Request Quote
(Ships tomorrow)
DS1721S/T&R Equivalent & Substitute Parts
Part Overview
The DS1721S/T&R is a digital temperature sensor manufactured by Analog Devices Inc./Maxim Integrated, designed for local temperature measurement across the -55°C to 125°C range with 11-bit resolution and I2C output. The device is packaged in 8-SOIC surface mount configuration and operates on 2.7V to 5.5V supply voltage.
This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Active alternatives with comparable or enhanced specifications are available from Texas Instruments and Microchip Technology, offering improved product status and compliance certifications.
Substiute Parts
Key Parameters
| Parameter | DS1721S/T&R |
|---|---|
| Sensor Type | Digital, Local |
| Sensing Temperature Range | -55°C ~ 125°C |
| Output Type | I2C |
| Supply Voltage | 2.7V ~ 5.5V |
| Resolution | 11 bits |
| Accuracy (Highest/Lowest) | ±1°C / ±2°C |
| Package / Case | 8-SOIC (0.154", 3.90mm Width) |
| Mounting Type | Surface Mount |
| Product Status | Obsolete |
| RoHS Status | RoHS non-compliant |
Substitute Part Grouping Explanation
Substitution for the DS1721S/T&R is determined by the following critical parameters:
Mandatory Compatibility Parameters:
- Package / Case: 8-SOIC (0.154", 3.90mm Width)
- Mounting Type: Surface Mount
- Supply Voltage: 2.7V ~ 5.5V minimum compatibility
- Sensor Type: Digital, Local
- Output Interface: I2C or I2C/SMBus compatible
Performance Parameters:
- Sensing Temperature Range: Must cover -55°C ~ 125°C or equivalent operational range
- Resolution: 11-bit preferred for functional equivalence
- Accuracy: ±1°C to ±2°C range acceptable
Substitute parts are grouped into two categories:
Direct Substitutes (Packaging Variant): DS1721S+T&R differs only in packaging format (Cut Tape vs. Tape & Reel) while maintaining identical electrical specifications and product lineage.
Functional Upgrades (Enhanced Specifications): Texas Instruments TMP175 and TMP275 series, and Microchip AT30TS74 series provide equivalent or superior performance with active product status and improved compliance certifications. These parts maintain 8-SOIC packaging, I2C/SMBus compatibility, and overlapping temperature ranges while offering enhanced accuracy or resolution in specific models.
Parameter Comparison
| Part Number | Manufacturer | Sensing Temp Range | Resolution | Accuracy (Highest) | Output Type | Supply Voltage | Package | Product Status | RoHS Status |
|---|---|---|---|---|---|---|---|---|---|
| DS1721S/T&R | Analog Devices Inc./Maxim | -55°C ~ 125°C | 11 b | ±1°C | I2C | 2.7V ~ 5.5V | 8-SOIC | Obsolete | Non-compliant |
| DS1721S+T&R | Analog Devices Inc./Maxim | -55°C ~ 125°C | 11 b | ±1°C | I2C | 2.7V ~ 5.5V | 8-SOIC | Active | ROHS3 Compliant |
| TMP175AID | Texas Instruments | -40°C ~ 125°C | 9 b | ±1.5°C | I2C/SMBus | 2.7V ~ 5.5V | 8-SOIC | Obsolete | ROHS3 Compliant |
| TMP175AIDR | Texas Instruments | -40°C ~ 125°C | 9 b | ±1.5°C | I2C/SMBus | 2.7V ~ 5.5V | 8-SOIC | Active | ROHS3 Compliant |
| TMP275AID | Texas Instruments | -40°C ~ 125°C | 11 b | ±0.5°C | SMBus | 2.7V ~ 5.5V | 8-SOIC | Obsolete | ROHS3 Compliant |
| TMP275AIDR | Texas Instruments | -40°C ~ 125°C | 11 b | ±0.5°C | SMBus | 2.7V ~ 5.5V | 8-SOIC | Active | ROHS3 Compliant |
| TMP75AID | Texas Instruments | -40°C ~ 125°C | 11 b | ±2°C | I2C/SMBus | 2.7V ~ 5.5V | 8-SOIC | Obsolete | ROHS3 Compliant |
| TMP75AIDR | Texas Instruments | -40°C ~ 125°C | 11 b | ±2°C | I2C/SMBus | 2.7V ~ 5.5V | 8-SOIC | Active | ROHS3 Compliant |
| TMP75AIDRG4 | Texas Instruments | -40°C ~ 125°C | 11 b | ±2°C | I2C/SMBus | 2.7V ~ 5.5V | 8-SOIC | Obsolete | ROHS3 Compliant |
| AT30TS74-SS8M-B | Microchip Technology | -55°C ~ 125°C | 11 b | ±2°C | I2C/SMBus | 1.7V ~ 5.5V | 8-SOIC | Active | ROHS3 Compliant |
| AT30TS74-SS8M-T | Microchip Technology | -55°C ~ 125°C | 11 b | ±2°C | I2C/SMBus | 1.7V ~ 5.5V | 8-SOIC | Active | ROHS3 Compliant |
Engineering Selection Recommendations
For Direct Replacement (Identical Specifications): DS1721S+T&R is the direct equivalent, differing only in packaging format (Cut Tape & Digi-Reel vs. Tape & Reel). This part maintains all electrical specifications and is the preferred choice for designs requiring no functional changes. Product status is Active with ROHS3 compliance, addressing the obsolescence and compliance limitations of the original DS1721S/T&R.
