AP3502MTR-G1 Diodes Incorporated

NOT RECOMMENDED FOR NEW DESIGN CONTACT US AP3502 340KHZ 2A SYNCHRONOUS DC-DC BUCK CONVERTER Description Pin Assignments The AP3502 is a 340kHz fixed frequency, current mode, PWM synchronous buck (step-down) DC-DC converter, capable of driving a (Top View) 2A load with high efficiency, excellent line and load regulation. The device integrates N-channel power MOSFET switches with low on- BS 8 SS 1 resistance. Current mode control provides fast transient response and cycle-by-cycle current limit. EN IN 2 7 The AP3502 employs complete protection to ensure system security, SW 3 6 COMP including output Over Voltage Protection, input Under Voltage Lock GND 4 5 FB Out, programmable soft-start, and Over Temperature Protection. This IC is available in SOIC-8 package. SOIC-8 Features Applications Input Voltage Range: 4.5V to 18V LCD TV Fixed 340kHz Frequency Set Top Box High Efficiency: up to 95% Portable DVD Output Current: 2A Digital Photo Frame Current Mode Control Built-In Over Current Protection Built-In Thermal Shutdown Function Built-In UVLO Function Built-In Over Voltage Protection Programmable Soft-Start 1 of 11 February 2020 AP3502 Diodes Incorporated www.diodes.com Document number: DS41518 Rev. 4 - 3 AP3502 Typical Applications Circuit Input Voltage=12V R4 C11 100k 10F/25V 1 8 BS SS C5 0.1F 2 7 IN EN C4 C6 10nF L 10H Output Voltage=3.3V Optional 3 6 SW COMP C3 R3 4.7nF 13k 4 5 GND FB R2 10k C21 C22 22F/25V 22F/25V D1 R1 Optional 26.1k Pin Descriptions Pin Number Pin Name Function Bootstrap pin. A bootstrap capacitor is connected between the BS pin and SW pin. The voltage 1 BS across the bootstrap capacitor drives the internal high-side power MOSFET Supply power input pin. A capacitor should be connected between the IN pin and GND pin to keep the 2 IN input voltage constant 3 SW Power switch output pin. This pin is connected to the inductor and bootstrap capacitor 4 GND Ground pin Feedback pin. This pin is connected to an external resistor divider to program the system output 5 FB voltage. When the FB pin voltage exceeds 1.1V, the over voltage protection is triggered. When the FB pin voltage is below 0.3V, the oscillator frequency is lowered to realize short circuit protection Compensation pin. This pin is the output of the transconductance error amplifier and the input to the 6 COMP current comparator. It is used to compensate the control loop. Connect a series RC network from this pin to GND. In some cases, an additional capacitor from this pin to GND pin is required Control input pin. EN is a digital input that turns the regulator on or off. Drive EN high/low to turn on/off 7 EN the regulator. Pull up with 100k resistor for automatic startup Soft-start control input pin. SS controls the soft-start period. Connect a capacitor from SS to GND to 8 SS set the soft-start period. A 0.1F capacitor sets the soft-start period to 15ms. To disable the soft-start feature, leave SS unconnected 2 of 11 February 2020 AP3502 Diodes Incorporated www.diodes.com Document number: DS41518 Rev. 4 - 3 AP3502