DS8817A Datasheet, PDF (2/21 Pages) Richtek Technology Corporation – Dual-Phase PWM Controller with PWM-VID Reference

RT8817A
Functional Pin Description
Pin No.
1
Pin Name
Pin Function
BOOT1
Bootstrap supply for PWM 1. This pin powers the high-side MOSFET driver.
2
UGATE1
High-side gate driver of PWM 1. This pin provides the gate drive for the converter's
high-side MOSFET. Connect this pin to the Gate of high-side MOSFET.
3
EN
Enable control input. Active high input. When PVCC POR, the input voltage must
not be over PVCC.
4
PSI
Power saving interface. When the voltage is pulled below 0.4V, the device will
operate into 1 phase DEM. When the voltage is between 0.7V to 0.88V, the device
will operate into 1 phase force CCM. When the voltage is between 1.08V to 1.35V,
the device will operate into 2 phase DEM. When the voltage is between 1.6V to
5.5V, the device will operate into 2 phase force CCM.
5
VID
Programming output voltage control input. Refer to PWM-VID Dynamic Voltage
Control.
6
REFADJ
Reference adjustment output. Refer to PWM-VID Dynamic Voltage Control.
7
REFIN
External reference input.
8
VREF
Reference voltage output. This is a high precision voltage reference (2V) from the
VREF pin to RGND pin.
9
TON
On-time/switching frequency adjustment input. Connect a 100pF ceramic
capacitor between CTON and ground is optional for noise immunity enhancement.
10
RGND
Negative remote sense Input. Connect this pin to the ground of output load.
11
VSNS
Positive remote sense Input. Connect this pin to the positive terminal of output
load.
Current limit setting. Connect a resistor from OCSET/SS to GND to set the current
12
OCSET/SS limit threshold. The external soft start time also can be set through by connecting a
capacitor from OCSET/SS pin to GND.
13, 14, 15, 22 NC
No internal connection.
16
PGOOD
17
UGATE2
18
BOOT2
19
PHASE2
20
LGATE2
21
PVCC
23
LGATE1
24
PHASE1
25
(Exposed Pad)
GND
Power good indicator output. Active high open-drain output.
High-side gate driver of PWM 2. This pin provides the gate drive for the converter's
high-side MOSFET. Connect this pin to the gate of high-side MOSFET.
Bootstrap supply for PWM 2. This pin powers the high-side MOSFET driver.
Switch node for PWM2. This pin is return node of the high-side driver of PWM 2.
Connect this pin to the Source of high-side MOSFET together with the drain of
low-side MOSFET and the inductor.
Low-side gate driver of PWM 2. This pin provides the gate drive for the converter's
low-side MOSFET. Connect this pin to the gate of low-side MOSFET.
Supply voltage input. Connect this pin to a 5V bias supply. Place a high quality
bypass capacitor from this pin to GND.
Low-side gate driver of PWM 1. This pin provides the gate drive for the converter's
low-side MOSFET. Connect this pin to the gate of low-side MOSFET.
Switch node for PWM1. This pin is return node of the high-side driver of PWM 1.
Connect this pin to the Source of high-side MOSFET together with the drain of
low-side MOSFET and the inductor.
Ground. The Exposed pad should be soldered to a large PCB and connected to
GND for maximum thermal dissipation.
Copyright ©2016 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8817A-00 September 2016