Analog Devices Inc./Maxim Integrated MAX17640AATA+T

Overview

MAX17640AATA+T from Analog Devices is a Himalaya-series synchronous step-down DC-DC converter with integrated high-side pMOS and low-side nMOS FETs, delivering up to 400mA at a fixed 3.3V output from a 4.5V–60V input. It employs peak-current-mode control, supports PWM/PFM mode selection via the MODE pin, and features internal soft-start, EN/UVLO threshold programming, and open-drain RESET for output monitoring. It targets space-constrained industrial power rails such as 4–20mA sensor transmitters.

For engineers reviewing the MAX17640AATA+T datasheet, MAX17640AATA+T pinout, MAX17640AATA+T application, or MAX17640AATA+T equivalent, key selection considerations include its 8-pin 2mm×2mm TDFN package, 3.3V fixed output with ±1.5% regulation accuracy, 465–535kHz switching frequency, 92% peak efficiency, and -40°C to +125°C ambient operating range.

Technical Context

The MAX17640AATA+T implements a fixed-frequency, internally compensated current-mode control architecture with cycle-by-cycle peak current limiting (0.62A typical) and hiccup-mode overcurrent protection. Its MODE pin latches at power-up to select between constant-frequency PWM (for EMI-sensitive systems) and PFM (for >90% light-load efficiency).

It integrates a 5V LDO (VCC) with 4.75V–5.25V output, 150mV dropout, and UVLO (3.8V falling), plus an EN/UVLO input with programmable 1.215V rising threshold and 2.2µA shutdown current. The FB/VOUT pin is internally connected to the 3.3V output divider, eliminating external resistors.

Key Specifications

Pinout & Package

MAX17640AATA+T is housed in an 8-pin, 2mm × 2mm, 0.5mm pitch TDFN package (package code T822CN+1) with exposed thermal pad for enhanced power dissipation. The pinout is validated per Analog Devices' official datasheet (Rev 1, 7/23) and EE-Sim® reference designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM5164QDDARQ1 and TPS54240DGQR, the MAX17640AATA+T offers superior integration for fixed 3.3V industrial rails - combining internal feedback, RESET, prebias startup, and 2mm×2mm packaging - while delivering lower system cost and faster time-to-market for non-automotive applications.

Availability

MAX17640AATA+T is available at Aetrix Electronics and suitable for industrial sensors, 4–20mA current loops, and HVAC control systems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for MAX17640AATA+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

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The MAX17640 family belongs to Analog Devices' Himalaya power portfolio, designed specifically for compact, high-efficiency, wide-input industrial DC-DC conversion where thermal performance, reliability, and minimal external components are critical.

FAQ

What is the output voltage tolerance of the MAX17640AATA+T under full load and temperature range?

The MAX17640AATA+T delivers a fixed 3.3V output with ±1.5% regulation accuracy over -40°C to +125°C ambient temperature and full 400mA load. This is verified per Electrical Characteristics table (VOUT-REG = 3.25V to 3.35V at MODE = GND, TA = -40°C to +125°C). The MAX17640AATA+T achieves this using an internal precision feedback divider and trimmed reference, eliminating external resistor drift errors.

Does the MAX17640AATA+T support startup into a prebiased output, and how is it implemented?

Yes, the MAX17640AATA+T supports monotonic startup into a prebiased output in both PWM and PFM modes. During startup, the internal error amplifier reference ramps up while the high-side FET remains off until the feedback voltage reaches regulation level - preventing reverse current flow and output capacitor discharge. This behavior is confirmed in the Detailed Description section and enables safe power sequencing in multi-rail systems containing the MAX17640AATA+T.

What is the function of the MODE pin on the MAX17640AATA+T, and how does it affect efficiency?

The MODE pin on the MAX17640AATA+T selects between forced-PWM (MODE = GND) and PFM (MODE floating) operation. In PFM mode, the MAX17640AATA+T skips switching cycles at light loads (<90mA), disabling negative inductor current and reducing quiescent current to 95µA typical - boosting light-load efficiency above 85%. In PWM mode, it maintains constant 500kHz frequency but draws 2.5mA typical IQ, trading efficiency for EMI predictability.

How does the RESET pin on the MAX17640AATA+T behave during undervoltage and recovery events?

The RESET pin on the MAX17640AATA+T is an open-drain output that pulls low when FB/VOUT falls below 92% of 3.3V (i.e., 3.036V), indicating output undervoltage. It transitions to high-impedance 2ms after FB/VOUT rises above 95% of 3.3V (3.135V). This hysteresis and delay prevent chatter during marginal conditions and provide clean reset signaling to downstream MCUs - a behavior explicitly specified in the Electrical Characteristics and Pin Description sections for the MAX17640AATA+T.

Can the MAX17640AATA+T replace a linear regulator in a high-input-voltage application, and what thermal benefits does it offer?

Yes, the MAX17640AATA+T is engineered as a direct replacement for inefficient high-input-voltage LDOs (e.g., 24V-to-3.3V). At 400mA load, a linear regulator would dissipate (24V – 3.3V) × 0.4A = 8.3W, whereas the MAX17640AATA+T dissipates only ~0.3W (92% efficient), reducing board temperature rise by >40°C in typical 4-layer PCB layouts. Its 2mm×2mm TDFN package with exposed thermal pad further enhances thermal performance versus SOIC-8 or TO-220 LDO packages.