Datasheet

8
7
6
5
4
3
2
1
FB
VIN
Exposed Pad on Bottom
Connect to Ground
VCC
RT/SD
SW
BST
RCL
RTN
1
2
3
4 5
8
7
6
FB
VIN
VCC
RT/SD
SW
BST
RCL
RTN
SM72485
SNVS697D –JANUARY 2011–REVISED APRIL 2013 www.ti.com
Connection Diagram
Figure 1. Top View Figure 2. Top View
8-Lead WSON 8-Lead VSSOP
PIN DESCIPTIONS
Pin Name Description Application Information
1 SW Switching Node Power switching node. Connect to the output inductor, re-circulating diode, and
bootstrap capacitor.
2 BST Boost Pin (Boot–strap capacitor An external capacitor is required between the BST and the SW pins. A 0.01 µF
input) ceramic capacitor is recommended. An internal diode charges the capacitor from
V
CC
during each off-time.
3 RCL Current Limit OFF time set pin A resistor between this pin and RTN sets the off-time when current limit is
detected. The off-time is preset to 35 µs if FB = 0V.
4 RTN Ground pin Ground for the entire circuit.
5 FB Feedback input from Regulated This pin is connected to the inverting input of the internal regulation comparator.
Output The regulation threshold is 2.5V.
6 RT/SD On time set pin A resistor between this pin and VIN sets the switch on time as a function of V
IN
.
The minimum recommended on time is 400 ns at the maximum input voltage.
This pin can be used for remote shutdown.
7 VCC Output from the internal high This regulated voltage provides gate drive power for the internal Buck switch. An
voltage series pass regulator. internal diode is provided between this pin and the BST pin. A local 0.47 µF
decoupling capacitor is required. The series pass regulator is current limited to 9
mA.
8 VIN Input voltage Input operating range: 6V to 95V.
EP Exposed Pad The exposed pad has no electrical contact. Connect to system ground plane for
reduced thermal resistance.
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