DG418DK Equivalent & Substitute Parts

Part Overview

The DG418DK is an 8-circuit IC switch manufactured by Analog Devices Inc./Maxim Integrated, configured as an SPST-NO (Single Pole Single Throw - Normally Open) multiplexer/demultiplexer with 8:1 switching capability. This component features 35Ohm on-state resistance and is housed in an 8-CERDIP through-hole package. The DG418DK is classified as obsolete, making identification of functionally equivalent active alternatives essential for new designs and production continuity.

Key Parameters

Parameter	Value
Switch Circuit Type	SPST - NO
Multiplexer/Demultiplexer Configuration	8:1
Number of Circuits	8
On-State Resistance (Max)	35Ohm
Channel-to-Channel Matching (ΔRon)	100mOhm
Voltage - Supply, Single (V+)	13V ~ 44V
Voltage - Supply, Dual (V±)	±7V ~ 22V
Switch Time (Ton, Toff) (Max)	175ns, 145ns
Charge Injection	3pC
Channel Capacitance (CS(off), CD(off))	8pF
Current - Leakage (IS(off)) (Max)	150nA
Crosstalk	-85dB @ 1MHz
Operating Temperature	-40°C ~ 85°C
Package / Case	8-CDIP (0.300", 7.62mm)
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the DG418DK is constrained by the following critical parameters:

Switch Circuit Type: Must remain SPST - NO
On-State Resistance: Maximum 35Ohm
Switch Timing: Ton (Max) 175ns, Toff (Max) 145ns
Charge Injection: 3pC
Channel Capacitance: 8pF
Crosstalk Performance: -85dB @ 1MHz
RoHS Compliance: ROHS3 Compliant
Moisture Sensitivity: MSL 1

The DG418CY+ is identified as the manufacturer-recommended substitute. However, this part exhibits a fundamental architectural difference: it is configured as a 1:1 multiplexer/demultiplexer with a single circuit, whereas the DG418DK provides 8:1 configuration with 8 circuits. This represents a functional incompatibility at the circuit topology level. The DG418CY+ is suitable only for applications requiring single-channel switching with equivalent electrical performance characteristics.

Parameter Comparison

Parameter	DG418DK (Main Part)	DG418CY+ (Substitute)	Compatibility
Switch Circuit Type	SPST - NO	SPST - NO	Match
Multiplexer/Demultiplexer Configuration	8:1	1:1	Incompatible
Number of Circuits	8	1	Incompatible
On-State Resistance (Max)	35Ohm	35Ohm	Match
Channel-to-Channel Matching (ΔRon)	100mOhm	3Ohm (Max)	Substitute Exceeds Specification
Voltage - Supply, Single (V+)	13V ~ 44V	10V ~ 30V	Substitute Range Narrower
Voltage - Supply, Dual (V±)	±7V ~ 22V	±4.5V ~ 20V	Substitute Range Narrower
Switch Time (Ton, Toff) (Max)	175ns, 145ns	175ns, 145ns	Match
Charge Injection	3pC	3pC	Match
Channel Capacitance (CS(off), CD(off))	8pF	8pF, 8pF	Match
Current - Leakage (IS(off)) (Max)	150nA	250pA	Substitute Superior
Crosstalk	-85dB @ 1MHz	-85dB @ 1MHz	Match
Operating Temperature	-40°C ~ 85°C	0°C ~ 70°C	Substitute Range Narrower
Mounting Type	Through Hole	Surface Mount	Incompatible
Package / Case	8-CDIP (0.300", 7.62mm)	8-SOIC (0.154", 3.90mm Width)	Incompatible
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Match
Product Status	Obsolete	Active	Substitute Available

Engineering Selection Recommendations

The DG418DK is obsolete and no longer in active production. The DG418CY+ is the manufacturer-designated substitute and maintains active product status with ROHS3 compliance certification.

Direct substitution of DG418CY+ for DG418DK is not feasible due to three critical incompatibilities:

Circuit Configuration: DG418CY+ provides 1:1 multiplexing versus the 8:1 configuration of DG418DK. Applications requiring 8-channel switching capability cannot be satisfied by this substitute without circuit redesign.
Mounting Technology: DG418CY+ is surface-mount (8-SOIC) while DG418DK is through-hole (8-CDIP). PCB layout and assembly process modifications are required.
Operating Temperature Range: DG418CY+ operates within 0°C ~ 70°C, which is narrower than the DG418DK range of -40°C ~ 85°C. Applications requiring extended temperature operation below 0°C or above 70°C cannot use this substitute.

For applications requiring 8-channel switching functionality with through-hole packaging and extended temperature range, alternative solutions from the DG418 family or equivalent multiplexer/demultiplexer IC families must be evaluated based on specific circuit requirements.

Frequently Asked Questions (FAQ)

Q: Can DG418CY+ directly replace DG418DK in existing designs?

A: No. The DG418CY+ is a single-channel switch (1:1) while DG418DK is an 8-channel multiplexer (8:1). Circuit topology differences prevent direct substitution. Additionally, DG418CY+ uses surface-mount packaging (8-SOIC) versus through-hole (8-CDIP) for DG418DK.

Q: What are the key electrical parameters that determine substitution compatibility?

A: For DG418DK substitutes, the following parameters must be matched or exceeded: switch circuit type (SPST-NO), on-state resistance (35Ohm maximum), switch timing (175ns/145ns), charge injection (3pC), channel capacitance (8pF), and crosstalk performance (-85dB @ 1MHz).

Q: Why is the operating temperature range different between DG418DK and DG418CY+?

A: DG418DK operates from -40°C to 85°C while DG418CY+ operates from 0°C to 70°C. This reflects different design specifications and manufacturing processes. Applications requiring operation below 0°C or above 70°C cannot use DG418CY+.

Q: What does the channel-to-channel matching specification mean?

A: Channel-to-Channel Matching (ΔRon) specifies the maximum variation in on-state resistance between different channels. DG418DK specifies 100mOhm maximum variation, while DG418CY+ specifies 3Ohm maximum. Lower values indicate tighter matching between channels.

Q: Are both parts RoHS compliant?

A: Yes. Both DG418DK and DG418CY+ are ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity level.

Q: What packaging considerations apply when evaluating substitutes?

A: DG418DK uses through-hole mounting (8-CDIP), suitable for breadboard prototyping and legacy PCB designs. DG418CY+ uses surface-mount technology (8-SOIC), requiring SMT assembly equipment and different PCB layout. Package selection depends on manufacturing capability and board design constraints.

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