AMS1027 AMS | Alldatasheet

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Technical content

DESCRIPTION

The AMS1027 is a 5-pin thin SOT23 current mode step up converter intended for small, low power applications. The AMS1027 switches at 1.3MHz and allows the use of tiny, low cost capacitors and inductors 2mm or less in height. Internal soft start results in small inrush current and extends battery life.The AMS1027 operates from an input voltage as low as 2.5V and can generate 12V at up to 200mA from a 5V supply. The AMS1027 includes under-voltage lockout, current limiting, and thermal overload protection to prevent damage in the event of an output overload. The AMS1027 is available in a small 5-pin SOT23 package.

FEATURES

ƒ On Board Power MOSFET ƒ Uses Tiny Capacitors and Inductors ƒ 1.3MHz Fixed Switching Frequency ƒ Internally Compensated ƒ Internal Soft-Start ƒ Operates with Input Voltage as Low as 2.5V and Output Voltage as High as 22V ƒ 12V at 200mA from 5V Input ƒ UVLO, Thermal Shutdown ƒ Internal Current Limit ƒ Available in a SOT23-5 Package

APPLICATIONS

ƒ Camera Phone Flash ƒ Handheld Computers and PDAs ƒ Digital Still and Video Cameras ƒ External Modems ƒ Small LCD Displays ƒ White LED Driver TYPICAL APPLICATION V IN V OUT 12V 200mA AMS1027 SWIN FBGND EN OFF ON AMS1027 Advanced Monolithic Systems http://www.ams-semitech.com Vout=1.25(1+R1/R2) (V)

Recommended Operating Conditions Supply Voltage V IN Output Voltage V OUT AMS1027 Advanced Monolithic Systems http://www.ams-semitech.com PWM COMPARATOR ERROR AMPLIFIER CONTROL LOGIC CURRENT SENSE AMPLIFIER SW GND FB 3 1.3MHz OSC 1.25V Functional Block Diagram

ELECTRICAL CHARACTERISTICS

V IN = V EN = 5V, T A = +25°C unless otherwise specified. Parameters Symbol Condition Min Typ Max Units Operating Input Voltage V IN 2.5 6 V Undervoltage Lockout 2.25 2.45 V Undervoltage Lockout Hysteresis 92 mV Supply Current (Shutdown) V EN = 0V 0.1 1 µA Supply Current (Quiescent) V FB = 1.3V 635 850 µA Switching Frequency f SW 1.0 1.3 1.5 MHz Maximum Duty Cycle V FB = 0V 85 92 % EN Threshold V EN Rising 1.1 1.35 1.6 V EN Threshold V EN Rising, V IN = 2.5V 0.8 V EN Hysteresis 90 mV EN Input Bias Current V EN = 0V, 5V 1 µA FB Voltage V FB 1.21 1.25 1.29 V FB Input Bias Current V FB = 1.25V –100 –30 nA SW On-Resistance R DS (ON) 0.5 Ω SW Current Limit 1.9 A SW Leakage V SW = 15V 1 µA Thermal Shutdown 160 °C AMS1027 Advanced Monolithic Systems http://www.ams-semitech.com PIN FUNCTIONS Pin # Name Function 1 SW Power Switch Output. SW is the drain of the internal MOSFET switch. Connect the power inductor and output rectifier to SW. SW can swing between GND and 22V. 2 GND Ground. 3 FB Feedback Input. FB voltage is 1.25V . Connect a resistor divider to FB. 4 EN Regulator On/Off Control Input. A high input at EN turns on the converter, and a low input turns it off. When not used, connect EN to the input source for automatic startup. The EN pin cannot be left floating. 5 IN Input Supply Pin. Must be locally bypassed.

TYPICAL APPLICATION CIRCUITS V OUT 12V 200mA MBR0520L AMS1027 SWIN

2 FBGND

V IN OFF ON V IN = 5V, V OUT = 12V, I OUT = 200mA Boost Circuit AMS1027 Advanced Monolithic Systems http://www.ams-semitech.com

PACKAGE INFORMATION

0.30 0.50 SEATING PLANE

0.95 BSC

0.84 0.90

1.00 MAX

0.00 0.10 TOP VIEW FRONT VIEW SIDE VIEW 2.80 3.00 1.50 1.70 2.60 3.00 1 3 0.09 0.20 NOTE: ALL DIMENSIONS ARE IN MILLIMETERS. AMS1027 Advanced Monolithic Systems http://www.ams-semitech.com