For Active Product Status with Enhanced Compliance: TMP175AIDR and TMP75AIDR from Texas Instruments provide active product status and ROHS3 compliance. TMP175AIDR offers 9-bit resolution with ±1.5°C accuracy, while TMP75AIDR maintains 11-bit resolution with ±2°C accuracy. Both support I2C/SMBus output and operate across -40°C to 125°C. These parts are suitable when product longevity and regulatory compliance are primary concerns, though the lower temperature limit (-40°C vs. -55°C) must be evaluated against application requirements.
For Superior Accuracy with Active Status: TMP275AIDR from Texas Instruments delivers the highest accuracy (±0.5°C) with 11-bit resolution, active product status, and ROHS3 compliance. This part operates across -40°C to 125°C with SMBus output. Selection is appropriate for applications requiring enhanced measurement precision, provided the -40°C lower limit is acceptable.
For Full Temperature Range Compatibility: AT30TS74-SS8M-B and AT30TS74-SS8M-T from Microchip Technology maintain the full -55°C to 125°C sensing range of the original part while offering active product status and ROHS3 compliance. These parts support I2C/SMBus output with 11-bit resolution and ±2°C accuracy. The lower supply voltage minimum (1.7V vs. 2.7V) provides additional design flexibility. Packaging options include both Tube (B variant) and Cut Tape & Digi-Reel (T variant).
Frequently Asked Questions (FAQ)
Q: Can DS1721S+T&R be used as a direct drop-in replacement for DS1721S/T&R?
A: Yes. DS1721S+T&R is electrically and functionally identical to DS1721S/T&R. The only difference is packaging format: DS1721S+T&R is supplied in Cut Tape format while DS1721S/T&R is supplied in Tape & Reel format. Both use the same 8-SOIC package and maintain identical pin configuration, electrical specifications, and performance characteristics.
Q: What is the primary limitation of the original DS1721S/T&R that makes substitution necessary?
A: The DS1721S/T&R is classified as obsolete and is RoHS non-compliant. These factors create supply chain risk and regulatory concerns for new designs and production continuity. Active alternatives with improved compliance certifications are available.
Q: Are Texas Instruments TMP175 and TMP275 series fully compatible with DS1721S/T&R?
A: TMP175 and TMP275 series maintain 8-SOIC packaging, I2C/SMBus output compatibility, and 2.7V to 5.5V supply voltage range. However, the lower temperature limit is -40°C instead of -55°C. TMP275AIDR offers superior accuracy (±0.5°C vs. ±1°C) and active product status. Compatibility depends on whether your application requires operation below -40°C.
Q: How does the Microchip AT30TS74 series compare to the original DS1721S/T&R?
A: AT30TS74-SS8M-B and AT30TS74-SS8M-T maintain the full -55°C to 125°C temperature range, 11-bit resolution, and 8-SOIC packaging. Both are active products with ROHS3 compliance. The AT30TS74 series supports I2C/SMBus output and offers a lower supply voltage minimum (1.7V), providing additional design flexibility. Accuracy is ±2°C, matching the original part's lower accuracy specification.
Q: What packaging options are available for substitute parts?
A: Substitute parts are available in multiple packaging formats: Tube (standard packaging for individual units), Cut Tape (CT) for automated assembly, and Cut Tape & Digi-Reel (CT & Digi-Reel) for high-volume production. Selection depends on your procurement and assembly requirements. DS1721S+T&R, TMP175AIDR, TMP275AIDR, and TMP75AIDR are available in Cut Tape & Digi-Reel format for high-volume applications.
Q: Can I use a substitute part with lower resolution (9-bit) instead of 11-bit?
A: TMP175AIDR provides 9-bit resolution compared to the original 11-bit specification. This reduces temperature measurement granularity from 0.0625°C to 0.125°C per step. Compatibility depends on your application's measurement precision requirements. If 11-bit resolution is mandatory, select TMP275AIDR, TMP75AIDR, or AT30TS74 series instead.
Q: What is the difference between I2C and SMBus output compatibility?
A: SMBus is a subset of I2C with stricter timing and protocol specifications. Devices supporting I2C/SMBus output (TMP175, TMP275, TMP75, AT30TS74 series) are compatible with both I2C and SMBus host controllers. The original DS1721S/T&R supports I2C output only. For applications using SMBus-specific features, verify host controller compatibility with your selected substitute.
Q: Which substitute part offers the best combination of active status, compliance, and full temperature range?
A: AT30TS74-SS8M-T from Microchip Technology provides active product status, ROHS3 compliance, full -55°C to 125°C temperature range, 11-bit resolution, and I2C/SMBus output in Cut Tape & Digi-Reel packaging. This part directly addresses the obsolescence and compliance limitations of the original DS1721S/T&R while maintaining functional equivalence.
Alternative Parts
SJ6012L2TP
Littelfuse Inc.
6 Alternative Parts
JMK107BBJ476MA-RE
Taiyo Yuden
10 Alternative Parts
GMK107BBJ475MA-T
Taiyo Yuden
5 Alternative Parts
SJ6020N2ARP
Littelfuse Inc.
3 Alternative Parts
SJ6025R2ATP
Littelfuse Inc.
4 Alternative Parts
2474-05L
API Delevan Inc.
1 Alternative Parts
4590R-684K
API Delevan Inc.
1 Alternative Parts
CM6560R-334
API Delevan Inc.
1 Alternative Parts
CM6460-104
API Delevan Inc.
1 Alternative Parts
5526-12
API Delevan Inc.
1 Alternative Parts