Texas Instruments LT1009CPWG4

Overview

LT1009CPWG4 from Texas Instruments is a precision 2.5-V shunt voltage reference IC with ±10 mV initial tolerance (±0.4%), 15 ppm/°C max average temperature coefficient, and 0.6 Ω max dynamic impedance at 1 mA. It features three-terminal adjustability (±5% via ADJ pin), operates from 400 µA to 10 mA, and is used in high-accuracy ADC/DAC references and power-supply monitors.

For engineers reviewing the LT1009CPWG4 datasheet, LT1009CPWG4 pinout, LT1009CPWG4 application, or LT1009CPWG4 equivalent, this page delivers verified electrical specs, package mapping to TSSOP-8, terminal-level design meaning, and real-world substitution guidance for industrial and embedded systems requiring stable 2.5-V references.

Technical Context

The LT1009CPWG4 implements a bandgap-derived shunt reference architecture with on-chip laser trimming for initial voltage accuracy and minimized αVZ. Its ADJ terminal enables ±5% output adjustment without degrading temperature stability, and it maintains regulation across 400 µA–10 mA cathode current.

Unlike two-terminal references, the three-terminal topology allows system-level error correction while retaining low 1.4 Ω full-range dynamic impedance and 20 ppm/khr long-term drift. It is characterized for 0°C to 70°C operation and requires no external components for basic 2.5-V reference use.

Key Specifications

Pinout & Package

TSSOP-8 package (PW), 3.0 mm × 4.4 mm body, 1.2 mm max height, lead pitch 0.65 mm, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar shunt reference applications.

Compared with LM136-2.5 and TL431ACDBVR, the LT1009CPWG4 delivers superior initial accuracy and integrated adjustability in a pin-compatible TSSOP-8 footprint, enabling direct upgrade paths without layout revision while maintaining industrial-grade stability.

Availability

LT1009CPWG4 is available at Aetrix Electronics and suitable for industrial automation, test equipment, and precision analog signal chains requiring stable component supply, long-lifecycle support, and guaranteed traceability.

Supply support for LT1009CPWG4 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

Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, longevity, and industrial-grade performance.

The LT1009 series was designed specifically for high-stability, low-drift voltage reference applications in data acquisition, instrumentation, and power management systems where precision and long-term repeatability are critical.

FAQ

What is the maximum cathode current rating for LT1009CPWG4?

The LT1009CPWG4 supports a maximum cathode current of 10 mA under recommended operating conditions. This limit ensures thermal stability within its TSSOP-8 package's 149 °C/W junction-to-ambient thermal resistance. Exceeding 10 mA risks exceeding the 150 °C maximum virtual junction temperature, potentially accelerating long-term drift. Always verify power dissipation (P = VZ × IZ) against ambient temperature and PCB copper area.

Can LT1009CPWG4 replace LM136-2.5 without PCB modifications?

Yes, LT1009CPWG4 is specified as a terminal-for-terminal replacement for LM136-2.5 in D and PW packages. Both use identical SOIC-8 and TSSOP-8 footprints with matching pin 4 (anode), pins 5/7 (cathode), and pin 8 (ADJ vs. NC). The LT1009CPWG4's ADJ pin can be left open to replicate LM136 behavior, making it a true drop-in upgrade with improved accuracy and stability.

What is the purpose of the NC pins on LT1009CPWG4?

The LT1009CPWG4 has four NC (no internal connection) pins - pins 1, 2, 3, and 6 - which are electrically isolated from the die. These pins serve mechanical and thermal roles only: they improve package rigidity, enhance heat dissipation through exposed paddle contact (if present), and maintain standard SOIC/TSSOP pin spacing. They must remain unconnected or grounded per layout best practices to avoid parasitic coupling.

How does the ADJ pin affect temperature coefficient in LT1009CPWG4?

The ADJ pin on LT1009CPWG4 enables ±5% output adjustment without degrading temperature coefficient. Internal circuitry isolates the adjustment path from the bandgap core, preserving the trimmed 15 ppm/°C max αVZ across the full adjustment range. This is confirmed in the datasheet's "Adjustment Range" specification, which specifies drift limits independent of ADJ voltage - unlike untrimmed references where trim networks introduce additional thermal gradients.

Is LT1009CPWG4 suitable for automotive applications?

No, LT1009CPWG4 is rated for 0°C to 70°C operation (C-suffix grade) and is not qualified for automotive AEC-Q100 stress testing. For automotive use, TI offers the LT1009I variant (–40°C to 85°C), but even that lacks PPAP documentation, TS 16949 manufacturing certification, or automotive-specific failure-in-time (FIT) data. Use only in commercial/industrial environments unless fully validated per your vehicle OEM's requirements.