MAX481CPA RS422/RS485 Half-Duplex Transceiver Equivalent & Substitute Parts

Part Overview

The MAX481CPA is a half-duplex RS422/RS485 transceiver IC in 8-DIP packaging manufactured by Analog Devices Inc./Maxim Integrated. This part is classified as obsolete, though 1,898 units remain in new original stock. The MAX481CPA operates as a 1/1 driver/receiver configuration with a 2.5 Mbps data rate and 70 mV receiver hysteresis. Due to its obsolete status, equivalent active-production alternatives are available that maintain identical electrical and mechanical specifications, enabling direct substitution in new designs or legacy system maintenance.

Key Parameters

Parameter	Value
Manufacturer Part Number	MAX481CPA
Manufacturer	Analog Devices Inc./Maxim Integrated
Type	Transceiver
Protocol	RS422, RS485
Number of Drivers/Receivers	1/1
Duplex	Half
Data Rate	2.5 Mbps
Receiver Hysteresis	70 mV
Voltage - Supply	4.75V ~ 5.25V
Operating Temperature	0°C ~ 70°C
Package / Case	8-DIP (0.300", 7.62mm)
Mounting Type	Through Hole
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution eligibility for the MAX481CPA is determined by strict parameter matching across electrical and mechanical specifications. The critical parameters governing substitution are:

Electrical Compatibility Parameters:

Protocol: RS422/RS485 half-duplex operation
Driver/Receiver Configuration: 1/1 topology
Data Rate: 2.5 Mbps minimum
Receiver Hysteresis: 70 mV
Supply Voltage Range: 4.75V ~ 5.25V
Operating Temperature Range: 0°C ~ 70°C minimum

Mechanical Compatibility Parameters:

Package Type: 8-DIP (0.300", 7.62mm)
Mounting Type: Through Hole
Supplier Device Package: 8-PDIP

Substitute parts are categorized into three groups:

Parametric Equivalents (Full Electrical & Mechanical Match): MAX1487CPA+, MAX1487ECPA+, MAX481CPA+, MAX481ECPA+, MAX485CPA+, MAX485ECPA+ — These parts maintain identical electrical specifications and package configuration, differing only in product status (active vs. obsolete) and RoHS compliance.

Direct Manufacturer Equivalent (Minor Parameter Variance): LTC1481CN8#PBF — Maintains identical mechanical and electrical specifications except receiver hysteresis is 45 mV (lower than 70 mV specification), suitable where reduced hysteresis is acceptable.

Manufacturer Recommended Alternatives (Enhanced Specifications): ADM1485ANZ, ADM1485JNZ, ADM485ANZ — These parts exceed the MAX481CPA specifications with higher data rates (5–30 Mbps) and extended operating temperature ranges (-40°C to 85°C), providing performance headroom for demanding applications while maintaining package and protocol compatibility.

Parameter Comparison

Part Number	Manufacturer	Protocol	Data Rate	Receiver Hysteresis	Supply Voltage	Operating Temp	Package	Product Status	RoHS Status
MAX481CPA	Analog Devices/Maxim	RS422/RS485	2.5 Mbps	70 mV	4.75V–5.25V	0°C–70°C	8-DIP	Obsolete	Non-compliant
MAX1487CPA+	Analog Devices/Maxim	RS422/RS485	2.5 Mbps	70 mV	4.75V–5.25V	0°C–70°C	8-DIP	Active	ROHS3 Compliant
MAX1487ECPA+	Analog Devices/Maxim	RS422/RS485	2.5 Mbps	70 mV	4.75V–5.25V	0°C–70°C	8-DIP	Active	ROHS3 Compliant
MAX481CPA+	Analog Devices/Maxim	RS422/RS485	2.5 Mbps	70 mV	4.75V–5.25V	0°C–70°C	8-DIP	Active	ROHS3 Compliant
MAX481ECPA+	Analog Devices/Maxim	RS422/RS485	2.5 Mbps	70 mV	4.75V–5.25V	0°C–70°C	8-DIP	Active	ROHS3 Compliant
MAX485CPA+	Analog Devices/Maxim	RS422/RS485	2.5 Mbps	70 mV	4.75V–5.25V	0°C–70°C	8-DIP	Active	ROHS3 Compliant
MAX485ECPA+	Analog Devices/Maxim	RS422/RS485	2.5 Mbps	70 mV	4.75V–5.25V	0°C–70°C	8-DIP	Active	ROHS3 Compliant
LTC1481CN8#PBF	Analog Devices	RS422/RS485	2.5 Mbps	45 mV	4.75V–5.25V	0°C–70°C	8-DIP	Active	ROHS3 Compliant
ADM1485ANZ	Analog Devices	RS422/RS485	30 Mbps	70 mV	4.75V–5.25V	-40°C–85°C	8-DIP	Active	ROHS3 Compliant
ADM1485JNZ	Analog Devices	RS422/RS485	30 Mbps	70 mV	4.75V–5.25V	0°C–70°C	8-DIP	Active	ROHS3 Compliant
ADM485ANZ	Analog Devices	RS422/RS485	5 Mbps	70 mV	4.75V–5.25V	-40°C–85°C	8-DIP	Active	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications): Select MAX481CPA+, MAX481ECPA+, MAX485CPA+, or MAX485ECPA+ when exact electrical and mechanical compatibility is required. These parts are active-production equivalents with ROHS3 compliance, eliminating obsolescence risk while maintaining the original 2.5 Mbps data rate and 70 mV hysteresis specification. The "E" temperature grade variants (ECPA+) support extended industrial temperature ranges and are preferred for demanding environments.

