Analog Devices Inc./Maxim Integrated MAX4509CPE

Overview

MAX4509CPE from Maxim Integrated is a dual 4-to-1 fault-protected analog multiplexer in 16-pin plastic DIP package, operating from ±4.5V to ±20V dual supplies or +9V to +36V single supply, featuring ±40V overvoltage protection with supplies off, 400Ω max on-resistance, and rail-to-rail signal handling - used in avionics signal routing and industrial redundant systems.

For engineers reviewing the MAX4509CPE datasheet, MAX4509CPE pinout, MAX4509CPE application, or MAX4509CPE equivalent, key selection criteria include fault-protection voltage margins (±40V power-off), dual 4-channel switching architecture, TTL/CMOS-compatible logic inputs, and output clamping behavior during overvoltage events.

Technical Context

The MAX4509CPE implements two independent 4-to-1 analog multiplexers (COMA/NO1A–NO4A and COMB/NO1B–NO4B) using parallel N- and P-channel FETs per channel to achieve rail-to-rail conduction and low on-resistance. Each NO_ input features dedicated comparators that detect excursions beyond V+ or V− by ~150mV, triggering immediate high-impedance isolation and output clamping via booster FETs.

Fault response is asymmetric: positive faults clamp COM to V+ via P2 FET; negative faults clamp COM to V− via N2 FET. Recovery times are 2.5µs (positive) and 1.3µs (negative), dependent on COM load capacitance and resistance - not fault amplitude. COM and address pins lack fault protection and must remain within supply rails.

Key Specifications

Pinout & Package

MAX4509CPE uses a 16-pin plastic DIP (P16-4) package with 0.300" width, lead-free finish, and through-hole mounting compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADG509FBRZ and MAX4509EPE+, the MAX4509CPE uniquely delivers dual independent 4-to-1 switching in a through-hole DIP package with commercial-temp cost efficiency - ideal for prototyping, legacy board upgrades, and avionics test fixtures where mechanical robustness and hand-solderability matter.

Availability

MAX4509CPE is available at Aetrix Electronics and suitable for avionics signal routing, industrial redundant systems, and data-acquisition front-ends requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for MAX4509CPE 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, mixed-signal, and power management ICs for demanding industrial, automotive, and communications applications.

The MAX4509CPE belongs to Maxim's fault-protected analog switch family, engineered specifically for high-reliability signal routing in harsh environments where overvoltage transients, power interruptions, and system redundancy are critical design constraints.

FAQ

What is the maximum allowable voltage on NO_ pins of the MAX4509CPE when power supplies are off?

The MAX4509CPE provides ±40V fault protection on NO_ pins with supplies off - meaning voltages from -40V to +40V relative to ground are safely tolerated without damage. This capability enables safe connection to unpowered sensor lines or field wiring during maintenance. The MAX4509CPE achieves this via internal high-impedance isolation and ESD diode structures that remain functional even with V+ and V− at 0V.

Does the MAX4509CPE support single-supply operation, and what is the valid voltage range?

Yes, the MAX4509CPE operates from a single supply of +9V to +36V, with V− tied to GND. In this mode, it maintains full fault protection (±25V on NO_ with +12V supply), rail-to-rail signal handling, and TTL/CMOS-compatible logic thresholds. The MAX4509CPE's internal level translators ensure correct gate drive regardless of supply configuration - eliminating need for external logic-level shifters.

Why are COMA and COMB pins not fault-protected on the MAX4509CPE?

COMA and COMB pins lack fault protection because they connect directly to the analog signal path output stage and internal clamp FETs (P2/N2). Exceeding V− to V+ on these pins forward-biases ESD diodes to the supplies, risking permanent damage. The MAX4509CPE datasheet explicitly states COM pins must be limited to supply rails - unlike NO_ pins, which feature dedicated comparator-based protection circuitry.

What is the on-resistance matching specification for the MAX4509CPE, and why does it matter?

The MAX4509CPE guarantees ≤15Ω maximum on-resistance mismatch (ΔR_ON) between any two channels. This tight matching ensures consistent gain and phase response across multiplexed signal paths - critical in applications like multi-channel data acquisition where channel-to-channel ratio accuracy affects measurement fidelity. The MAX4509CPE achieves this via matched FET sizing and symmetric layout in its dual-mux die structure.

Can the MAX4509CPE be used in a hot-swap application where power is applied after signal connections?

Yes - the MAX4509CPE is explicitly designed for such scenarios. Its "all channels off with power off" behavior prevents backfeeding, and ±40V NO_ fault tolerance allows safe pre-connection of field signals before power-up. During hot insertion, the MAX4509CPE immediately isolates overvoltage transients without requiring external protection components, making it suitable for modular avionics racks and programmable logic controller I/O carriers.