TPS7A6550-Q1_15 Datasheet, PDF (9/18 Pages) Texas Instruments – 300-mA 40-V LOW-DROPOUT REGULATOR WITH 25-μA QUIESCENT CURRENT

www.ti.com
Undervoltage Shutdown
These devices have an integrated undervoltage
lockout (UVLO) circuit to shut down the output if the
input voltage (V_IN) falls below an internally fixed
UVLO threshold level (V_IN-UVLO) as shown in Figure 7.
This ensures that the regulator does not latch into an
unknown state during low input-voltage conditions.
The regulator normally powers up when the input
voltage exceeds the V_IN(POWERUP) threshold.
Low-Voltage Tracking
At low input voltages, the regulator drops out of
regulation, and the output voltage tracks input minus
a voltage based on the load current (I_OUT) and switch
resistance (R_SW) as shown in Figure 7. This allows for
a smaller input capacitor and can possibly eliminate
the need of using a boost convertor during cold crank
conditions.
TPS7A6533-Q1
TPS7A6550-Q1
SLVSA98C – MAY 2010 – REVISED JULY 2012
Integrated Fault Protection
These devices feature integrated fault protection to
make them ideal for use in automotive applications.
In order to keep them in a safe area of operation
during certain fault conditions, they use internal
current-limit protection and current-limit foldback to
limit the maximum output current. This protects them
from excessive power dissipation. For example,
during a short-circuit condition on the output; limiting
current through the pass element to I_CL protects the
device from excessive power dissipation.
Thermal Shutdown
These devices incorporate a thermal shutdown (TSD)
circuit as a protection from overheating. For
continuous normal operation, the junction
temperature should not exceed the TSD trip point. If
the junction temperature exceeds the TSD trip point,
the output turns off. When the junction temperature
falls below the TSD trip point, the output turns on
again. Figure 8 shows this.
0
5V or 3.3V
VIN-UVLO
VIN
VOUT
0
Tracking
Figure 7. Undervoltage Shutdown and Low-
Voltage Tracking
Figure 8. Thermal Cycling Waveform for
TPS7A6550-Q1 (V_IN = 24 V, I_OUT = 300 mA, V_OUT = 5
V)
Copyright © 2010–2012, Texas Instruments Incorporated
Submit Documentation Feedback
9
Product Folder Link(s): TPS7A6533-Q1 TPS7A6550-Q1