Datasheet
][Rx)
- 1
V
V
(=R
2F
FB
O
F1
:
LM4510
www.ti.com
SNVS533C –SEPTEMBER 2007–REVISED MAY 2013
ON/OFF CONTROL
The LM4510 shuts down when the EN pin is low. In this mode the feedback resistors and the load are
disconnected from the input in order to avoid leakage current flow and to allow the output voltage to drop to 0V.
The LM4510 turns on when EN is high. There is an internal pull-down resistor on the EN pin so the device is in a
normally off state.
SHORT CIRCUIT PROTECTION
When V
OUT
goes down to V
IN
–0.7V (typ.), the device stops switching due to the short-circuit protection circuitry
and the short-circuit output current is limited to I
INIT_CHARGE
.
FEEDBACK FAULT PROTECTION
The LM4510 features unique Feedback Fault Protection to maximize safety when the feedback resistor is not
properly connected to a circuit or the feedback node is shorted directly to ground.
Feedback fault triggers V
OUT
monitoring. During monitoring, if V
OUT
reaches a protection level, the device shuts
down. When the feedback network is reconnected and V
OUT
is lower than the OFF threshold level of Feedback
Fault Protection, V
OUT
monitoring stops. V
OUT
is then regulated by the control loop.
INPUT UNDER-VOLTAGE LOCK-OUT
The LM4510 has dedicated circuitry to protect the IC and the external components when the battery voltage is
lower than the preset threshold. This under-voltage lock-out with hysteresis prevents malfunctions during startup
or abnormal power off.
THERMAL SHUTDOWN
If the die temperature exceeds 150°C (typ.), the thermal protection circuitry shuts down the device. The switches
remain off until the die temperature is reduced to approximately 140°C (typ.).
Application Information
ADJUSTING OUTPUT VOLTAGE
The output voltage is set using the feedback pin and a resistor voltage divider (R
F1
, R
F2
) connected to the output
as shown in the Typical Application Circuit.
The ratio of the feedback resistors sets the output voltage.
R
F2
Selection
First of all choose a value for R
F2
generally between 10 kΩ and 25 kΩ.
R
F1
Selection
Calculate R
F1
using the following equation:
(1)
Table 1 gives suggested component values for several typical output voltages.
Copyright © 2007–2013, Texas Instruments Incorporated Submit Documentation Feedback 11
Product Folder Links: LM4510