MAX4729EXT Equivalent & Substitute Parts

Part Overview

The MAX4729EXT is a single-circuit SPDT (Single-Pole Double-Throw) IC switch manufactured by Analog Devices Inc./Maxim Integrated, configured as a 2:1 multiplexer/demultiplexer with 5.5Ohm on-state resistance in SC-70-6 surface mount packaging. The device operates across a single supply voltage range of 1.8V to 5.5V and is designed for high-speed signal switching applications with 300MHz bandwidth capability.

The MAX4729EXT is classified as obsolete, which necessitates identification of functionally equivalent alternatives. Substitute parts must maintain compatibility with the original electrical specifications, mechanical packaging, and operating parameters to ensure direct replacement capability in existing designs.

Key Parameters

Parameter	Value	Unit
Switch Circuit Type	SPDT	—
Multiplexer/Demultiplexer Configuration	2:1	—
Number of Circuits	1	—
On-State Resistance (Maximum)	5.5	Ohm
Channel-to-Channel Matching (ΔRon)	50	mOhm
Supply Voltage Range (Single)	1.8 to 5.5	V
Switch Time (Ton, Toff Maximum)	45, 26	ns
-3dB Bandwidth	300	MHz
Charge Injection	3	pC
Channel Capacitance (CS(off), CD(off))	6.5	pF
Current - Leakage (IS(off) Maximum)	2	nA
Crosstalk	-67	dB @ 1MHz
Operating Temperature Range	-40 to 85	°C
Mounting Type	Surface Mount	—
Package / Case	6-TSSOP, SC-88, SOT-363	—
Supplier Device Package	SC-70-6	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the MAX4729EXT is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Switch circuit type must be SPDT
Multiplexer/demultiplexer configuration must be 2:1
Single circuit configuration (1 circuit)
Surface mount packaging compatible with SC-70-6, SC-88, or SOT-363 footprints
Operating temperature range must encompass -40°C to 85°C
Supply voltage range must support the application's operating conditions
On-state resistance and associated parameters must be within acceptable tolerance for the application

Electrical Compatibility Parameters:

On-state resistance (Ohm)
Channel-to-channel matching (ΔRon in mOhm)
Supply voltage range (V)
Switch timing characteristics (Ton, Toff in ns)
Bandwidth capability (-3dB in MHz)
Leakage current (nA)
Crosstalk performance (dB)

Substitute parts are grouped based on their on-state resistance characteristics, as this parameter directly affects signal integrity and power dissipation in switching applications. Parts with lower on-state resistance provide improved performance but must maintain compatibility with the original circuit design parameters.

Parameter Comparison

Parameter	MAX4729EXT	MAX4729EXT+	FSA4157AP6X	NC7SB3157P6X	PI5A4599BCEX	TS5A4624DCKR	TS5A9411DCKR
Manufacturer	Analog Devices	Analog Devices	onsemi	onsemi	Diodes Inc.	Texas Instruments	Texas Instruments
Product Status	Obsolete	Active	Active	Active	Last Time Buy	Active	Active
Switch Circuit	SPDT	SPDT	SPDT	SPDT	SPDT	SPDT	SPDT
Multiplexer Config	2:1	2:1	2:1	2:1	2:1	2:1	2:1
Number of Circuits	1	1	1	1	1	1	1
On-State Resistance (Max)	5.5 Ohm	5.5 Ohm	1.15 Ohm	15 Ohm	11 Ohm	900 mOhm	9 Ohm
ΔRon (Max)	50 mOhm	50 mOhm	60 mOhm	150 mOhm	150 mOhm	50 mOhm	30 mOhm
Supply Voltage (V+)	1.8 to 5.5V	1.8 to 5.5V	2.7 to 5.5V	1.65 to 5.5V	1.6 to 6V	1.65 to 5.5V	2.25 to 5.5V
Ton (Max)	45 ns	45 ns	35 ns	5.2 ns	15 ns	22 ns	9 ns
Toff (Max)	26 ns	26 ns	15 ns	3.5 ns	7 ns	8 ns	7 ns
-3dB Bandwidth	300 MHz	300 MHz	300 MHz	250 MHz	350 MHz	90 MHz	100 MHz
Charge Injection	3 pC	3 pC	20 pC	7 pC	5 pC	15.5 pC	12.5 pC
Channel Capacitance	6.5 pF	6.5 pF	12 pF	6.5 pF	2.5 pF	18 pF	3.5 pF
IS(off) (Max)	2 nA	2 nA	2 nA (Typ)	100 nA	100 nA	20 nA	500 pA
Crosstalk	-67 dB @ 1MHz	-67 dB @ 1MHz	-70 dB @ 1MHz	-54 dB @ 10MHz	-82 dB @ 1MHz	-63 dB @ 1MHz	-85 dB @ 1MHz
Operating Temperature	-40 to 85°C	-40 to 85°C	-40 to 85°C	-40 to 85°C	-40 to 85°C	-40 to 85°C	-40 to 85°C
Package / Case	SC-70-6	SC-70-6	SC-88 (SC-70-6)	SC-88 (SC-70-6)	SOT-363-6 (SC-70)	SC-70-6	SC-70-6
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

Direct Replacement (Identical Electrical Specifications):

The MAX4729EXT+ is the direct active replacement for the obsolete MAX4729EXT. Both parts share identical electrical parameters including 5.5Ohm on-state resistance, 50mOhm channel matching, 1.8V to 5.5V supply range, and 300MHz bandwidth. The MAX4729EXT+ is currently in active production status and carries ROHS3 compliance certification, making it the preferred choice for new designs and obsolescence mitigation. The parts are pin-compatible and footprint-compatible with SC-70-6 packaging.

