Datasheet LT1944 (Analog Devices)
| Hersteller | Analog Devices |
| Beschreibung | Dual Micropower Step-Up DC/DC Converter |
| Seiten / Seite | 8 / 1 — FEATURES. DESCRIPTIO. Low Quiescent Current:. A in Active Mode. <1. A … |
| Dateiformat / Größe | PDF / 168 Kb |
| Dokumentensprache | Englisch |
FEATURES. DESCRIPTIO. Low Quiescent Current:. A in Active Mode. <1. A in Shutdown Mode. Operates with V. IN as Low as 1.2V
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LT1944 Dual Micropower Step-Up DC/DC Converter
U FEATURES DESCRIPTIO
■
Low Quiescent Current:
The LT®1944 is a dual micropower step-up DC/DC con-
20
µ
A in Active Mode
verter in a 10-pin MSOP package. Each converter is
<1
µ
A in Shutdown Mode
designed with a 350mA current limit and an input voltage ■
Operates with V
range of 1.2V to 15V, making the LT1944 ideal for a wide
IN as Low as 1.2V
■ Low V variety of applications. Both converters feature a quies- CESAT Switch: 250mV at 300mA ■ Uses Small Surface Mount Components cent current of only 20µA at no load, which further reduces ■ High Output Voltage: Up to 34V to 0.5µA in shutdown. A current limited, fixed off-time ■ Tiny 10-Pin MSOP Package control scheme conserves operating current, resulting in high efficiency over a broad range of load current. The 36V
U
switch allows high voltage outputs up to 34V to be easily
APPLICATIO S
generated in a simple boost topology without the use of ■ costly transformers. The LT1944’s low off-time of 400ns LCD Bias ■ permits the use of tiny, low profile inductors and capaci- Handheld Computers ■ tors to minimize footprint and cost in space-conscious Battery Backup ■ portable applications. Digital Cameras , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO Dual Output (5V, 30V) Boost Converter 5V Output Efficiency
L1 90 4.7 V µH D1 IN 5V 85 2.7V 80mA TO 4.2V VIN = 4.2V 8 10 80 4.7pF 1M VIN SW1 75 2 1 VIN = 2.7V SHDN1 FB1 C1 70 LT1944 C2 4.7µF 10µF 4 5 65 EFFICIENCY (%) SHDN2 FB2 324k GND PGND PGND SW2 60 3 7 9 6 55 86.6k 50 0.1 1 10 100 LOAD CURRENT (mA) C3 4.7pF 2M 1µF 1944 TA01a L2 10µH D2 30V 8mA C1: TAIYO YUDEN JMK212BJ475 1944 TA01 C2: TAIYO YUDEN JMK316BJ106 C3: TAIYO YUDEN GMK316BJ105 D1, D2: ON SEMI MBR0540 L1: MURATA LQH3C4R7 L2: MURATA LQH3C100 1
U FEATURES DESCRIPTIO
■
Low Quiescent Current:
The LT®1944 is a dual micropower step-up DC/DC con-
20
µ
A in Active Mode
verter in a 10-pin MSOP package. Each converter is
<1
µ
A in Shutdown Mode
designed with a 350mA current limit and an input voltage ■
Operates with V
range of 1.2V to 15V, making the LT1944 ideal for a wide
IN as Low as 1.2V
■ Low V variety of applications. Both converters feature a quies- CESAT Switch: 250mV at 300mA ■ Uses Small Surface Mount Components cent current of only 20µA at no load, which further reduces ■ High Output Voltage: Up to 34V to 0.5µA in shutdown. A current limited, fixed off-time ■ Tiny 10-Pin MSOP Package control scheme conserves operating current, resulting in high efficiency over a broad range of load current. The 36V
U
switch allows high voltage outputs up to 34V to be easily
APPLICATIO S
generated in a simple boost topology without the use of ■ costly transformers. The LT1944’s low off-time of 400ns LCD Bias ■ permits the use of tiny, low profile inductors and capaci- Handheld Computers ■ tors to minimize footprint and cost in space-conscious Battery Backup ■ portable applications. Digital Cameras , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO Dual Output (5V, 30V) Boost Converter 5V Output Efficiency
L1 90 4.7 V µH D1 IN 5V 85 2.7V 80mA TO 4.2V VIN = 4.2V 8 10 80 4.7pF 1M VIN SW1 75 2 1 VIN = 2.7V SHDN1 FB1 C1 70 LT1944 C2 4.7µF 10µF 4 5 65 EFFICIENCY (%) SHDN2 FB2 324k GND PGND PGND SW2 60 3 7 9 6 55 86.6k 50 0.1 1 10 100 LOAD CURRENT (mA) C3 4.7pF 2M 1µF 1944 TA01a L2 10µH D2 30V 8mA C1: TAIYO YUDEN JMK212BJ475 1944 TA01 C2: TAIYO YUDEN JMK316BJ106 C3: TAIYO YUDEN GMK316BJ105 D1, D2: ON SEMI MBR0540 L1: MURATA LQH3C4R7 L2: MURATA LQH3C100 1