Analog Devices Inc./Maxim Integrated MAX16909RATE/V+

Overview

MAX16909RATE/V+ from Maxim Integrated is a 3A, current-mode, automotive-grade step-down DC-DC converter with integrated 70mΩ high-side MOSFET, operating from 3.5V to 36V input and delivering 5V fixed or 1V–10V adjustable output. It features 30µA no-load quiescent current, 220kHz–1MHz resistor-programmable switching frequency, and operates across –40°C to +125°C for engine control units and ADAS power rails.

For engineers reviewing the MAX16909RATE/V+ datasheet, MAX16909RATE/V+ pinout, MAX16909RATE/V+ application, or MAX16909RATE/V+ equivalent, this page delivers verified electrical specs, thermal behavior under load-dump transients, skip-mode efficiency trade-offs, and validated pin-level interface guidance for automotive power-supply sequencing and cold-crank operation.

Technical Context

The MAX16909RATE/V+ implements constant-frequency current-mode control with internal slope compensation, enabling stable regulation at up to 98% duty cycle during undervoltage transients (e.g., 5V cold-crank). Its dual supply inputs-SUP (3.5V–36V for bias circuitry) and SUPSW (3.5V–36V for high-side switch)-allow independent voltage handling and maintain regulation even when SUPSW drops below VOUT.

It integrates a 5V/100mA linear regulator (BIAS), a transconductance error amplifier (gm = 900µS), and a programmable soft-start (8.5ms). The FSYNC input accepts external clocks ≥10% above internal fSW, while the 110ns minimum on-time ensures reliable 1MHz operation at high VIN–VOUT differentials.

Key Specifications

Pinout & Package

MAX16909RATE/V+ is packaged in a 16-pin TQFN (5mm × 5mm) with exposed pad, optimized for thermal dissipation in high-power-density automotive modules. Pin functions are electrically identical to the TSSOP variant but with improved thermal performance (θ_JA = 35°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM61480QPWPRQ1 and TPS543B20RTWT, MAX16909RATE/V+ uniquely combines cold-crank capability (5V operation), integrated 5V BIAS LDO, and 42V transient tolerance-making it the only option among the three qualified for direct connection to automotive battery without upstream protection.

Availability

MAX16909RATE/V+ is available at Aetrix Electronics and suitable for automotive ECU power supplies, ADAS camera modules, and infotainment head units requiring stable component supply across extended temperature and transient conditions.

Supply support for MAX16909RATE/V+ 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+ belongs to Maxim's automotive power-management portfolio, engineered specifically for harsh-environment DC-DC conversion in engine control, ADAS, and body electronics where cold-crank resilience and low IQ are mandatory.

FAQ

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

The MAX16909RATE/V+ tolerates 42V input transients for durations less than 1 second, complying with ISO 7637-2 Pulse 5a (load dump) requirements. This rating applies to both SUP and SUPSW pins, eliminating the need for external TVS diodes in most automotive battery-connected applications. The device remains fully functional during and after the transient event, with automatic recovery from overvoltage protection if triggered.

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

Yes, the MAX16909RATE/V+ supports fixed 5V output by connecting the FB pin directly to the BIAS pin. This configuration disables the external feedback divider, reduces component count, and ensures factory-trimmed 5V ±1.5% accuracy across temperature. The internal 5V BIAS regulator supplies both internal circuitry and the feedback reference, enabling true resistorless 5V operation.

How does the MAX16909RATE/V+ behave during cold-crank (5V battery condition)?

During cold-crank, the MAX16909RATE/V+ maintains regulation by operating at up to 98% duty cycle, enabled by its dual-supply architecture (SUP and SUPSW). Even when SUPSW sags below the target output voltage, the controller sustains output by maximizing on-time. This behavior is confirmed in the "Undervoltage Pulse" test waveform (Figure toc10), showing stable 5V output under 5V/20ms input dip with 3A resistive load.

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

The I.C. pin (Pin 16) on the MAX16909RATE/V+ is internally connected and must be tied to GND for proper operation. It serves no user-accessible function and is reserved for internal wafer-level testing. Leaving it floating or connecting it to any other voltage violates the absolute maximum ratings and may cause malfunction or damage. The datasheet explicitly states "Connect to ground for proper operation."

Can the MAX16909RATE/V+ be synchronized to an external clock, and what are the constraints?

Yes, the MAX16909RATE/V+ accepts external synchronization via the FSYNC pin. The external clock frequency must exceed the internal oscillator frequency by at least 10% for reliable acquisition, and the input must meet CMOS logic thresholds (V_{FSYNC_HI} = 1.4V, V_{FSYNC_LO} = 0.4V). Synchronization occurs within one clock cycle (t_FSYNC = 1 cycle), enabling precise EMI alignment in multi-converter systems such as automotive domain controllers.