LM75ADP - Digital Temp Sensor & Thermal Watchdog | NXP
N.º da peça: LM75ADP ✗ Fim de vida| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $1.42 | $1,42 |
| 10 | $1.18 | $11,80 |
| 100 | $0.93 | $93,00 |
| 500 | $0.78 | $390,00 |
| 1.000 | $0.66 | $660,00 |
LM75ADP Visão geral
A digital temperature sensor is an IC that converts on-die thermal energy into a binary word readable by a host processor over a serial bus (typically I²C). Within the broader hierarchy, the LM75ADP sits in the sensor chain as a local-only device (no remote diode), beneath which fall thermistors, RTDs and analog temperature sensors. It functions as a thermal management building block at the board level, alongside fan controllers and supervisory circuits.
The LM75A's headline features include ±2 °C accuracy over the -55 °C to +125 °C range, an I²C/SMBus-compatible interface with three selectable address pins (allowing up to eight devices on one bus), and a programmable OVERTEMP output that asserts when the measured temperature crosses a user-defined threshold. The device also integrates a configurable hysteresis register to prevent chatter around the trip point, and offers both a normal mode for periodic monitoring and a shutdown mode that drops supply current below 10 µA.
Internally, the architecture pairs a precision bandgap reference with a Sigma-Delta modulator; the modulator's 1-bit stream is filtered by a decimation filter to produce the 11-bit signed result (8-bit integer plus 3-bit fraction). The OVERTEMP pin is implemented as an open-drain comparator output with the trip level and hysteresis both stored in on-chip registers, which lets the host configure thermal-window alarming in software rather than with external analog parts.
Typical applications include PC/embedded system thermal monitoring, industrial controller over-temperature protection, battery-pack charge management, LCD/projector overheat shutdown, and any HVAC-style closed-loop where a low-cost, low-pin-count digital sensor is preferred over a thermistor plus ADC. Because the LM75ADP is industry-standard LM75 register-compatible, it is a frequent retrofit into LM75 sockets where higher resolution is required without firmware changes.
When designing with the LM75A, observe I²C pull-up sizing: the open-drain SDA/SCL lines must be pulled to VCC through 4.7 kΩ resistors on a 3.3 V bus; the OVERTEMP pin also requires an external pull-up because it is open-drain. Decouple VCC with a 100 nF ceramic capacitor placed within 5 mm of the supply pin.
This page synthesizes distributor pricing, drop-in alternatives sourced from the NXP/ADT75/TI cross-references, and practical design notes not collected in any single manufacturer datasheet.
Alternativas drop-in para LM75ADP — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Variantes desta série
Modelos da mesma série compatíveis como drop-in com LM75ADP (mesmo formato e footprint) — diferindo em Package, Sensor Type.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
LM75ADP,118
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LM75AD
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
ADT75ARZ
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
ADT75ARZ-REEL7
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
TMP1075DSGR
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LM75BTP
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
LM75ADP Classificações máximas e características elétricas
| Tipo de sensor | Digital, Local (on-die bandgap) |
| Tipo de saída | I²C/SMBus, 11-bit signed |
| Temperature Accuracy | ±2 °C (max, -55 °C to +125 °C) |
| Temperature Resolution | 0.125 °C (11-bit, 3-bit fraction) |
| Faixa de temperatura de operação | -55 °C to +125 °C |
| Supply Voltage (VCC) | 2.8 V to 5.5 V |
| Supply Current (active) | 1 mA (typ, conversions active) |
| Supply Current (shutdown) | 10 µA (max) |
| OVERTEMP Output | Open-drain, programmable trip + hysteresis |
| I²C Address Pins | 3 (A0/A1/A2), supports up to 8 devices per bus |
| I²C Clock Rate | Up to 400 kHz (Fast Mode) |
| Encapsulamento | 8-pin TSSOP (SOT505-1, 3.0 × 3.0 mm) |
| Tipo de montagem | Surface Mount |
| Nível MSL | 1 (per JEDEC J-STD-020) |
| Status RoHS | Compliant |
| Conversion Technique | Sigma-Delta A-to-D conversion with on-chip bandgap |
| Legacy Compatibility | Pin-for-pin replacement for industry-standard LM75 |
Configuração de pinos do LM75ADP
| Pino 1 | SDA — I²C serial data (open-drain, requires pull-up) |
| Pino 2 | SCL — I²C serial clock (open-drain, requires pull-up) |
| Pino 3 | OS/OVERTEMP — Over-temperature alarm output (open-drain, active low) |
| Pino 4 | GND — Ground reference |
| Pino 5 | A2 — I²C address select bit 2 (tie to VCC, GND, or float) |
| Pino 6 | A1 — I²C address select bit 1 (tie to VCC, GND, or float) |
| Pino 7 | A0 — I²C address select bit 0 (tie to VCC, GND, or float) |
| Pino 8 | VCC — Supply voltage 2.8 V to 5.5 V; decouple with 100 nF |
Aplicações típicas
LM75ADP é adequado para 7 aplicaçãos: PC & Embedded Board Thermal Monitoring, Industrial Over-Temperature Protection, Battery Pack Thermal Management, LCD Projector & Display Overheat Shutdown, Server Fan Control & Hot-Swap Monitoring, HVAC & Building Automation Sensors, Medical Point-of-Care & Wearable Devices.
