SC1408 Datasheet, PDF (1/12 Pages) Semtech Corporation – LOW VOLTAGE, BOOST DC-DC CONTROLLER

LOW VOLTAGE, BOOST DC-DC
CONTROLLER
SC1408
August 22, 2000
TEL:[phone] FAX:[phone] WEB:http://www.semtech.com
DESCRIPTION
The SC1408 is a low voltage boost controller that oper-
ates from a 1.8V to 16.5V input range. A shutdown pin
allows the user to turn the controller off reducing sup-
ply current to less than 2µA typical. Output voltage can
be preset to 5V or is adjustable from 3V to 16.5V with
a resistor divider. The controller changes frequency in
low load conditions to improve efficiency.
The SC1408 was designed for two cell Alkaline or sin-
gle cell Lithium Ion battery applications. With the
proper external components it can be used as a boost
converter or a buck/boost converter.
A current sense is implemented with an external resis-
tor that is not in the load current path.
The SC1408 operates in “bootstrapped” mode. When
the input voltage to the device is less than 2.5V during
startup, a low voltage 50% fixed duty cycle oscillator is
switched in to initiate boost action.
FEATURES
•= 1.8V to 16.5V input range
•= Up to 10W output power
•= Preset 5V or adjustable output
•= Up to 300kHz switching frequency
•= 10µA max shutdown current
•= Industrial temperature range
•= SO-8 or MSOP-8 package
APPLICATIONS
•= PDA Power supplies
•= Battery powered applications
•= Positive LCD Bias generator
•= Portable communications (cellular phones)
•= Peripheral card supplies
•= Industrial power supplies
ORDERING INFORMATION
Part Number⁽¹⁾
SC1408IS.TR
Package
SO-8
Temp. Range (T_A)
-40° to +85°C
SC1408IMS.TR MSOP-8
Note:
(1) Only available in tape and reel packaging. A reel
contains 2500 devices.
TYPICAL APPLICATION - BOOST CONFIGURATION
Vin (1.8V to 16.5V)
L1
D1
Vout (3V to 16.5V)
+
C2
U1
2 _BST
GATE ¹
4 _{SHDN ISENSE} 8
5 _REF
FB ³
7 _{GND AGND} 6
SC1408IS
C5
Q1
R3
+ _C3
R2
R4
© 2000 SEMTECH CORP.
1
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