Datasheet

SW
BST
NC
NC
NC
NC
RTN
FB
SS
11
10
9
5
4
3
2
1
6
7 8
12
13
14
VCC
VIN
RON/SD
SGND
ISEN
SW
BST
RTN
VCC
FB
SS
VIN
10
9
8
7
6
5
4
3
2
1
RON/SD
SGND
ISEN
LM2694
SNVS444A –MAY 2006–REVISED APRIL 2013 www.ti.com
Connection Diagrams
Figure 1. 14-Lead TSSOP Package Figure 2. 10-Lead WSON Package
See Package Number PW0014A See Package Number DSC0010A
Pin Descriptions
PIN NUMBER
NAME DESCRIPTION APPLICATION INFORMATION
WSON-10 TSSOP-14
1 2 SW Switching Node Internally connected to the buck switch source.
Connect to the inductor, free-wheeling diode, and
bootstrap capacitor.
2 3 BST Boost pin for bootstrap capacitor Connect a 0.022 µF capacitor from SW to the BST
pin. The capacitor is charged from VCC via an
internal diode during the buck switch off-time.
3 4 ISEN Current sense During the buck switch off-time, the inductor current
flows through the internal sense resistor, and out of
the ISEN pin to the free-wheeling diode. The current
limit is nominally set at 0.62A.
4 5 SGND Current Sense Ground Re-circulating current flows into this pin to the current
sense resistor.
5 6 RTN Circuit Ground Ground return for all internal circuitry other than the
current sense resistor.
6 9 FB Voltage feedback input from the Input to both the regulation and over-voltage
regulated output comparators. The FB pin regulation level is 2.5V.
7 10 SS Softstart An internal current source charges the SS pin
capacitor to 2.5V to soft-start the reference input of
the regulation comparator.
8 11 RON/SD On-time control and shutdown An external resistor from VIN to the RON/SD pin sets
the buck switch on-time. Grounding this pin shuts
down the regulator.
9 12 VCC Output of the startup regulator The voltage at VCC is nominally regulated at 7V.
Connect a 0.1 µF, or larger capacitor from VCC to
ground, as close as possible to the pins. An external
voltage can be applied to this pin to reduce internal
dissipation. MOSFET body diodes clamp VCC to VIN
if V
CC
> V
IN
.
10 13 VIN Input supply voltage Nominal input range is 8V to 30V. Input bypass
capacitors should be located as close as possible to
the VIN pin and RTN pins.
1,7,8,14 NC No connection. No internal connection. Can be connected to ground
plane to improve heat dissipation.
EP EP Exposed Pad Exposed metal pad on the underside of the WSON
package. It is recommended to connect this pad to
the PC board ground plane to aid in heat dissipation.
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