PC & Embedded Board Thermal Monitoring
The LM75ADP's 11-bit (0.125 °C) resolution and standard I²C/SMBus interface make it well-suited for motherboard and SBC thermal monitoring where firmware already expects an LM75-style register map. With ±2 °C accuracy over -55 °C to +125 °C and three address pins, up to eight sensors can monitor CPU zone, chipset zone, VRM zone, and ambient on a single bus. Designers place the TSSOP-8 within the airflow boundary and rely on the on-chip bandgap to track silicon-die temperature trends without a remote diode. The shutdown mode (<10 µA) helps idle-state standby power budgets in laptops and fan-less IoT boards. Compared with a thermistor + ADC approach, the LM75ADP eliminates the analog front-end entirely and reduces BOM by one resistor and one ADC channel.
Recomendado
Industrial Over-Temperature Protection
The LM75ADP's open-drain OVERTEMP output with programmable trip and hysteresis registers enables hardware-level thermal shutdown independent of the host CPU, which is critical in industrial PLCs and motor drives. Engineers program T_os and T_hyst via I²C, then route OVERTEMP directly to a MOSFET gate driver or relay for fail-safe load removal. The wide -55 °C to +125 °C operating range covers outdoor enclosures and factory-floor ambient extremes. Pull-up sizing on the OVERTEMP line (10 kΩ to VCC) ensures reliable logic-low signaling even at 125 °C. Compared with a discrete thermistor + comparator solution, the LM75ADP replaces the analog RC network with a digital register read, simplifying EMI qualification.
Recomendado
Battery Pack Thermal Management
Battery management systems benefit from the LM75ADP's low 10 µA shutdown current and 2.8-5.5 V supply that maps directly onto a single Li-ion cell range (3.0-4.2 V). The TSSOP-8 package mounts flat against a cell pouch, and the 0.125 °C resolution lets the BMS detect early thermal-runaway precursors before a hot spot reaches critical mass. Three address pins allow per-cell monitoring of multi-cell packs on one I²C bus, simplifying the wiring harness versus NTC thermistor arrays. The OVERTEMP output can gate the charge MOSFET through a logic-level translator for hardware-backed charge inhibit. Compared with a discrete NTC, the LM75ADP removes the analog-to-digital conversion step and removes the calibration curve.
Recomendado
LCD Projector & Display Overheat Shutdown
Projectors and large-format LCDs use the LM75ADP as a fail-safe thermal watchdog because its open-drain OVERTEMP pin can directly drive a lamp ballast or backlight driver shutdown input without host intervention. The TSSOP-8 mounts on the lamp housing, and the programmable trip threshold matches the bulb's derating curve as specified by the lamp manufacturer. With ±2 °C accuracy across the full 0-100 °C projector operating range, the trip can be set with only a small safety margin, preserving bulb life. The I²C interface also lets a service technician read the recorded peak temperature for warranty diagnostics. Compared with a single-point bimetallic thermostat, the LM75ADP provides software-configurable trip and hysteresis, plus a digital log path.
Recomendado
Server Fan Control & Hot-Swap Monitoring
In 1U/2U server and storage enclosures, the LM75ADP serves as an LM75-compatible thermal sensor in the chassis management plane, where multiple boards already expect LM75 register semantics over I²C. Its TSSOP-8 footprint fits on a mezzanine card edge, and three address pins let the BMC distinguish between PSU inlet, CPU exhaust, and HDD backplane zones. The 1 mA active current is negligible against the server's rail budget, and the <10 µA shutdown current lets unused zones be powered down individually. The OVERTEMP output can interrupt a hot-swap controller's ENABLE line for hardware-level cut-off. Compared with remote-diode sensors that need a transistor pair, the LM75ADP is self-contained and simplifies board bring-up.
Recomendado
HVAC & Building Automation Sensors
The LM75ADP's -55 °C to +125 °C operating range covers the full HVAC envelope from freezer aisles to boiler rooms, and its I²C interface allows wall-mount sensor tiles to bus into a building automation controller with minimal wiring. Three address pins let a single controller poll up to eight zones per I²C segment, reducing cable runs versus analog 4-20 mA loops. The 0.125 °C resolution supports setpoint-deadband control tighter than the human-comfort limit, and the OVERTEMP output can directly trigger a relay or TRIAC driver for heater cut-off. Compared with an analog LM35 + ADC front end, the LM75ADP replaces an op-amp, two resistors and one ADC channel, and adds software-configurable hysteresis.
