PART OBSOLETE - USE AP3211 and AP5100 Preliminary Datasheet 1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211H General Description Features Input Voltage Range: 4.5V to 23V The AP3211H is a 1.4MHz fixed frequency, current Fixed 1.4MHz Frequency mode, PWM buck (step-down) DC-DC converter, High Efficiency: up to 92% capable of driving a 1.5A load with high efficiency, Output Current: 1.5A excellent line and load regulation. The device Current Mode Control integrates N-channel power MOSFET switch with Built-in Over Current Protection low on-resistance. Current mode control provides fast Built-in Thermal Shutdown Function transient response and cycle-by-cycle current limit. Built-in UVLO Function Built-in Over Voltage Protection A standard series of inductors are available from several different manufacturers optimized for use Built-in Soft-start with the AP3211H. This feature greatly simplifies the design of switch-mode power supplies. Applications The AP3211H is available in SOT-23-6 package. LCD TV DPF Portable DVD SOT-23-6 Figure 1. Package Type of AP3211H Jun. 2014 Rev. 2. 4 BCD Semiconductor Manufacturing Limited 1 OBSOLETE PART DISCONTINUED PART OBSOLETE - USE AP3211 and AP5100 Preliminary Datasheet 1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211H Pin Configuration K Package (SOT-23-6) Pin 1 Mark 1 6 SW BS 5 GND 2 IN FB EN 3 4 Figure 2. Pin Configuration of AP3211H (Top View) Pin Description Pin Number Pin Name Function Bootstrap pin. A bootstrap capacitor is connected between the 1 BS BS pin and SW pin. The voltage across the bootstrap capacitor drives the internal high-side NMOS switch 2 GND Ground pin Feedback pin. This pin is connected to an external resistor divider to program the system output voltage. When V FB exceeds 20% of the nominal regulation value of 0.81V, the 3 FB OVP is triggered. When V 0.25V, the oscillator frequency FB is lowered to realize short circuit protection Control input pin. Forcing this pin above 1.5V enables the IC. Forcing this pin below 0.4V shuts down the IC. When the IC 4 EN is in shutdown mode, all functions are disabled to decrease the supply current below 1 A Supply input pin. A capacitor should be connected between 5 IN the IN pin and GND pin to keep the DC input voltage constant Power switch output pin. This pin is connected to the inductor 6 SW and bootstrap capacitor Jun. 2014 Rev. 2. 4 BCD Semiconductor Manufacturing Limited 2 OBSOLETE PART DISCONTINUED