SC4517A
POWER MANAGEMENT
Pin Configurations
TOP VIEW
BST
IN
SW
GND
1
2
3
4
8
7
6
5
SYNC
COMP
FB
EN
Ordering Information
Part Number
(1)(2)(3)
SC4517AIMSXXTRT
SC4517AIMSTRT
SC4517AIMLXXTRT
SC4517AIMLTRT
S C 4517A E V B
P ackag e
MSOP-8
MLPD-8
Evaluation Board
(8 Pin MSOP)
TOP VIEW
Notes:
(1) Where XX denotes voltage options. Available
voltages are: 1.8V (18), 2.5V (25), 3.3V (33) and 5.0V
(50). Leave blank for adjustable voltage option.
(2) Only available in tape and reel packaging. A reel
contains 2500 for MSOP and 3000 for MLP devices.
(3) Lead-free product. This product is fully WEEE and
RoHS compliant.
(8 Pin MLPD)
Pin Descriptions
Pin #
1
2
Pin Name Pin Function
BST
IN
This pin provides power to the internal NPN switch. The minimum turn on voltage for this switch is
2.7V.
Pi n IN deli vers all power requi red by control and power ci rcui try. Thi s pi n sees hi gh di /dt duri ng
switching actions of the switch. A decoupling capacitor should be attached to this pin as close as
possible.
Pin SW is the emitter of the internal switch. The external freewheeling diode should be connected as
close as possible to this pin.
All voltages are measured with respect to this pin. The decoupling capacitor and the freewheeling
diode should be connected to GND as short as possible.
This is the chip enable input. The regulator is switched on if EN is high, and it is off if EN is low. The
regulator i s i n standby mode when E N i s low, and the i nput supply current i s reduced to a few
microamperes. It needs to be pulled up to Vin if not used.
Feedback input for adjustable output controllers. For fixed output controllers, this pin should be directly
connected to the output since the voltage dividers have been integrated into the chips (SC4517A-
XX).
Thi s i s the o utp ut o f the i nte rna l e rro r a mp li fi e r a nd i np ut o f the p e a k c urre nt c o mp a ra to r. A
compensation network is connected to this pin to achieve the specified performance.
This is synchronous control pin used to synchronize the internal oscillator to an external pulse control
signal. When not used, it should be connected to GND.
3
4
5
SW
GND
EN
6
FB
7
8
COMP
SYNC
THERMAL Pad for heatsinking purpose. Connect to ground plane using multiple vias. Not electrically connected
PAD
internally.
(MLPD only)
2006 Semtech Corp.
5
www.semtech.com
SEMTECH [ SEMTECH CORPORATION ]
