Microchip Technology ZL70571UDJ

Overview

ZL70571UDJ from Microsemi is a 5-terminal, solder-bumped silicon thyristor-based medical surge protection device designed for implantable cardiac pacemakers and neurostimulators. It provides sub-150 ns turn-on, <13 V peak clamping voltage during 8 A/10 ms defibrillation surges, and ultra-low off-state leakage (<150 nA at +8.5 V), enabling direct parallel connection to protected IC pins without signal interference.

For engineers reviewing the ZL70571UDJ datasheet, ZL70571UDJ pinout, ZL70571UDJ application, or ZL70571UDJ equivalent, this page delivers verified electrical specs, substrate-connected terminal mapping (SUB1/SUB2), EN-45502/EN-50061 compliance context, and validated alternatives for high-reliability implantable electronics design.

Technical Context

ZL70571UDJ implements a five-branch self-triggering thyristor-diode architecture with two dedicated substrate terminals (SUB1, SUB2) - a functional distinction from the 6- or 7-terminal ZL70573/74/88 variants. Its dual substrate connections enable optimized current sharing and thermal path control in flip-chip mounted implants.

The device achieves rapid transient response via low-dynamic-resistance thyristor conduction (Ron ≤ 1 Ω) and exhibits guaranteed dV/dt immunity >100 V/µs at 9 V (T–T) and 8.5 V (T–SUB), ensuring robust operation against fast-rising defibrillation transients without false triggering.

Key Specifications

Pinout & Package

Solder-bumped die in waffle tray packaging; 528 ± 25 µm thickness; flip-chip assembly with Sn/Pb 63/37 bumps. Requires underfill for mechanical reliability in implanted systems.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar medical surge protection applications.

Compared with ZL70572UDJ, ZL70571UDJ offers tighter voltage clamping for low-voltage pacemaker ICs; compared with ZL70573UDJ, it trades some dV/dt immunity for superior thermal management via dual substrate ties - critical for repeated surge events in chronic implants.

Availability

ZL70571UDJ is available at Aetrix Electronics and suitable for pacemaker lead protection, neurostimulator electrode interfaces, ICD sensing front-ends, implantable loop recorder telemetry protection, and EN-45502-compliant active implantable medical device development requiring stable component supply across long production lifecycles.

Supply support for ZL70571UDJ 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

Microsemi Corporation (now part of Microchip Technology) designs high-reliability semiconductors for aerospace, defense, and life-critical medical applications, with rigorous quality standards rooted in MIL-PRF-38535.

ZL70571UDJ belongs to Microsemi's ZL7057x medical surge protection family, engineered specifically to meet EN-45502 and EN-50061 requirements for active implantable devices - prioritizing ultra-low leakage, sub-150 ns response, and full lot traceability.

FAQ

What is the primary function of ZL70571UDJ in an implantable medical device?

ZL70571UDJ functions as a self-triggering, parallel-connected transient voltage suppressor that clamps dangerous defibrillation surges (up to 8 A/10 ms) to ≤13 V, protecting sensitive pacemaker or neurostimulator ICs. Its ultra-low leakage (<150 nA) ensures no interference with low-power analog sensing or telemetry circuits during normal operation.

How does ZL70571UDJ differ from ZL70573UDJ in terms of pin configuration and use case?

ZL70571UDJ has five terminals including two dedicated substrate connections (SUB1, SUB2), enabling optimized thermal and current distribution in case-grounded implants. ZL70573UDJ has six terminals but no substrate pins, offering higher dV/dt immunity (>2300 V/µs) and lower capacitance (50 pF) - better for compact, non-case-grounded devices where substrate access is unavailable.

Is ZL70571UDJ qualified for EN-45502 compliance, and what testing validates this?

Yes, ZL70571UDJ is explicitly designed and tested to meet EN-45502 "Active Implantable Medical Devices" requirements. Validation includes passing 140 V/300 Ω defibrillation pulse sequences while maintaining full functionality of protected electronics - confirmed via surge testing per Figure 4-1 and peak voltage measurement per Figure 4-5 in the official datasheet.

What assembly method is required for ZL70571UDJ, and are there board layout constraints?

ZL70571UDJ is supplied as a solder-bumped die for flip-chip reflow assembly. All bumps associated with each terminal (e.g., all T3 bumps, all SUB1 bumps) must be connected together on the PCB using either individual matched pads or continuous rectangular pads. Underfill is mandatory to mitigate thermal stress on solder joints in implanted environments.

Does ZL70571UDJ require external biasing or control signals to operate?

No, ZL70571UDJ operates autonomously without external bias, control lines, or power supply. It relies entirely on intrinsic thyristor-diode physics: remaining in high-impedance state (<150 nA leakage) until voltage across any terminal pair exceeds its breakover threshold (9–12.2 V), then latching into low-impedance conduction to shunt surge current.