Analog Devices Inc./Maxim Integrated MAX321ESA+T

Overview

MAX321ESA+T from Maxim Integrated is a precision dual-channel normally closed (NC) analog switch IC operating from ±3V to ±8V dual supplies. It delivers 35Ω max on-resistance, <2Ω channel-to-channel R_ON matching, and <4Ω R_ON flatness at ±5V, with 150ns max turn-on time and 100pA max leakage - enabling high-fidelity signal routing in ±5V DAC/ADC interfaces and battery-powered test equipment.

For engineers reviewing the MAX321ESA+T datasheet, MAX321ESA+T pinout, MAX321ESA+T application, or MAX321ESA+T equivalent, key selection criteria include bipolar supply compatibility, guaranteed NC logic behavior, low charge injection (<5pC), ESD robustness (>2000V), and SO-8 package suitability for space-constrained industrial signal conditioning designs.

Technical Context

The MAX321ESA+T implements complementary MOSFET-based SPST switches with integrated level-shifting logic to ensure reliable NC operation across its full ±3V to ±8V supply range. Its internal architecture guarantees break-before-make timing only in the MAX322 variant - not applicable here - and uses substrate-biased design (substrate tied to V+) to minimize leakage over temperature.

All channels support bidirectional analog signal switching from V− to V+, with on-resistance variation tightly controlled (<4Ω flatness) and leakage limited to <2.5nA at +85°C. Charge injection is minimized to 2pC typical (5pC max) via matched transistor sizing and layout symmetry, critical for sample-and-hold accuracy.

Key Specifications

Pinout & Package

MAX321ESA+T is housed in an 8-pin SO (Small Outline) package, 3.9mm × 4.9mm body size, with standard 1.27mm lead pitch and gull-wing leads. RoHS-compliant, surface-mount compatible, rated for −40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX321ESA+T, MAX321EPA+ offers identical performance in a through-hole package ideal for development, while ADG1412BRUZ trades native bipolar logic compatibility for lower R_ON - making MAX321ESA+T optimal for cost-sensitive, volume SMT deployments in established ±5V signal chains.

Availability

MAX321ESA+T is available at Aetrix Electronics and suitable for battery-operated test equipment, ±5V data acquisition systems, and military radio signal conditioning requiring stable component supply, full traceability, and long-term lifecycle support.

Supply support for MAX321ESA+T 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 U.S.-based semiconductor company specializing in high-performance analog and mixed-signal ICs for industrial, communications, and automotive markets.

The MAX320/MAX321/MAX322 family was designed specifically for precision analog signal routing in dual-supply systems where low leakage, low R_ON, and guaranteed NC/NO behavior are essential - targeting instrumentation, defense, and medical equipment.

FAQ

What is the logic behavior of MAX321ESA+T?

The MAX321ESA+T implements two independent normally closed (NC) analog switches. When logic input (IN1 or IN2) is low, the corresponding NC terminal connects to its common terminal (COM); when high, the path opens. This fail-safe behavior ensures default signal continuity - critical in safety-critical routing such as guidance system backups. The MAX321ESA+T does not support break-before-make operation, unlike the MAX322 variant.

Can MAX321ESA+T operate from a single supply?

No - the MAX321ESA+T requires true dual supplies (e.g., +5V and −5V) and is not specified for single-supply operation. Its internal circuitry relies on symmetric bipolar rails for proper threshold referencing and leakage control. For single-supply alternatives, refer to the MAX323/MAX324/MAX325 series, which share functional equivalence but use different biasing architectures optimized for 3V–15V unipolar rails.

What is the maximum analog signal voltage range supported by MAX321ESA+T?

The MAX321ESA+T supports analog signals from V− to V+, meaning the full differential supply range - e.g., −5V to +5V with ±5V supplies. Signals exceeding this range are clamped by internal diodes, so absolute maximum ratings must not be violated: V+ must stay within (V− − 0.3V) to +17V, and analog pins must remain between (V− − 0.3V) and (V+ + 0.3V). Exceeding these risks permanent damage.

How does charge injection affect sample-and-hold performance with MAX321ESA+T?

With 5pC max charge injection, the MAX321ESA+T introduces ≤5mV error on a 1nF hold capacitor - sufficient for 12-bit accuracy (LSB ≈ 2.4mV at 10V full scale). This value is guaranteed across temperature and supply voltage, enabling predictable settling behavior in precision data acquisition. Layout best practices (minimizing stray capacitance at COM/NC nodes) further reduce effective glitch magnitude in actual MAX321ESA+T implementations.

Is MAX321ESA+T pin-compatible with other variants in the MAX320 family?

Yes - all MAX320/MAX321/MAX322 variants share identical 8-pin SO, DIP, and µMAX packages and pinouts. The MAX321ESA+T uses the same pin mapping as MAX320ESA+ and MAX322ESA+, differing only in internal switch configuration (NC vs NO vs mixed). This allows direct PCB reuse across designs requiring different default states, provided logic polarity and system-level fail-safe requirements align.