PART OBSOLETE NO ALTERNATE PART AP3433 3A 2MHZ HIGH PERFORMANCE SYNCHRONOUS BUCK CONVERTER Description Pin Assignments The AP3433 is a current mode, PWM synchronous buck (step-down) DC-DC converter, capable of driving a 3A load with high efficiency, (Top View) excellent line and load regulation. The device integrates two N-channel power MOSFETs with low on- Pin 1 Mark resistance. Current mode control provides fast transient response and 16 15 14 13 cycle-by-cycle current limit. VIN 12 SW 1 11 SW 2 VIN The switching frequency of AP3433 can be programmable from E P GND 10 SW 3 300kHz to 2MHz, which allows small-sized components, such as 4 9 capacitors and inductors. A standard series of inductors from several GND SS different manufacturers are available. This feature greatly simplifies 5 6 7 8 the design of switch-mode power supplies. Under voltage lockout is internally set at 2.6V, but can be increased by programming the threshold with a resistor network on the enable pin. The output voltage startup ramp is controlled by the soft-start pin. QFN-33-16 An open drain power good signal indicates the output is within 93% to 107% of its nominal voltage. The AP3433 is available in QFN-33-16 package. Applications Low-voltage, High-density Power Systems Features Point of Load Regulation for Consumer Applications such as Set Input Voltage Range: 2.95V to 5.5V Top Boxes, LCD Displays, CPE Equipment 0.827V Reference Voltage with 3% Precision Two 45m(typical) MOSFETs for High Efficiency at 3A Load High Efficiency: up to 94% Output Current: 3A Programmable Frequency:300kHz to 2MHz Current Mode Control Synchronizes to External Clock Adjustable Soft-start Soft Start-up into Pre-biased Output UV and OV Power Good Output Built-in Over Current Protection Built-in Thermal Shutdown Function Programmable UVLO Function Built-in Over Voltage Protection Thermally Enhanced 3mm3mm 16-pin QFN 1 of 11 AP3433 October 2018 Diodes Incorporated www.diodes.com Document number: DS41485 Rev. 1 - 4 OBSOLETE PART DISCONTINUED VIN AGND EN FB PGD COMP BOOT RT/CLK PART OBSOLETE NO ALTERNATE PART AP3433 Typical Applications Circuit U1 L1 1.5 mH V =5V V =1.8V IN OUT 16 10 SW VIN R8 2.2 1 11 VIN SW (Optional) C2 C3 R4 12 C6 2 C1 R1 VIN SW 100k 0.1 mF 10 mF 0.1 mF C10 2.2nF 13 14 BOOT PGD (Optional) 15 AP3433 6 FB EN R6 7 3 12k COMP GND R7 C8 C9 8 4 R2 10k RT/CLK GND 22mF 22mF 9 5 SS AGND R3 7.5k R5 C7 C5 180k Optional C4 0.01 mF 3.3nF Pin Descriptions Pin Number Pin Name Function Supply input pin. A capacitor should be connected between the VIN and GND pin to keep the DC 1,2,16 VIN input voltage constant 3,4 GND Power ground. This pin should be electrically connected to the power pad under the IC 5 AGND Analog ground. This pin should be electrically connected to GND close to the device 6 FB Feedback pin. Inverting node of the transconductance error amplifier Compensation pin. This pin is the output of the transconductance error amplifier and the input to the 7 COMP current comparator. Connect external compensation elements to this pin to stabilize the control loop 8 RT/CLK Resistor timing or external clock input pin Soft-start pin. An external capacitor connected to this pin sets the output voltage rise time. This pin 9 SS can also be used for tracking 10,11,12 SW Internal power switch output pin. This pin is connected to the inductor and bootstrap capacitor Bootstrap pin. A bootstrap capacitor is connected between the BOOT pin and SW pin. The voltage 13 BOOT across the bootstrap capacitor drives the internal high-side power MOSFET Power good indicator output. Asserts low if output voltage is low due to thermal shutdown, over- 14 PGD current, over/under-voltage or EN shut down Enable pin, internal pull-up current source. Pull below 1.2V to disable. Float to enable. Can be used to 15 EN set the on/off threshold (adjust UVLO) with two additional resistors 2 of 11 AP3433 October 2018 Diodes Incorporated www.diodes.com Document number: DS41485 Rev. 1 - 4 OBSOLETE PART DISCONTINUED