Analog Devices Inc./Maxim Integrated MAX16939ATERB/V+T

Overview

MAX16939ATERB/V+T from Maxim Integrated is a 3.5A, 36V input automotive-grade current-mode step-down converter with integrated high-side and low-side MOSFETs, 28µA no-load quiescent current, resistor-programmable 220kHz–2.2MHz switching frequency, and fixed 5V output (±2% accuracy). It operates across -40°C to +125°C and supports 98% duty cycle during cold-crank transients in automotive power systems.

For engineers reviewing the MAX16939ATERB/V+T datasheet, MAX16939ATERB/V+T pinout, MAX16939ATERB/V+T application, or MAX16939ATERB/V+T equivalent, this page delivers verified technical context, validated pin functions, confirmed automotive thermal and OVP behavior, and real-world design implications for RF-sensitive power rails and cascaded supply architectures.

Technical Context

The MAX16939ATERB/V+T implements a current-mode control architecture with internal slope compensation, enabling stable operation with fast transient response and inherent cycle-by-cycle current limiting. Its dual-supply inputs (SUP and SUPSW) decouple logic and switch driver power domains, supporting robust operation down to 3.5V input during automotive cold-crank events.

It features a dedicated 180° out-of-phase SYNCOUT signal for interleaved multi-phase designs, automatic LX slew-rate adjustment (4ns at >1.1MHz), and factory-set spread-spectrum modulation (±6%) to reduce EMI-active only when not synchronized to an external clock. The device includes tight overvoltage protection (105% rising threshold) specific to the MAX16939 variant.

Key Specifications

Pinout & Package

MAX16939ATERB/V+T is housed in a 16-pin 5mm × 5mm TQFN-EP package with exposed thermal pad (EP) connected to PGND for enhanced thermal performance. Pin numbering follows standard top-view orientation with EP centered.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX16935ATERB/V+T, the MAX16939ATERB/V+T provides tighter overvoltage protection and factory spread-spectrum for EMI reduction-critical for RF-sensitive automotive modules-while LM61480QRNXTQ1 trades integration for ultra-low IQ and higher peak efficiency, requiring additional layout effort for synchronous rectification.

Availability

MAX16939ATERB/V+T is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera power, and telematics gateway designs requiring stable component supply, AEC-Q100 compliance, and cold-crank resilience.

Supply support for MAX16939ATERB/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 MAX16935/MAX16939 product line targets automotive power conversion with emphasis on cold-crank operation, low IQ, AEC-Q100 qualification, and EMI-aware features like spread-spectrum and FPWM mode.

FAQ

What is the key functional difference between MAX16939ATERB/V+T and MAX16935ATERB/V+T?

The MAX16939ATERB/V+T features a tighter overvoltage protection threshold of 105% (rising) versus 107% for the MAX16935ATERB/V+T, and includes factory-enabled spread-spectrum modulation to reduce EMI. Both share identical pinout, package, quiescent current, and switching frequency range. These differences make MAX16939ATERB/V+T preferred for RF-sensitive automotive applications where output voltage overshoot and conducted emissions must be minimized.

Does MAX16939ATERB/V+T require an external Schottky diode despite having integrated MOSFETs?

Yes, MAX16939ATERB/V+T requires an external Schottky diode connected from LX to AGND. Although it integrates both high-side and low-side MOSFETs, the low-side MOSFET is used only for forced-PWM operation and cannot replace the diode's role in all operating conditions-particularly during startup, fault recovery, and certain light-load transitions. The diode ensures reliable conduction path and improves efficiency across the full load range.

How does the MAX16939ATERB/V+T handle cold-crank conditions below 6V input?

MAX16939ATERB/V+T sustains regulation during cold-crank events by operating up to 98% duty cycle, allowing V_OUT = 5V even when V_SUP drops to 3.5V. Its dual-supply architecture (SUP and SUPSW) isolates logic and switch driver domains, preventing lockup. The device remains functional across -40°C to +125°C and includes thermal shutdown with automatic recovery, ensuring robustness during prolonged low-voltage operation typical in automotive engine start scenarios.

Can MAX16939ATERB/V+T be synchronized to an external clock, and what are the timing constraints?

Yes, MAX16939ATERB/V+T can synchronize to an external clock applied to the FSYNC pin. The external clock frequency must be within ±20% of the internal oscillator frequency, with minimum pulse width ≥100ns. The device locks to the external clock within one cycle and reverts to internal oscillation if the external signal is absent for >2 cycles. Spread-spectrum modulation is disabled during external sync, but any modulation present on the input clock passes through to SYNCOUT.

What is the purpose of the 180° out-of-phase SYNCOUT signal in MAX16939ATERB/V+T?

The SYNCOUT pin on MAX16939ATERB/V+T outputs an open-drain 180° out-of-phase clock signal relative to the internal oscillator. This enables direct cascading of multiple MAX16939ATERB/V+T devices in interleaved configurations-reducing input/output ripple, improving thermal distribution, and easing EMI filter design. No external phase-shift circuitry is needed, simplifying multi-rail power architectures in automotive ADAS and infotainment systems.