AX3821
AX3821 is 600KHz Synchronous Rectified Step-Down Converter manufactured by AXElite.
AX3821 1.6A, 13V, 600KHz Synchronous Rectified Step-Down Converter
GENERAL DESCRIPTION The AX3821 is a monolithic synchronous buck regulator. The device integrates two 100mΩ MOSFETs, and provides 1.6A of continuous load current over a wide input voltage of 4.5V to 13V. Current mode control provides fast transient response and cycle-by-Cycle current limit. Internal soft-start prevents inrush current at turn-on, and in shutdown mode the supply current drops to 1μA. This device, available in SOT-23-6L package, provides a very pact solution with minimal external ponents. Features
1.6A Output Current Wide 4.5V to 13V Operating Input Range Integrated 100mΩ Power MOSFET Switches Output adjust from VFB to 11V Internal pensation Up to 94% Efficiency Stable with Low ESR Ceramic Output Capacitors Fixed 600KHz Frequency Cycle-by-Cycle Over Current Protection Thermal shutdown and short circuit protections
BLOCK DIAGRAM
CURRENT SENSE AMPLIFIER OSCILLATOR FB 100KHz/600KHz BS RAMP CLK IN
+ 5 V
+ 0.6V ERROR AMPLIFIER
M1 100mΩ
- CURRENT PARATOR M2 100mΩ
+
GND GND
IN EN
+
1.5V
INTERNAL REGULATORS SHUTDOWN PARATOR
5V
- 1/9
Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.2 May.08, 2013
PIN ASSIGNMENT The package of AX3821 is SOT-23-6L; the pin assignment is given by: Name Description Bootstrap. A 10n F capacitor is connected between SW and BS pins to drive the BS power switch’s gate above the supply voltage. Ground Pin. Connect this pin to exposed GND pad. (Top View) Feedback. An external resistor divider FB from the output to GND, tapped to the FB BS 1 6 SW pin sets the output voltage. Power Supply Input. Drive 4.5V to 13V 5 VIN GND 2 voltage to this pin to power on this chip. VIN Connect a 10μF ceramic bypass FB 3 4 EN capacitor between VIN and GND to eliminate noise. SOT-23-6L Switch Output. Connect this pin to the SW switch end of the inductor. Enable Input. EN is a digital input...
