Analog Devices Inc./Maxim Integrated MAX321ESA

Overview

MAX321ESA from Maxim Integrated is a precision dual-channel, normally closed (NC) SPST analog switch operating from ±3V to ±8V dual supplies. It delivers 35Ω max on-resistance, <2Ω channel-to-channel R_ON matching, and <100ns turn-off time. Designed for ±5V DAC/ADC signal routing in battery-powered test equipment and military radios, it supports bidirectional analog signals across the full supply range with 100pA max leakage at +85°C.

For engineers reviewing the MAX321ESA datasheet, MAX321ESA pinout, MAX321ESA application, or MAX321ESA equivalent, key selection criteria include NC switching logic, bipolar supply tolerance, guaranteed charge injection ≤5pC, ESD robustness (>2000V), and SO-8 package compatibility with industrial temperature operation (–40°C to +85°C).

Technical Context

The MAX321ESA implements complementary MOSFET pairs per channel with integrated level-shifting circuitry to ensure reliable NC operation under ±3V to ±8V supplies. Its logic inputs accept TTL/CMOS-compatible thresholds referenced to V+, enabling direct interfacing with microcontrollers without external level translation.

Each NC switch features matched R_ON flatness (<4Ω) over the full analog signal range (V– to V+), low 9pF off-capacitance, and break-before-make timing only in the MAX322 variant - not applicable to MAX321ESA. Charge injection is tightly controlled at ≤5pC to minimize sampling error in precision hold circuits.

Key Specifications

Pinout & Package

MAX321ESA is housed in an 8-pin SO (Small Outline) package compliant with JEDEC MS-012, measuring 4.9mm × 3.9mm × 1.75mm, 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 NC analog switch applications.

Compared with MAX321ESA, MAX321EPA offers identical analog performance in a through-hole package ideal for lab use, while ADG1411BRZ delivers superior R_ON and charge injection but sacrifices NC fail-safe behavior and introduces single-supply complexity - making MAX321ESA optimal for ruggedized, dual-rail systems where reliability trumps marginal parameter gains.

Availability

MAX321ESA is available at Aetrix Electronics and suitable for battery-operated test equipment, military radio signal routing, and ±5V DAC output switching requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX321ESA 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 MAX320/MAX321/MAX322 family was engineered specifically for high-fidelity analog signal routing in dual-supply environments where NC default state, low leakage, and predictable R_ON behavior are mandatory - such as avionics, defense electronics, and portable instrumentation.

FAQ

What is the default switching state of MAX321ESA?

The MAX321ESA features two normally closed (NC) analog switches. When both IN1 and IN2 inputs are at logic low (≤V+–2.5V), the respective NC1 and NC2 terminals remain conductive to their COM1 and COM2 pins. This fail-safe NC behavior ensures signal continuity during power loss or controller reset - a key requirement in guidance and control systems where uninterrupted sensor data flow is critical. The MAX321ESA does not implement break-before-make timing.

Can MAX321ESA operate from a single +5V supply?

No, MAX321ESA requires dual supplies: a positive rail (V+) and a negative rail (V–). Its specified operating range is ±3V to ±8V, meaning it needs both +3V to +8V on V+ and –3V to –8V on V–. Attempting single-supply operation violates absolute maximum ratings and will damage the device. For single-supply alternatives, refer to the MAX323/MAX324/MAX325 series - but note those lack the NC configuration of MAX321ESA.

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

The MAX321ESA supports analog signals spanning the full supply range: from V– to V+. With ±5V supplies, this means signals from –5V to +5V can be switched bidirectionally with minimal R_ON variation (<4Ω flatness). The device clamps input voltages exceeding V+ or V– via internal diodes, but sustained overvoltage beyond absolute maximum ratings (V+ – V– ≤ 17V) risks permanent damage. Always observe proper power sequencing: apply V+ first, then V–, before analog signals.

How does MAX321ESA handle logic level translation?

MAX321ESA uses V+-referenced logic thresholds: VIH ≥ V+–1.5V and VIL ≤ V+–2.5V. This allows direct interface with +5V CMOS/TTL logic when V+ = +5V, and with lower-voltage controllers (e.g., 3.3V MCU) when V+ is set to +3.3V - provided V– is correspondingly adjusted (e.g., –3.3V). Inputs tolerate voltages down to V– without damage. No external level shifters are needed, simplifying system design versus rail-to-rail logic-compatible switches that require separate V_LOGIC supplies.

Is MAX321ESA RoHS-compliant?

The base MAX321ESA variant is not RoHS/lead-free; it uses standard SnPb solder finish. However, RoHS-compliant versions are available under suffixes + (e.g., MAX321ESA+) and T&R (e.g., MAX321ESA+T), both featuring lead-free terminations and compliant with EU Directive 2011/65/EU. All variants share identical electrical specifications and SO-8 packaging - only the finish and marking differ. Confirm compliance status using the full part number when ordering.