-ON
RESET
INPUT FILTER
V
DD
LEDn
97 kHz
25 MHz
OSCILLATOR
24.3 kHz
GRPFREQ
REGISTER
MUX/
CONTROL
GRPPWM
REGISTER
'0' – permanently OFF
'1' – permanently ON
190 Hz
OE
002aac135
Remark:
Only one LED output shown for clarity.
Fig 1. Block diagram of PCA9634
PCA9634_4
© NXP B.V. 2007. All rights reserved.
Product data sheet
Rev. 04 — 5 January 2007
4 of 37
NXP Semiconductors
PCA9634
8-bit Fm+ I
2
C-bus LED driver
6. Pinning information
6.1 Pinning
A0
A1
A2
A3
A4
LED0
LED1
LED2
LED3
1
2
3
4
5
6
7
8
9
20 V
DD
19 SDA
18 SCL
17 A6
16 A5
15 OE
14 LED7
13 LED6
12 LED5
11 LED4
002aac131
A0
A1
A2
A3
A4
LED0
LED1
LED2
LED3
1
2
3
4
5
6
7
8
9
20 V
DD
19 SDA
18 SCL
17 A6
16 A5
15 OE
14 LED7
13 LED6
12 LED5
11 LED4
002aac132
PCA9634D
PCA9634PW
V
SS
10
V
SS
10
Fig 2. Pin configuration for SO20
20 A1
19 A0
terminal 1
index area
Fig 3. Pin configuration for TSSOP20
17 SDA
16 SCL
15 A6
14 A5
13 OE
12 LED7
11 LED6
LED5 10
6
7
8
V
SS
9
LED4
18 V
DD
A2
A3
A4
LED0
LED1
1
2
3
4
5
PCA9634BS
LED2
LED3
002aac133
Transparent top view
Fig 4. Pin configuration for HVQFN20
6.2 Pin description
Table 2.
Symbol
A0
A1
A2
A3
A4
LED0
LED1
LED2
LED3
PCA9634_4
Pin description for SO20 and TSSOP20
Pin
1
2
3
4
5
6
7
8
9
Type
I
I
I
I
I
O
O
O
O
Description
address input 0
address input 1
address input 2
address input 3
address input 4
LED driver 0
LED driver 1
LED driver 2
LED driver 3
© NXP B.V. 2007. All rights reserved.
Product data sheet
Rev. 04 — 5 January 2007
5 of 37
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