MAX491ECSD Equivalent & Substitute Parts

Part Overview

The MAX491ECSD is a 1/1 full-duplex RS422/RS485 transceiver IC manufactured by Analog Devices Inc./Maxim Integrated in a 14-SOIC surface mount package. This component is classified as obsolete, with 1,260 units currently in stock. Due to its obsolete status, identifying equivalent and substitute parts is essential for system redesign, long-term supply chain planning, and new production runs. Substitute parts must maintain electrical compatibility across protocol support, driver/receiver configuration, duplex mode, and physical packaging while meeting modern compliance standards.

Key Parameters

Parameter	MAX491ECSD
Manufacturer	Analog Devices Inc./Maxim Integrated
Type	Transceiver
Protocol	RS422, RS485
Number of Drivers/Receivers	1/1
Duplex Mode	Full
Receiver Hysteresis	70 mV
Data Rate	2.5 Mbps
Voltage Supply	4.75V ~ 5.25V
Operating Temperature	0°C ~ 70°C
Package / Case	14-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution logic for the MAX491ECSD is based on the following critical parameters:

Primary Compatibility Criteria:

Protocol support: RS422 and RS485
Driver/Receiver configuration: 1/1 (single driver, single receiver)
Duplex mode: Full-duplex operation
Package type: 14-SOIC surface mount
Voltage supply range: 4.75V to 5.25V nominal operation
Operating temperature range: 0°C to 70°C minimum

Substitution Categories:

Parametric Equivalents maintain all primary electrical and mechanical parameters with identical or superior specifications. These parts are direct functional replacements with the same pinout and performance envelope.

Direct Manufacturer Equivalents are alternative product lines from the same or related manufacturers (Analog Devices family) that meet all core electrical requirements but may have minor variations in data rate or hysteresis specifications.

Manufacturer Recommended Substitutes are parts explicitly recommended by manufacturers as functional alternatives. These may have enhanced specifications (higher data rates, extended temperature ranges) but remain compatible within the application envelope.

Parameter Comparison

Part Number	Manufacturer	Protocol	Drivers/Receivers	Duplex	Hysteresis (mV)	Data Rate	Supply Voltage	Temp Range	Package	Product Status	RoHS Status
MAX491ECSD	Analog Devices/Maxim	RS422, RS485	1/1	Full	70	2.5 Mbps	4.75V ~ 5.25V	0°C ~ 70°C	14-SOIC	Obsolete	Non-compliant
MAX491CSD+	Analog Devices/Maxim	RS422, RS485	1/1	Full	70	2.5 Mbps	4.75V ~ 5.25V	0°C ~ 70°C	14-SOIC	Active	ROHS3 Compliant
MAX491ECSD+	Analog Devices/Maxim	RS422, RS485	1/1	Full	70	2.5 Mbps	4.75V ~ 5.25V	0°C ~ 70°C	14-SOIC	Active	ROHS3 Compliant
LTC491CS#PBF	Analog Devices	RS422, RS485	1/1	Full	70	—	4.75V ~ 5.25V	0°C ~ 70°C	14-SOIC	Active	ROHS3 Compliant
LTC491CS#TRPBF	Analog Devices	RS422, RS485	1/1	Full	70	—	4.75V ~ 5.25V	0°C ~ 70°C	14-SOIC	Active	ROHS3 Compliant
ISL8491EIBZ	Renesas Electronics	RS422, RS485	1/1	Full	70	10 Mbps	4.5V ~ 5.5V	-40°C ~ 85°C	14-SOIC	Active	ROHS3 Compliant
ISL8491EIBZ-T	Renesas Electronics	RS422, RS485	1/1	Full	70	10 Mbps	4.5V ~ 5.5V	-40°C ~ 85°C	14-SOIC	Active	ROHS3 Compliant
LT1791CS#PBF	Analog Devices	RS422, RS485	1/1	Full	20	250 kbps	4.75V ~ 5.25V	0°C ~ 70°C	14-SOIC	Active	ROHS3 Compliant
LT1791CS#TRPBF	Analog Devices	RS422, RS485	1/1	Full	20	250 kbps	4.75V ~ 5.25V	0°C ~ 70°C	14-SOIC	Active	ROHS3 Compliant
LTC1687CS#PBF	Analog Devices	RS422, RS485	1/1	Full	25	52 Mbps	4.75V ~ 5.25V	0°C ~ 70°C	14-SOIC	Active	ROHS3 Compliant
LTC1687CS#TRPBF	Analog Devices	RS422, RS485	1/1	Full	25	52 Mbps	4.75V ~ 5.25V	0°C ~ 70°C	14-SOIC	Active	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications): MAX491CSD+ and MAX491ECSD+ are parametric equivalents with identical electrical performance to the MAX491ECSD. Both are active products with ROHS3 compliance, making them suitable for new designs and production runs requiring the same 2.5 Mbps data rate and 70 mV hysteresis. The primary difference is packaging format (Tube vs. Tape & Reel).

