Analog Devices Inc. LT1999HMS8-20#PBF

Overview

LT1999HMS8-20#PBF from Analog Devices is a high-voltage, bidirectional current sense amplifier with 20V/V fixed gain, –5V to 80V input common mode range, 2MHz bandwidth, and ±0.5% gain accuracy. It operates from a 4.5V–5.5V supply, draws 1.55mA, and supports high-side or low-side sensing in H-bridge motor controls and battery charge monitoring.

For engineers reviewing the LT1999HMS8-20#PBF datasheet, LT1999HMS8-20#PBF pinout, LT1999HMS8-20#PBF application, or LT1999HMS8-20#PBF equivalent, this page delivers verified specifications, FMEA-optimized MSOP-8 pinout, automotive-grade (–40°C to 125°C) performance data, and real-world use context for precision current measurement in high-voltage industrial and automotive systems.

Technical Context

The LT1999HMS8-20#PBF uses matched internal 4kΩ input resistors and an on-chip 80kΩ feedback resistor to achieve its precise 20V/V gain. Its transconductance input stage enables smooth, continuous operation across the full –5V to 80V common mode range without gain discontinuity or offset shift.

It features dual-mode REF pin operation-default mid-supply bias via internal 160kΩ divider or external reference override-and integrated 2µA SHDN pull-up enabling active-by-default behavior. The output drives ≥200pF loads directly and recovers from ±50V common mode transients in ≤1.0µs.

Key Specifications

Pinout & Package

LT1999HMS8-20#PBF is housed in an 8-lead plastic MSOP package (MS8), pinout engineered for FMEA compliance per Analog Devices' design. This variant uses Pin 3 as NC (no connect), eliminating potential fault paths in safety-critical current monitoring.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current sense amplifier applications.

Compared with INA240A1QDRQ1 and MAX40056ATA+T, the LT1999HMS8-20#PBF uniquely combines AEC-Q100 H-grade qualification, FMEA-optimized MSOP-8 pinout, and guaranteed 2MHz bandwidth across –40°C to 125°C-making it the only option qualified for ASIL-B automotive current monitoring without layout redesign.

Availability

LT1999HMS8-20#PBF is available at Aetrix Electronics and suitable for H-bridge motor control, automotive battery management, and high-voltage industrial power supplies requiring stable component supply across extended temperature ranges.

Supply support for LT1999HMS8-20#PBF 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LT1999 product line delivers high-voltage, high-accuracy current sensing for safety-critical and high-reliability applications-including automotive powertrain, industrial motor drives, and renewable energy inverters-where precision, wide common mode, and robustness are mandatory.

FAQ

What is the maximum common mode voltage supported by the LT1999HMS8-20#PBF?

The LT1999HMS8-20#PBF supports an input common mode voltage range of –5V to 80V. This specification is guaranteed over the full operating temperature range of –40°C to 125°C and enables direct sensing on high-side MOSFETs in 48V and 60V systems without external level-shifting circuitry. Absolute maximum ratings extend to –5.25V to 88V, but operation beyond 80V may degrade gain accuracy or reliability.

Does the LT1999HMS8-20#PBF require external components for basic operation?

The LT1999HMS8-20#PBF operates with minimal external components: two 0.1µF supply bypass capacitors (V+ to GND) are mandatory. The REF pin defaults to mid-supply (2.5V) via internal 160kΩ dividers, so no external resistors are needed unless custom reference voltage is required. No gain-setting resistors are needed-the 20V/V ratio is laser-trimmed on-die.

How does the FMEA-optimized pinout of the LT1999HMS8-20#PBF differ from the standard MSOP version?

The LT1999HMS8-20#PBF uses the FMEA-optimized pinout where Pin 3 is designated NC (no connect), unlike the original MSOP version where Pin 3 is –IN. This eliminates potential fault paths during overvoltage or ESD events and supports ISO 26262 functional safety requirements. The +IN and –IN functions are reassigned to Pins 1 and 2 respectively, preserving signal integrity in safety-critical current monitoring.

Can the LT1999HMS8-20#PBF be used in bidirectional battery current monitoring?

Yes, the LT1999HMS8-20#PBF is explicitly designed for bidirectional current sensing. Its output voltage swings above and below the REF pin voltage to indicate current direction: positive VOUT–VREF indicates current flow from +IN to –IN (e.g., battery discharge), while negative VOUT–VREF indicates reverse flow (e.g., regenerative charging). This capability is validated across the full –5V to 80V common mode range and –40°C to 125°C temperature range.

What is the shutdown behavior of the LT1999HMS8-20#PBF, and how is it controlled?

The LT1999HMS8-20#PBF enters low-power shutdown when the SHDN pin (Pin 8) is pulled to ≤0.5V relative to GND, reducing supply current to <10µA. When SHDN is left floating, an internal 2µA pull-up current source biases the pin high, placing the device in active mode. No external pull-up resistor is required. Turn-on and turn-off times are both ≤1µs, enabling rapid enable/disable in burst-mode power systems.