MAX491CPD RS422/RS485 Transceiver Equivalent & Substitute Parts

Part Overview

The MAX491CPD is a 1/1 full-duplex RS422/RS485 transceiver manufactured by Analog Devices Inc./Maxim Integrated in a 14-pin DIP package. This part is classified as obsolete, though 14,872 units remain in stock as new original inventory. The MAX491CPD operates at 2.5 Mbps data rate with a 70 mV receiver hysteresis and requires a 4.75V to 5.25V supply voltage across an operating temperature range of 0°C to 70°C. Due to its obsolete status and non-RoHS3 compliance, identifying active equivalent and substitute parts is essential for new designs and long-term supply chain planning.

Key Parameters

Parameter	MAX491CPD
Manufacturer	Analog Devices Inc./Maxim Integrated
Product Status	Obsolete
Type	Transceiver
Protocol	RS422, RS485
Number of Drivers/Receivers	1/1
Duplex	Full
Data Rate	2.5 Mbps
Receiver Hysteresis	70 mV
Voltage - Supply	4.75V ~ 5.25V
Operating Temperature	0°C ~ 70°C
Package / Case	14-DIP (0.300", 7.62mm)
RoHS Status	RoHS non-compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution for the MAX491CPD is determined by strict adherence to the following electrical and mechanical parameters:

Critical Substitution Parameters:

Protocol support: RS422 and RS485
Configuration: 1/1 Drivers/Receivers, Full Duplex
Package: 14-DIP (0.300", 7.62mm)
Supply voltage range: 4.75V ~ 5.25V
Mounting type: Through Hole
Moisture Sensitivity Level: 1 (Unlimited)

Substitute Categories:

Parametric Equivalents maintain identical electrical specifications including data rate (2.5 Mbps), receiver hysteresis (70 mV), and operating temperature range (0°C ~ 70°C). These parts differ only in product status (Active vs. Obsolete) and RoHS compliance.

Direct Manufacturer Equivalents are manufactured by Analog Devices and share the same protocol, configuration, and package but may have different receiver hysteresis or unspecified data rate parameters.

Manufacturer Recommended Alternatives represent different product lines (LT1791 series) that maintain core RS422/RS485 functionality and package compatibility but feature different receiver hysteresis (20 mV), lower data rate (250 kbps), and extended operating temperature ranges (-40°C ~ 125°C or -40°C ~ 85°C).

Parameter Comparison

Part Number	Manufacturer	Product Status	Protocol	Drivers/Receivers	Data Rate	Receiver Hysteresis	Supply Voltage	Operating Temperature	Package	RoHS Status
MAX491CPD	Analog Devices Inc./Maxim Integrated	Obsolete	RS422, RS485	1/1	2.5 Mbps	70 mV	4.75V ~ 5.25V	0°C ~ 70°C	14-DIP	Non-compliant
MAX491CPD+	Analog Devices Inc./Maxim Integrated	Active	RS422, RS485	1/1	2.5 Mbps	70 mV	4.75V ~ 5.25V	0°C ~ 70°C	14-DIP	ROHS3 Compliant
MAX491ECPD+	Analog Devices Inc./Maxim Integrated	Active	RS422, RS485	1/1	2.5 Mbps	70 mV	4.75V ~ 5.25V	0°C ~ 70°C	14-DIP	ROHS3 Compliant
LTC491CN#PBF	Analog Devices Inc.	Active	RS422, RS485	1/1	—	70 mV	4.75V ~ 5.25V	0°C ~ 70°C	14-DIP	ROHS3 Compliant
LTC491IN#PBF	Analog Devices Inc.	Active	RS422, RS485	1/1	—	70 mV	4.75V ~ 5.25V	-40°C ~ 85°C	14-DIP	ROHS3 Compliant
LT1791CN#PBF	Analog Devices Inc.	Active	RS422, RS485	1/1	250 kbps	20 mV	4.75V ~ 5.25V	0°C ~ 70°C	14-DIP	ROHS3 Compliant
LT1791ACN#PBF	Analog Devices Inc.	Active	RS422, RS485	1/1	250 kbps	20 mV	4.75V ~ 5.25V	0°C ~ 70°C	14-DIP	ROHS3 Compliant
LT1791HN#PBF	Analog Devices Inc.	Active	RS422, RS485	1/1	250 kbps	20 mV	4.75V ~ 5.25V	-40°C ~ 125°C	14-DIP	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Identical Electrical Performance):

MAX491CPD+ and MAX491ECPD+ are the primary substitutes for the obsolete MAX491CPD. Both parts maintain identical electrical specifications including 2.5 Mbps data rate, 70 mV receiver hysteresis, and 0°C to 70°C operating temperature. Both are active products with ROHS3 compliance, addressing the obsolescence and regulatory compliance limitations of the original part. MAX491CPD+ carries 2,020 units in stock, while MAX491ECPD+ has 2,500 units available.

