AS1341-TD_EK_ST ams

AS1341 650mA, Ultra low Ripple Step Down DC/DC Converter 1 General Description 2 Key Features Output Voltages: Fixed 5V or Adjustable The AS1341 is a high-efficiency step-down converter with adjustable output voltages from 1.25V to VIN using supply voltages of up to Input Voltage Range: 4.5V to 20V 20V. An integrated current-limited 0.4 MOSFET delivers load currents Output Current: Up to 600mA up to 600mA. 1.25V Lowest Output Voltage The AS1341 also includes a 100% duty cycle LDO mode with a low dropout of only 250mV for high efficiency if input voltages is in the Efficiency: up to 96% range of the output voltage. Quiescent Supply Current: 12A The AS1341 has a low quiescent current (12A) to improve light- load efficiency and minimize battery use, and draws only 0.8A in Power-OK Output shutdown mode. High switching frequencies (up to 200kHz) allow the use of small Internal 0.4 P-Channel MOSFET surface-mount inductors and output capacitors. Shutdown Current: 0.8A The device is available in a TDFN-8 3x3mm pin package. 100% Maximum Duty Cycle for Low Dropout Current-Limited Architecture Thermal Shutdown TDFN-8 3x3mm Package 3 Applications The device is ideal for notebook computers, distributed power systems, keep-alive supplies, and any other battery-operated, Figure 1. AS1341 - Typical Application portable device. V IN L1 V = 5V 4.5V to 20V 5 4 OUT IN LX D1 + 7 CIN COUT SHDNN 8 6 AS1341 OUT ILIMIT RPULL 3 POK 2 1 GND FB Indicates High-Power Trace www.ams.com/DC-DC Step-Up/AS1341 Revision 1.09 1 - 18AS1341 Datasheet - P in A s s ig n me nt s 4 Pin Assignments Figure 2. Pin Assignments (Top View) FB 1 8 OUT GND 2 7 SHDNN AS1341 POK 3 6 ILIMIT 9 LX 4 5 IN 4.1 Pin Descriptions Table 1. Pin Descriptions Pin Number Pin Name Description Feedback Input. For the fixed 5V output connect this pin to GND. For adjustable output, connect to a 1 FB resistive divider between VOUT and GND to set the output voltage between 1.25V and VIN. 2 GND Ground Power OK. Active-low open-drain reset output. 3 POK Note: Connect pin POK to GND when the Power-Ok feature is not used. 4 LX Inductor Connection. Connect this pin to an external inductor. 5 IN 4.5V to 20V Input Supply Voltage Peak Current Control Input. Connect this pin to IN or GND to set peak current limit (see Setting 6 ILIMIT Current Limit on page 11). Shutdown Input. A low on this pin puts the AS1341 into shutdown mode. Supply current is reduced to 7 SHDNN 0.8A and LX goes high-impedance. Regulated Output Voltage High-Impedance Sense Input. For the fixed 5V output connect this pin to 8 OUT VOUT. For adjustable output connect this pin to GND. Exposed Pad. This pad is not connected internally. Connect to GND or do not connect. 9 NC www.ams.com/DC-DC Step-Up/AS1341 Revision 1.09 2 - 18