Analog Devices Inc./Maxim Integrated MAX5429EGA

Overview

MAX5429EGA from Maxim Integrated is a one-time programmable, linear-taper digital potentiometer with 10kΩ end-to-end resistance, 32 wiper positions, and ultra-low 1.5µA static supply current. It replaces mechanical potentiometers in precision calibration circuits, operates from 2.7V to 5.5V, and features a 2-wire serial interface for wiper adjustment and optional POR position programming.

For engineers reviewing the MAX5429EGA datasheet, MAX5429EGA pinout, MAX5429EGA application, or MAX5429EGA equivalent, key selection criteria include its 10kΩ resistance value, QFN-EP package with exposed paddle (GND), ±2.0mA max wiper current, 35ppm/°C end-to-end tempco, and one-time programmability for factory-set power-on reset position.

Technical Context

The MAX5429EGA implements a resistor ladder with 32 discrete tap points between H and L terminals, controlled via a 2-wire CS/U/D interface. Its internal up/down counter drives wiper position, and a dedicated one-time programmable block stores either POR position (5-pulse mode) or locks wiper + disables interface (6-pulse mode).

It uses BiCMOS process technology (2270 transistors), supports make-before-break wiper switching, and guarantees operation over –40°C to +85°C. The VPP pin accepts 11V for programming, while normal operation requires VPP tied to GND or left floating.

Key Specifications

Pinout & Package

MAX5429EGA is housed in an 8-pin QFN-EP package (3mm × 3mm, 0.5mm pitch) with exposed thermal paddle electrically connected to GND. This package enables low-inductance grounding and improved thermal performance in space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital potentiometer applications.

Compared with AD5170BRMZ-10 and MCP45HV51-103E/MS, the MAX5429EGA uniquely offers irreversible interface disablement and guaranteed 1.5µA quiescent current-making it optimal for unattended, maintenance-free calibration in sealed industrial or medical enclosures.

Availability

MAX5429EGA is available at Aetrix Electronics and suitable for medical sensor calibration, industrial analog input conditioning, automotive cabin temperature sensor trim, and test equipment auto-calibration requiring stable component supply and long-term calibration integrity.

Supply support for MAX5429EGA 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 and mixed-signal ICs for industrial, medical, and communications applications, emphasizing low-power, high-reliability performance.

The MAX5427/MAX5428/MAX5429 family targets factory-programmable analog trimming-delivering mechanical potentiometer replacement with nonvolatile, tamper-resistant calibration storage in miniature packages.

FAQ

What is the maximum wiper current rating for MAX5429EGA?

The MAX5429EGA supports a maximum continuous wiper current of ±2.0mA. This rating is confirmed in the Absolute Maximum Ratings table and applies across the full –40°C to +85°C operating temperature range. Exceeding this current may cause irreversible damage to the internal resistor ladder or wiper switch. The MAX5429EGA's 10kΩ end-to-end resistance and ±2.0mA limit define safe operating voltage ranges-for example, ≤20V across H–L in variable-resistor mode. Always verify current paths in your schematic before finalizing layout.

Can MAX5429EGA be reprogrammed after initial one-time programming?

No, MAX5429EGA cannot be reprogrammed after one-time programming. Its OTP (one-time programmable) block uses fusible links-once programmed (with either 5 or 6 pulses), the stored wiper position or lockout state is permanent. Five pulses set the power-on reset position but leave the interface active; six pulses both set POR and disable CS/U/D permanently. There is no erase or rewrite capability. For applications requiring field updates, consider alternatives like EEPROM-based digital pots-but note they lack the MAX5429EGA's guaranteed 1.5µA static current and irreversible lockout.

What is the function of the VPP pin on MAX5429EGA?

The VPP pin on MAX5429EGA serves exclusively for one-time programming: it must be supplied with 11V (±0.55V) during the programming sequence to enable fuse blowing in the OTP block. During normal operation, VPP must be connected to GND or left floating-applying voltage to VPP outside programming will damage the device. The datasheet specifies that VPP requires ≥5mA sourcing capability and low-impedance decoupling (22µF capacitor with <40Ω parasitic resistance). No current flows into VPP during standard operation, making it safe to omit external components when not programming.

How does the MAX5429EGA differ from MAX5427EGA and MAX5428EGA?

The MAX5429EGA differs from MAX5427EGA and MAX5428EGA solely in end-to-end resistance: MAX5429EGA is 10kΩ, MAX5428EGA is 50kΩ, and MAX5427EGA is 100kΩ. All three share identical pinout, package (8-pin QFN-EP), 32-tap resolution, 2.7V–5.5V supply, 1.5µA IDD, 35ppm/°C tempco, and OTP functionality. Wiper current ratings differ slightly: MAX5429EGA supports ±2.0mA, while MAX5427EGA/MAX5428EGA support ±1.5mA. Selection depends on required impedance level for signal chain loading, power dissipation, and noise sensitivity-10kΩ suits low-impedance op-amp interfaces, while 100kΩ minimizes supply current draw in high-impedance bias networks.

Is the exposed paddle on the MAX5429EGA QFN package required to be grounded?

Yes, the exposed paddle on the MAX5429EGA QFN package must be soldered to a PCB pad connected to GND. The datasheet explicitly states "EXPOSED PADDLE. CONNECTED TO GND" in the Pin Configurations section. This connection provides critical thermal dissipation (enabling 1951mW power handling at +70°C) and reduces ground inductance for stable analog performance. Leaving the paddle unconnected or floating violates Absolute Maximum Ratings and risks thermal runaway or increased noise susceptibility. Use ≥4 thermal vias under the paddle, each ≥0.3mm diameter, connected to an internal GND plane.