Microchip Technology T6818-TUSY-66

Overview

T6818-TUSY-66 from Microchip Technology (formerly Atmel) is a triple half-bridge DMOS output driver IC designed for automotive and industrial load control. It integrates three independently controllable high-side/low-side driver pairs, supports up to 1.5 A per channel, features R_DS(on) ≤ 1.1 Ω at 150°C, operates from 7.5 V to 40 V VS supply, and delivers diagnostic feedback via a 2 MHz daisy-chainable serial interface.

For engineers reviewing the T6818-TUSY-66 datasheet, T6818-TUSY-66 pinout, T6818-TUSY-66 application, or T6818-TUSY-66 equivalent, this page provides verified technical context, validated pin functions, confirmed thermal and short-circuit protection behavior, real-world diagnostic register mapping, and precise SO14 power package mechanical data - all directly extracted from Rev. 4530G–BCD–09/05.

Technical Context

The T6818-TUSY-66 implements six discrete DMOS power switches internally configured as three independent half-bridges, each with integrated reverse diodes and current-limited switching. Its BCD-MOS process enables simultaneous high-voltage operation (VS up to 40 V), logic-level compatibility (5 V CMOS inputs), and robust fault handling including open-load detection thresholds of ±15–45 mA and overtemperature prewarning at 120–170°C.

Control is executed via a 16-bit serial interface with LSB-first protocol, chip-select–gated DO tri-state output, and dedicated status bits for short-circuit (SCD), open-load (OPL), power-supply fail (PSF), and thermal prewarning (TP). Inhibit (INH) input reduces quiescent current to <5 µA at VS and <25 µA at VCC in standby mode.

Key Specifications

Pinout & Package

Package: SO14 Power package (lead-free, tubed), 8.75 mm × 4.8 mm body, 1.4 mm height, exposed GND tab on pins 1/7/8/14 for thermal dissipation (R_thJA = 65 K/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple half-bridge driver applications.

Compared with ATA6828-T2SY, T6818-TUSY-66 offers lower-cost SO14 packaging with adequate thermal performance for intermittent loads; compared with BD3539FV, it delivers superior fault visibility and 5 V native interface compatibility but requires more PCB area for decoupling capacitors.

Availability

T6818-TUSY-66 is available at Aetrix Electronics and suitable for automotive body control, industrial valve actuation, off-highway lighting, and commercial appliance motor control requiring stable component supply across extended temperature and voltage ranges.

Supply support for T6818-TUSY-66 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

Microchip Technology acquired Atmel in 2016 and maintains full product support, qualification, and documentation for legacy Atmel automotive ICs including the T6818 family.

The T6818 product line was originally developed by Atmel for automotive-grade load driving with integrated diagnostics and EMC resilience, targeting body electronics, chassis systems, and industrial control units where functional safety and long-term supply stability are essential.

FAQ

What is the maximum continuous output current per channel for the T6818-TUSY-66?

The T6818-TUSY-66 supports up to 1.5 A continuous output current per half-bridge channel under specified thermal conditions (T_J ≤ 150°C, R_thJA = 65 K/W). This rating assumes proper PCB copper pour on GND pins 1/7/8/14 and use of recommended 22 µF + 100 nF VS decoupling. Exceeding 1.5 A triggers overcurrent shutdown unless disabled via OCS bit.

Does the T6818-TUSY-66 support daisy-chaining with other identical ICs?

Yes, the T6818-TUSY-66 supports daisy-chaining via its serial interface: DI of the next device connects to DO of the previous one, sharing CLK and CS lines. Each device uses its own CS signal for individual addressing, and DO remains tri-stated when CS is high, enabling multi-drop configurations without bus contention.

How does the open-load detection function in the T6818-TUSY-66?

The T6818-TUSY-66 detects open-load conditions by monitoring current through active high-side or low-side switches. If sensed current falls below ±15–45 mA (depending on temperature and channel), the OPL bit in the status register is set after 200–600 µs delay. The condition persists until cleared by writing SRR = 1 in the input register.

What package type is used for the T6818-TUSY-66 and how does it affect thermal performance?

The T6818-TUSY-66 uses the SO14 power package with exposed GND pads on pins 1/7/8/14. Its thermal resistance is R_thJA = 65 K/W and R_thJP = 30 K/W (junction-to-pin). This differs from the PSO14 variant (ATA6828) which adds a heat slug for R_thJA = 30 K/W - making T6818-TUSY-66 suitable for moderate-duty cycles where board-level copper pour suffices.

Can the T6818-TUSY-66 drive inductive loads like DC motors without external flyback protection?

Yes, the T6818-TUSY-66 integrates reverse diodes across each high-side and low-side switch, enabling safe commutation of inductive loads such as DC motors without external flyback diodes. However, negative voltage spikes exceeding –0.3 V at OUTx pins may trigger overtemperature protection; placing RC snubbers or optimizing PCB layout minimizes this risk.