For Analog Devices Family Continuity: LTC491CS#PBF and LTC491CS#TRPBF maintain the same electrical envelope and are active products with ROHS3 compliance. These parts are suitable when supply chain preference favors the LTC product line within Analog Devices.

For Enhanced Performance Requirements: ISL8491EIBZ and ISL8491EIBZ-T (Renesas Electronics) offer superior specifications including 10 Mbps data rate, extended temperature range (-40°C to 85°C), and wider supply voltage tolerance (4.5V to 5.5V). These are recommended for applications requiring higher data rates or operation outside the 0°C to 70°C range.

For High-Speed Applications: LTC1687CS#PBF and LTC1687CS#TRPBF support 52 Mbps data rate with 25 mV hysteresis, suitable for applications requiring significantly higher bandwidth than the original MAX491ECSD specification.

For Low-Speed, Noise-Sensitive Applications: LT1791CS#PBF and LT1791CS#TRPBF feature 20 mV hysteresis and 250 kbps data rate, appropriate for applications prioritizing noise immunity over bandwidth.

All substitute parts listed maintain ROHS3 compliance and active product status, ensuring long-term availability and regulatory alignment for new production.

Frequently Asked Questions (FAQ)

Q: Can MAX491CSD+ directly replace MAX491ECSD in existing designs? A: Yes. MAX491CSD+ is a parametric equivalent with identical electrical specifications (2.5 Mbps, 70 mV hysteresis, 4.75V–5.25V supply, 0°C–70°C operating range) and the same 14-SOIC package. The primary difference is product status (Active vs. Obsolete) and RoHS compliance (ROHS3 vs. non-compliant). Pin-for-pin compatibility is maintained.

Q: What is the difference between MAX491ECSD+ and MAX491CSD+? A: Both are parametric equivalents with identical electrical performance. The suffix designation indicates different manufacturing grades or temperature ratings within the MAX491 family. Both are active products with ROHS3 compliance and suitable for direct substitution.

Q: Why would I choose ISL8491EIBZ over MAX491CSD+? A: ISL8491EIBZ offers enhanced specifications: 10 Mbps data rate (vs. 2.5 Mbps), extended operating temperature range (-40°C to 85°C vs. 0°C to 70°C), and wider supply voltage tolerance (4.5V–5.5V vs. 4.75V–5.25V). Select this part if your application requires higher bandwidth or operation outside standard industrial temperature ranges.

Q: Are LTC491CS and MAX491ECSD pin-compatible? A: Yes. LTC491CS maintains the same 14-SOIC package and electrical specifications (RS422/RS485, 1/1 configuration, full-duplex, 70 mV hysteresis, 4.75V–5.25V supply, 0°C–70°C range). Both are surface mount devices with identical pinout.

Q: What packaging options are available for substitute parts? A: Substitute parts are available in Tube packaging (standard for component distribution) and Tape & Reel (TR) or Cut Tape (CT) & Digi-Reel packaging (for automated assembly). Select based on your production volume and assembly process requirements.

Q: Can LTC1687CS replace MAX491ECSD in bandwidth-limited applications? A: LTC1687CS is electrically compatible but offers 52 Mbps data rate, significantly exceeding the MAX491ECSD's 2.5 Mbps specification. It is suitable for direct replacement and provides performance headroom for future bandwidth requirements. The 25 mV hysteresis is tighter than the original 70 mV, improving noise immunity.

Q: What is the significance of RoHS3 compliance for substitute selection? A: All active substitute parts listed are ROHS3 compliant, meeting current environmental and regulatory standards for electronic components. The original MAX491ECSD is RoHS non-compliant, making compliant substitutes necessary for new production runs and systems subject to RoHS regulations.

Q: Are there supply voltage compatibility concerns when substituting parts? A: Most substitutes operate within the original 4.75V–5.25V range. ISL8491EIBZ and ISL8491EIBZ-T accept a wider range (4.5V–5.5V), providing additional design flexibility. Verify your power supply specifications before selection.

Q: Which substitute is recommended for long-term production? A: MAX491CSD+ or MAX491ECSD+ are recommended for direct replacement with identical specifications and active product status. For enhanced reliability and extended temperature operation, ISL8491EIBZ is a manufacturer-recommended alternative with superior performance margins.

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