SC420A
POWER MANAGEMENT
Pin Configuration
Ordering Information
Device (1)
Package
Temp Range (TJ)
Top View
(3)
SC420AIMLTRT
MLP-12
-40° to 125°C
Note:
(1) Only available in tape and reel packaging. A reel
contains 3000 devices.
12
10
11
9
8
7
1
2
BG
TG
BST
CO
(2) This device is ESD sensitive. Use of standard ESD
handling precautions is required.
VIN
3
CDELAY
(3) Lead Free package compliant with J-STD-020B.
Qualified to support maximum IR reflow temperature of
260oC for 30 seconds.
6
4
5
(MLP-12)
Pin Descriptions
Pin
#
Pin
Name
Pin Function
1
2
3
4
TG
BST
CO
Output gate drive for the switching (high-side) MOSFET.
Bootstrap pin. A capacitor is connected between BST and DRN pins to develop the floating bootstrap
voltage for the high-side MOSFET. The capacitor value is typically between 0.1µF and 1µF (ceramic).
Logic level PWM input signal to the SC420 supplied by external controller.
Input power (VBAT) to the DC/DC converter. Used as supply reference for internal Combi-Sense TM
circuitry. Connect as close as possible to Drain of TOP switching MOSFET.
VIN2
Active high logic level input signal. A logic High enables TG and BG switching. A low level disables
5
6
EN
outputs and reduces quiescent current to IQ
SD
Virtual Phase Node. Connect an RC between this pin and the output sense point to Enable Combi-
Sense TM operation.
VPN
The capacitance connected between this pin and GND sets the additional propagation delay for BG
7
8
CDELAY going low to TG going high. Total propagation delay =20ns + 1ns/pF. If no capacitor is connected, the
propragation delay = 20ns.
Input supply for the bottom drive and the Logic. A 1µF-10µF Ceramic Capacitor must be connected
VIN
from this pin to PGND, placed less than 0.5" from SC420.
9
BG
PGND
N.C.
Output drive for the synchronous (bottom) MOSFET.
Ground. Keep this pin close to the synchronous MOSFETs source.
No Connect
10
11
This pin connects to the junction of the switching and synchronous MOSFETs . This pin can be subjected
to a -2V minimum relative to PGND without affecting operation.
12
DRN
2004 Semtech Corp.
5
United States Patent No. 6,441,597
www.semtech.com
SEMTECH [ SEMTECH CORPORATION ]
