Datasheet
0
0.02
0.04
0.06
0.08
0.1
0.12
0 200 400 600 800 1000 1200 1400 1600
I - Output Current - mA
O
Dropout Voltage - V
Operation
www.ti.com
4.3 Dropout Voltage, V
DO
TPS740xxDGK offers very low dropout performance and allows the device to be used in place of a dc/dc
converter and still achieve good efficiency. The V
IN
dropout voltage, V
IN
-V
OUT
, for the TPS740xxDGK is
specified to be a maximum of 300 mV at 1.5-A load for V
BIAS
= V
OUT
+ 2 V. The V
IN
dropout voltage
decreases as V
BIAS
increases.
Figure 4. Dropout Voltage, V
DO
, Measurement of TPS74001DGKEVM for V
BIAS
= 5 V, V
OUT
= 1.5 V
4.4 Enable/Shutdown, Fixed Voltage Version Only – TPS74012DGK
The EN pin is active high and enables the regulator. When V
EN
is above 1.1 V, the regulator turns on.
When V
EN
is below 0.4 V, the regulator turns off. The enable circuitry has hysteresis and deglitching to
help avoid on/off cycling as a result of small glitches in the V
EN
signal. V
EN
threshold is typically 0.8 V but
varies slightly with temperature and process variations. See the TPS740xx data sheet for more
information.
4.5 Internal Current Limit
TPS740xxDGK features an internal current-limit protection circuitry that is designed to protect against
overload conditions. The current limit responds in approximately 10 µs to reduce the current during a
short-circuit fault. The current-limit circuitry allows up to a maximum of 4 A before clamping the output
current. The resulting V
OUT
is 80% of V
OUT
, nominal. See the TPS740xx data sheet for more information.
4.6 Thermal Protection
TPS740xxDGK comes with a thermal protection circuit that disables the output of the IC when the junction
temperature rises to approximately 160°C. When the junction temperature cools down to approximately
140°C, the output circuitry is once again enabled. The thermal protection circuit may cycle on and off
depending on the power dissipation, thermal resistance, and ambient temperature of the EVM. See the
TPS740xx data sheet for more information.
6
TPS740xxDGKEVM-722 Evaluation Module SLVU475A–June 2011–Revised June 2011
Submit Documentation Feedback
Copyright © 2011, Texas Instruments Incorporated