Analog Devices Inc. LH0070-2H

Overview

LH0070-2H from National Semiconductor (acquired by Texas Instruments) is a precision 10V buried-Zener voltage reference IC operating in series or shunt mode, delivering ±0.02% initial output accuracy, ≤5ppm/°C temperature drift over –25°C to 85°C, <6µV_P-P (0.1–10Hz) noise, and 10mA sourcing/sinking capability - used in high-resolution ADC/DAC calibration, inertial navigation systems, and portable metrology standards.

For engineers reviewing the LH0070-2H datasheet, LH0070-2H pinout, LH0070-2H application, or LH0070-2H equivalent, this page provides verified technical context, validated pin functions, real-world application constraints (e.g., thermal regulation sensitivity, air-turbulence-induced noise), and confirmed alternative options for precision reference design.

Technical Context

The LH0070-2H implements a subsurface Zener diode structure eliminating surface-breakdown noise and long-term drift issues inherent in bandgap or surface-Zener references. Its circuit supports dual-mode operation: as a three-terminal series regulator (IN/OUT/GND) or two-terminal shunt device (OUT/GND with input open).

Thermal regulation is minimized via low-power design (1.2–1.7mA quiescent current) and optimized package thermal resistance (θ_JA = 150°C/W); output trimming is achieved by injecting current into the GND pin using a 5Ω series resistor, enabling fine adjustment while preserving ultralow drift performance.

Key Specifications

Pinout & Package

H Package: 3-lead TO-39 metal can (0.165–0.185" height, 0.305–0.335" diameter), hermetically sealed, with kovar leads sensitive to thermoelectric noise from air turbulence.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LH0070-2H, LT1031BMH offers enhanced temperature range and tighter initial accuracy at higher cost, while AD581JH trades significant performance (drift, noise, stability) for lower price and legacy compatibility - making LH0070-2H the optimal balance for high-accuracy, moderate-temp industrial metrology.

Availability

LH0070-2H is available at Aetrix Electronics and suitable for high-resolution data acquisition, inertial navigation systems, and precision portable metrology requiring stable component supply with guaranteed long-term availability and traceable lot history.

Supply support for LH0070-2H 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

National Semiconductor, now part of Texas Instruments, pioneered high-precision analog ICs with emphasis on stability, noise, and thermal performance for test & measurement and aerospace markets.

The LH0070 series was designed specifically for ultra-stable voltage referencing in portable and field-deployable instrumentation, leveraging buried-Zener technology to surpass bandgap and surface-Zener alternatives in long-term drift and low-frequency noise.

FAQ

What is the guaranteed temperature coefficient specification for LH0070-2H?

The LH0070-2H guarantees ≤5ppm/°C output voltage drift over the –25°C to +85°C range, as confirmed in the Electrical Characteristics table. This applies to the full operating temperature span-not just at 25°C-and is critical for maintaining accuracy in field-deployed instruments where ambient temperature varies significantly. The LH0070-2H achieves this via its buried Zener structure and low-power internal design, avoiding heater-based compensation.

Can LH0070-2H operate in shunt mode, and what are the minimum current requirements?

Yes, LH0070-2H supports true shunt-mode operation (two-terminal configuration) with the INPUT pin left open. In this mode, it requires ≥1.1mA minimum shunt current at 25°C to maintain regulation, dropping to 0mA if INPUT is connected and biased appropriately. This dual-mode capability allows drop-in replacement of discrete Zener diodes in legacy designs while retaining precision characteristics-verified in the LH0070 datasheet's "Shunt Mode Current Limit" and "Shunt Characteristics" curves.

How does air movement affect LH0070-2H output noise, and how can it be mitigated?

Air turbulence induces thermoelectric noise in the LH0070-2H's kovar TO-39 leads, increasing 0.01–1Hz output noise nearly 10× when unshielded-as demonstrated in the "Noise Induced by Air Turbulence" plot (TA07). Mitigation requires physical shielding (e.g., small foam cup) around the package to block airflow, especially in lab-grade metrology setups. This effect is specific to metal-can packages; plastic-packaged alternatives do not exhibit the same sensitivity.

What is the recommended method to trim the output voltage of LH0070-2H?

LH0070-2H output voltage is trimmed by injecting current into the GROUND (Pin 3) terminal using a 5Ω series resistor, as shown in Figure TA04. A trim potentiometer supplies up to 1.5mA from the LH0070-2H or 3.5mA from a –15V rail. This method preserves low drift: the 5Ω resistor limits induced thermal drift to ≤2ppm/°C. Increasing resistor values proportionally reduces current but raises induced drift-so the 5Ω value is optimized for LH0070-2H's ±0.02% grade.

Is LH0070-2H pin-compatible with LT1031 or AD581, and what are the key electrical differences?

Yes, LH0070-2H is pin-compatible with LT1031 and AD581 in the TO-39 H package (Pin 1=INPUT, Pin 2=OUTPUT, Pin 3=GND). Electrically, LH0070-2H matches LT1031's buried-Zener architecture and shares identical functional specifications (10V output, dual-mode operation, low noise), but differs from AD581 in drift (5ppm/°C vs. 20ppm/°C), noise (<6µV_P-P vs. >10µV_P-P), and long-term stability (±0.05%/year vs. ±0.2%/year). These differences are documented in the cross-reference guide and electrical tables.