Analog Devices Inc./Maxim Integrated MAX4520EUA

Overview

The MAX4520EUA from Maxim Integrated is a normally open (NO), fault-protected, single-pole/single-throw (SPST) analog switch with rail-to-rail signal handling, ±36V fault protection under power, and 160Ω maximum on-resistance at ±15V supplies. It operates from dual supplies (±4.5V to ±20V) or single +9V to +36V, features 0.5nA off-leakage at +25°C, and is housed in an 8-pin µMAX package. It is used in industrial process-control systems where overvoltage transients must be contained without signal path interruption.

For engineers reviewing the MAX4520EUA datasheet, MAX4520EUA pinout, MAX4520EUA application, or MAX4520EUA equivalent, key selection considerations include fault voltage rating with/without power, rail-to-rail analog signal range, leakage performance across temperature, logic compatibility with TTL/CMOS, and µMAX package thermal derating (4.10mW/°C above +70°C).

Technical Context

The MAX4520EUA uses parallel N- and P-channel FETs (N1/P1) for low on-resistance and rail-to-rail conduction, unlike traditional triple-FET fault-protected switches. Two dedicated comparators continuously monitor NO pin voltage against V+ and V− to detect faults exceeding supply rails by ~50mV.

During positive or negative overvoltage faults, N1/P1 turn off-making the NO pin high-impedance-while booster FETs (P2/N2) activate to clamp COM to V+ or sink from V−, delivering up to ±13mA. Fault response delay is <10ns; recovery times are 3.5µs (positive) and 1.3µs (negative), dependent on COM load capacitance and resistance.

Key Specifications

Pinout & Package

Package: 8-pin µMAX (3mm × 3mm, 0.8mm height, exposed pad). Thermal resistance θ_JA = 244°C/W; derating 4.10mW/°C above +70°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADG5412BRUZ and TMUX6212RUMR, the MAX4520EUA uniquely combines unpowered ±40V fault tolerance, rail-to-rail clamping with active current sourcing/sinking, and compact µMAX packaging - making it optimal for space-constrained, safety-critical systems requiring guaranteed protection during power loss.

Availability

The MAX4520EUA is available at Aetrix Electronics and suitable for industrial process-control systems, avionics sensor interfaces, and ATE equipment requiring stable component supply, long-term lifecycle support, and guaranteed fault-protection specifications across temperature.

Supply support for MAX4520EUA 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 demanding industrial, automotive, and communications applications.

The MAX4520EUA belongs to Maxim's fault-protected analog switch product line, engineered specifically for robust signal routing in harsh environments where wiring faults, ESD, and power interruptions must not compromise system integrity.

FAQ

What is the maximum fault voltage the MAX4520EUA can withstand when powered versus unpowered?

The MAX4520EUA withstands ±36V on the NO pin with power applied (V+ and V− active), and ±40V with all supplies at 0V. This unpowered rating is critical for systems experiencing brownouts or hot-swap events. The COM and IN pins are not fault-protected - their voltages must stay within V− to V+ at all times to prevent damage via internal ESD diodes. The MAX4520EUA datasheet specifies these limits in Absolute Maximum Ratings (Note 2).

Does the MAX4520EUA require power-supply sequencing, and what happens if V+ and V− are applied out of order?

No, the MAX4520EUA requires no power-supply sequencing: V+, V−, and IN may be powered in any order without risk of latch-up or undefined behavior. Internal logic-level translators isolate digital control from analog switching paths, and the device defaults to OFF (NO open) when power is absent. This feature simplifies system design in modular or hot-pluggable architectures where supply ramp timing cannot be controlled. The MAX4520EUA truth table confirms all switches are OFF with power removed.

How does the MAX4520EUA achieve rail-to-rail signal handling despite using CMOS FETs?

The MAX4520EUA achieves rail-to-rail conduction by paralleling complementary N- and P-channel FETs (N1 and P1) between NO and COM. Their gates are driven out-of-phase by internal level translators referenced to V+ and V−, ensuring one FET remains enhanced across the full input range - from V− to V+. Unlike conventional single-FET switches that cut off near the rails, this architecture maintains low R_ON throughout. The MAX4520EUA functional diagram (Figure 1) illustrates this dual-FET topology and its gate-drive scheme.

What is the role of the two NC pins (pins 5 and 6) on the MAX4520EUA µMAX package?

Pins 5 and 6 on the MAX4520EUA are no-connect (NC) terminals - they are not bonded to the die and serve no electrical function. Per Maxim's package drawing and pin description table, these pins must be left unconnected (floating) or optionally tied to GND for mechanical stability; neither connection affects operation. Routing traces or applying solder to NC pins is unnecessary and may risk shorting adjacent terminals due to the µMAX's fine pitch (0.65mm). The MAX4520EUA pin configuration diagram explicitly labels both as "N.C."

Can the MAX4520EUA be used with a single +12V supply, and how does performance differ from ±15V operation?

Yes, the MAX4520EUA operates from a single +12V supply with V− tied to GND. On-resistance increases slightly (260Ω typical vs. 160Ω at ±15V) due to reduced gate overdrive on the P-channel FET, and fault recovery time lengthens marginally. Logic thresholds remain compatible (+0.8V / +2.4V), and fault protection holds at ±36V (powered). The MAX4520EUA Electrical Characteristics tables provide separate columns for single +12V and dual ±15V conditions, confirming all key specs remain valid across both configurations.