PART OBSOLETE - NO ALTERNATE PART AP3440 4A, 2MHZ HIGH PERFORMANCE SYNCHRONOUS BUCK CONVERTER Description Pin Assignments The AP3440 is a current mode, PWM synchronous buck (step-down) DC-DC converter, capable of driving a 4A 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 cycle-by-cycle current limit. 16 15 14 13 SW The switching frequency of AP3440 can be programmable from VIN 1 12 200kHz to 2MHz, which allows small-sized components, such as 11 SW 2 VIN capacitors and inductors. A standard series of inductors from several E P different manufacturers are available. This feature greatly simplifies 10 SW GND 3 the design of switch-mode power supplies. 4 9 GND SS Under voltage lockout is internally set at 2.6V, but can be increased 5 6 7 8 by programming the threshold with a resistor network on the enable pin. The output voltage startup ramp is controlled by the soft-start pin. An open drain power good signal indicates the output is within 93% to 107% of its nominal voltage. The AP3440 is available in U-QFN3030-16 package. U-QFN3030-16 Features Input Voltage Range: 2.95V to 5.5V 0.8V Reference Voltage with 3% Precision Two 30m (Typical) MOSFETs for High Efficiency at 4A Load Applications High Efficiency: Up to 94% Low-voltage, High-density Power Systems Output Current: 4A Point of Load Regulation for High Performance DSPs, FPGAs, Programmable Frequency:200kHz to 2MHz ASICs and Microprocessors Current Mode Control Broadband, Networking and Optical Communications Synchronizes to External Clock Infrastructure 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 U-QFN3030-16 Totally Lead-free & Fully RoHS Compliant (Note1 & 2) Halogen and Antimony Free. Green Device (Note 3) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS), 2011/65/EU (RoHS 2) & 2015/863/EU (RoHS 3) compliant. 2. See PART OBSOLETE - NO ALTERNATE PART AP3440 Typical Applications Circuit U1 V =5V L1 1.5 mH V =1.8V IN OUT 16 10 VIN SW R8 2.2 11 1 SW VIN (Optional) C3 C2 R4 C6 2 12 C1 SW R1 VIN 100k 0.1 mF 10 mF 0.1 mF C10 2.2nF 13 14 BOOT PGD (Optional) 15 6 AP3440 FB EN R6 12.5k 7 3 COMP GND R7 C8 C9 8 4 R2 10k RT/CLK GND 22mF 22mF 9 5 SS AGND R3 7.5k R5 C5 C7 180k Optional 0.01mF C4 2.7nF Pin Description Pin Number Pin Name Function Supply input pin. A capacitor should be connected between the VIN and GND pin to keep the 1,2,16 VIN DC 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 7 COMP to the 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 9 SS pin 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 13 BOOT voltage 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, 14 PGD over-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 15 EN used to set the on/off threshold (adjust UVLO) with two additional resistors Exposed Pad can be connected to GND, for best thermal performance thermal vias are EP Exposed Thermal Pad recommended under the package 2 of 15 AP3440 October 2018 Diodes Incorporated www.diodes.com Document number: DS36691 Rev. 4 - 4 OBSOLETE PART DISCONTINUED