Datasheet

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Power-Good
Manual Reset Pins ( MR1 and MR2)
Sense (V
SENSE1
, V
SENSE2
)
FB1 and FB2
RESET Indicator
V
IN1
and V
IN2
V
OUT1
and V
OUT2
TPS70745, TPS70748
TPS70751, TPS70758
TPS70702
SLVS291D – MAY 2000 – REVISED DECEMBER 2007
The PG1 is an open drain, active high output terminal that indicates the status of the V
OUT1
regulator. When the
V
OUT1
reaches 95% of its regulated voltage, PG1 goes to a high impedance state. It goes to a low impedance
state when it is pulled below 95% (for example, doing an overload condition) of its regulated voltage. The open
drain output of the PG1 terminal requires a pull-up resistor.
MR1 and MR2 are active low input terminals used to trigger a reset condition. When either MR1 or MR2 is pulled
to logic low, a POR ( RESET) occurs. These terminals have a 6- µ A pull-up current to V
IN1
.
The sense terminals of fixed-output options must be connected to the regulator output, and the connection
should be as short as possible. Internally, sense connects to high-impedance, wide-bandwidth amplifiers through
a resistor-divider network and noise pickup feeds through to the regulator output. It is essential to route the
sense connection in such a way to minimize or avoid noise pickup. Adding RC networks between the V
SENSE
terminals and V
OUT
terminals to filter noise is not recommended because these networks can cause the
regulators to oscillate.
FB1 and FB2 are input terminals used for adjustable-output devices and must be connected to the external
feedback resistor divider. FB1 and FB2 connections should be as short as possible. It is essential to route them
in such a way as to minimize or avoid noise pickup. Adding RC networks between the FB terminals and V
OUT
terminals to filter noise is not recommended because these networks can cause the regulators to oscillate.
The TPS707xx features a RESET (SVS, POR, or Power-On Reset). RESET can be used to drive power-on reset
circuitry or a low-battery indicator. RESET is an active low, open drain output that indicates the status of the
V
OUT2
regulator and both manual reset pins ( MR1 and MR2). When V
OUT2
exceeds 95% of its regulated voltage,
and MR1 and MR2 are in the high impedance state, RESET goes to a high-impedance state after 120ms delay.
RESET goes to a low-impedance state when V
OUT2
is pulled below 95% (for example, an overload condition) of
its regulated voltage. To monitor V
OUT1
, the PG1 output pin can be connected to MR1 or MR2. The open drain
output of the RESET terminal requires a pullup resistor. If RESET is not used, it can be left floating.
V
IN1
and V
IN2
are input to the regulators. Internal bias voltages are powered by V
IN1
.
V
OUT1
and V
OUT2
are output terminals of the LDO.
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