Recomendado
Medical Point-of-Care & Wearable Devices
Wearable and point-of-care medical devices use the LM75ADP as an LM75-compatible skin/skin-proximate temperature sensor where firmware is already validated on the standard register map. The TSSOP-8 footprint mounts inside the battery compartment, and the 10 µA shutdown current keeps standby drain below the IEC 60601-1 patient-leakage budget. The 11-bit resolution (0.125 °C) is sufficient for trend logging in continuous-temperature monitoring patches, and three address pins allow multi-zone sensing in a single wrist strap. The OVERTEMP output can wake a host MCU from deep sleep via a GPIO interrupt when skin temperature crosses a fever threshold. Compared with analog NTC, the LM75ADP eliminates manual calibration and factory trim steps.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para LM75ADP — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | LM75ADP,118 | LM75AD | ADT75ARZ | ADT75ARZ-REEL7 | TMP1075DSGR | LM75BTP |
|---|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | Analog Devices | Analog Devices | Texas Instruments | Texas Instruments |
| Package | TSSOP-8 (SOT505-1) | TSSOP-8 (SOT505-1) - same | SO-8 (SOT96-1) - 8-pin same pinout, different body | TSSOP-8 - same | TSSOP-8 - same | TSSOP-8 - same | TSSOP-8 - same |
| Temperature Resolution | 11-bit (0.125 °C) | 11-bit (0.125 °C) | 11-bit (0.125 °C) | 11-bit (0.125 °C) | 11-bit (0.125 °C) | 11-bit (0.125 °C) | 11-bit (0.125 °C) |
| Temperature Accuracy (max) | ±2 °C | ±2 °C | ±2 °C | ±2 °C | ±2 °C | ±1 °C (better) | ±2 °C |
| Supply Voltage Range | 2.8 V to 5.5 V | 2.8 V to 5.5 V | 2.8 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 1.7 V to 5.5 V (wider) | 3.0 V to 5.5 V |
| Shutdown Current | <10 µA | <10 µA | <10 µA | <10 µA | <10 µA | <0.5 µA (better) | <1 µA (better) |
| I²C Address Pins | 3 (8 addresses) | 3 (8 addresses) | 3 (8 addresses) | 3 (8 addresses) | 3 (8 addresses) | 3 (8 addresses) | 3 (8 addresses) |
| Lifecycle Status | NRND (per NXP) | NRND | NRND | Active | Active | Active | Active |
| Approx. Qty-1 Price (USD) | $1.42 (as of 2026-10-08) | $1.42 | $1.40 | $2.10 | $2.10 | $1.10 | $1.30 |
Principais diferenciais
- Industry-standard LM75 register compatibility (vs MCP9808 (Microchip))
- Wider 2.8-5.5 V supply vs original 5 V LM75 (vs Original LM75)
- 11-bit (0.125 °C) resolution vs 9-bit (0.5 °C) LM75 (vs Original LM75)
Notas de projeto
Place a 100 nF X7R ceramic decoupling capacitor within 5 mm of the VCC pin (pin 8) and connect the GND pin (pin 4) to a low-impedance ground pour. The LM75ADP's 1 mA active current spikes occur at each conversion; without local decoupling these spikes couple into the analog bandgap reference and add ~0.5 °C of measurement noise. For multi-sensor buses, give each LM75ADP its own 100 nF rather than sharing one bulk cap across multiple devices.
Route SDA and SCL traces as a matched pair with no sharp 90° corners, keeping them short (<50 mm) and away from switching node traces. The TSSOP-8 thermal pad (pin 4 GND) should be soldered to a ground pour of at least 10 mm² to keep the die-to-ambient thermal resistance low; the LM75ADP's on-die sensor measures the package temperature, so thermal coupling to the board is critical for accurate tracking. Pull-up resistors (4.7 kΩ typical on a 3.3 V bus, 2.2 kΩ at 5 V) must be placed near the bus master, not near each sensor.
Three common LM75ADP pitfalls: (1) leaving the address pins (A0/A1/A2) floating - they MUST be tied to VCC, GND, or actively driven, because floating inputs on CMOS address pins cause indeterminate I²C addressing and bus contention; (2) forgetting the pull-up on the OVERTEMP pin (pin 3) - it is open-drain and will float high-impedance if unconnected, defeating the over-temperature alarm; (3) reading the temperature MSB/LSB without combining the two bytes correctly - the 11-bit result spans bytes 0x00 and 0x01, and a single-byte read returns stale data; always perform a 2-byte I²C burst read of pointer 0x00.
Estimated: at 25 °C ambient with the TSSOP-8 thermal pad soldered to a 20 mm² 1 oz copper pour, the junction-to-ambient thermal resistance is approximately 200 °C/W, so self-heating from the 1 mA active supply current is roughly 0.2 °C at 5.5 V. At 5 V VCC and continuous conversions, self-heating is negligible (<0.3 °C). However, if the LM75ADP is placed directly adjacent to a hot component (DC-DC converter, power MOSFET), the on-die sensor will report a composite temperature and must be physically isolated by 5-10 mm of PCB or a thermal cut-out in the copper pour.
Informações de conformidade
RoHS and REACH compliant per NXP product page. Not AEC-Q100 qualified (industrial-grade part); automotive applications should use the ADT75 automotive grade variant. Halogen-free per NXP packaging materials declaration.
