Analog Devices Inc. LT1999CS8-20#TRPBF

Overview

LT1999CS8-20#TRPBF from Analog Devices is a high-speed, bidirectional current sense amplifier with 20V/V fixed gain, –5V to 80V input common mode range, 2MHz bandwidth, and ±0.5% gain accuracy. It senses current via external shunt resistor and outputs a voltage referenced to mid-supply or external REF, enabling precise monitoring in H-bridge motor control and battery charge/discharge systems.

For engineers reviewing the LT1999CS8-20#TRPBF datasheet, LT1999CS8-20#TRPBF pinout, LT1999CS8-20#TRPBF application, or LT1999CS8-20#TRPBF equivalent, this device delivers verified bidirectional sensing, automotive-grade AEC-Q100 qualification (H-grade variant), FMEA-optimized MSOP pinout options, and robust 4kV HBM ESD tolerance - critical for high-reliability power stage monitoring.

Technical Context

The LT1999CS8-20#TRPBF employs a matched-resistor transconductance architecture with internal 4kΩ differential input impedance and on-chip 80kΩ gain-setting resistor (RG), delivering precise 20V/V amplification independent of supply variation. Its dual-path biasing (D1 conduction below V+, high-impedance operation above V+) ensures smooth, continuous operation across the full –5V to 80V common mode range without gain discontinuity or offset shift.

It integrates a dedicated REF pin with 60–100kΩ input impedance and ±2.5V input range, allowing flexible output common-mode setting. The shutdown pin (SHDN) enables <10µA quiescent current, and the output drives ≥200pF loads directly while maintaining 3V/µs slew rate and 2.5µs 0.5% settling time for ±2V steps.

Key Specifications

Pinout & Package

LT1999CS8-20#TRPBF is housed in an 8-lead plastic SO (narrow) package (S8), RoHS-compliant, with 1.27mm lead pitch and JEDEC MO-153 compliance. Thermal resistance θ_JA = 190°C/W.

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 LT1999CS8-20#TRPBF offers guaranteed AEC-Q100 qualification, seamless –5V to 80V common mode continuity, and factory-trimmed mid-supply REF - reducing BOM count and layout complexity in automotive and high-reliability power systems.

Availability

LT1999CS8-20#TRPBF is available at Aetrix Electronics and suitable for H-bridge motor control, high-voltage battery monitoring, and solenoid actuator protection requiring stable component supply across automotive, industrial, and energy storage design cycles.

Supply support for LT1999CS8-20#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 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 precision, high-voltage current sensing for demanding power conversion and motor control applications - engineered for accuracy, robustness, and seamless integration into safety-critical systems.

FAQ

What is the operating temperature range for LT1999CS8-20#TRPBF?

The LT1999CS8-20#TRPBF is specified for 0°C to 70°C ambient operation. It belongs to the C-grade family, with full electrical performance guaranteed across this range. For extended temperature applications, consider I-grade (–40°C to 85°C), H-grade (–40°C to 125°C), or MP-grade (–55°C to 150°C) variants such as LT1999IS8-20#TRPBF or LT1999HS8-20#TRPBF - all sharing identical gain, bandwidth, and pinout with LT1999CS8-20#TRPBF.

Can LT1999CS8-20#TRPBF sense current on the high side of a 60V bus?

Yes. The LT1999CS8-20#TRPBF supports input common mode voltages from –5V to 80V, making it fully compatible with 60V bus monitoring. Its architecture maintains stable gain and offset across the entire range, including operation above the 5V supply rail. No level-shifting circuitry or external biasing is required - simply connect +IN and –IN across the shunt resistor placed between the 60V rail and load.

Does LT1999CS8-20#TRPBF require external resistors for the REF pin?

No. The LT1999CS8-20#TRPBF includes internal 160kΩ resistors forming a mid-supply divider from V+ to GND, establishing a default REF voltage of V+/2 (2.5V at 5V supply). External resistors are optional only if a non-mid-supply reference is needed - for example, to align with an ADC's input range or controller reference. When driving REF externally, ensure voltage stays within 1.125V to (V+ – 1.125V).

How does the shutdown function work on LT1999CS8-20#TRPBF?

The SHDN pin (Pin 8) is active-low. Pulling it below 0.5V places LT1999CS8-20#TRPBF into shutdown mode, reducing supply current to <10µA. Leaving SHDN floating enables operation via an internal 2µA pull-up current source. No external pull-up resistor is required. Turn-on and turn-off times are both ≤1µs, enabling rapid power cycling in burst-mode applications without compromising measurement latency.

Is LT1999CS8-20#TRPBF pin-compatible with other gain versions like LT1999CS8-10#TRPBF?

Yes. All LT1999-x variants in the same package (e.g., S8 or MS8) share identical pinout, footprint, and electrical interface. LT1999CS8-20#TRPBF, LT1999CS8-10#TRPBF, and LT1999CS8-50#TRPBF differ only in internal gain-setting resistor (RG = 80kΩ, 40kΩ, or 200kΩ respectively) and full-scale sense voltage (±0.2V, ±0.35V, or ±0.08V). This allows drop-in replacement during design iteration or calibration tuning without PCB changes.