Analog Devices Inc./Maxim Integrated DG421CJ

Overview

DG421CJ from Maxim Integrated is a precision dual SPST CMOS analog switch with latchable TTL/CMOS-compatible control inputs, 20Ω typical on-resistance, 15pC max charge injection, and rail-to-rail signal handling from ±4.5V to ±20V bipolar or +10V to +30V single supply. It operates in battery-powered test equipment and audio routing systems requiring low leakage (<5nA at +85°C) and fast switching (175ns tON).

For engineers reviewing the DG421CJ datasheet, DG421CJ pinout, DG421CJ application, or DG421CJ equivalent, key selection criteria include guaranteed on-resistance matching (≤3Ω), latch timing (tWW = 200ns), off-isolation rejection ratio (12dB), and compatibility with microprocessor-controlled analog signal paths in industrial and communications hardware.

Technical Context

The DG421CJ integrates two independent SPST switches with transparent-latch logic architecture controlled by WR (Write) and RS (Reset) inputs, enabling synchronous microprocessor interfacing without external clocking. Its silicon-gate 44V process ensures rail-to-rail analog conduction and ESD tolerance of ≥2000V per Method 3015.7.

Switch operation supports both single-supply (+10V to +30V) and bipolar-supply (±4.5V to ±20V) configurations, with guaranteed on-resistance flatness (≤4Ω) and channel-to-channel matching (≤3Ω) only under bipolar conditions. Logic supply VL is fixed at +5V for TTL compatibility, while analog terminals tolerate signals from V− to V+.

Key Specifications

Pinout & Package

DG421CJ is housed in a 16-pin plastic DIP package (0.300" wide), operating from 0°C to +70°C. Pin 13 is GND; pins 11 and 14 are V+ and V−; pin 12 is VL (+5V logic supply); pins 9 and 1 are S1 and D1; pins 16 and 8 are S2 and D2; pins 10 and 15 are IN1 and IN2; pins 2 and 7 are WR and RS; pins 3, 4, 5, and 6 are no-connect.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADG1419BRUZ and MAX4617ESA+, the DG421CJ uniquely combines latch functionality, bipolar supply support, and guaranteed channel matching-making it irreplaceable in µP-synchronized, wide-voltage-range analog multiplexing where layout simplicity and timing determinism are critical.

Availability

DG421CJ is available at Aetrix Electronics and suitable for test equipment signal routing, audio channel switching, modem analog front-ends, battery-powered data acquisition, and guidance system I/O conditioning requiring stable component supply across commercial temperature ranges.

Supply support for DG421CJ 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 industrial, communications, and computing applications.

The DG421CJ belongs to Maxim's DG42x family of latch-equipped CMOS analog switches, engineered specifically for microprocessor-controlled signal routing in environments demanding rail-to-rail operation, low leakage, and robust ESD performance.

FAQ

What is the maximum allowable supply voltage for DG421CJ?

The DG421CJ has absolute maximum ratings of V+ = 44V and V− = −44V referenced to GND, with recommended operating ranges of ±4.5V to ±20V (bipolar) or +10V to +30V (single supply). Exceeding these limits risks permanent damage. The DG421CJ must never operate with |V+ − V−| > 44V, and VL must remain at +5V for TTL compatibility. These constraints are defined in the Absolute Maximum Ratings table of the DG421CJ datasheet.

Does DG421CJ support single-supply operation?

Yes, DG421CJ supports single-supply operation from +10V to +30V, with analog signals ranging from GND to V+. However, on-resistance matching (≤3Ω) and flatness (≤4Ω) are guaranteed only under bipolar-supply conditions (±4.5V to ±20V). In single-supply mode, DG421CJ retains rail-to-rail capability, 20Ω typical rDS(ON), and latch functionality-but matching specifications do not apply. DG421CJ requires VL = +5V regardless of analog supply configuration.

What is the function of the WR and RS pins on DG421CJ?

The WR (Write) pin clocks the states of IN1 and IN2 into internal D-type latches on its rising edge, enabling synchronous µP control without bus contention. The RS (Reset) pin forces both switches OFF when high, overriding IN1/IN2 and WR-providing fail-safe shutdown. Neither pin affects analog signal integrity directly; both operate at TTL/CMOS levels with ≤0.5µA input current. This dual-control architecture is intrinsic to the DG421CJ's design for deterministic switching in noise-sensitive systems.

Can DG421CJ be used with logic supplies other than +5V?

No-DG421CJ requires VL = +5V for guaranteed TTL-compatible input thresholds (VINH ≥ 2.4V, VINL ≤ 0.8V) and correct latch operation. Connecting VL to V+ or another voltage violates the datasheet specification and may cause metastability or incorrect switching. While CMOS-level operation is possible at other VL values, DG421CJ's guaranteed performance-including input current, timing, and latch reliability-is specified exclusively at VL = +5V.

What is the thermal performance of DG421CJ in plastic DIP packaging?

In its 16-pin plastic DIP package, DG421CJ has a continuous power dissipation limit of 842mW at TA = +70°C, derating linearly at 10.53mW/°C above that temperature. The package's thermal resistance θJA is approximately 119°C/W, meaning a 100mW internal power dissipation raises junction temperature by ~12°C above ambient. DG421CJ's 0°C to +70°C operating range is validated for this package; exceeding +70°C ambient requires derating or heatsinking to maintain reliability.