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DETAILED DESCRIPTION

TPL9202

8-CHANNEL RELAY DRIVER

WITH INTEGRATED 5-V LDO AND BROWN-OUT DETECTION

SLIS124D – JUNE 2006 – REVISED FEBRUARY 2008

The 5-V regulator is powered from VIN, and the regulated output is within 5 V ± 5% over the operating conditions.

The open-drain power-on reset (RST) pin remains low until the regulator exceeds the set threshold, and the timer

value set by the capacitor on the reset delay (RDELAY) pin expires. If both of these conditions are satisfied, RST is

asserted high. This signifies to the microcontroller that serial communications can be initiated to the TPL9202.

The serial communications is an 8-bit format, with data transfer synchronized using a serial clock from the

microcontroller. A single register controls all the outputs (one bit per output). The default value is zero (OFF). If

an output requires pulse width modulation (PWM) function, the register must be updated at a rate faster than the

desired PWM frequency. OUT1 can be controlled by serial input from the microcontroller or with the dedicated

enable (EN1) pin. If EN1 is pulled low or left open, the serial input through the shift register controls OUT1. If

EN1 is pulled high, OUT1 always is turned on, and the serial input for OUT1 is ignored.

The brown-out (BO) input is a resistor divided from the input supply and is used to determine if the supply

voltage drops to undesired levels. If the input drops below the programmed value, BO_OUTZ is pulled low, and

all outputs are disabled. Once the input supply line returns to the minimum desired level, the outputs are enabled

to the previous programmed states.

If RST is asserted, all outputs are turned OFF internally, and the input register is reset to all zeroes. The

microcontroller must write to the register to turn the outputs ON again.

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Product Folder Link(s): TPL9202