Analog Devices Inc./Maxim Integrated MAX17521ATG+T

Overview

MAX17521ATG+T from Maxim Integrated is a dual-output, synchronous step-down DC-DC converter with integrated high-side pMOS and low-side nMOS FETs, operating from 4.5V to 60V input and delivering up to 1A per output. It features peak-current-mode control, ±1.7% feedback regulation accuracy over –40°C to +125°C, and pin-selectable 300kHz or 560kHz switching frequency. It is used in industrial CPU/FPGA point-of-load power supplies requiring robust hiccup-mode overload protection and monotonic startup into prebiased loads.

For engineers reviewing the MAX17521ATG+T datasheet, MAX17521ATG+T pinout, MAX17521ATG+T application, or MAX17521ATG+T equivalent, key selection considerations include dual independent EN/UVLO and soft-start pins, per-output RESET monitoring with 92.5%/95.5% thresholds, PFM/PWM mode selection via MODE pins, and thermal shutdown at +165°C with 10°C hysteresis.

Technical Context

The MAX17521ATG+T implements peak-current-mode control with internal transconductance error amplifiers (GM = 510–650 µS) and slope compensation for stable loop response. Each channel uses independent current-sense transresistance (RCS = 0.455–0.545 Ω) and cycle-by-cycle peak current limiting (1.35–1.85 A).

It supports three operational modes per output: PFM (pulse-skipping, >90% peak efficiency, 1 µA shutdown), PWM (constant-frequency, negative inductor current allowed), and hiccup-mode fault recovery (4096-cycle timeout). Frequency synchronization is enabled via SYNC pin accepting 1.1×–1.4× fSW external clocks.

Key Specifications

Pinout & Package

MAX17521ATG+T is housed in a 24-pin, 4mm × 5mm TQFN package with exposed pad (EP) for thermal enhancement. Pin layout supports dual independent buck channels with separate power grounds (PGND1/PGND2), analog grounds (SGND1/SGND2), and dedicated control pins per channel.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output synchronous buck regulator applications.

Compared with LM5164QDPRRQ1 and TPS54240DGQR, the MAX17521ATG+T uniquely delivers dual independent 1A outputs in one package with true PFM efficiency, hiccup-mode protection, and per-rail monitoring-reducing BOM count and simplifying sequencing in industrial and FPGA power systems.

Availability

MAX17521ATG+T is available at Aetrix Electronics and suitable for industrial control power supplies, CPU/DSP/FPGA power, and distributed supply regulation requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX17521ATG+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 high-performance analog and mixed-signal ICs for industrial, automotive, and communications applications.

The MAX17521ATG+T belongs to Maxim's high-voltage DC-DC converter product line, engineered for rugged point-of-load regulation in environments demanding wide input range, thermal resilience, and functional safety features like hiccup-mode protection and monotonic startup.

FAQ

What is the maximum input voltage rating for MAX17521ATG+T?

The MAX17521ATG+T supports an absolute maximum input voltage of +65V across VIN1 and VIN2 pins, with recommended continuous operation from 4.5V to 60V. This enables direct connection to 48V industrial buses and telecom supplies while maintaining margin against transients. Operation above 60V requires verification of thermal derating and duty-cycle constraints per the datasheet's VIN(MIN)/VIN(MAX) equations.

Does MAX17521ATG+T support power sequencing between its two outputs?

Yes, MAX17521ATG+T supports multiple sequencing methods: independent soft-start (via separate SS1/SS2 caps), coincident tracking (tie SS1/SS2 together), or ratiometric tracking (connect SS pins to external resistor dividers). Additionally, EN/UVLO and RESET pins can be daisy-chained across channels or to external controllers to enforce strict turn-on/turn-off order in complex multi-rail systems.

How does the PFM mode improve light-load efficiency in MAX17521ATG+T?

In PFM mode, MAX17521ATG+T skips switching cycles when output voltage exceeds 103% of regulation, entering hibernate state where most internal blocks are disabled. This reduces quiescent current to ~135µA (vs. 5mA in PWM), achieving >85% efficiency at 10mA load. However, output ripple increases and switching frequency becomes variable - making PFM ideal for battery-powered standby but less suitable for noise-sensitive analog circuits.

What thermal performance can be expected from MAX17521ATG+T in a standard four-layer PCB?

On a JEDEC-standard four-layer board, MAX17521ATG+T exhibits θJA = 35°C/W and θJC = 1.8°C/W. With 1A load per channel at 24V input, typical power dissipation is ~450mW, resulting in ~16°C junction-to-ambient rise above ambient. The exposed pad (EP) must be soldered to a solid SGND copper plane to realize this rating; inadequate thermal vias or single-layer layouts will significantly degrade performance and risk thermal shutdown.

Can MAX17521ATG+T operate safely into a prebiased output?

Yes, MAX17521ATG+T guarantees monotonic startup into prebiased outputs. At power-up, both high-side and low-side FETs remain off until the soft-start ramp reaches the output voltage level, preventing reverse current flow and avoiding output voltage droop or overshoot. This behavior is confirmed across –40°C to +125°C and is critical for hot-swap and modular power system applications.