RT7275/76
9
DS7275/76-04 April 2017 www.richtek.com
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Copyright 2017 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
Pin No.
Pin Name Pin Function
TSSOP-14
(Exposed Pad)
WDFN-10L 3x3
1 -- VOUT
Optional output voltage discharge connection. This open drain
output connects to ground when the device is disabled. If output
voltage discharge is desired, connect VOUT to the output
voltage.
2 2 FB
Feedback input voltage. Connect FB to the midpoint of the
external feedback resistive divider to sense the output voltage.
Place the resistive divider within 5mm from the FB pin. The IC
regulates V
FB
at 0.765V (typical).
3 3 PVCC
Linear regulator output. PVCC is the output of the internal 5.1V
linear regulator powered by VIN (WDFN-10L 3x3) or VINR
(TSSOP-14 (Exposed Pad)). Connect a 1F ceramic capacitor
from PVCC to ground.
4 4 SS
Soft-start control. Connect an external capacitor between this
pin and ground to set the soft-start time.
5 -- GND Analog ground.
6 5 PGOOD
Open drain power-good output. PGOOD connects to PGND
whenever V
FB
is less than 90% of its regulation threshold
(typical).
7 1 EN
Enable control input. Connect EN to a logic-high voltage to
enable the IC or to a logic-low voltage to disable. Do not leave
this high impedance input unconnected.
8, 9, 15
(Exposed pad)
11 (Exposed pad) PGND
Power ground. PGND connects to the Source of the internal
N-channel MOSFET synchronous rectifier and to other power
ground nodes of the IC. The exposed pad and the 2 PGND pins
(TSSOP-14 (Exposed Pad)) should be well soldered to the
input and output capacitors and to a large PCB area for good
power dissipation.
10, 11 6, 7 SW
Switching node. SW is the Source of the internal N-channel
MOSFET switch and the Drain of the internal N-channel
MOSFET synchronous rectifier. Connect SW to the inductor
with a wide short PCB trace and minimize its area to reduce
EMI.
12 8 BOOT
Bootstrap supply for high-side gate driver. Connect a 0.1F
capacitor between BOOT and SW to power the internal gate
driver.
13 9, 10 VIN
Power input. VIN is the Drain of the internal N-channel
MOSFET switch. Connect VIN to the input capacitor. For the
WDFN-10L 3x3 package, VIN also supplies power to the
internal linear regulator.
14 -- VINR
Internal linear regulator supply input. For the TSSOP-14
(Exposed Pad) package, VINR supplies power for the internal
linear regulator that powers the IC. Connect VIN to the input
voltage and bypass to ground with a 0.1F ceramic capacitor.
Functional Pin Description
