Diodes Incorporated AP3585CMPTR-G1

Overview

AP3585CMPTR-G1 from Diodes Incorporated is a single-phase synchronous buck PWM controller in SO-8EP package, operating from 4.5V to 13.2V input and delivering regulated output as low as 0.6V with ±2% reference accuracy. It integrates dual MOSFET drivers (1.5A sink/1A source), built-in bootstrap diode, and voltage-mode control with 10MHz GBW error amplifier for fast transient response in DDR/SDRAM bus termination and graphics card subsystems.

For engineers reviewing the AP3585CMPTR-G1 datasheet, AP3585CMPTR-G1 pinout, AP3585CMPTR-G1 application, or AP3585CMPTR-G1 equivalent, key selection criteria include fixed 200kHz switching frequency, lossless R_DS(ON)-based overcurrent protection, thermal shutdown at +160°C, and compatibility with pre-biased load startup - all critical for industrial and consumer power supply design.

Technical Context

This controller implements voltage-mode PWM control with a single feedback loop referenced to an internal 0.6V bandgap reference (AP3585C variant), supporting duty cycle range of 0%–89% and maximum 200kHz oscillator frequency. Its adaptive shoot-through protection monitors UGATE and PHASE timing to prevent cross-conduction.

The error amplifier delivers 55–70dB open-loop DC gain, 6V/µs slew rate, and 10MHz gain-bandwidth product, enabling high-loop bandwidth for sub-100µs load transient recovery. Overcurrent threshold is programmable via external resistor on LGATE/OCSET pin using a 10µA current source.

Key Specifications

Pinout & Package

AP3585CMPTR-G1 is housed in a thermally enhanced SO-8EP (exposed pad) package, with the exposed pad soldered directly to PCB ground plane for optimal thermal dissipation (θ_JA = 70°C/W). Pin functions are validated per Diodes DS36819 Rev. 1–2.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck controller applications.

Compared with MP2307DN-LF-Z and LM5116PWPR, AP3585CMPTR-G1 offers optimal balance of integration (built-in boot diode, 200kHz fixed frequency), precision (0.6V ±2% reference), and protection (R_DS(ON) OCP, pre-bias startup), making it ideal for mid-power DDR and graphics subsystems where discrete FET control and thermal robustness are prioritized.

Availability

AP3585CMPTR-G1 is available at Aetrix Electronics and suitable for DDR3/DDR4 memory termination, graphics card subsystems, industrial PLC I/O modules, and cable modem power management requiring stable component supply across production lifecycles.

Supply support for AP3585CMPTR-G1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-efficiency power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The AP3585 series belongs to Diodes' synchronous buck controller product line, designed specifically for compact, high-reliability point-of-load regulation in memory interface and graphics subsystem applications with emphasis on thermal robustness and protection integration.

FAQ

What is the difference between AP3585A, AP3585B, and AP3585C variants?

The AP3585A uses a 0.8V internal reference and 300kHz switching frequency; AP3585B uses 0.6V reference and 300kHz; AP3585C uses 0.6V reference and 200kHz. Soft-start intervals differ: 2ms (A), 1.5ms (B), and 2.4ms (C). AP3585CMPTR-G1 corresponds to the C variant, confirmed by its 200kHz frequency and 0.6V reference in DS36819 Rev. 1–2.

Does AP3585CMPTR-G1 support start-up into a pre-biased output?

Yes - AP3585CMPTR-G1 explicitly supports pre-biased output startup, as documented in the Functional Descriptions section of DS36819. The controller monitors PHASE voltage during initial UGATE turn-on and enters hiccup mode if VIN is absent, then safely ramps output once input is valid, avoiding reverse current flow.

How is overcurrent protection implemented without a sense resistor?

AP3585CMPTR-G1 implements lossless overcurrent protection by sensing voltage drop across the low-side MOSFET's R_DS(ON). A 10µA internal current source flows through an external resistor (ROCSET) on the LGATE/OCSET pin, setting the OCP threshold as V_OCP = I_OCSET × R_OCSET. When this voltage exceeds 0.375V, protection triggers.

What is the role of the exposed pad in the SO-8EP package?

The exposed pad on AP3585CMPTR-G1 serves as both thermal conduction path and electrical ground connection. It must be soldered to a minimum 200mm² PCB copper area tied directly to the system ground plane. This reduces junction-to-ambient thermal resistance to 70°C/W and ensures reliable operation at full load in ambient temperatures up to +85°C.