Vishay Siliconix DG643DY

Overview

DG643DY from Vishay Siliconix is a dual SPDT analog switch IC designed for high-fidelity video and RF signal routing in bidirectional wideband applications. It delivers 500 MHz bandwidth, <5 Ω typical R_DS(on), –87 dB crosstalk at 5 MHz, and TTL-compatible digital control - enabling precise RGB switching and video multiplexing in broadcast and test equipment.

For engineers reviewing the DG643DY datasheet, DG643DY pinout, DG643DY application, or DG643DY equivalent, key selection criteria include its dual SPDT topology, ±14 V_p-p off-state blocking capability, SOIC-16 narrow-body package, and verified performance across –40 °C to +85 °C with dual-supply (V+ = +15 V, V– = –3 V) operation.

Technical Context

The DG643DY integrates two independent SPDT switches fabricated on Vishay's proprietary D/CMOS process, supporting true bidirectional analog signal flow with matched on-resistance and low charge injection (–19 pC). Its on-chip regulator ensures TTL logic compatibility across full supply voltage range without external level-shifting.

Each switch channel exhibits symmetrical source/drain behavior, supports up to ±5 V analog signals when biased with V+ = +12 V and V– = –5 V, and features epitaxial layer latchup protection. Off-isolation exceeds –60 dB at 5 MHz, and dynamic performance remains stable over temperature due to low R_DS(on) drift and controlled capacitance (<20 pF on-state).

Key Specifications

Pinout & Package

Package: 16-pin narrow SOIC (JEDEC MS-012), body dimensions 9.80–10.00 mm × 3.80–4.00 mm × 1.35–1.75 mm, lead pitch 1.27 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX4683ESE+ and ADG732BRUZ, the DG643DY uniquely combines dual SPDT topology, ±14 V_p-p blocking, 500 MHz bandwidth, and negative supply support - making it irreplaceable for high-fidelity video routing and wideband RF switching where signal integrity and voltage range are non-negotiable.

Availability

DG643DY is available at Aetrix Electronics and suitable for RGB video routing, ATE signal multiplexing, satellite receiver IF selection, and radar/FLIR video overlay requiring stable component supply across industrial temperature range and long production lifecycles.

Supply support for DG643DY 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 aerospace applications.

The DG643DY belongs to Vishay's high-performance video switch product line, engineered specifically for wideband analog signal integrity in broadcast infrastructure, defense electronics, and automated test equipment where low crosstalk, fast switching, and robust supply flexibility are mandatory.

FAQ

What is the maximum analog signal voltage swing supported by the DG643DY?

The DG643DY supports analog signals from V– to V+, with absolute maximum ratings allowing V+ to V– up to 21 V. When operated at V+ = +15 V and V– = –3 V, it reliably handles ±14 V_p-p signals. The DG643DY datasheet specifies an analog signal range of –5 V to +8 V under full temperature conditions, ensuring safe operation without forward-biasing internal clamping diodes.

Does the DG643DY require external decoupling capacitors, and if so, what values are recommended?

Yes, the DG643DY requires dedicated decoupling on both V+ and V– pins to maintain 500 MHz bandwidth and minimize switching transients. Vishay recommends a 10 µF tantalum bead capacitor plus a 0.1 µF ceramic capacitor placed as close as possible to each supply pin. This dual-capacitor approach addresses both low-frequency supply sag and high-frequency noise coupling, which is critical for stable DG643DY operation in video and RF applications.

Can the DG643DY operate from a single positive supply, and how does that affect its analog signal range?

Yes, the DG643DY can operate from a single positive supply by tying V– to GND. In this configuration, the analog signal range becomes 0 V to V+ – 1.5 V (e.g., 0 V to +13.5 V with V+ = +15 V). However, performance trade-offs occur: on-capacitance increases, and the ability to handle bipolar or negative-going video signals is lost. The DG643DY achieves optimal video linearity and lowest R_DS(on) with V– ≈ –3 V, as confirmed in the datasheet's typical characteristics.

How does the DG643DY compare to the DG642DY in terms of channel count and pin compatibility?

The DG643DY implements two independent SPDT switches (four total channels), while the DG642DY provides only one SPDT switch (two channels). They are not pin-compatible: DG643DY uses a 16-pin narrow SOIC package with four ground pins and separate D/S/IN assignments per switch pair, whereas DG642DY uses an 8-pin narrow SOIC. Both share the same D/CMOS process and core electrical specs, but the DG643DY's expanded channel count and layout require distinct PCB footprint and routing - no direct drop-in replacement exists between DG643DY and DG642DY.

Is the DG643DY suitable for DC-coupled video applications, and what design considerations apply?

Yes, the DG643DY is suitable for DC-coupled video due to its low charge injection (–19 pC) and matched R_DS(on). To prevent DC offset errors, ensure V– is set to a stable negative rail (e.g., –3 V) and use tight-tolerance resistors in downstream termination networks. Avoid exceeding the specified analog signal range (–5 V to +8 V), and verify that input source impedance remains low (<100 Ω) to minimize gain error - all validated in DG643DY application circuits for RGB and composite video.