LT1611

Features:

Better Regulation Than a Charge Pump
Effective Output Impedance: 0.1
5V at 150mA from a 5V Input
Uses Tiny Capacitors and Inductor
Internally Compensated
Fixed Frequency 1.4MHz Operation
Low Shutdown Current: <1A
Low V_CESAT Switch: 300mV at 300mA
5-Lead SOT-23 Package


Application

Digital Camera CCD Bias
MR Head Bias
LCD Bias
Positive-to-Negative Conversion
GaAs FET Bias


Pinout




Specifications

V_IN Voltage ............................................................... 10V
SW Voltage ..............................................................0.4V to 36V
NFB Voltage ............................................................. 3V
Current into NFB Pin ................................................ ±1mA
SHDN Voltage .......................................................... 10V
Maximum Junction Temperature .............................. 125°C
Operating Temperature Range
    Commercial ......................................................... 0°C to 70°C
    Extended Commercial (Note 2)............................ 40°C to 85°C
Storage Temperature Range .................................. 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................... 300°C


Description

The LT^®1611 is the industry's first inverting 5-lead SOT-23 current mode DC/DC converter. Intended for use in small, low power applications, it operates from an input voltage as low as 1.1V and switches at 1.4MHz, allowing the use of tiny, low cost capacitors and inductors 2mm or less in height. Its small size and high switching frequency enable the complete DC/DC converter function to take up less than 0.25 square inches of PC board area. Capable of generating 5V at 150mA from a 5V supply or 5V at 100mA from a 3V supply, the LT1611 replaces nonregulated "charge pump" solutions in many applications.

The LT1611 operates in a dual inductor inverting topology which filters the input side as well as the output side of the DC/DC converter. Fixed frequency switching ensures a clean output free from low frequency noise typically present with charge pump solutions. No load quiescent current of the LT1611 is 3mA, while in shutdown quiescent current drops to 0.5A. The 36V switch allows V_IN to V_OUT differential of up to 33V.

The LT1611 is available in the 5-lead SOT-23 package.