HIGH-EFFICIENCY STEP-DOWN
DC-DC CONVERTER
January 29, 1998
SC1578
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
The SC1578 is a high performance step-down DC-DC
converter, designed to drive an external P-channel
MOSFET to generate programmable output voltages.
Two main schemes of pulse-skipping and pulse-
frequency modulation are employed to maintain low
quiescent current and high conversion efficiency over
wide ranges of input voltage and loads. The SC1578
delivers 10mA to 2A of output current with 87%-93%
efficiency at V
IN
=9V, V
OUT
=5V. A current sense
comparator with both inverting and non-inverting inputs
uncommitted is included to provide the crucial function
of either current limit protection or constant output
current control. When the SC1578 is used in a high-
side current sensing step-down constant current
source, the efficiency is typically greater than 90%.
Duty cycle can be adjusted to greater than 90% by
connecting a resistor from the DUTY pin to V
IN
.
Quiescent current is about 90碌A(chǔ) and can be reduced
to 8碌A(chǔ) in shutdown mode. With a switching frequency
range of 90kHz to 280kHz, small size switching
components may be used, which is ideal for battery
powered portable equipment.
FEATURES
鈥?/div>
4V to 24V input voltage operation.
鈥?/div>
High efficiency (up to 95%).
鈥?/div>
Low quiescent current at 90碌A(chǔ).
鈥?/div>
Pulse-skipping and pulse-frequency modulation.
鈥?/div>
Inputs-uncommitted current sense comparator.
鈥?/div>
Duty cycle adjustable
鈥?/div>
90kHz to 280kHz oscillator frequency
鈥?/div>
Power-saving shutdown mode (8碌A(chǔ) Typical).
鈥?/div>
Push-pull driver output
APPLICATIONS
鈥?/div>
Notebook 5V/3.3V main power
鈥?/div>
Step-down DC-DC converter module.
鈥?/div>
Constant current source for battery chargers.
BLOCK DIAGRAM
ORDERING INFORMATION
DEVICE
(1)
PACKAGE
SO-8
SC1578CS
Note:
(1) Add suffix 鈥楾R鈥?for tape and reel.
PIN CONFIGURATION
ABSOLUTE MAXIMUM RATINGS
Parameter
Supply Voltage
Duty Voltage
SHDN Voltage
Operating
Temperature Range
Storage Temperature
Range
Symbol
V
IN
V
DUTY
V
SHDN
T
A
T
STG
Maximum
24
20
15
0 to 70
-65 to 150
Units
V
V
V
擄C
擄C
漏 1997 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
SC1578CS相關(guān)型號PDF文件下載
-
型號
版本
描述
廠商
下載
-
英文版
Smart UPS SC, 1440VA/865W, Input 120V/Output 120V, 2U Rack H...
APC
-
英文版
TRIAC|200V V(DRM)|15A I(T)RMS|TO-220
ETC
-
英文版
TRIAC|400V V(DRM)|15A I(T)RMS|TO-220
ETC
-
英文版
TRIAC|600V V(DRM)|15A I(T)RMS|TO-220
ETC
-
英文版
TRIAC|200V V(DRM)|15A I(T)RMS|TO-220
ETC
-
英文版
TRIAC|400V V(DRM)|15A I(T)RMS|TO-220
ETC
-
英文版
TRIAC|500V V(DRM)|15A I(T)RMS|TO-220
ETC
-
英文版
TRIAC|600V V(DRM)|15A I(T)RMS|TO-220
ETC
-
英文版
200mA & 250mA SmartLDOs
-
英文版
200mA & 250mA SmartLDOs
SEMTECH [S...
-
英文版
400mA SmartLDOTM with Internal Pass MOSFET
-
英文版
400mA SmartLDOTM with Internal Pass MOSFET
SEMTECH [S...
-
英文版
400mA SmartLDOTM
-
英文版
400mA SmartLDOTM
SEMTECH [S...
-
英文版
700mA SmartLDOTM
-
英文版
700mA SmartLDOTM
SEMTECH [S...
-
英文版
DUAL LINEAR CONTROLLER
-
英文版
DUAL LINEAR CONTROLLER
SEMTECH [S...
-
英文版
300mA AND 500mA LOW DROPOUT VOLTAGE REGULATORS WITH ENABLE
-
英文版
400mA/200mA Dual 3.3V Smart Power Switch
1
2
3
4
5
