Analog Devices Inc./Maxim Integrated MAX4521EGE

Overview

MAX4521EGE from Maxim Integrated is a quad, low-voltage, normally closed (NC) SPST analog switch IC designed for precision signal routing in battery-powered and mixed-signal systems. It features 100Ω max on-resistance (±5V supplies), 4Ω max channel-to-channel on-resistance matching, rail-to-rail analog signal handling (±6V dual or +12V single supply), and 1nA max off-leakage at +25°C. It is used in data acquisition front-ends where low distortion and minimal charge injection are critical.

For engineers reviewing the MAX4521EGE datasheet, MAX4521EGE pinout, MAX4521EGE application, or MAX4521EGE equivalent, key selection considerations include its NC configuration, QFN-EP 16-pin package with exposed pad tied to V+, -40°C to +85°C industrial temperature range, and compatibility with TTL/CMOS logic under ±5V or +5V supply conditions.

Technical Context

The MAX4521EGE implements four independent CMOS transmission gates with complementary N- and P-channel MOSFETs per switch, enabling bidirectional rail-to-rail analog conduction. Its logic-level translators isolate digital control inputs (IN1–IN4) from analog supplies (V+, V−), supporting TTL/CMOS thresholds (0.8V/2.4V) regardless of supply configuration.

Internal ESD protection diodes clamp analog pins to V+ and V−, limiting signal excursion beyond supply rails. The exposed-pad QFN package (G1644-1) provides low thermal resistance and requires EP connection to V+ for optimal performance and ESD robustness (>2kV per Method 3015.7).

Key Specifications

Pinout & Package

The MAX4521EGE is housed in a 16-pin QFN-EP package (4mm × 4mm × 0.9mm, pkg code G1644-1) with an exposed thermal pad that must be soldered to V+ for electrical and thermal performance. Pin 1 is located at the bottom-left corner adjacent to the marking dot.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog switch applications.

Compared with MAX4522EGE (NO variant) and ADG1411BRUZ (higher-voltage alternative), the MAX4521EGE offers optimal NC default behavior, QFN thermal performance, and seamless DG211 footprint compatibility - making it ideal for compact, battery-operated, fail-closed signal routing.

Availability

MAX4521EGE is available at Aetrix Electronics and suitable for portable instrumentation, avionics signal conditioning, and industrial PLC analog I/O modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX4521EGE 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 high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The MAX4521/MAX4522/MAX4523 family was engineered for low-voltage, low-leakage, rail-to-rail analog switching in space- and power-constrained systems - emphasizing precision, reliability, and direct upgrade paths from legacy DG-series switches.

FAQ

What is the default switch state of the MAX4521EGE?

The MAX4521EGE features four normally closed (NC) SPST switches. When the digital input (IN1–IN4) is logic low (≤0.8V), the corresponding switch conducts between COMx and NCx. When the input is logic high (≥2.4V), the switch opens. This fail-closed behavior ensures signal continuity during power-up, reset, or control failure - a critical safety feature in measurement and control systems using MAX4521EGE.

Can the MAX4521EGE operate from a single 3.3V supply?

Yes, the MAX4521EGE supports single-supply operation from +2.7V to +3.6V. At V+ = 3.3V, typical on-resistance is 260Ω, and logic thresholds remain compatible (0.8V/2.4V). However, analog signal range is limited to 0V to 3.3V, and leakage increases slightly versus ±5V operation. System design must ensure all analog signals stay within this rail-to-rail window when using MAX4521EGE in 3.3V-only systems.

How should the exposed pad (EP) on the MAX4521EGE QFN package be connected?

Per Maxim's datasheet, the exposed pad (Pin EP) of the MAX4521EGE must be soldered directly to the V+ net on the PCB. It is electrically connected to the die substrate and serves both thermal dissipation and ESD current return functions. Leaving EP floating or connecting it to GND violates the device's internal biasing and may cause latch-up or degraded ESD performance. Proper EP-to-V+ connection is mandatory for reliable operation of MAX4521EGE.

Does the MAX4521EGE require external ESD protection?

No, the MAX4521EGE integrates >2kV HBM ESD protection on all pins per Method 3015.7, eliminating the need for external TVS diodes in most applications. Its internal clamping diodes route ESD transients to V+ and V−, provided those supplies are adequately decoupled (e.g., 0.1µF ceramic capacitors near V+/V− pins). External protection is only recommended in extreme environments exceeding IEC 61000-4-2 Level 4 - and even then, MAX4521EGE's robust on-chip protection reduces component count versus unprotected alternatives.

Is the MAX4521EGE pin-compatible with the DG211?

Yes, the MAX4521EGE is explicitly designed as a pin-compatible upgrade to the industry-standard DG211 in QFN-EP packaging. Both share identical pin functions, NC switch topology, and logic polarity. However, MAX4521EGE improves on DG211 with lower on-resistance (100Ω vs. 120Ω), tighter RON matching (4Ω vs. 10Ω), and enhanced ESD rating (>2kV vs. 2kV). No PCB layout changes are required when replacing DG211 with MAX4521EGE in existing designs.