DG643DY Equivalent & Substitute Parts

Part Overview

The DG643DY is a dual SPDT analog switch IC manufactured by Vishay Siliconix, designed for signal routing and multiplexing applications in interface circuits. This component features a 2:1 multiplexer/demultiplexer configuration with 15Ohm on-state resistance and operates across a wide supply voltage range of 3V to 15V (single supply) or ±3V to 15V (dual supply). The DG643DY is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations.

Key Parameters

Parameter	Value
Switch Circuit Configuration	SPDT (Single Pole Double Throw)
Multiplexer/Demultiplexer Circuit	2:1
Number of Circuits	2
On-State Resistance (Max)	15Ohm
Channel-to-Channel Matching (ΔRon)	1Ohm
Voltage - Supply, Single (V+)	3V ~ 15V
Voltage - Supply, Dual (V±)	±3V ~ 15V
Switch Time (Ton, Toff) (Max)	70ns, 50ns
-3dB Bandwidth	500MHz
Charge Injection	19pC
Channel Capacitance (CS(off), CD(off))	12pF, 12pF
Current - Leakage (IS(off)) (Max)	10nA
Crosstalk	-87dB @ 5MHz
Operating Temperature	-40°C ~ 85°C (TA)
Package / Case	16-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	RoHS non-compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the DG643DY is determined by strict equivalence across the following critical parameters:

Functional Architecture: Both the main part and substitute must maintain identical switch circuit configuration (SPDT) and multiplexer circuit topology (2:1) with matching number of circuits (2).

Electrical Performance: On-state resistance, channel-to-channel matching, supply voltage ranges (both single and dual), switching times, bandwidth, charge injection, channel capacitance, leakage current, and crosstalk performance establish the electrical substitution envelope.

Physical Compatibility: Package type (16-SOIC with 0.154" width, 3.90mm) and mounting type (Surface Mount) must be identical to ensure PCB-level compatibility without redesign.

Environmental Specifications: Operating temperature range (-40°C ~ 85°C) and moisture sensitivity level (MSL 1) define the environmental operating envelope.

The ADG436BRZ from Analog Devices Inc. qualifies as a substitute based on matching functional architecture, compatible electrical performance within specified tolerances, identical package and mounting specifications, and equivalent environmental ratings.

Parameter Comparison

Parameter	DG643DY (Vishay Siliconix)	ADG436BRZ (Analog Devices Inc.)	Compatibility Notes
Switch Circuit	SPDT	SPDT	Identical
Multiplexer/Demultiplexer Circuit	2:1	2:1	Identical
Number of Circuits	2	2	Identical
On-State Resistance (Max)	15Ohm	12Ohm (Typ)	ADG436BRZ provides lower resistance
Channel-to-Channel Matching (ΔRon)	1Ohm	1Ohm	Identical
Voltage - Supply, Single (V+)	3V ~ 15V	3V ~ 30V	ADG436BRZ supports extended range
Voltage - Supply, Dual (V±)	±3V ~ 15V	±3V ~ 20V	ADG436BRZ supports extended range
Switch Time Ton (Max)	70ns	70ns (Typ)	Equivalent
Switch Time Toff (Max)	50ns	60ns (Typ)	ADG436BRZ slightly slower
-3dB Bandwidth	500MHz	Not specified	DG643DY specifies bandwidth
Charge Injection	19pC	10pC	ADG436BRZ provides lower charge injection
Channel Capacitance (CS(off), CD(off))	12pF, 12pF	13pF	ADG436BRZ slightly higher capacitance
Current - Leakage (IS(off)) (Max)	10nA	250pA	ADG436BRZ provides significantly lower leakage
Crosstalk	-87dB @ 5MHz	-90dB @ 1MHz	ADG436BRZ provides better crosstalk isolation
Operating Temperature	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)	Identical
Package / Case	16-SOIC (0.154", 3.90mm Width)	16-SOIC (0.154", 3.90mm Width)	Identical
Mounting Type	Surface Mount	Surface Mount	Identical
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ADG436BRZ meets RoHS3 requirements
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	Identical

Engineering Selection Recommendations

The ADG436BRZ qualifies as a direct substitute for the DG643DY based on functional equivalence and electrical compatibility. Key selection considerations include:

Product Status: The DG643DY is classified as obsolete, while the ADG436BRZ maintains active product status, ensuring long-term availability and continued manufacturer support.

Regulatory Compliance: The ADG436BRZ achieves ROHS3 compliance, whereas the DG643DY is RoHS non-compliant. Systems requiring RoHS compliance must transition to the ADG436BRZ.

Electrical Performance: The ADG436BRZ demonstrates superior electrical characteristics in multiple parameters: lower on-state resistance (12Ohm typical vs. 15Ohm maximum), reduced charge injection (10pC vs. 19pC), significantly lower leakage current (250pA vs. 10nA), and improved crosstalk isolation (-90dB vs. -87dB). These improvements provide enhanced signal integrity and reduced power consumption.

Supply Voltage Range: The ADG436BRZ supports extended supply voltage ranges (3V ~ 30V single supply, ±3V ~ 20V dual supply) compared to the DG643DY (3V ~ 15V single supply, ±3V ~ 15V dual supply), offering greater design flexibility for systems operating at higher supply voltages.

Package and Thermal Compatibility: Both devices utilize identical 16-SOIC packaging and share the same operating temperature range (-40°C ~ 85°C), ensuring direct PCB-level compatibility without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the ADG436BRZ directly replace the DG643DY without PCB modifications?

A: Yes. Both devices share identical 16-SOIC package dimensions (0.154" width, 3.90mm) and pin configurations, enabling direct substitution without PCB redesign. Pin-for-pin compatibility is maintained across all functional and control signals.

Q: What are the key electrical differences between these parts?

A: The ADG436BRZ provides superior performance in on-state resistance (12Ohm typical vs. 15Ohm maximum), charge injection (10pC vs. 19pC), leakage current (250pA vs. 10nA), and crosstalk (-90dB vs. -87dB). The ADG436BRZ also supports extended supply voltage ranges. These differences favor the ADG436BRZ for low-noise and low-power applications.

Q: Are there any performance trade-offs when substituting to the ADG436BRZ?

A: The ADG436BRZ exhibits slightly longer turn-off switching time (60ns typical vs. 50ns maximum for the DG643DY) and marginally higher channel capacitance (13pF vs. 12pF). These differences are negligible for most applications operating within the specified frequency and switching speed requirements.

Q: Does the ADG436BRZ support the same supply voltage range as the DG643DY?

A: The ADG436BRZ supports an extended supply voltage range. For single supply operation, it supports 3V ~ 30V (vs. 3V ~ 15V for the DG643DY). For dual supply operation, it supports ±3V ~ 20V (vs. ±3V ~ 15V for the DG643DY). Systems operating within the DG643DY voltage range are fully compatible with the ADG436BRZ.

Q: What is the moisture sensitivity level for both devices?

A: Both the DG643DY and ADG436BRZ are classified as MSL 1 (Unlimited), indicating no moisture sensitivity restrictions during storage or handling.

Q: Is the ADG436BRZ suitable for RoHS-compliant applications?

A: Yes. The ADG436BRZ achieves ROHS3 compliance, making it suitable for applications requiring RoHS certification. The DG643DY is RoHS non-compliant and cannot be used in RoHS-mandated applications.

Q: What is the operating temperature range for both devices?

A: Both devices operate across the identical temperature range of -40°C to 85°C (TA), ensuring thermal compatibility in equivalent environmental conditions.

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