LT1999

RECOMMENDED FOR NEW DESIGNS

High Voltage, Bidirectional Current Sense Amplifier

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Overview

  • Buffered Output with 3 Gain Options: 10V/V, 20V/V, 50V/V
  • Gain Accuracy: 0.5% Max
  • Input Common Mode Voltage Range: –5V to 80V
  • AC CMRR > 80dB at 100kHz
  • Input Offset Voltage: 1.5mV Max
  • Smooth, Continuous Operation Over Entire Common Mode Range
  • –3dB Bandwidth: 2MHz
  • 4kV HBM Tolerant and 1kV CDM Tolerant
  • Low Power Shutdown <10µA
  • –55°C to 150°C Operating Temperature Range
  • 8-Lead MSOP and 8-Lead SO (Narrow) Packages
  • 8-Lead MSOP Pinout Option Engineered for FMEA
  • AEC-Q100 Qualified for Automotive Applications
LT1999
High Voltage, Bidirectional Current Sense Amplifier
LT1999-10-1999-20-1999-50 Application circuit LT1999-10-1999-20-1999-50 Pin configuration LT1999-10-1999-20-1999-50 Pin Configuration LT1999-10-1999-20-1999-50 Pin Configuration LT1999-10-1999-20-1999-50 Performance Graph
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Tools & Simulations

LTspice 1


Models for the following parts are available in LTspice:

  • LT1999-10
  • LT1999-20
  • LT1999-50
LTspice

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.


Evaluation Kits

eval board
DC1698A

LT1999-10 (MS8) Demoboard

Product Details

Demonstration circuit 1698A features the LT1999, a high voltage, bi-directional current sense amplifier.

The demo board amplifies the voltage drop across an on board current sense resistor. The output voltage is a bi-directional signal that is centered on the VREF voltage and is proportional to the current through the sense resistor. The output is scaled by one of three fixed gain options. The gain options are: 10V/V (DC1698A-A), 20V/V (DC1698A-B) and 50V/V (DC1698A-C). The input voltage range is from –5V to 80V (independent of the device supply voltage) allowing the part to be used for high or low side current sensing. The LT1999 requires a separate 5V supply voltage.

DC1698A
LT1999-10 (MS8) Demoboard
DC1698A-A - Schematic

Reference Designs

ADPS30146-RD Power Tree
ADPS30146-RD Industrial Power Solution Circuits from the lab

High‑Efficiency GaN Motor Drive Control Solution for BLDC and Servo Motors

Features and Benefits

  • Compact GaN servo drive with integrated gate drive and sensing
  • Accurate current sensing improves torque regulation and dynamic response
  • Adjustable 25–100 kHz PWM with fine dead time control for low-noise efficiency
  • GaN efficiency removes need for external cooling
  • Small PCB footprint with optional LC/LCL filtering for clean output and motor integration
  • Compatible with multiple controllers, supporting 50–750 W across diverse motor types

Electrical Requirements:

  • Input Voltage: 48–58 V battery source
  • Output Voltage: 50–750 W
  • Board V1 Output: Conventional GaN switching waveform
  • Board V2 Output: Sine wave output generated through LC/LCL filtering

Control & Feedback Requirements:

  • PWM Frequency: 25–100 kHz
  • PWM Tuning Parameters: Switching frequency and dead time adjustment
  • Current Sensing Method: In-line sensing, two-phase measurement (U and W)
  • Scalability: Configurable sense resistor and amplifier gain

Mechanical Requirements:

  • PCB Size: 40 × 50 mm
  • Setup Variations: Extended cable connection between driver board and motor. Driver board mechanically integrated within the motor assembly
  • Thermal Constraints: Passive cooling only (no heatsink and no forced airflow)
  • Motor Load: MINAS A6 48 V, 400 W (MSMD04BL1S). Hollow shaft BLDC motors

Protection Requirements:

  • Provision for DC bus back EMF energy dissipation
ADPS30146-RD Industrial Power Solution
High‑Efficiency GaN Motor Drive Control Solution for BLDC and Servo Motors
ADPS30146-RD Power Tree
ADPS30146-RD EVB 3D View Image
ADPS30146-RD EVB Top View Image
ADPS30146-RD EVB Bottom View Image

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