Analog Devices Inc. LT1031BCH

Overview

LT1031BCH from Analog Devices (formerly Linear Technology) is a precision 10V buried Zener voltage reference IC with ultralow drift (≤5ppm/°C), <1ppm_P-P noise (0.1Hz–10Hz), and dual-mode operation (series or shunt). It sources/sinks up to 10mA, maintains ±0.005% initial accuracy, and delivers stable output in high-accuracy data acquisition systems requiring metrology-grade voltage references.

For engineers reviewing the LT1031BCH datasheet, LT1031BCH pinout, LT1031BCH application, or LT1031BCH equivalent, key selection criteria include its guaranteed 5ppm/°C max temperature coefficient over –25°C to +85°C, 100dB+ ripple rejection, minimum 11V input requirement, and compatibility with LH0070/AD581-based designs where improved thermal stability and lower noise are critical.

Technical Context

The LT1031BCH uses a subsurface buried Zener structure-eliminating surface-breakdown noise and instability-to achieve superior long-term stability (15ppm over 1000 hours) and reduced thermal hysteresis (5ppm). Its unique architecture enables simultaneous sourcing and sinking in series mode without external components.

It operates across two distinct configurations: three-terminal series mode (IN/OUT/GND) with 1.2–1.7mA quiescent current, and two-terminal shunt mode (OUT/GND) with 1.1–1.5mA minimum current. Line regulation is specified at 1–4ppm/V (11.5–14.5V) and load regulation at 12–25ppm/mA (sourcing, 0–10mA).

Key Specifications

Pinout & Package

H package: 3-lead TO-39 metal can (0.165"–0.185" height, 0.350"–0.370" diameter), hermetically sealed, lead temperature rated to 300°C for 10 sec.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD581LH and LH0070-2H, the LT1031BCH delivers the lowest combined drift-noise-PSRR profile in the TO-39 form factor-making it optimal for new designs demanding 16-bit-plus accuracy without external filtering or trimming.

Availability

LT1031BCH is available at Aetrix Electronics and suitable for high-accuracy data acquisition systems, precision laboratory instrumentation, and aerospace-grade inertial navigation calibration requiring stable component supply with traceable lot history and extended lifecycle support.

Supply support for LT1031BCH 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 acquired Linear Technology in 2017; Linear pioneered high-performance analog ICs including precision references, amplifiers, and power management solutions.

The LT1031 product line was designed specifically for metrology, test equipment, and aerospace applications demanding ultralow drift, low noise, and long-term stability-leveraging buried Zener technology to surpass bandgap alternatives.

FAQ

What is the guaranteed temperature coefficient specification for LT1031BCH?

The LT1031BCH guarantees a maximum temperature coefficient of 5ppm/°C over the –25°C to +85°C range, as confirmed in the Electrical Characteristics table. This specification applies to the B-grade variant and is tighter than the C- and D-grades. The LT1031BCH achieves this via laser-trimmed buried Zener core and proprietary thermal design-critical for maintaining accuracy in portable calibration standards where ambient temperature varies.

Can LT1031BCH operate in shunt mode, and what is the minimum current required?

Yes, the LT1031BCH supports true two-terminal shunt-mode operation with a minimum current of 1.1mA to 1.5mA (typical 1.3mA) when the input is open. In this configuration, it functions like a precision Zener diode-regulating voltage between OUTPUT and GROUND terminals. This capability allows drop-in replacement of discrete Zeners in legacy designs while retaining 10V accuracy and ultralow drift, as verified in the Absolute Maximum Ratings and Electrical Characteristics sections.

What is the output noise performance of LT1031BCH, and how is it measured?

The LT1031BCH delivers 6µV_P-P (≈1ppm_P-P) output noise in the 0.1Hz to 10Hz band, measured under standard conditions (T_A = 25°C, C_OUT = 0, no airflow). This ultra-low noise stems from its subsurface buried Zener structure and is validated in TPC07 and TPC16 curves. To maintain this performance, shielding from air turbulence (e.g., foam cup enclosure) is recommended-especially in TO-39 metal-can packages where thermoelectric effects dominate low-frequency noise.

Is LT1031BCH pin-compatible with LH0070 and AD581, and what are the key improvements?

Yes, the LT1031BCH is explicitly pin-compatible with LH0070-2H and AD581LH per the datasheet's "Pin Compatible" note and cross-reference guide. Key improvements include 5ppm/°C vs. 7–10ppm/°C drift, 6µV_P-P vs. 15µV_P-P noise, >100dB vs. ~90dB ripple rejection, and enhanced long-term stability (15ppm/1000h vs. 2000ppm/1000h for AD581). These gains stem from Linear's buried Zener process and optimized topology-making LT1031BCH a direct upgrade path.

What is the minimum input voltage required for LT1031BCH to regulate properly?

The LT1031BCH requires a minimum input voltage of 11.0V (guaranteed) to maintain regulation at load currents ≤1mA, as specified in the Electrical Characteristics table under "Minimum Input Voltage (Note 7)". This headroom ensures stable operation even with aging supplies or resistive drops in PCB traces. At higher loads (e.g., 10mA), the minimum input rises slightly-see TPC03 curve for exact V_IN(min) vs. I_LOAD behavior across temperature.