Vishay Siliconix DG643DJ

Overview

DG643DJ from Vishay Siliconix is a dual SPDT analog switch IC designed for high-fidelity RF and video signal routing in bidirectional wideband applications. It delivers 500 MHz bandwidth, 5 Ω typical R_DS(on) (per switch), –87 dB crosstalk at 5 MHz, TTL-compatible control, and ±14 V_p-p signal blocking capability - deployed in RGB video multiplexing and satellite receiver front-ends.

For engineers reviewing the DG643DJ datasheet, DG643DJ pinout, DG643DJ application, or DG643DJ equivalent, key selection criteria include its dual SPDT topology, 16-pin DIP package, –40 °C to +85 °C operating range, low charge injection (–19 pC), and compatibility with split-supply (V+ = +15 V, V– = –3 V) or single-supply (V– = GND) configurations.

Technical Context

The DG643DJ implements two independent SPDT switches fabricated on Vishay's proprietary D/CMOS process, enabling true bidirectional conduction with matched on-resistance and minimal nonlinearity. Each switch supports analog signals from V– to V+, with substrate isolation preventing latchup and internal clamping diodes limiting overvoltage stress.

Its digital interface uses standard TTL thresholds (V_INH ≥ 2.4 V, V_INL ≤ 0.8 V), and an on-chip regulator maintains logic compatibility across the full supply range. The device operates with V+ to V– up to 21 V, and analog signal swing is limited only by supply rails - supporting ±5 V ac handling when biased at V+ = +12 V, V– = –5 V.

Key Specifications

Pinout & Package

Package: 16-pin plastic DIP (Dual-In-Line), JEDEC MS-001, body width 0.300", lead pitch 0.100". Dimensions: 19.18 mm × 6.60 mm × 4.06 mm (L × W × H).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX4683ESE+ and ADG633BRUZ, the DG643DJ uniquely balances ultra-low crosstalk, 500 MHz bandwidth, and dual-supply flexibility - making it optimal for high-fidelity video and RF routing where signal integrity is non-negotiable.

Availability

DG643DJ is available at Aetrix Electronics and suitable for RGB video multiplexing, satellite receiver signal routing, radar/FLIR channel selection, and ATE analog signal path switching requiring stable component supply across industrial and broadcast design cycles.

Supply support for DG643DJ 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

Vishay Siliconix is a global leader in discrete semiconductors and passive components, specializing in high-reliability analog switching, power management, and sensing solutions for demanding industrial and communications applications.

The DG643DJ belongs to Vishay's wideband analog switch product line, engineered specifically for high-fidelity signal routing in video, RF, and test equipment where low distortion, fast settling, and rail-to-rail analog handling are essential.

FAQ

What is the maximum analog signal voltage range supported by the DG643DJ?

The DG643DJ supports analog signals from V– to V+, with absolute maximum ratings of V+ to V– ≤ 21 V and V– to GND ≥ –19 V. When operated at V+ = +15 V and V– = –3 V, it handles ±5 V_p-p signals. Signals exceeding V+ or V– are clamped by internal diodes - forward current must be limited to 20 mA per diode to avoid damage. This makes the DG643DJ suitable for both single-supply (V– = GND) and split-supply video/RF systems.

Does the DG643DJ require external decoupling capacitors, and if so, what values are recommended?

Yes, the DG643DJ requires dedicated decoupling on both V+ and V– pins to maintain 500 MHz bandwidth and minimize switching noise. Vishay specifies a 10 µF tantalum bead capacitor plus a 0.1 µF ceramic capacitor placed as close as possible to each supply pin. Poor decoupling degrades off-isolation and increases crosstalk - especially critical because the substrate is tied to V–, making its decoupling essential for RF stability. Layout guidelines recommend star-grounding these capacitors to avoid ground-loop coupling.

How does the DG643DJ's dual SPDT configuration differ from using two separate SPDT switches like the DG642DJ?

The DG643DJ integrates two fully independent SPDT switches in one 16-pin DIP package, sharing only the V+, V–, GND, and control input - whereas two DG642DJ devices would occupy double the board area and require duplicated supply filtering. Its truth table shows simultaneous complementary control: logic 0 activates SW3/SW4 while deactivating SW1/SW2, and logic 1 reverses this state. This synchronized operation simplifies timing-critical applications like video frame switching, eliminating inter-switch skew that could cause visible artifacts in RGB routing.

Can the DG643DJ be used in single-supply applications, and how does performance change compared to split-supply operation?

Yes, the DG643DJ supports single-supply operation with V– connected to GND and V+ ≥ 5 V. In this mode, analog signal range is limited to 0 V to V+ – 1.5 V (e.g., 0–8 V with V+ = 12 V). Performance trade-offs include higher on-capacitance (due to loss of body-effect reduction), slightly reduced bandwidth (~450 MHz), and increased R_DS(on) mismatch. However, TTL compatibility and fast switching are preserved - making it viable for cost-sensitive consumer video gear where split supplies are impractical.

What is the purpose of the epitaxial layer in the DG643DJ's construction, and how does it affect reliability?

The epitaxial layer in the DG643DJ provides inherent latchup immunity by electrically isolating the DMOS switch transistors from the silicon substrate. This prevents parasitic SCR activation during overvoltage transients, ESD events, or supply sequencing faults - a critical feature for field-deployed video and RF equipment. Vishay validates this structure per JEDEC JESD78, ensuring the DG643DJ sustains >2 kV HBM ESD rating and operates reliably across –40 °C to +85 °C without functional interruption, even under repeated fault conditions.