For Extended Temperature Range Applications:

LTC491IN#PBF provides identical electrical performance to the MAX491CPD with an extended operating temperature range of -40°C to 85°C. This part is suitable for applications requiring operation beyond the standard 0°C to 70°C range while maintaining the same 70 mV receiver hysteresis and supply voltage specifications. 2,200 units are in stock.

For Lower Data Rate Applications with Extended Temperature:

LT1791HN#PBF operates across -40°C to 125°C with a 20 mV receiver hysteresis and 250 kbps data rate. This part is appropriate for applications where the full 2.5 Mbps capability is not required and extended temperature operation is necessary. 760 units are available.

For Standard Temperature Range with Alternative Hysteresis:

LT1791CN#PBF and LT1791ACN#PBF both operate at 0°C to 70°C with 250 kbps data rate and 20 mV receiver hysteresis. These parts are suitable for applications where reduced hysteresis and lower data rate are acceptable within the standard temperature range. LT1791CN#PBF has 2,840 units in stock, and LT1791ACN#PBF has 1,067 units available.

All substitute parts maintain the 14-DIP package format, through-hole mounting, 4.75V to 5.25V supply voltage range, and MSL 1 rating of the original MAX491CPD.

Frequently Asked Questions (FAQ)

Q: Can MAX491CPD+ be used as a direct replacement for MAX491CPD?

A: Yes. MAX491CPD+ is electrically identical to MAX491CPD, maintaining the same 2.5 Mbps data rate, 70 mV receiver hysteresis, and 0°C to 70°C operating temperature. The primary differences are product status (Active vs. Obsolete) and RoHS3 compliance. Both use the 14-DIP package and are pin-compatible.

Q: What is the difference between MAX491ECPD+ and MAX491CPD+?

A: Both parts are electrically identical with 2.5 Mbps data rate and 70 mV receiver hysteresis. The difference lies in the temperature grade designation (E suffix), though both operate across 0°C to 70°C. Both are active products with ROHS3 compliance and 14-DIP packaging.

Q: Can LT1791 series parts replace MAX491CPD in all applications?

A: LT1791 series parts (LT1791CN#PBF, LT1791ACN#PBF, LT1791HN#PBF) are package and protocol compatible but feature reduced data rate (250 kbps vs. 2.5 Mbps) and lower receiver hysteresis (20 mV vs. 70 mV). These parts are suitable only for applications where the lower data rate and hysteresis specifications are acceptable. Extended temperature variants (LT1791HN#PBF) offer -40°C to 125°C operation.

Q: What is the advantage of LTC491 series parts over MAX491 equivalents?

A: LTC491CN#PBF and LTC491IN#PBF maintain the 70 mV receiver hysteresis of the original MAX491CPD. LTC491IN#PBF extends the operating temperature to -40°C to 85°C. Both are active products with ROHS3 compliance. Data rate specifications are not provided for LTC491 parts.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts (MAX491CPD+, MAX491ECPD+, LTC491CN#PBF, LTC491IN#PBF, LT1791CN#PBF, LT1791ACN#PBF, LT1791HN#PBF) are ROHS3 compliant, addressing the non-compliant status of the obsolete MAX491CPD.

Q: Do all substitute parts use the same 14-DIP package?

A: Yes. All substitute parts use the 14-DIP (0.300", 7.62mm) package with through-hole mounting, maintaining mechanical compatibility with the original MAX491CPD.

Q: Which substitute part has the highest inventory availability?

A: MAX491ECPD+ has the highest inventory with 2,500 units in stock, followed by LT1791CN#PBF with 2,840 units and LTC491IN#PBF with 2,200 units.

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