Datasheet LT1611 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Inverting 1.4MHz Switching Regulator in 5-Lead SOT-23 |
| Pages / Page | 12 / 1 — FEATURES. DESCRIPTIO. Very Low Noise: 1mVP–P Output Ripple. – 5V at 150mA … |
| File Format / Size | PDF / 271 Kb |
| Document Language | English |
FEATURES. DESCRIPTIO. Very Low Noise: 1mVP–P Output Ripple. – 5V at 150mA from a 5V Input. Better Regulation Than a Charge Pump
Model Line for this Datasheet
Text Version of Document
LT1611 Inverting 1.4MHz Switching Regulator in SOT-23
U FEATURES DESCRIPTIO
■
Very Low Noise: 1mVP–P Output Ripple
The LT®1611 is the industry’s first inverting 5-lead SOT-23 ■
– 5V at 150mA from a 5V Input
current mode DC/DC converter. Intended for use in small, ■
Better Regulation Than a Charge Pump
low power applications, it operates from an input voltage ■ Effective Output Impedance: 0.14Ω as low as 1.1V and switches at 1.4MHz, allowing the use ■ Uses Tiny Capacitors and Inductors of tiny, low cost capacitors and inductors 2mm or less in ■ Internally Compensated height. Its small size and high switching frequency enable ■ Fixed Frequency 1.4MHz Operation the complete DC/DC converter function to consume less ■ Low Shutdown Current: <1µA than 0.25 square inches of PC board area. Capable of ■ Low VCESAT Switch: 300mV at 300mA generating – 5V at 150mA from a 5V supply or – 5V at ■ Tiny 5-Lead SOT-23 Package 100mA from a 3V supply, the LT1611 replaces nonregulated “charge pump” solutions in many applications.
U
The LT1611 operates in a dual inductor inverting topology
APPLICATIO S
which filters the input side as well as the output side of the ■ MR Head Bias DC/DC converter. Fixed frequency switching ensures a ■ Digital Camera CCD Bias clean output free from low frequency noise typically present ■ LCD Bias with charge pump solutions. No load quiescent current of ■ GaAs FET Bias the LT1611 is 3mA, while in shutdown quiescent current ■ Positive-to-Negative Conversion drops to 0.5µA. The 36V switch allows VIN to VOUT differential of up to 33V. The LT1611 is available in the 5-lead SOT-23 package. , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO
C2 L1A L1B
Transient Response
1µF 22µH 22µH VIN 5V D1 VIN SW VOUT –5V SHDN R1 150mA + VOUT C1 LT1611 29.4k 1200pF 20mV/DIV 22µF C3 NFB 22µF AC COUPLED GND R2 10k 150mA LOAD CURRENT 50mA C1: AVX TAJB226M010 1611 TA01 C2: TAIYO YUDEN LMK212BJ105MG 100µs/DIV 1611 F10 C3: TAIYO YUDEN JMK325BJ226MM (1210 SIZE) D1: MBR0520 L1: SUMIDA CLS62-220 OR 2× MURATA LQH3C220 (UNCOUPLED)
Figure 1. 5V to – 5V, 150mA Low Noise Inverting DC/DC Converter
1
U FEATURES DESCRIPTIO
■
Very Low Noise: 1mVP–P Output Ripple
The LT®1611 is the industry’s first inverting 5-lead SOT-23 ■
– 5V at 150mA from a 5V Input
current mode DC/DC converter. Intended for use in small, ■
Better Regulation Than a Charge Pump
low power applications, it operates from an input voltage ■ Effective Output Impedance: 0.14Ω as low as 1.1V and switches at 1.4MHz, allowing the use ■ Uses Tiny Capacitors and Inductors of tiny, low cost capacitors and inductors 2mm or less in ■ Internally Compensated height. Its small size and high switching frequency enable ■ Fixed Frequency 1.4MHz Operation the complete DC/DC converter function to consume less ■ Low Shutdown Current: <1µA than 0.25 square inches of PC board area. Capable of ■ Low VCESAT Switch: 300mV at 300mA generating – 5V at 150mA from a 5V supply or – 5V at ■ Tiny 5-Lead SOT-23 Package 100mA from a 3V supply, the LT1611 replaces nonregulated “charge pump” solutions in many applications.
U
The LT1611 operates in a dual inductor inverting topology
APPLICATIO S
which filters the input side as well as the output side of the ■ MR Head Bias DC/DC converter. Fixed frequency switching ensures a ■ Digital Camera CCD Bias clean output free from low frequency noise typically present ■ LCD Bias with charge pump solutions. No load quiescent current of ■ GaAs FET Bias the LT1611 is 3mA, while in shutdown quiescent current ■ Positive-to-Negative Conversion drops to 0.5µA. The 36V switch allows VIN to VOUT differential of up to 33V. The LT1611 is available in the 5-lead SOT-23 package. , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO
C2 L1A L1B
Transient Response
1µF 22µH 22µH VIN 5V D1 VIN SW VOUT –5V SHDN R1 150mA + VOUT C1 LT1611 29.4k 1200pF 20mV/DIV 22µF C3 NFB 22µF AC COUPLED GND R2 10k 150mA LOAD CURRENT 50mA C1: AVX TAJB226M010 1611 TA01 C2: TAIYO YUDEN LMK212BJ105MG 100µs/DIV 1611 F10 C3: TAIYO YUDEN JMK325BJ226MM (1210 SIZE) D1: MBR0520 L1: SUMIDA CLS62-220 OR 2× MURATA LQH3C220 (UNCOUPLED)
Figure 1. 5V to – 5V, 150mA Low Noise Inverting DC/DC Converter
1
