Analog Devices Inc. LT1389BCS8-2.5#TRPBF

Overview

LT1389BCS8-2.5#TRPBF from Analog Devices (formerly Linear Technology) is a nanopower precision shunt voltage reference delivering 2.500 V nominal output with ±0.05% initial accuracy, 20 ppm/°C max temperature coefficient, and 0.75 Ω typical dynamic impedance at 0.9 µA operating current. It operates from 0.9 µA to 2 mA reverse current and supports precision applications including portable meters and high-resolution ADCs.

For engineers reviewing the LT1389BCS8-2.5#TRPBF datasheet, LT1389BCS8-2.5#TRPBF pinout, LT1389BCS8-2.5#TRPBF application, or LT1389BCS8-2.5#TRPBF equivalent, key selection criteria include guaranteed 20 ppm/°C drift over 0°C to 70°C, sub-1 µA minimum operating current, low 50 µV_P-P 0.1 Hz–10 Hz noise, and SO-8 package compatibility with guard-ring layout for leakage mitigation.

Technical Context

The LT1389BCS8-2.5#TRPBF uses trimmed thin-film resistors and advanced curvature correction to achieve 0.05% initial voltage accuracy and 20 ppm/°C max drift across 0°C to 70°C. Its bandgap-based shunt architecture maintains regulation down to 0.9 µA reverse current without requiring an output compensation capacitor.

Dynamic impedance remains below 2 Ω over 0.9 µA–2 mA current range and up to 10 kHz frequency, enabling stable operation with capacitive loads up to 0.1 µF. Board leakage sensitivity is mitigated via internal DNC pins and recommended guard-ring routing tied to V_OUT.

Key Specifications

Pinout & Package

LT1389BCS8-2.5#TRPBF is housed in an 8-lead plastic SO (narrow, 0.150") package per LTC DWG #05-08-1610. Four pins are internally disconnected (DNC) and must remain unconnected; guard-ring routing around these pins is required to limit board leakage-induced error.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT1634BCS8-2.5, LT1389BCS8-2.5#TRPBF trades 10 ppm/°C lower drift for 14× lower operating current, making it optimal for battery longevity; versus REF3025AIDBZR, it delivers 4× tighter initial accuracy and integrated guard-ring support for leakage-sensitive layouts.

Availability

LT1389BCS8-2.5#TRPBF is available at Aetrix Electronics and suitable for portable meters, precision regulators, and high-resolution A/D converters requiring stable component supply with guaranteed long-term availability and traceable lot history.

Supply support for LT1389BCS8-2.5#TRPBF 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 and maintains full product support, documentation, and manufacturing continuity for all LT-branded precision analog ICs.

The LT1389 family was designed specifically for nanopower, high-accuracy shunt reference applications in battery-powered instrumentation and sensor signal chains where ultra-low current and guaranteed drift are mandatory.

FAQ

What is the minimum operating current for LT1389BCS8-2.5#TRPBF?

The LT1389BCS8-2.5#TRPBF guarantees regulation down to 0.7 µA reverse current across 0°C to 70°C. At 0.9 µA, it achieves its specified 2.500 V ±0.05% output and 20 ppm/°C drift. This nanopower capability makes LT1389BCS8-2.5#TRPBF ideal for multi-year battery life in portable calibrators and handheld test equipment.

Does LT1389BCS8-2.5#TRPBF require an output capacitor?

No, LT1389BCS8-2.5#TRPBF is stable with 0 µF output capacitance and does not require an external compensation capacitor. It remains stable with capacitive loads up to 0.1 µF, simplifying design in space-constrained applications. However, a 0.1 µF capacitor is recommended when operating above 1 mA to reduce noise and improve transient response.

How should the DNC pins on LT1389BCS8-2.5#TRPBF be handled in PCB layout?

All DNC pins (1, 2, 3, 5, 6) on LT1389BCS8-2.5#TRPBF must remain unconnected. To prevent board leakage from inducing output error, a guard ring tied to V_OUT must encircle these pins. Leakage exceeding 2.5 nA into a DNC pin causes ≥0.2% error; proper guard routing reduces this to <10 pA in FR-4 with solder mask coverage.

What is the low-frequency noise specification for LT1389BCS8-2.5#TRPBF?

LT1389BCS8-2.5#TRPBF delivers 50 µV_P-P peak-to-peak noise over 0.1 Hz to 10 Hz at 0.9 µA reverse current. This low noise supports 16+ bit ADC performance without oversampling. The measurement uses a single-pole high-pass filter at 0.1 Hz and dual-pole low-pass at 10 Hz, per standard JEDEC methodology.

Can LT1389BCS8-2.5#TRPBF replace LT1004 or LM385 in existing designs?

Yes, LT1389BCS8-2.5#TRPBF is a direct functional upgrade to LT1004 and LM385, offering ±0.05% initial accuracy (vs. ±1% for LM385), 20 ppm/°C drift (vs. 50–100 ppm/°C), and 0.7 µA min current (vs. 20 µA). Pinout differs - LT1389BCS8-2.5#TRPBF uses SO-8 with 4 DNC pins, while LT1004/LM385 are 3-pin devices - so PCB redesign is required for replacement.