ISL5123IB Equivalent & Substitute Parts

Part Overview

The ISL5123IB 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 component 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 ISL5123IB is classified as obsolete. Identifying functionally equivalent substitute parts is necessary to maintain design continuity and ensure component availability for new production runs and field replacements.

Key Parameters

Parameter	ISL5123IB
Switch Circuit Configuration	SPDT
Multiplexer/Demultiplexer Circuit	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 / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
RoHS Status	RoHS Non-Compliant

Substitute Part Grouping Explanation

Substitute parts for the ISL5123IB must satisfy the following core electrical and mechanical criteria:

Mandatory Compatibility Parameters:

Switch circuit configuration: SPDT
Multiplexer/demultiplexer circuit: 2:1
Number of circuits: 1
Supply voltage range: 2.7V ~ 12V (minimum overlap required)
Package / Case: 8-SOIC (0.154", 3.90mm Width)
Mounting type: Surface Mount

Functional Tolerance Parameters:

On-state resistance: Substitutes may exceed the ISL5123IB specification of 20Ohm, provided the application circuit design accommodates the higher resistance value
Channel-to-channel matching: 800mOhm (common across all candidates)
Leakage current: 100pA (common across all candidates)
Channel capacitance: 8pF (common across all candidates)

The MAX4544 family (Analog Devices Inc./Maxim Integrated) meets all mandatory compatibility criteria. All four MAX4544 variants feature identical electrical specifications with 60Ohm on-state resistance, which represents a 3x increase over the ISL5123IB. This higher resistance is the primary design consideration for substitution evaluation.

Parameter Comparison

Parameter	ISL5123IB	MAX4544CSA+	MAX4544CSA+T	MAX4544ESA+	MAX4544ESA+T
Switch Circuit	SPDT	SPDT	SPDT	SPDT	SPDT
Multiplexer/Demultiplexer	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	800mOhm	800mOhm	800mOhm	800mOhm	800mOhm
Supply Voltage (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 / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Packaging Type	—	Tube	Tape & Reel (TR)	Tube	Cut Tape (CT) & Digi-Reel®
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	RoHS Non-Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

All four MAX4544 variants are active, in-stock components manufactured by Analog Devices Inc./Maxim Integrated and comply with ROHS3 standards. Selection among these variants depends on procurement and assembly requirements:

MAX4544CSA+ and MAX4544ESA+ are supplied in tube packaging, suitable for manual assembly or lower-volume production runs.

MAX4544CSA+T is supplied in Tape & Reel (TR) format with 3225 units in stock, optimized for automated pick-and-place assembly.

MAX4544ESA+T is supplied in Cut Tape (CT) & Digi-Reel® format with the highest inventory (15600 units), providing maximum availability and flexibility for high-volume production.

The MAX4544ESA+ and MAX4544ESA+T variants maintain the full operating temperature range of -40°C to 85°C, matching the ISL5123IB specification. The MAX4544CSA+ and MAX4544CSA+T variants operate within a narrower range of 0°C to 70°C and are suitable only for applications that do not require extended low-temperature operation.

Frequently Asked Questions (FAQ)

Q: Can MAX4544 parts directly replace ISL5123IB without circuit modifications?

A: The MAX4544 family maintains electrical compatibility in supply voltage range, circuit configuration, and package form factor. However, the on-state resistance is 60Ohm compared to 20Ohm for the ISL5123IB. Circuit designs must accommodate this 3x resistance increase. Applications with low-impedance signal paths or tight timing requirements may require circuit analysis to confirm compatibility.

Q: What is the difference between the four MAX4544 variants?

A: All four variants share identical electrical specifications. Differences are limited to packaging format (tube, tape & reel, or cut tape) and operating temperature range. MAX4544CSA+/CSA+T operate from 0°C to 70°C, while MAX4544ESA+/ESA+T operate from -40°C to 85°C. Select the temperature-rated variant matching your application requirements and the packaging format compatible with your assembly process.

Q: Why does the ISL5123IB show as obsolete?

A: The ISL5123IB is no longer manufactured by Renesas Electronics Corporation. The MAX4544 family provides equivalent functionality and is actively produced, making it the appropriate substitute for new designs and ongoing production support.

Q: Are there any compliance differences between ISL5123IB and MAX4544 parts?

A: The ISL5123IB is RoHS non-compliant. All MAX4544 variants are ROHS3 compliant, meeting current environmental and regulatory standards. Both part families are REACH unaffected and carry EAR99 export classification.

Q: How do switching times compare between ISL5123IB and MAX4544?

A: The ISL5123IB features faster switching times (35ns turn-on, 30ns turn-off) compared to MAX4544 variants (100ns turn-on, 75ns turn-off). Applications requiring sub-100ns switching performance must evaluate whether the slower MAX4544 response time is acceptable for the intended signal bandwidth and timing constraints.

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