PGND |
1, 20, 21,
22, 24, 25 |
G |
Power ground of internal low-side MOSFET |
SW |
2 |
O |
Output switching terminal of the power converter. No external
connection needed. Do not connect. |
VCC |
3 |
I/O |
Internal 4.5-V LDO output. Float or connect to an external power
supply between 4.75 V and 5.3 V to save the power losses on the
internal LDO. The voltage source on this pin powers both the
internal circuitry and gate driver. A 1-μF bypass capacitor is built
in. No external bypass capacitors are required. |
VIN |
4, 5, 16,
17, 23 |
P |
Power-supply input pins for the integrated power MOSFET pair and
the internal LDO. Place the decoupling input capacitors from the VIN
pins to PGND pins as close as possible. |
BOOT |
6 |
I/O |
Supply rail for the high-side gate driver. A boot capacitor is
integrated inside module. No external connection is needed. Do not
connect. |
MODE |
7 |
I |
The MODE pin sets Forced continuous-conduction mode (FCCM) or
Skip-mode operation. It also selects the operating frequency by
connecting a resistor from the MODE pin to AGND pin. ±1% tolerance
resistor is recommended. See Table 7-1 for details. |
AGND |
8,
14 |
G |
Ground pin. Reference point for the internal control
circuits |
TRIP |
9 |
I/O |
Current limit setting pin. Connect a resistor to AGND to set the
current limit trip point. ±1% tolerance resistor is highly
recommended. See Section 7.3.9 for details on the OCL setting. |
VOUT |
10,
11 |
O |
These pins are connected to the output terminal of inductor.
Connect these pins to output bypass capacitors. |
FB |
12 |
I |
Output voltage feedback input. A resistor divider from the
VOUT to VSNS– (tapped to FB pin) sets the output
voltage. |
VSNS– |
13 |
I |
The return connection for a remote voltage sensing configuration.
It is also used as ground for the internal reference. Short to AGND
for a single-end sense configuration. |
SS/REFIN |
15 |
I/O |
Dual-function pin. Soft-start function: Connecting a capacitor to
the VSNS– pin programs the soft-start time. Minimum soft-start time
(1.5 ms) is fixed internally. REFIN function: The device always
looks at the voltage on this SS/REFIN pin as the reference for the
control loop. The internal reference voltage can be overridden by an
external DC voltage source on this pin for tracking
application. |
EN |
18 |
I |
Enable pin. The enable pin turns the DC/DC switching converter on
or off. Floating the EN pin before start-up disables the converter.
The recommended operating condition for EN pin is maximum 5.5 V.
Do not connect the EN pin to the VIN pin
directly. |
PGOOD |
19 |
O |
Open-drain power-good status signal. When the FB voltage moves
outside the specified limits, PGOOD goes low after a 2-µs
delay. |