Datasheet LT1946A (Linear Technology)
| Manufacturer | Linear Technology |
| Description | 2.7MHz Boost DC/DC Converter with 1.5A Switch and Soft-Start |
| Pages / Page | 12 / 1 — FEATURES. DESCRIPTIO. 1.5A, 36V Internal Switch. 2.7MHz Switching … |
| Revision | S |
| File Format / Size | PDF / 326 Kb |
| Document Language | English |
FEATURES. DESCRIPTIO. 1.5A, 36V Internal Switch. 2.7MHz Switching Frequency. Integrated Soft-Start Function. APPLICATIO S
Model Line for this Datasheet
Text Version of Document
LT1946A 2.7MHz Boost DC/DC Converter with 1.5A Switch and Soft-Start
U FEATURES DESCRIPTIO
■
1.5A, 36V Internal Switch
The LT®1946A is a fixed frequency step-up DC/DC con- ■
2.7MHz Switching Frequency
verter containing an internal 1.5A, 36V switch. Capable of ■
Integrated Soft-Start Function
generating 12V at 430mA from a 5V input, the LT1946A is ■ Adjustable Output from V ideal for powering large TFT-LCD panels. The LT1946A IN to 35V ■ Low V switches at 2.7MHz, allowing the use of tiny, low profile CESAT Switch: 300mV at 1.5A (Typical) ■ 12V at 430mA from a 5V Input inductors and low value ceramic capacitors. Loop com- ■ Small Thermally Enhanced 8-Lead MSOP Package pensation can be either internal or external, giving the user flexibility in setting loop compensation and allowing opti-
U
mized transient response with low ESR ceramic output
APPLICATIO S
capacitors. Soft-start is controlled with an external capaci- ■ tor which determines the input current ramp rate during TFT-LCD Bias Supplies ■ start up. The 8-lead MSOP package and high switching GPS Receivers ■ frequency ensure a low profile overall solution less than DSL Modems ■ 1.1mm high. Local Power Supply , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO
L1 D1
Efficiency
2.2µH V V OUT IN 12V 5V 90 6 5 430mA V R1 85 IN SW 3 182k OFF ON SHDN 2 80 C1 LT1946A FB 2.2µF 1 7 V COMP C2 75 C 2.2µF RC SS GND* 27.4k R2 70 8 4 C C 21k C SS 65 270pF 100nF EFFICIENCY (%) 60 1946A TA01 C1: 2.2µF, X5R or X7R, 6.3V C2: 2.2µF, X5R or X7R, 16V 55 D1: MICROSEMI UPS120 OR EQUIVALENT L1: SUMIDA CR43-2R2 50 * EXPOSED PAD MUST ALSO BE GROUNDED 0 100 200 300 400 500 LOAD CURRENT (mA)
Figure 1. 5V to 12V, 430mA Step-Up DC/DC Converter
1946A TA01 sn1946a 1946afs 1
U FEATURES DESCRIPTIO
■
1.5A, 36V Internal Switch
The LT®1946A is a fixed frequency step-up DC/DC con- ■
2.7MHz Switching Frequency
verter containing an internal 1.5A, 36V switch. Capable of ■
Integrated Soft-Start Function
generating 12V at 430mA from a 5V input, the LT1946A is ■ Adjustable Output from V ideal for powering large TFT-LCD panels. The LT1946A IN to 35V ■ Low V switches at 2.7MHz, allowing the use of tiny, low profile CESAT Switch: 300mV at 1.5A (Typical) ■ 12V at 430mA from a 5V Input inductors and low value ceramic capacitors. Loop com- ■ Small Thermally Enhanced 8-Lead MSOP Package pensation can be either internal or external, giving the user flexibility in setting loop compensation and allowing opti-
U
mized transient response with low ESR ceramic output
APPLICATIO S
capacitors. Soft-start is controlled with an external capaci- ■ tor which determines the input current ramp rate during TFT-LCD Bias Supplies ■ start up. The 8-lead MSOP package and high switching GPS Receivers ■ frequency ensure a low profile overall solution less than DSL Modems ■ 1.1mm high. Local Power Supply , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO
L1 D1
Efficiency
2.2µH V V OUT IN 12V 5V 90 6 5 430mA V R1 85 IN SW 3 182k OFF ON SHDN 2 80 C1 LT1946A FB 2.2µF 1 7 V COMP C2 75 C 2.2µF RC SS GND* 27.4k R2 70 8 4 C C 21k C SS 65 270pF 100nF EFFICIENCY (%) 60 1946A TA01 C1: 2.2µF, X5R or X7R, 6.3V C2: 2.2µF, X5R or X7R, 16V 55 D1: MICROSEMI UPS120 OR EQUIVALENT L1: SUMIDA CR43-2R2 50 * EXPOSED PAD MUST ALSO BE GROUNDED 0 100 200 300 400 500 LOAD CURRENT (mA)
Figure 1. 5V to 12V, 430mA Step-Up DC/DC Converter
1946A TA01 sn1946a 1946afs 1
