Analog Devices Inc. LT6109HMS-1#TRPBF

Overview

LT6109HMS-1#TRPBF from Analog Devices (formerly Linear Technology) is a high-side current sense amplifier with integrated 400mV reference and dual latching comparators in opposing polarity configuration, designed for overcurrent/undercurrent fault detection in industrial and automotive power systems. It delivers 125µV max input offset, 0.2% max gain error, 1MHz bandwidth, and operates across –40°C to 125°C.

For engineers reviewing the LT6109HMS-1#TRPBF datasheet, LT6109HMS-1#TRPBF pinout, LT6109HMS-1#TRPBF application, or LT6109HMS-1#TRPBF equivalent, this device supports fast-response current monitoring in motor control, battery protection, and remote sensing where precision, latchable fault flags, and wide 2.7V–60V supply range are critical.

Technical Context

The LT6109HMS-1#TRPBF implements a high-impedance current-output sense amplifier that forces SENSEHI to track SENSELO, generating IOUTA = VSENSE/RIN. Its two comparators share an internal 400mV reference and are configured with opposing polarity - one triggers on rising input (overcurrent), the other on falling input (undercurrent).

Propagation delay is 1.4µs typical, with comparator hysteresis of 3–15mV and total threshold error ±1.25%. The open-drain OUTC1/OUTC2 outputs support voltage-level shifting up to 60V above V–, enabling direct interface with higher-voltage logic or external FET drivers without level-shifting circuitry.

Key Specifications

Pinout & Package

LT6109HMS-1#TRPBF is housed in a 10-lead MSOP package (3mm × 3mm, 0.5mm pitch) with exposed pad for thermal performance. Pin 1 is SENSELO; pin 10 is SENSEHI. The package supports θJA = 160°C/W and is RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX40056ASA+T and INA301A3IDBVR, the LT6109HMS-1#TRPBF uniquely integrates dual latching comparators with opposing polarity, a precision 400mV reference, and full 60V operation - enabling compact, self-contained fault protection without external components or logic.

Availability

LT6109HMS-1#TRPBF is available at Aetrix Electronics and suitable for motor control, battery management, and automotive load disconnect applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LT6109HMS-1#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors for precision instrumentation, power management, and industrial systems.

The LT6109 product line was designed specifically for robust, high-accuracy high-side current sensing in harsh environments - emphasizing low offset, latchable fault flags, wide supply range, and automotive-grade temperature qualification.

FAQ

What is the key functional difference between LT6109HMS-1#TRPBF and LT6109HMS-2#TRPBF?

The LT6109HMS-1#TRPBF features comparators with opposing polarity: one triggers on rising input (overcurrent), the other on falling input (undercurrent). In contrast, LT6109HMS-2#TRPBF configures both comparators with the same polarity - typically used for window or dual-threshold overcurrent detection. This makes LT6109HMS-1#TRPBF ideal for independent over/under fault signaling, while LT6109HMS-2#TRPBF suits redundancy or tighter tolerance monitoring. Both share identical amplifier specs, reference, and pinout.

Can LT6109HMS-1#TRPBF operate with a 3.3V logic interface for its comparator outputs?

Yes - the open-drain OUTC1 and OUTC2 pins of LT6109HMS-1#TRPBF are compatible with 3.3V logic. Simply connect external pull-up resistors to 3.3V. The outputs can sink ≥500µA at VOL ≤ 150mV (V+ = 2.7V), ensuring clean low-level assertion. No level shifter is required, and the 60V absolute maximum rating protects against voltage transients on the pull-up rail.

How does the LT6109HMS-1#TRPBF achieve Kelvin sensing, and why is it important?

LT6109HMS-1#TRPBF achieves Kelvin sensing via separate SENSELO (Pin 1) and SENSEHI (Pin 10) inputs, allowing direct 4-wire connection to a shunt resistor. This isolates sense traces from high-current paths, eliminating voltage drop errors caused by PCB trace resistance (e.g., 0.5mΩ trace adds 1mV error at 2A). For precision applications like battery fuel gauging or motor phase current, Kelvin connection ensures measurement accuracy remains within ±125µV offset limits - critical for detecting subtle fault signatures.

What is the minimum recommended value for RIN in LT6109HMS-1#TRPBF, and what happens if it's too small?

The minimum recommended RIN for LT6109HMS-1#TRPBF is 100Ω. Smaller values increase IOUTA (IOUTA = VSENSE/RIN), improving step response but risking instability or exceeding the 1mA output current limit. At RIN < 100Ω, loop stability degrades and output settling time increases due to parasitic capacitance interaction. Also, very low RIN raises power dissipation in the internal MOSFET and may cause thermal drift. Always verify stability with ROUT and layout parasitics per Figure 3 in the datasheet.

Does LT6109HMS-1#TRPBF require external capacitors for stability, and where should they be placed?

LT6109HMS-1#TRPBF does not require external compensation capacitors for basic operation, but a 0.1µF bypass capacitor between V+ and V– is mandatory for supply decoupling. For optimal noise immunity and comparator stability, place a 2pF capacitor (CLC) between each comparator input (INC1, INC2) and V–, as shown in Figure 3 of the datasheet. Additionally, a small ceramic cap (100pF–1nF) across ROUT improves step response fidelity when driving high-impedance ADC inputs or long traces.