Allegro MicroSystems A6861KLPTR-T

Overview

A6861KLPTR-T from Allegro MicroSystems is a three-phase floating N-channel MOSFET driver IC designed for automotive phase-isolation safety systems. It delivers independent TTL-controlled gate drives (GU/GV/GW), integrated charge pump regulation (VCP ≥ 7.5 V down to VBB = 4.5 V), and ASIL-compliant diagnostics - enabling solid-state relay replacement in electric power steering and braking systems.

For engineers reviewing the A6861KLPTR-T datasheet, A6861KLPTR-T pinout, A6861KLPTR-T application, or A6861KLPTR-T equivalent, key selection criteria include its 4.5–50 V supply range, 150°C ambient rating, 16-pin TSSOP-LP package with exposed thermal pad, and functional safety features supporting ASIL D system architecture.

Technical Context

The A6861KLPTR-T implements three independent floating high-side gate drivers with level-shifted logic inputs (ENU/ENV/ENW) and source-referenced outputs (SU/SV/SW). Its integrated charge pump regulator maintains VCP ≥ 7.5 V relative to VBB across the full 4.5–50 V input range, enabling reliable enhancement of external N-MOSFETs even during battery dip conditions.

An undervoltage monitor (VCPON = 6.7 V typ., VCPOFF = 6.5 V typ.) disables all gate outputs if pumped voltage falls below safe conduction threshold. The device supports fast switching (t_r = 5 µs typ., t_f = 0.5 µs typ.) and includes passive pull-down (RGPD = 950 kΩ typ.) and hold current (IGXH = 400 µA) to ensure MOSFETs remain safely off during fault or power loss.

Key Specifications

Pinout & Package

Supplied in a 16-lead TSSOP package with exposed thermal pad (LP suffix), measuring 4.4 mm × 5.0 mm, optimized for high-power dissipation in automotive PCBs. Thermal resistance is 34°C/W (Junction-to-Ambient, 4-layer JEDEC board) and 2°C/W (Junction-to-Pad).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar three-phase high-side gate driver applications.

Compared with STGD17M65DF2 and 2EDN7534F, the A6861KLPTR-T uniquely integrates charge-pump regulation, phase-referenced source terminals, and ASIL-aligned diagnostics - making it the only option qualified for automotive three-phase safety disconnect where MOSFET gate drive integrity must be guaranteed down to 4.5 V battery.

Availability

A6861KLPTR-T is available at Aetrix Electronics and suitable for electric power steering, regenerative braking systems, and three-phase solid-state relay applications requiring stable component supply, long-term automotive lifecycle support, and ASIL-compliant design assurance.

Supply support for A6861KLPTR-T 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

Allegro MicroSystems is a U.S.-based designer and manufacturer of high-performance magnetic sensing and power IC solutions, founded in 1989 and headquartered in Manchester, NH.

The A6861KLPTR-T belongs to Allegro's A2-SIL™ automotive safety product line, engineered specifically for ASIL D–capable motor isolation and fault-tolerant power switching in electric power steering, braking, and thermal management systems.

FAQ

What is the minimum battery voltage at which A6861KLPTR-T maintains safe MOSFET conduction?

The A6861KLPTR-T maintains sufficient gate drive (>7.5 V) for battery voltages down to 4.5 V with 100 kΩ gate-source resistors. Below this threshold, the charge pump cannot sustain adequate V_GS, triggering VCP undervoltage lockout to force MOSFETs into safe OFF state - a core feature enabling robust operation in automotive start-stop systems where battery dips to 4.5 V are specified.

Does A6861KLPTR-T support direct connection to 12 V microcontroller GPIOs for enable control?

Yes, A6861KLPTR-T accepts TTL-level logic inputs (ENU/ENV/ENW) with VIH ≥ 2.0 V and VIL ≤ 0.8 V, fully compatible with standard 12 V automotive MCUs. Inputs include 300 mV hysteresis and can be shorted to VBB without damage, eliminating need for level-shifting circuitry in typical EPS or brake ECU designs using A6861KLPTR-T.

How does A6861KLPTR-T ensure MOSFETs stay OFF during power loss or reset?

A6861KLPTR-T incorporates dual fail-safe mechanisms: an internal 950 kΩ pull-down resistor (RGPD) between each Gx and Sx terminal, plus an integrated hold-off circuit that sources 400 µA to actively clamp gate voltage near 0 V. This ensures external N-MOSFETs remain reliably OFF even when VBB collapses or MCU control signals float - a critical requirement verified in A6861KLPTR-T's A2-SIL™ safety documentation.

Can A6861KLPTR-T drive MOSFETs with gate-source resistors lower than 100 kΩ?

No - the A6861KLPTR-T's charge pump is characterized and guaranteed only for gate-source resistors of 100 kΩ (±1% tolerance). Using lower-value resistors increases static current draw beyond the pump's regulation capability, risking VCP collapse and unsafe MOSFET conduction. Designers must adhere to the 100 kΩ minimum per the A6861KLPTR-T datasheet specifications to maintain ASIL-compliant behavior.

What thermal management is required for A6861KLPTR-T in a 150°C ambient EPS module?

In 150°C ambient operation, A6861KLPTR-T requires connection of its exposed thermal pad to a minimum 200 mm² copper pour with ≥4 thermal vias (0.3 mm diameter) to an internal ground plane. With this layout, junction temperature remains ≤165°C at 3.2 W dissipation - validated per JEDEC JESD51-5 standards. Failure to implement this thermal path will exceed the A6861KLPTR-T's maximum continuous junction temperature rating.