For RoHS Compliance Upgrade: If legacy designs require RoHS compliance certification, MAX1487CPA+, MAX1487ECPA+, MAX481CPA+, MAX481ECPA+, MAX485CPA+, or MAX485ECPA+ provide direct substitution with ROHS3 compliance. All maintain identical electrical performance and 8-DIP through-hole packaging.

For Reduced Receiver Hysteresis: LTC1481CN8#PBF operates with 45 mV receiver hysteresis instead of 70 mV, reducing noise immunity but improving sensitivity. This part is suitable only where lower hysteresis is explicitly acceptable in system design.

For Enhanced Performance Margin: ADM1485JNZ (30 Mbps, 0°C–70°C) or ADM485ANZ (5 Mbps, -40°C–85°C) provide higher data rates and extended temperature ranges. ADM1485ANZ supports the widest temperature specification (-40°C–85°C) for industrial applications. These parts exceed MAX481CPA specifications and are suitable for new designs requiring performance headroom.

Frequently Asked Questions (FAQ)

Q: Can MAX481CPA+ directly replace MAX481CPA in existing PCBs? A: Yes. MAX481CPA+ is a direct parametric equivalent with identical electrical specifications (2.5 Mbps, 70 mV hysteresis, 4.75V–5.25V supply) and 8-DIP through-hole package. The only differences are active product status and ROHS3 compliance. No circuit modifications are required.

Q: What is the difference between MAX481CPA+ and MAX485CPA+? A: Both parts are parametric equivalents with identical electrical and mechanical specifications. The difference is in the base product series designation (MAX481 vs. MAX485). Both are suitable substitutes for MAX481CPA with no functional distinction in this application.

Q: Why would I choose ADM1485JNZ over MAX481CPA+? A: ADM1485JNZ offers 30 Mbps data rate versus 2.5 Mbps, providing 12× performance margin. It maintains identical 70 mV hysteresis and 8-DIP packaging. Select ADM1485JNZ for new designs requiring higher bandwidth or when future protocol upgrades are anticipated.

Q: Is LTC1481CN8#PBF a suitable replacement? A: LTC1481CN8#PBF maintains identical package, supply voltage, and data rate specifications. However, receiver hysteresis is 45 mV instead of 70 mV, reducing noise immunity by approximately 36%. Use only if system design explicitly tolerates lower hysteresis margins.

Q: What is the advantage of the "E" temperature grade (ECPA+)? A: The "E" grade supports extended operating temperature range (typically -40°C to 85°C or 0°C to 70°C depending on variant) compared to standard grades. For industrial or automotive applications, "E" grade variants provide thermal margin and are preferred for reliability.

Q: Are all substitute parts RoHS compliant? A: All active-production substitutes listed (MAX1487CPA+, MAX481CPA+, MAX485CPA+, LTC1481CN8#PBF, ADM1485ANZ, ADM1485JNZ, ADM485ANZ) are ROHS3 compliant. The original MAX481CPA is RoHS non-compliant due to obsolete status.

Q: Can I use ADM485ANZ as a drop-in replacement? A: ADM485ANZ is mechanically compatible (8-DIP through-hole) and electrically compatible (RS422/RS485, 70 mV hysteresis, 4.75V–5.25V supply). However, its 5 Mbps data rate exceeds the MAX481CPA specification of 2.5 Mbps. It is suitable for direct replacement with performance margin but not required for legacy 2.5 Mbps applications.

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