ADP1108AN-12
器件描述：Micropower DC-DC Converter Adjustable and Fixed 3.3 V, 5 V, 12 V
器件厂商：AD [Analog Devices]
文件大小：234.49KB，共12页
Sponsor by e络盟器件资料摘要：
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
a
Micropower DC-DC Converter
Adjustable and Fixed 3.3 V, 5 V, 12 V
ADP1108
FUNCTIONAL BLOCK DIAGRAMS
SET
V
IN
GAIN BLOCK/
ERROR AMP
COMPARATOR
SW2
FBGND
SW1
AO
I
LIM
OSCILLATOR
DRIVER
A1
A2
1.245V
REFERENCE
ADP1108
SET
V
IN
GAIN BLOCK/
ERROR AMP
COMPARATOR SW2
SENSEGND
SW1
AO
I
LIM
OSCILLATOR
DRIVER
A1
A2
1.245V
REFERENCE
ADP1108-3.3
ADP1108-5
ADP1108-12
R2
753kΩ
R1
ADP1108-3.3: R1 = 456kΩ
ADP1108-5: R1 = 250kΩ
ADP1108-12: R1 = 87.4kΩ
GENERAL DESCRIPTION
The ADP1108 is a highly versatile micropower switch-mode
dc-dc converter that operates from an input voltage supply as
low as 2.0 V and typically starts up from 1.8 V.
The ADP1108 can be programmed into a step-up or step-down
dc-to-dc converter with only three external components. The
fixed outputs are 3.3 V, 5 V and 12 V. An adjustable version is
also available. In step-up mode, supply voltage range is 2.0 V to
12 V, and 30 V in step-down mode. The ADP1108 can deliver
150 mA at 5 V from a 2 AA cell input and 300 mA at 5 V from
a 9 V input in step-down mode. Switch current limit can be
programmed with a single resistor.
For battery operated and power conscious applications, the
ADP1108 offers a very low power consumption of less than
110 µA.
The auxiliary gain block available in ADP1108 can be used
as a low battery detector, linear post regulator, under voltage
lockout circuit or error amplifier.
FEATURES
Operates at Supply Voltages From 2.0 V to 30 V
Consumes Only 110 mA Supply Current
Step-Up or Step-Down Mode Operation
Minimum External Components Required
Low Battery Detector Comparator On-Chip
User-Adjustable Current Limit
Internal 1 A Power Switch
Fixed or Adjustable Output Voltage Versions
8-Pin DIP or SO-8 Package
APPLICATIONS
Notebook/Palm Top Computers
3 V to 5 V, 5 V to 12 V Converters
9 V to 5 V, 12 V to 5 V Converters
LCD Bias Generators
Peripherals and Add-On Cards
Battery Backup Supplies
Cellular Telephones
Portable Instruments
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 World Wide Web Site: http://www.analog.com
Fax: 617/326-8703 © Analog Devices, Inc., 1997
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
a
Micropower DC-DC Converter
Adjustable and Fixed 3.3 V, 5 V, 12 V
ADP1108
FUNCTIONAL BLOCK DIAGRAMS
SET
V
IN
GAIN BLOCK/
ERROR AMP
COMPARATOR
SW2
FBGND
SW1
AO
I
LIM
OSCILLATOR
DRIVER
A1
A2
1.245V
REFERENCE
ADP1108
SET
V
IN
GAIN BLOCK/
ERROR AMP
COMPARATOR SW2
SENSEGND
SW1
AO
I
LIM
OSCILLATOR
DRIVER
A1
A2
1.245V
REFERENCE
ADP1108-3.3
ADP1108-5
ADP1108-12
R2
753kΩ
R1
ADP1108-3.3: R1 = 456kΩ
ADP1108-5: R1 = 250kΩ
ADP1108-12: R1 = 87.4kΩ
GENERAL DESCRIPTION
The ADP1108 is a highly versatile micropower switch-mode
dc-dc converter that operates from an input voltage supply as
low as 2.0 V and typically starts up from 1.8 V.
The ADP1108 can be programmed into a step-up or step-down
dc-to-dc converter with only three external components. The
fixed outputs are 3.3 V, 5 V and 12 V. An adjustable version is
also available. In step-up mode, supply voltage range is 2.0 V to
12 V, and 30 V in step-down mode. The ADP1108 can deliver
150 mA at 5 V from a 2 AA cell input and 300 mA at 5 V from
a 9 V input in step-down mode. Switch current limit can be
programmed with a single resistor.
For battery operated and power conscious applications, the
ADP1108 offers a very low power consumption of less than
110 µA.
The auxiliary gain block available in ADP1108 can be used
as a low battery detector, linear post regulator, under voltage
lockout circuit or error amplifier.
FEATURES
Operates at Supply Voltages From 2.0 V to 30 V
Consumes Only 110 mA Supply Current
Step-Up or Step-Down Mode Operation
Minimum External Components Required
Low Battery Detector Comparator On-Chip
User-Adjustable Current Limit
Internal 1 A Power Switch
Fixed or Adjustable Output Voltage Versions
8-Pin DIP or SO-8 Package
APPLICATIONS
Notebook/Palm Top Computers
3 V to 5 V, 5 V to 12 V Converters
9 V to 5 V, 12 V to 5 V Converters
LCD Bias Generators
Peripherals and Add-On Cards
Battery Backup Supplies
Cellular Telephones
Portable Instruments
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 World Wide Web Site: http://www.analog.com
Fax: 617/326-8703 © Analog Devices, Inc., 1997