ISL5123CB Equivalent & Substitute Parts

Part Overview

The ISL5123CB is a single-circuit SPDT (Single Pole Double Throw) analog switch manufactured by Renesas Electronics Corporation, configured as a 2:1 multiplexer/demultiplexer in an 8-SOIC surface mount package. This device features a 20Ohm on-state resistance and operates across a 2.7V to 12V single supply voltage range with switching times of 35ns (turn-on) and 30ns (turn-off).

The ISL5123CB is classified as obsolete. Identifying functionally compatible substitute parts is necessary to support ongoing system maintenance, design updates, and procurement continuity for applications currently utilizing this component.

Key Parameters

Parameter	ISL5123CB Value
Switch Circuit Type	SPDT
Multiplexer/Demultiplexer Configuration	2:1
Number of Circuits	1
On-State Resistance (Max)	20Ohm
Channel-to-Channel Matching (ΔRon)	800mOhm
Supply Voltage Range (Single)	2.7V ~ 12V
Switch Time - Turn-On (Max)	35ns
Switch Time - Turn-Off (Max)	30ns
Charge Injection	5pC
Channel Capacitance (CS(off), CD(off))	8pF, 8pF
Leakage Current (IS(off)) Max	100pA
Crosstalk	-105dB @ 1MHz
Operating Temperature Range	-40°C ~ 85°C
Package Type	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	RoHS non-compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the ISL5123CB are identified based on the following critical parameters that define functional compatibility:

Mandatory Matching Criteria:

Switch circuit type: SPDT
Multiplexer/demultiplexer configuration: 2:1
Number of circuits: 1
Package type: 8-SOIC surface mount
Supply voltage range: Must encompass or match 2.7V ~ 12V
Channel-to-channel matching (ΔRon): 800mOhm

Allowable Variation Parameters:

On-state resistance: The ISL5123CB specifies 20Ohm maximum. Substitute parts with higher on-state resistance (60Ohm) are acceptable where circuit design accommodates increased resistance without performance degradation.
Switch timing: Substitute parts with longer switching times are acceptable where application timing margins permit.
Charge injection and crosstalk: Variations within the specified ranges are acceptable based on application requirements.
Operating temperature range: Substitute parts must support the minimum required temperature range for the application.

The MAX4544 series (Analog Devices Inc./Maxim Integrated) meets all mandatory matching criteria. All four variants listed operate as SPDT 2:1 switches in 8-SOIC packages with 2.7V ~ 12V supply compatibility. The primary difference is on-state resistance (60Ohm versus 20Ohm) and product status (active versus obsolete).

Parameter Comparison

Parameter	ISL5123CB	MAX4544CSA+	MAX4544CSA+T	MAX4544ESA+	MAX4544ESA+T
Switch Circuit Type	SPDT	SPDT	SPDT	SPDT	SPDT
Multiplexer/Demultiplexer Configuration	2:1	2:1	2:1	2:1	2:1
Number of Circuits	1	1	1	1	1
On-State Resistance (Max)	20Ohm	60Ohm	60Ohm	60Ohm	60Ohm
Channel-to-Channel Matching (ΔRon)	800mOhm	800mOhm	800mOhm	800mOhm	800mOhm
Supply Voltage Range (Single)	2.7V ~ 12V	2.7V ~ 12V	2.7V ~ 12V	2.7V ~ 12V	2.7V ~ 12V
Switch Time - Turn-On (Max)	35ns	100ns	100ns	100ns	100ns
Switch Time - Turn-Off (Max)	30ns	75ns	75ns	75ns	75ns
Charge Injection	5pC	1pC	1pC	1pC	1pC
Channel Capacitance (CS(off), CD(off))	8pF, 8pF	8pF, 8pF	8pF, 8pF	8pF, 8pF	8pF, 8pF
Leakage Current (IS(off)) Max	100pA	100pA	100pA	100pA	100pA
Crosstalk	-105dB @ 1MHz	-90dB @ 1MHz	-90dB @ 1MHz	-90dB @ 1MHz	-90dB @ 1MHz
Operating Temperature Range	-40°C ~ 85°C	0°C ~ 70°C	0°C ~ 70°C	-40°C ~ 85°C	-40°C ~ 85°C
Package Type	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging Format	-	Tube	Tape & Reel (TR)	Tube	Cut Tape (CT) & Digi-Reel®

