Specifications
| Type | Description |
|---|---|
| Part Number | TMP421 |
| Manufacturer | Texas Instruments |
| Product Type | remote and local temperature sensor |
| Category | Sensors |
| Package / Case | SOT23-8 (DCN); TMP421C also DSBGA-8/WCSP (YZD) |
| Remote Temperature Channels | 1 |
| Local Temperature Channels | 1 |
| Interface | Two-wire / SMBus serial interface |
| Supply Voltage Range | 2.7 to 5.5 V |
| Supply Voltage Range | 2.55 to 5.5 V |
| Local Temperature Error | ±1.25 typ, ±2.5 max °C |
| Local Temperature Error | ±0.25 typ, ±1.5 max °C |
| Remote Temperature Error | ±0.25 typ, ±1 max °C |
| Remote Temperature Error | ±1 typ, ±3 max °C |
| Remote Temperature Error | ±3 typ, ±5 max °C |
| Temperature Error vs Supply | ±0.2 typ, ±0.5 max °C/V |
| Temperature Error vs Supply | ±0.2 typ, ±0.5 max °C/V |
| Conversion Time | 100 min, 115 typ, 130 max ms |
| Local Temperature Resolution | 12 bits |
| Remote Temperature Resolution | 12 bits |
| Remote Sensor Source Current High | 120 µA |
| Remote Sensor Source Current Medium High | 60 µA |
| Remote Sensor Source Current Medium Low | 12 µA |
| Remote Sensor Source Current Low | 6 µA |
| Remote Transistor Ideality Factor | 1.008 |
| SMBus Logic Input High Voltage | 2.1 V min |
| SMBus Logic Input Low Voltage | 0.8 V max |
| SMBus Input Hysteresis | 500 mV |
| SMBus Output Low Sink Current | 6 mA |
| SDA Output Low Voltage | 0.15 typ, 0.4 max V |
| Logic Input Current | -1 min, +1 max µA |
| SMBus Input Capacitance | 3 pF |
| SMBus Clock Frequency | 3.4 MHz max |
| SMBus Timeout | 25 min, 30 typ, 35 max ms |
| SCL Falling Edge to SDA Valid Time | 1 µs max |
| Digital Input Capacitance | 3 pF |
| Digital Input High Voltage | 0.7(V+) min, (V+)+0.5 max V |
| Digital Input Low Voltage | -0.5 min, 0.3(V+) max V |
| Digital Input Leakage Current | 1 µA max |
| Quiescent Current | 32 typ, 38 max µA |
| Quiescent Current | 400 typ, 525 max µA |
| Shutdown Current | 3 typ, 10 max µA |
| Shutdown Current | 90 µA typ |
| Shutdown Current | 350 µA typ |
| Undervoltage Lockout | 2.3 min, 2.4 typ, 2.6 max V |
| Power-On Reset Threshold | 1.6 min, 2.3 max V |
| Specified Temperature Range | -40 to +125 °C |
| Storage Temperature Range | -60 to +130 °C |
| Thermal Resistance | 100 °C/W |
| Thermal Resistance | 128 °C/W |
| Absolute Maximum Supply Voltage | +7 V |
| Absolute Maximum Input Voltage | -0.5 to VS+0.5 V |
| Absolute Maximum Input Voltage | -0.5 to 7 V |
| Absolute Maximum Input Current | 10 mA |
| Absolute Maximum Operating Temperature | -55 to +127 °C |
| Maximum Junction Temperature | +150 °C |
| ESD Rating HBM | 3000 V |
| ESD Rating CDM | 1000 V |
| ESD Rating MM | 200 V |
| Two-Wire Address | 10011xx |
| Package Marking | DACI |
| SDA Pin Type | Open-drain; requires pull-up resistor to V+ |
| SCL Pin Type | Open-drain; requires pull-up resistor to V+ |
| Datasheet Status | request_only |
Product Overview
The TMP421 is a Texas Instruments remote and local temperature sensor in the Sensor category. For TMP421, the device integrates one local temperature channel and one remote temperature channel, with device configuration and readout handled through a two-wire/SMBus serial interface. The TMP421 two-wire address is 10011xx, and the SOT23-8 DCN package marking is DACI.
The SOT23-8 version is specified for a 2.7 to 5.5 V supply range, while TMP421C in DSBGA-8 is specified from 2.55 to 5.5 V. Temperature conversion time is 100 ms minimum, 115 ms typical, and 130 ms maximum per channel. Both local and remote temperature measurements support 12-bit resolution. Remote sensor current settings include 120 µA, 60 µA, 12 µA, and 6 µA, with a 1.008 optimized remote transistor ideality factor.
Assembly and interface details include open-drain SDA and SCL pins that require pull-up resistors to V+. The device is specified across -40 to +125 °C, with storage limits from -60 to +130 °C.
Key Features
- One remote and one local temperature channel
- Two-wire/SMBus serial interface for configuration and readout
- 2.7 to 5.5 V TMP421 SOT23-8 supply range
- 12-bit local and remote temperature resolution
- 100 to 130 ms conversion time per channel
- 3.4 MHz maximum SMBus clock frequency
- Open-drain SDA and SCL require pull-up resistors
- 120, 60, 12, and 6 µA remote source currents
- Specified operating range from -40 to +125 °C
- SOT23-8 DCN package with DACI marking
Typical Applications
- Remote temperature sensing
- Local board temperature sensing
- SMBus temperature readout
- Two-wire sensor systems
- Low-current shutdown designs
- SOT23-8 sensor assemblies
- Remote transistor temperature measurement
Procurement Notes
When requesting a quote for TMP421, buyers should confirm the manufacturer, package or case, required quantity, target date code, compliance documents, packing method, destination country and expected delivery schedule.
If alternatives are acceptable, buyers should share the approved vendor list, required electrical or optical limits, package constraints and qualification requirements. Any alternative part should be reviewed by the buyer's engineering team before production use.
For analog and signal-chain sourcing, supply voltage, bandwidth, accuracy, noise level, package, temperature grade, input/output configuration and qualification requirements should be verified before approval.
FAQ
How many temperature channels does the TMP421 provide?
The TMP421 provides one remote temperature channel and one local temperature channel. Both local and remote temperature measurements have 12-bit resolution according to the extracted datasheet facts.
What serial interface is used for TMP421 readout?
TMP421 configuration and readout use a two-wire/SMBus serial interface. The SMBus clock frequency is specified up to 3.4 MHz, and the TMP421 two-wire address format is 10011xx.
What supply range applies to the TMP421 package options?
For TMP421 in SOT23-8, the supply voltage range is 2.7 to 5.5 V. For TMP421C in DSBGA-8, the extracted facts specify a 2.55 to 5.5 V supply range.
What package information is specified for TMP421?
The TMP421 package case is SOT23-8 (DCN), and TMP421C is also listed with DSBGA-8/WCSP (YZD). The TMP421 SOT23-8 DCN package marking is DACI.
Technical Review & Sourcing Note
Prepared by LDeepAI Component Sourcing Team. Reviewed for RFQ, documentation and alternative sourcing use. Last updated: July 28, 2026.
This page is based on manufacturer datasheet information and LDeepAI sourcing review. Specifications should be verified against the official manufacturer datasheet before final procurement or design approval. Final electrical, optical and reliability approval should be confirmed by the buyer's engineering team.