STMicroelectronics STLM20W87F

Overview

STLM20W87F from STMicroelectronics is a precision analog-output temperature sensor in SOT323-5L package, designed for ultra-low-power battery-operated systems. It delivers ±1.5 °C max accuracy at 25 °C, operates from 2.4 V to 5.5 V, draws only 4.8 µA typical quiescent current, and supports –55 °C to 130 °C (Grade 7) operation - enabling accurate thermal monitoring in compact portable medical instruments and RF power transistor bias circuits.

For engineers reviewing the STLM20W87F datasheet, STLM20W87F pinout, STLM20W87F application, or STLM20W87F equivalent, key selection criteria include its analog voltage output transfer function, grade-specific temperature range limitation at low supply voltages, negligible self-heating due to sub-8 µA IQ, and dual-package availability requiring careful mapping of NC/GND pin usage per footprint.

Technical Context

The STLM20W87F implements a second-order parabolic transfer function: V_OUT = (–3.88 × 10^–6 × T²) + (–1.15 × 10^–2 × T) + 1.8639 V, optimized for ±2.5 °C max error across its full –55 °C to 130 °C range at V_CC ≥ 2.7 V. Its output impedance is 160 Ω, supporting up to 300 pF capacitive load without instability.

It features two configurable terminals: Pin 1 (NC) may be left floating or grounded; Pin 2 (GND) is thermally critical - grounding maximizes thermal conductivity to PCB ground plane. The device exhibits ±0.4% non-linearity over –20 °C to 80 °C and maintains ±4% V_OUT tolerance only in Grade 9 variants (not applicable to W87F).

Key Specifications

Pinout & Package

SOT323-5L 5-lead small outline transistor package (ECOPACK® compliant, 1.80 × 2.00 mm footprint, 1.10 mm height), optimized for thermal coupling via exposed GND pad contact to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog-output temperature sensor applications.

Compared with LM75BIMM/NOPB and MAX6611ASA+, the STLM20W87F uniquely combines Grade 7 temperature range, sub-8 µA quiescent current, and analog voltage output in a 5-lead SOT323 - making it irreplaceable for battery-powered, high-temperature, direct-ADC thermal monitoring where digital overhead or self-heating must be minimized.

Availability

STLM20W87F is available at Aetrix Electronics and suitable for smartphone thermal management, portable medical instrument calibration, and RF power transistor monitor applications requiring stable component supply across extended temperature ranges and ultra-low power budgets.

Supply support for STLM20W87F 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

The STLM20 series belongs to ST's precision analog sensor product line, engineered specifically for ultra-low-power, high-accuracy temperature measurement in space-constrained, battery-sensitive applications - with emphasis on thermal stability, minimal self-heating, and seamless ADC interface compatibility.

FAQ

What is the maximum operating temperature for STLM20W87F at 2.4 V supply?

At V_CC = 2.4 V, the STLM20W87F's minimum operating temperature degrades from –55 °C to –30 °C while the upper limit remains +130 °C. This is explicitly defined in Section 1 of the datasheet (Doc ID 12495 Rev 13) and confirmed in Table 5's ambient temperature specification footnote for Grade 7 devices.

Can Pin 1 (NC) and Pin 2 (GND) be shorted together on the PCB?

Yes - Pin 1 (NC) has no internal connection and may be tied to GND without electrical risk; doing so improves mechanical anchoring and thermal mass coupling. However, Pin 2 (GND) must always be connected to the system ground plane to ensure proper thermal conduction and noise immunity, as emphasized in Figure 2 and Section 1 of the datasheet.

Does STLM20W87F require an external filter capacitor on V_OUT?

A 0.1 µF bypass capacitor between V_CC and GND is mandatory per datasheet recommendation. An external RC filter on V_OUT is optional but advised for noisy environments or capacitive loads exceeding 300 pF; Table 7 specifies 200 Ω + 1 µF as the standard configuration to preserve thermal time constant while attenuating high-frequency noise.

How does the STLM20W87F's parabolic transfer function improve accuracy versus linear approximation?

The parabolic equation reduces temperature-to-voltage error to ±0.004 °C in narrow bands (e.g., 20–30 °C), whereas linear approximations introduce up to ±0.65 °C deviation over –40 °C to 85 °C (Table 2). This eliminates need for on-device or host-side polynomial correction, simplifying firmware and preserving ADC resolution for critical medical or timing applications.