NR885E Datasheet, PDF (6/12 Pages) Sanken electric – Synchronous Buck Regulator

3A, 18V, 350kHz , Synchronous Buck Regulator
NR885E
Oct./30/2013
Functional Block Diagram
2 _５ IN
VIN
C1
C2
R1
7
ON/
３
EN
OFF
Σ
OSC
P.REG
VREF
0.8V
TSD
6
７
NC
UVLO
１
GND ⁴
Current
Sense
OCP
Drive
REG
PWM
LOGIC
Compensation
0.8V
Error Amp.
SS
１
SS ⁸
C9
1
６
BS _R3
C10
3
L1
VO
４
SW
R5
D1
C4
C5
R4
5
８
FB
R6
Pin Assignments & Functions
Pin Functions
Pin No. Symbol
1
BS
2
IN
3
SW
4
GND
5
FB
6
NC
7
EN
8
SS
Pin Assignments
Description
High-side Boost input.
BS supplies the drive for High-side Nch-MOSFET switch.
Connect a capacitor and a resistor between SW to BS.
Power input. IN supplies the power to the IC as well as the regulator switches
Power switching output.
SW supplies power to the output.
Connect the LC filter from SW to the output.
Note that a capacitor is required from SW to BS to supply the power the High-side
switch
Ground
Connect the exposed pad to Pin No.4
Feedback input Pin to compare Reference Voltage. The feedback threshold is 0.8V.
To set the output voltage, FB Pin is required to connect between resistive voltage divider
R4 and R6.
No Connection.
Enable input.
Drive EN Pin high to turn on the regulator, low to turn it off.
Soft-Start control input.
To set the soft-start period, connect to a capacitor between GND.
Rev.1.1
SANKEN ELECTRIC CO., LTD.
6
http://www.sanken-ele.co.jp