Datasheet
FB
V
IN
V
CC
SW
RTN
ON TIMER
DRIVER
V
IN
BST
LEVEL
SHIFT
SD/
R
ON
2.5V
THERMAL
SHUTDOWN
0.725A
BUCK
SWITCH
CURRENT
SENSE
COMPLETE
R
CL
START
R
CL
COMPLETE
START
Ron
100 PH
L1
C2
15 PF
R3
3.01k
R4
1k
R2
100k
R
ON
200k
C4
0.01 PF
C3
0.1 PF
12V -42V
10V
LM25007
UVLO
FB
R5
1
UVLO
REGULATION
COMPARATOR
OVER-VOLTAGE
COMPARATOR
2.875V
SD
SD
COMPLETE
START
MINIMUM OFF
TIMER
C1
1 PF
8
6
5
3
4
1
2
7
7V SERIES
REGULATOR
CURRENT LIMIT
OFF TIMER
SHUTDOWN
C5
0.1 PF,
100V
D1
Q
CLR
Q
SET
S
R
+
-
+
-
+
-
LM25007
www.ti.com
SNVS401C –JANUARY 2006–REVISED FEBRUARY 2013
Pin Descriptions
Pin Name Description Application Information
1 SW Switching Node Power switching node. Connect to the inductor, bootstrap capacitor, and free-wheeling
diode.
2 BST Boost Boot–strap An external capacitor is required between the BST and the SW pins. A 0.01µF ceramic
capacitor input capacitor is recommended.
3 RCL Current Limit OFF time A resistor between this pin and RTN sets the off-time when current limit is detected.
programming pin The off-time is preset to 17 µs if FB = 0V .
4 RTN Circuit Ground
5 FB Feedback Signal from This pin is connected to the inverting input of the internal regulation comparator. The
Regulated Output regulation threshold is 2.5V.
6 RON/SD On-time set pin A resistor between this pin and VIN sets the switch on-time as a function of Vin. The
minimum recommended on-time is 300ns at the maximum input voltage.
7 VCC Output from the internal If an auxiliary voltage is available to raise the voltage on this pin above the regulation
high voltage bias setpoint (7V), the internal series pass regulator will shutdown, reducing the IC power
regulator. dissipation. Do not exceed 14V. This output provides gate drive power for the internal
Buck switch. An internal diode is provided between this pin and the BST pin. A local
0.1uF decoupling capacitor is recommended.
8 VIN Input supply voltage Recommended operating range: 9V to 42V.
- EP Exposed pad, underside Exposed metal pad on the WSON package underside. It is recommended to connect
of the WSON package this pad to the PC board ground plane to aid in heat dissipation.
option
Typical Application Circuit and Block Diagram
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