Engineering Selection Recommendations

All four MAX4544 variants are functionally equivalent substitutes for the ISL5123CB based on core switching architecture and electrical compatibility. Selection among these variants depends on procurement and application requirements:

MAX4544ESA+ and MAX4544ESA+T are preferred for applications requiring the full operating temperature range of -40°C to 85°C, matching the ISL5123CB specification. Both variants are ROHS3 compliant and active products.

MAX4544CSA+ and MAX4544CSA+T operate within a narrower temperature range (0°C to 70°C) and are suitable only for applications that do not require extended low-temperature operation below 0°C.

Packaging considerations: MAX4544ESA+T and MAX4544CSA+T are supplied in Tape & Reel or Cut Tape formats suitable for automated assembly. MAX4544ESA+ and MAX4544CSA+ are supplied in Tube packaging for manual handling or lower-volume applications.

All substitute parts are ROHS3 compliant, addressing environmental compliance requirements that the obsolete ISL5123CB does not meet. The increased on-state resistance (60Ohm versus 20Ohm) and longer switching times of the MAX4544 series must be evaluated against specific circuit design margins and signal integrity requirements.

Frequently Asked Questions (FAQ)

Q: Can MAX4544 variants directly replace ISL5123CB in existing designs?

A: Electrical pin compatibility and functional operation are equivalent. However, the 60Ohm on-state resistance of MAX4544 parts versus the 20Ohm specification of ISL5123CB requires circuit analysis to confirm acceptable performance. Applications with tight impedance matching or high-frequency signal requirements may require design adjustment.

Q: What is the difference between MAX4544CSA+ and MAX4544ESA+ variants?

A: Both are functionally identical SPDT 2:1 switches in 8-SOIC packages. The primary difference is operating temperature range: MAX4544CSA+ operates 0°C to 70°C, while MAX4544ESA+ operates -40°C to 85°C. Select MAX4544ESA+ for applications requiring full temperature range compatibility with ISL5123CB.

Q: What is the difference between Tube and Tape & Reel packaging?

A: Tube packaging (MAX4544CSA+, MAX4544ESA+) is suitable for manual component handling and lower-volume production. Tape & Reel (MAX4544CSA+T) and Cut Tape & Digi-Reel (MAX4544ESA+T) formats are designed for automated pick-and-place assembly equipment. Select based on manufacturing process requirements.

Q: Are all MAX4544 variants RoHS compliant?

A: Yes. All four MAX4544 variants are ROHS3 compliant. The ISL5123CB is RoHS non-compliant. Substitution with MAX4544 parts addresses RoHS compliance requirements for new designs or system updates.

Q: How do switching times affect circuit performance?

A: ISL5123CB specifies 35ns turn-on and 30ns turn-off. MAX4544 variants specify 100ns turn-on and 75ns turn-off. Applications with timing-critical signal paths or high-frequency multiplexing must confirm that the longer switching times do not degrade system performance or introduce unacceptable signal distortion.

Q: What is charge injection and why does it differ?

A: Charge injection is the amount of charge transferred to the signal path during switching transitions. ISL5123CB specifies 5pC; MAX4544 variants specify 1pC. Lower charge injection in MAX4544 parts reduces signal distortion in precision analog applications, representing an improvement over the original part.

Q: Can I use MAX4544CSA+ in applications requiring -40°C operation?

A: No. MAX4544CSA+ is rated only to 0°C minimum. For applications requiring operation below 0°C, use MAX4544ESA+ or MAX4544ESA+T, which are rated to -40°C.

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