TCA6507_10 Datasheet, PDF (2/32 Pages) Texas Instruments – LOW-VOLTAGE 7-BIT I2C AND SMBus LED DRIVER WITH INTENSITY CONTROL AND SHUTDOWN

TCA6507
LOW-VOLTAGE 7-BIT I²C AND SMBus LED DRIVER
WITH INTENSITY CONTROL AND SHUTDOWN
SCPS164B – MAY 2007 – REVISED NOVEMBER 2007
www.ti.com
DESCRIPTION/ORDERING INFORMATION (CONTINUED)
T_A
–40°C to 85°C
ORDERING INFORMATION
PACKAGE ^{(1) (2)}
ORDERABLE PART NUMBER
BGA – ZXU (Pb-free) Reel of 2500
TCA6507ZXUR
QFN – RUE
Reel of 3000
TCA6507RUER
TSSOP – PW
Reel of 2000
TCA6507PWR
TOP-SIDE MARKING
PH507
2M
PH507
(1) Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
(2) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
website at www.ti.com.
This device can be used for driving LEDs and for general-purpose parallel output expansion. The TCA6507 has
three Select registers (Select0, Select1 and Select2), which can be used to configure each LED output into one
of seven different operating modes. At power on, the outputs are in high impedance.
When used to drive LEDs, the seven outputs can be configured into two banks of outputs (BANK0 and BANK1).
Each bank of outputs can be independently controlled for dimming rate and intensity through the I²C bus. The
dimming and blink rates are fully programmable. The intensity of each bank of LEDs is controlled by dynamically
varying the duty cycle of the signal, which has a period of approximately 8 ms and a pulse rate of 125 times per
second, driving the outputs. The TCA6507 has two independent dimming/blinking modules—PWM0 and
PWM1—driven by a single internal oscillator that supports these features. PWM0 determines the characteristics
of BANK0 and PWM1 determines the characteristics of BANK1.
The TCA6507 has a master intensity level known as the ambient light detection (ALD) value. The associated
pulse width modulation (PWM) signal for this value is PWMALD. The TCA6507 can be programmed such that
PWMALD overrides PWM0 or PWM1 so selected LEDs are on steadily at the master intensity level. Further, the
TCA6507 can be programmed such that the ALD value can override the maximum intensity values for PWM0
and PWM1. Thus, the ALD value can control the brightness of all LEDs whether they are on steadily or controlled
by one of the dimming modules. The ALD value is stored in the lower four bits of the One-Shot / Master Intensity
register.
When the I²C bus is idle, and intensity control is not used, the TCA6507 can be put into shutdown mode by
setting the enable (EN) pin low. This mode provides additional power savings, as it is a low-power mode where
the LEDs are off. A low signal on the EN pin also resets the registers and I²C/SMBus state machine in the
TCA6507 to their default state.
An initial setup command must be sent from the I²C master to the TCA6507 to program the dimming rate and
intensity (and intensity ramp if needed) for each bank of outputs. From then on, only one command from the bus
master is required to turn each individual output ON, OFF, or to cycle at the programmed dimming rate. The
default value for all time parameters is 256 ms so the default blink rate is approximately one per second.
The TCA6507 is optimized for 1.65 V to 3.6 V on the SDA/SCL side, but the LEDs can be driven by any voltage
up to 5.5 V. This allows the TCA6507 to interface with next-generation microprocessors and microcontrollers,
where supply levels are dropping down to conserve power.
This LED dimmer supports hot insertion.
ZXU PACKAGE TERMINAL ASSIGNMENTS
C
1
P1
2
P3
3
P4
4
P5
B
A
P2
GND
EN
SDA
P0
SCL
P6
V_CC
2
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