Analog Devices Inc./Maxim Integrated MAX16909RATE/V+T

Overview

MAX16909RATE/V+T from Maxim Integrated is a 3A, current-mode synchronous step-down DC-DC converter with integrated high-side MOSFET, designed for automotive and industrial power supplies. It operates from 3.5V to 36V input, delivers 5V fixed or 1V–10V adjustable output, achieves 220kHz–1MHz programmable switching frequency, and consumes only 30µA quiescent current in standby mode-enabling reliable operation during cold-crank undervoltage transients.

For engineers reviewing the MAX16909RATE/V+T datasheet, MAX16909RATE/V+T pinout, MAX16909RATE/V+T application, or MAX16909RATE/V+T equivalent, key selection considerations include its 42V transient tolerance, 98% max duty cycle at 1MHz, integrated 70mΩ high-side switch, PGOOD monitoring, and thermal/overvoltage/overcurrent protection - all validated across –40°C to +125°C.

Technical Context

The MAX16909RATE/V+T implements constant-frequency current-mode control with internal slope compensation, enabling stable regulation under wide VIN/VOUT differentials and fast load-transient response. Its dual-supply architecture (SUP and SUPSW) isolates bias and switch power domains, allowing sustained 98% duty cycle during 5V cold-crank events while maintaining 5V output regulation.

It features a dedicated BIAS LDO (5V ±5%, 100mA capable), FSYNC synchronization input accepting external clocks up to 10% above internal fSW, and skip-mode operation that reduces no-load current to 30µA by powering internal circuitry from VOUT when VOUT = 3–5.5V.

Key Specifications

Pinout & Package

MAX16909RATE/V+T is packaged in a 16-pin TQFN (5mm × 5mm) with exposed pad, optimized for thermal performance in space-constrained automotive PCBs. The exposed pad must be soldered to a large contiguous copper ground plane for effective heat dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down converter applications.

Compared with LM61480RQR and TPS650361RSLR, MAX16909RATE/V+T uniquely combines automotive-grade temperature range (–40°C to +125°C), 30µA standby current, 98% cold-crank duty cycle, and FSYNC capability - making it the optimal choice for safety-critical, always-on automotive subsystems where reliability under extreme conditions is non-negotiable.

Availability

MAX16909RATE/V+T is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC power supplies, ADAS camera modules, and telematics control units requiring stable component supply across extended temperature and long product lifecycles.

Supply support for MAX16909RATE/V+T 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

Maxim Integrated, now part of Analog Devices, designs precision analog, mixed-signal, and power-management ICs for automotive, industrial, and communications markets.

The MAX16909RATE/V+T belongs to Maxim's automotive-grade power-management portfolio, engineered specifically for demanding 12V/24V vehicle electrical systems requiring high reliability, low quiescent current, and robust transient handling.

FAQ

What is the maximum input voltage transient the MAX16909RATE/V+T can withstand?

The MAX16909RATE/V+T withstands 42V input transients for durations under 1 second, complying with ISO 7637-2 Pulse 5a (load dump) requirements. This eliminates the need for external TVS diodes in most automotive applications, reducing system cost and PCB area while ensuring uninterrupted operation during alternator load-dump events.

Does the MAX16909RATE/V+T support fixed 5V output without external resistors?

Yes, the MAX16909RATE/V+T supports fixed 5V output by connecting the FB pin directly to the BIAS pin. This configuration disables the feedback divider, leverages the internal 1.0V reference, and reduces quiescent current to 30µA - ideal for automotive modules requiring minimal external components and ultra-low standby power.

How does the MAX16909RATE/V+T achieve 98% duty cycle during cold-crank conditions?

The MAX16909RATE/V+T achieves 98% duty cycle by separating the bias supply (SUP) from the switch supply (SUPSW), allowing the control loop to sustain near-maximum on-time even when SUPSW drops to 5V. This dual-rail architecture maintains 5V output regulation during automotive cold-crank events, unlike single-supply buck converters that fail below ~7V input.

What is the purpose of the I.C. pin on the MAX16909RATE/V+T?

Pin 16 (I.C.) on the MAX16909RATE/V+T is an internally connected terminal that must be tied to GND for proper device operation. It is not a functional signal pin and serves no user-accessible purpose; leaving it floating may cause undefined behavior or startup failure.

Can the MAX16909RATE/V+T synchronize to an external clock, and what are the requirements?

Yes, the MAX16909RATE/V+T synchronizes to an external clock applied to the FSYNC pin. The external clock frequency must exceed the internal oscillator frequency by at least 10% (e.g., 440kHz for a 400kHz internal setting) and meet TTL/CMOS logic thresholds (V_{FSYNC_HI} ≥ 1.4V, V_{FSYNC_LO} ≤ 0.4V). Synchronization enables EMI reduction in multi-converter systems.