TMP235 Datasheet Explained: Specs, Pinout, Formula & Circuit

Is the TMP235 right for your design?

It’s a good fit if:

• You want a temperature reading on any ADC, with no library
• Your board runs on 3.3 V (ESP32, Pico, STM32)
• You need to read below 0 °C on a single supply
• Battery life matters (9 µA)
• You’re replacing an LM35 or TMP36
• You need up to 150 °C

Look elsewhere if:

• You need better than about ±1 °C guaranteed
• The sensor sits at the end of a long cable (use a digital sensor)
• Your ADC is too noisy to resolve millivolts
• You need a waterproof probe out of the box

TMP235 key specifications

TMP235 pinout

TMP235 typical application circuit

1. 0.1 µF on VDDRight at the pin. On a noisy supply, TI suggests adding 100 Ω in series with VDD to form a small filter.
2. Keep the output’s load smallThe TMP235 is stable with up to 1000 pF on its output, and that budget includes your ADC’s own input capacitance. TI suggests about 680 pF as a filter capacitor, placed at the ADC pin. A big “smoothing” capacitor here can make it oscillate.
3. Mount it to what you measureThe sensor reads its own die temperature, which follows whatever its pins and pad are bonded to. Good thermal contact matters more than anything else (see our measured response test below).

TMP235 formula and code

From −40 to 100 °C the transfer function is a straight line: VOUT = 500 mV + 10 mV/°C × T, so T = (VOUT_mV − 500) ÷ 10. 25 °C reads 750 mV; 100 °C reads 1.5 V. Above 100 °C the slope rises slightly (10.1 then 10.6 mV/°C), and TI gives a piecewise formula if you need that range.

// ESP32 (Arduino core): GPIO34 is an ADC1 pin, safe with Wi-Fi on
float readTMP235() {
  long sum = 0;
  for (int i = 0; i < 32; i++) sum += analogReadMilliVolts(34);
  float mv = sum / 32.0;
  return (mv - 500.0) / 10.0;      // degrees C, valid -40 to 100 C
}

// Arduino Uno with a 3.3 V reference on AREF (call analogReference(EXTERNAL) first)
float readTMP235_uno() {
  float mv = analogRead(A0) * 3300.0 / 1023.0;
  return (mv - 500.0) / 10.0;
}

Because it uses the same 500 mV offset and 10 mV/°C as the TMP36, code written for a TMP36 works unchanged. On an ESP32 at the default attenuation, the ADC’s recommended range is roughly 0.15 to 2.45 V, which covers the TMP235 from about −35 to 150 °C (0.15 to about 2.02 V).

TMP235 vs LM35

For a new 3.3 V or battery design, the TMP235 is the easier part. Moving from an LM35 means one code change: subtract 500 mV before dividing by 10.

Frequently asked questions

© Ramanu Systems · Precision electronics modules, Made in India · TMP235 figures from the Texas Instruments TMP235/TMP236 datasheet SBOS857E. LM35 figures are typical values from the TI LM35 datasheet. ESP32 ADC range from Espressif’s ADC documentation. Found an error? Tell us and we will fix it and credit you.