Analog Devices Inc. TMP03FT9

Overview

TMP03FT9 from Analog Devices is a monolithic temperature sensor IC with open-collector serial digital output, generating a ratiometric mark-space pulse train proportional to absolute temperature. It delivers ±1.5°C typical accuracy from –25°C to +100°C, operates from 4.5 V to 7 V, consumes ≤1.3 mA at 5 V, and is housed in a 3-lead TO-92 package for isolated thermal monitoring in power systems.

For engineers reviewing the TMP03FT9 datasheet, TMP03FT9 pinout, TMP03FT9 application, or TMP03FT9 equivalent, this page provides verified technical context, real-world timing behavior (T1/T2 encoding), isolation-ready output drive capability (5 mA sink), and validated alternatives for thermal protection and environmental control designs.

Technical Context

The TMP03FT9 implements a first-order sigma-delta modulator with an onboard PTAT voltage generator and precision comparator, producing a ratiometric digital output independent of clock drift. Its encoding uses nominal T1 = 10 ms and T2 varying with temperature, enabling software decoding via Temperature (°C) = 235 − 400 × (T1/T2).

It features an open-collector NPN output rated for 5 mA sink current and 18 V max collector-emitter voltage, optimized for optocoupler-driven isolated circuits. Thermal self-heating in TO-92 is ∆T = 0.73°C at 5 V in free air, with θ_JA = 162°C/W.

Key Specifications

Pinout & Package

Package: 3-lead TO-92 (T-3-1), bottom view with leads numbered 1–3 left-to-right. Lead 1 = DOUT (open-collector output), Lead 2 = V+ (supply input), Lead 3 = GND (ground reference).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar temperature sensing applications.

Compared with LM35DH and MAX6611ASA+, the TMP03FT9 uniquely combines open-collector isolation readiness, ratiometric clock independence, and TO-92 simplicity-making it optimal for cost-sensitive, safety-critical thermal cutoffs where minimal component count and proven reliability are mandatory.

Availability

TMP03FT9 is available at Aetrix Electronics and suitable for industrial process control, computer thermal monitoring, and thermal protection requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TMP03FT9 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The TMP03FT9 belongs to Analog Devices' precision temperature sensor product line, designed specifically for applications demanding robust, isolated, and drift-free thermal measurement without external calibration or complex interface circuitry.

FAQ

What is the output format of the TMP03FT9 and how is temperature calculated?

The TMP03FT9 outputs a ratiometric square wave with mark-space encoding: T1 (high time) and T2 (low time). Temperature in °C is calculated as 235 − 400 × (T1/T2), using microcontroller timer capture. This ratiometric method makes the result independent of both the TMP03FT9's internal clock and the host system's counting clock, ensuring accuracy despite frequency drift or variation.

Can the TMP03FT9 drive an optocoupler directly, and what are the key electrical limits?

Yes, the TMP03FT9 can drive optocouplers directly via its open-collector output. It sinks up to 5 mA at V_OL ≤ 2 V (–40°C to 0°C) and supports up to 18 V collector-emitter voltage. For reliable switching, use a 4.7 kΩ pull-up to 5 V (yielding ~1 mA LED current), matching the 4N32 or HCPL-2630 turn-on/turn-off symmetry to avoid T1/T2 skew.

What is the thermal response time of the TMP03FT9 in TO-92 packaging?

In still air, the TMP03FT9 in TO-92 exhibits ~40 seconds to reach 63% of final temperature during heating (τ ≈ 40 s), per TPC 23. In forced air (200 FPM), thermal time constant drops to ~140 seconds (TPC 21). These values reflect the device's physical mass and TO-92 thermal resistance (θ_JA = 162°C/W), critical for selecting enclosure airflow or thermal mass in thermal protection loops.

How does supply voltage variation affect TMP03FT9 accuracy, and what is its PSRR?

The TMP03FT9 has a Power Supply Rejection Ratio of 0.7–1.4°C/V over 4.5 V–7 V, meaning a 1 V supply shift introduces ≤1.4°C error. TPC 4 confirms normalized output frequency varies <±5% across supply range. For highest accuracy, maintain V+ within ±0.25 V of nominal (e.g., 4.75–5.25 V) and use local 10 µF + 0.1 µF bypassing as specified in the TMP03FT9 datasheet.

Is the TMP03FT9 RoHS compliant, and what is its lead finish?

Yes, the TMP03FT9 is RoHS compliant. Per the Analog Devices ordering guide, the "Z" suffix denotes RoHS-compliant packaging; TMP03FT9Z is the RoHS variant. The TO-92 package uses matte tin (Sn) lead finish, qualified to JEDEC J-STD-020 moisture sensitivity level 1 (unlimited floor life at ≤30°C/85% RH), and supports standard SnPb or lead-free reflow profiles.