SN75LP1185DBR RS232 Transceiver Equivalent & Substitute Parts

Part Overview

The SN75LP1185DBR is a full-duplex RS232 transceiver manufactured by Texas Instruments, featuring 3 drivers and 5 receivers in a 20-SSOP surface mount package. This device is classified as Last Time Buy, indicating discontinued production. Alternative equivalent parts are necessary for ongoing design support, production continuity, and component sourcing flexibility.

Key Parameters

Parameter	Value
Manufacturer Part Number	SN75LP1185DBR
Manufacturer	Texas Instruments
Type	Transceiver
Protocol	RS232
Number of Drivers/Receivers	3/5
Duplex	Full
Package / Case	20-SSOP (0.209", 5.30mm Width)
Voltage - Supply	4.75V ~ 5.25V
Operating Temperature	0°C ~ 70°C
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Product Status	Last Time Buy

Substitute Part Grouping Explanation

Substitution eligibility for the SN75LP1185DBR is determined by the following critical parameters:

Primary Compatibility Criteria:

Protocol: RS232
Type: Transceiver
Duplex: Full
Number of Drivers/Receivers: 3/5 configuration
Package / Case: 20-SSOP form factor (0.209", 5.30mm Width)
Mounting Type: Surface Mount
RoHS Status: ROHS3 Compliant

Electrical Compatibility Criteria:

Voltage - Supply: Must support 4.75V ~ 5.25V operating range
Operating Temperature: Must support minimum 0°C ~ 70°C range
Receiver Hysteresis: Acceptable range 500 mV to 1 V
Data Rate: Minimum 120 Kbps

Substitute parts are grouped into two categories based on package configuration:

Category A - Direct Package Match (20-SSOP): GD75232DBR, MAX3185CAP+, MAX3185CAP+T, MAX3185EAP+, MAX3185EAP+T, ST75185CTR

Category B - Different Package (28-SSOP): MAX3238EAI+, MAX3238EAI+T (5/3 configuration, not recommended for direct substitution)

Parameter Comparison

Part Number	Manufacturer	Drivers/Receivers	Package	Voltage Supply	Operating Temp	Data Rate	Receiver Hysteresis	Product Status	Inventory
SN75LP1185DBR	Texas Instruments	3/5	20-SSOP	4.75V ~ 5.25V	0°C ~ 70°C	—	1 V	Last Time Buy	1323 Pcs
GD75232DBR	Texas Instruments	3/5	20-SSOP	5V, ±7.5V ~ 15V	0°C ~ 70°C	120 Kbps	500 mV	Active	43200 Pcs
MAX3185CAP+	Analog Devices Inc./Maxim Integrated	3/5	20-SSOP	4.5V ~ 5.5V	0°C ~ 70°C	230 Kbps	650 mV	Active	3300 Pcs
MAX3185CAP+T	Analog Devices Inc./Maxim Integrated	3/5	20-SSOP	4.5V ~ 5.5V	0°C ~ 70°C	230 Kbps	650 mV	Active	2334 Pcs
MAX3185EAP+	Analog Devices Inc./Maxim Integrated	3/5	20-SSOP	4.5V ~ 5.5V	-40°C ~ 85°C	230 Kbps	650 mV	Active	1107 Pcs
MAX3185EAP+T	Analog Devices Inc./Maxim Integrated	3/5	20-SSOP	4.5V ~ 5.5V	-40°C ~ 85°C	230 Kbps	650 mV	Active	2800 Pcs
ST75185CTR	STMicroelectronics	3/5	20-TSSOP	4.5V ~ 5.5V	0°C ~ 70°C	120 Kbps	500 mV	Active	19800 Pcs
MAX3238EAI+	Analog Devices Inc./Maxim Integrated	5/3	28-SSOP	3V ~ 5.5V	-40°C ~ 85°C	250 Kbps	300 mV	Active	2000 Pcs
MAX3238EAI+T	Analog Devices Inc./Maxim Integrated	5/3	28-SSOP	3V ~ 5.5V	-40°C ~ 85°C	250 Kbps	300 mV	Active	3300 Pcs

Engineering Selection Recommendations

Recommended Direct Substitutes (20-SSOP, 3/5 Configuration):

GD75232DBR and ST75185CTR are functionally equivalent alternatives with Active product status and high inventory availability. Both maintain the 3/5 driver/receiver configuration and 20-SSOP package footprint. GD75232DBR offers extended supply voltage range (±7.5V ~ 15V) and higher data rate (120 Kbps). ST75185CTR provides higher inventory (19800 Pcs) and operates within the 4.5V ~ 5.5V range.

MAX3185 series (CAP+, CAP+T, EAP+, EAP+T) from Analog Devices Inc./Maxim Integrated are pin-compatible alternatives with identical 3/5 configuration and 20-SSOP package. These devices feature higher data rates (230 Kbps) and extended operating temperature ranges (EAP+ variants: -40°C ~ 85°C). All MAX3185 variants are Active status with ROHS3 compliance.

Not Recommended for Direct Substitution:

MAX3238EAI+ and MAX3238EAI+T feature inverted driver/receiver configuration (5/3 instead of 3/5) and 28-SSOP package, requiring PCB redesign and are unsuitable for direct replacement.

Compliance Verification:

All recommended substitutes maintain ROHS3 compliance, REACH Unaffected status, and EAR99 ECCN classification, matching the original SN75LP1185DBR specifications.

Frequently Asked Questions (FAQ)

Q: Can MAX3238EAI+ replace SN75LP1185DBR directly?

A: No. The MAX3238EAI+ has a different driver/receiver configuration (5/3 vs. 3/5) and uses a 28-SSOP package instead of 20-SSOP. Direct substitution requires PCB redesign.

Q: What is the primary difference between GD75232DBR and MAX3185CAP+?

A: GD75232DBR supports extended supply voltage (±7.5V ~ 15V) and operates at 120 Kbps data rate. MAX3185CAP+ operates at 4.5V ~ 5.5V with higher data rate (230 Kbps). Both maintain identical 3/5 configuration and 20-SSOP package.

Q: Are MAX3185CAP+ and MAX3185CAP+T electrically identical?

A: Yes. The difference is packaging: CAP+ uses Tube packaging, while CAP+T uses Tape & Reel (TR) packaging. Electrical specifications and performance are identical.

Q: Which substitute offers the widest operating temperature range?

A: MAX3185EAP+, MAX3185EAP+T, MAX3238EAI+, and MAX3238EAI+T all operate from -40°C ~ 85°C, compared to the original SN75LP1185DBR range of 0°C ~ 70°C.

Q: Is ST75185CTR compatible with the original SN75LP1185DBR footprint?

A: ST75185CTR uses 20-TSSOP package (0.173", 4.40mm Width) versus the original 20-SSOP (0.209", 5.30mm Width). While both are 20-pin SSOP variants, the width difference requires PCB layout verification before substitution.

Q: What inventory availability should I consider for production?

A: GD75232DBR offers highest availability (43200 Pcs), followed by ST75185CTR (19800 Pcs). MAX3185 series variants range from 1107 to 3300 Pcs. Original SN75LP1185DBR has 1323 Pcs remaining stock.

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