Alternative Substitutes Based on Application Requirements:

Selection of alternative substitute parts depends on specific application constraints regarding on-state resistance, bandwidth, and supply voltage compatibility:

TS5A9411DCKR (Texas Instruments): Offers superior performance with 9Ohm on-state resistance, 30mOhm channel matching, and exceptional crosstalk performance (-85dB @ 1MHz). Active production status with ROHS3 compliance. Suitable for applications requiring lower leakage current (500pA) and improved signal isolation. Supply voltage range 2.25V to 5.5V requires verification against application minimum voltage requirements.

PI5A4599BCEX (Diodes Incorporated): Provides 11Ohm on-state resistance with excellent crosstalk performance (-82dB @ 1MHz) and lowest channel capacitance (2.5pF). Extended supply voltage range to 6V. Currently in Last Time Buy status; inventory availability should be confirmed before design commitment.

FSA4157AP6X (onsemi): Delivers lowest on-state resistance (1.15Ohm) with fastest switching times (35ns, 15ns) and 300MHz bandwidth. Active production status with ROHS3 compliance. Suitable for applications prioritizing minimal signal attenuation and power dissipation. Supply voltage minimum of 2.7V must be verified for compatibility.

TS5A4624DCKR (Texas Instruments): Offers 900mOhm on-state resistance with 50mOhm channel matching identical to the original part. Active production status with ROHS3 compliance. Reduced bandwidth (90MHz) limits applicability to lower-frequency switching applications.

NC7SB3157P6X (onsemi): Provides 15Ohm on-state resistance with fastest switching times (5.2ns, 3.5ns) and lowest supply voltage minimum (1.65V). Active production status with ROHS3 compliance. Suitable for ultra-low-power applications with relaxed bandwidth requirements (250MHz).

All substitute parts maintain identical operating temperature range (-40°C to 85°C), MSL rating (1 - Unlimited), and surface mount packaging compatibility.

Frequently Asked Questions (FAQ)

Q: Can MAX4729EXT+ be used as a direct replacement for MAX4729EXT?

A: Yes. The MAX4729EXT+ is the direct active equivalent with identical electrical specifications, pin configuration, and SC-70-6 packaging. The primary difference is product status (Active vs. Obsolete) and RoHS compliance (ROHS3 vs. Non-compliant). No circuit modifications are required.

Q: What is the primary difference between the substitute parts listed?

A: The substitute parts differ primarily in on-state resistance, which ranges from 900mOhm (TS5A4624DCKR) to 15Ohm (NC7SB3157P6X). On-state resistance directly affects signal attenuation, power dissipation, and bandwidth performance. Selection depends on application requirements for signal integrity and power efficiency.

Q: Are all substitute parts compatible with the original SC-70-6 footprint?

A: All listed substitute parts are available in SC-70-6, SC-88, or SOT-363 packaging variants. Physical footprints are compatible across these package designations. Verify PCB layout compatibility with the specific package variant selected.

Q: What supply voltage range must be verified when selecting a substitute?

A: The original MAX4729EXT operates from 1.8V to 5.5V. Substitute parts have varying minimum supply voltages: FSA4157AP6X (2.7V minimum), TS5A9411DCKR (2.25V minimum), and NC7SB3157P6X (1.65V minimum). Confirm the selected substitute's minimum voltage specification meets the application's lowest operating voltage requirement.

Q: Which substitute offers the best performance for high-frequency applications?

A: PI5A4599BCEX provides the highest -3dB bandwidth (350MHz) and lowest channel capacitance (2.5pF), making it optimal for high-frequency signal switching. TS5A9411DCKR offers excellent crosstalk performance (-85dB @ 1MHz) with 100MHz bandwidth, suitable for precision analog switching.

Q: Are all substitute parts RoHS compliant?

A: All listed substitute parts carry ROHS3 compliance certification. The original MAX4729EXT is RoHS non-compliant. This compliance difference may be relevant for applications subject to environmental or regulatory requirements.

Q: What is the significance of channel-to-channel matching (ΔRon)?

A: Channel-to-channel matching specifies the maximum resistance variation between the two switch channels. Lower values (30mOhm for TS5A9411DCKR) indicate better matching and more uniform signal handling across both channels. This parameter is critical for applications requiring balanced signal routing.

Q: Can TS5A4624DCKR be used in applications requiring 300MHz bandwidth?

A: No. TS5A4624DCKR has a -3dB bandwidth of 90MHz, which is insufficient for applications requiring 300MHz bandwidth. FSA4157AP6X, MAX4729EXT+, and PI5A4599BCEX all support 300MHz or higher bandwidth.

Q: What is the product status significance for long-term supply planning?

A: Active status parts (MAX4729EXT+, FSA4157AP6X, TS5A4624DCKR, TS5A9411DCKR, NC7SB3157P6X) have ongoing production and supply availability. Last Time Buy status (PI5A4599BCEX, TS5A4624DCKT, TS5A9411DCKT) indicates limited remaining inventory; designs should transition to Active status alternatives for long-term production.

Q: How does leakage current affect substitute selection?

A: Leakage current (IS(off)) ranges from 500pA (TS5A9411DCKR) to 100nA (NC7SB3157P6X, PI5A4599BCEX). Lower leakage current reduces power consumption in battery-powered applications and improves signal integrity in precision analog circuits. The original MAX4729EXT specifies 2nA maximum leakage.

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