SC4503 Semtech Corporation, SC4503 Datasheet - Page 3

• Manufacturer Part Number: SC4503
• Description: 1.3MHz Step-Up Switching Regulator
• Manufacturer: Semtech Corporation

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Unless specifi ed: V
 2007 Semtech Corp.
Pin Confi guration - TSOT - 23
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Pin Descriptions - TSOT -23
Parameter
SHDN/SS Switching Threshold
Shutdown Input High Voltage
Shutdown Input Low Voltage
SHDN/SS Pin Bias Current
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
Pin
1
2
3
4
5
Pin Name
SHDN/SS
IN
GND
= V
GND
SW
SW
FB
FB
IN
SHDN/SS
5-LEAD TSOT-23
1
2
3
= 3V, -40°C < T
Top View
Collector of the internal power transistor. Connect to the boost inductor and the freewheeling
diode. The maximum switching voltage spike at this pin should be limited to 34V.
Ground. Tie to ground plane.
The inverting input of the error amplifi er. Tie to an external resistive divider to set the output volt-
age.
Shutdown and Soft-start Pin. Pulling this pin below 0.4 shuts down the converter. Applying more
than 2V at this pin enables the SC4503. An external resistor and an external capacitor con-
nected to this pin soft-start the switching regulator. The SC4503 will try to pull the SHDN/SS pin
below its 1.4V switching threshold regardless of the external circuit attached to the pin if VIN
is below the under-voltage lockout threshold. Tie this pin through an optional resistor to IN or
to the output of a controlling logic gate if soft-start is not used. See Applications Information for
more details.
Power Supply Pin. Bypassed with capacitor close to the pin.
Pin Functions
A
= T
5
4
J
< 85°C
SHDN/SS
IN
V
V
V
Conditions
SHDN/SS
SHDN/SS
SHDN/SS
V
FB
= 0V
3
= 1.8V
= 2V
= 0V
(1) Available in tape and reel only. A reel contains 3,000 devices.
(2) Available in lead-free package only. Device is WEEE and
RoHS compliant.
Notes:
Ordering Information
SC4503TSKTRT
SC4503EVB
Device
(1,2)
Min
2
Top Mark
Typ
155
1.4
BH00
22
20
10
Evaluation Board
Max
0.4
0.1
50
45
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SC4503
Package
TSOT-23
Units
µA
°C
V
V