Analog Devices Inc./Maxim Integrated MAX724CCK

Overview

The MAX724CCK from Maxim Integrated is a monolithic, bipolar, PWM switch-mode DC-DC buck regulator with an on-chip 5A NPN power switch, 100kHz fixed-frequency oscillator, and internal current limiting (6.5A typical). It operates from 8V to 40V input and delivers adjustable output voltages from 2.5V to 35V, optimized for high-current step-down conversion in industrial power supplies and distributed bus architectures.

For engineers reviewing the MAX724CCK datasheet, MAX724CCK pinout, MAX724CCK application, or MAX724CCK equivalent, key selection criteria include its TO-220 package thermal performance (2.5°C/W junction-to-case), cycle-by-cycle overcurrent protection, feedback-controlled duty cycle, and compatibility with standard external compensation networks using VC and FB pins.

Technical Context

The MAX724CCK implements a classic synchronous-buck–compatible topology using an internal NPN power switch driven by a 100kHz oscillator and error amplifier with 5000 µmho transconductance. Its current-limit comparator responds within ~600ns to overcurrent events, and the VC pin provides direct access to the error amplifier output for external compensation or synchronization.

It supports multiple configurations beyond buck mode-including inverting, negative-boost, and flyback-enabled by its VSW node's ability to swing 35V below ground and its wide 8V–40V input range (5V minimum in inverting/boost modes). The device features a preset 2.21V reference and uses a single-series RC network from VC to GND for loop stability.

Key Specifications

Pinout & Package

The MAX724CCK is housed in a 5-pin TO-220 package with case connected to GND; staggered leads are standard, straight leads available on request.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar switch-mode DC-DC regulator applications.

Compared with LM2596S-5.0 and TPS54560B, the MAX724CCK offers unique multi-topology operation and robust 5A bipolar switch integration but lacks programmable frequency and modern thermal metrics-making it suitable only for legacy redesigns or niche inverting/flyback implementations where its VSW swing and current limit architecture provide decisive advantage.

Availability

MAX724CCK is available at Aetrix Electronics and suitable for industrial power supplies, distributed bus converters, and high-current inverter circuits requiring stable component supply despite end-of-life status.

Supply support for MAX724CCK 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) is a semiconductor company specializing in analog, mixed-signal, and power management ICs for industrial, communications, and computing applications.

The MAX724CCK belongs to Maxim's legacy high-current PWM DC-DC regulator product line, designed specifically for robust, single-chip step-down conversion in harsh environments where reliability and fault tolerance are critical.

FAQ

What is the maximum continuous output current supported by the MAX724CCK?

The MAX724CCK supports up to 5A continuous output current in buck configuration, constrained by its internal 6.5A current limit and thermal limits. Actual achievable current depends on PCB layout, heatsinking, ambient temperature, and input/output voltage differential. At 25°C ambient with adequate TO-220 heatsink, sustained 5A operation is feasible per the 2.5°C/W θ_JC specification. The MAX724CCK datasheet confirms this rating under standard test conditions with VIN = 25V and VOUT = 5V.

Can the MAX724CCK be used in inverting or negative-boost configurations?

Yes, the MAX724CCK can be configured as an inverter or negative-boost converter by reassigning ground connections and leveraging its VSW pin's ability to swing 35V below GND. In inverting mode, GND is tied to the negative output, enabling generation of –5V from +24V input. In negative-boost mode, GND connects to the negative output while VIN is applied to the negative rail. These configurations are explicitly validated in the MAX724CCK datasheet's Typical Applications section.

What is the purpose of the VC pin on the MAX724CCK, and how is it used?

On the MAX724CCK, the VC pin is the error amplifier output, providing direct access to the transconductance amplifier stage (g_m ≈ 5000 µmho). It is used for external compensation via a series RC network to ground, enabling loop stability tuning. The VC pin also accepts external sync pulses (300ns low pulse) to synchronize the 100kHz oscillator to an external clock between 110kHz–160kHz. This dual functionality makes the VC pin essential for both regulation accuracy and system-level timing coordination in the MAX724CCK.

Does the MAX724CCK include built-in protection features?

Yes, the MAX724CCK integrates cycle-by-cycle current limiting that responds within ~600ns to overcurrent or short-circuit faults, protecting both the IC and external components. It also features frequency foldback: when FB voltage drops below ~1.3V (indicating severe overload), the switching frequency reduces from 100kHz to ~20kHz to maintain controllable duty cycle and prevent thermal runaway. These protections are inherent to the MAX724CCK's architecture and require no external components.

Is the MAX724CCK still recommended for new designs?

No, the MAX724CCK is Not Recommended for New Designs per Maxim's official documentation. It was manufactured using an obsolete wafer process no longer available, and Maxim recommends evaluating replacements such as the TPS54560B or industry second-sources. However, Aetrix Electronics maintains traceable inventory and supply support for legacy systems requiring MAX724CCK for repair, maintenance, or long-lifecycle industrial deployments.