Analog Devices Inc. LT4356CS-1#PBF

Overview

LT4356CS-1#PBF from Analog Devices is a high-voltage surge stopper IC that protects downstream loads by regulating output voltage during overvoltage transients (e.g., automotive load dump) via external N-channel MOSFET gate control, features 4V–80V operating range, 50mV overcurrent sense threshold, and 7µA shutdown current, used in automotive power distribution systems.

For engineers reviewing the LT4356CS-1#PBF datasheet, LT4356CS-1#PBF pinout, LT4356CS-1#PBF application, or LT4356CS-1#PBF equivalent, key selection criteria include fault timer adjustability, reverse input tolerance (–60V), SOIC-16 package compatibility, and LT4356-1 vs. LT4356-2 shutdown behavior differences.

Technical Context

The LT4356CS-1#PBF implements dual-fault protection: overvoltage regulation via FB-pin servoing to 1.25V with adjustable clamp set by external resistor divider, and overcurrent limiting via SNS–VCC differential sensing capped at 50mV. Fault detection triggers a VDS-dependent current source charging the TMR capacitor.

During overvoltage, GATE is actively controlled to maintain regulated output; during overcurrent, GATE is pulled down with 10mA sink current. The SHDN pin enables <7µA quiescent operation, and the FLT pin provides early warning (1.25V TMR threshold) before full shutdown (1.35V TMR threshold).

Key Specifications

Pinout & Package

LT4356CS-1#PBF is housed in a 16-lead plastic SO (Small Outline) package with exposed pad optional grounding, footprint compatible with industry-standard SOIC-16 layouts and reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT4356IS-1#PBF and LT4356HS-1#PBF, the LT4356CS-1#PBF offers identical surge protection, pin compatibility, and SOIC-16 packaging at a lower cost-but is limited to 0°C to 70°C ambient, making it ideal for cost-sensitive commercial and non-under-hood automotive applications.

Availability

LT4356CS-1#PBF is available at Aetrix Electronics and suitable for automotive load dump protection, hot-swap power distribution, intrinsic safety barriers, and battery-powered high-side switching requiring stable component supply and long-term production continuity.

Supply support for LT4356CS-1#PBF 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and automotive markets.

The LT4356 family is designed as a robust, wide-input-range surge stopper IC line targeting automotive, industrial, and safety-critical power systems where reliable overvoltage and overcurrent protection is mandatory.

FAQ

What is the maximum reverse voltage the LT4356CS-1#PBF can withstand on its VCC and SHDN pins?

The LT4356CS-1#PBF supports –60V reverse voltage on both VCC and SHDN pins without damage, enabling direct connection to automotive batteries without external reverse-polarity protection diodes. This rating is absolute and applies across the full operating temperature range. The SNS pin also tolerates –60V relative to ground, provided the voltage difference between SNS and VCC remains within 30V. These specifications are verified per Analog Devices' Absolute Maximum Ratings table.

How does the LT4356CS-1#PBF differ from the LT4356CS-2#PBF in shutdown mode?

The LT4356CS-1#PBF reduces total supply current to less than 7µA in shutdown, disabling all functional blocks including the auxiliary amplifier. In contrast, the LT4356CS-2#PBF draws 60µA during shutdown while keeping the internal 1.25V reference and auxiliary amplifier active-enabling undervoltage lockout monitoring or always-on bias generation. Both share identical pinout, package, and protection functionality outside shutdown.

Can the LT4356CS-1#PBF drive logic-level N-channel MOSFETs at low input voltages?

Yes-the LT4356CS-1#PBF's GATE pin delivers a minimum of 4.5V above OUT when VCC = 4V, sufficient to fully enhance logic-level N-channel MOSFETs down to cold-crank automotive conditions (~4.0V). At higher VCC (≥8V), GATE swing increases to ≥10V, supporting standard-threshold MOSFETs. Gate drive strength is confirmed by IGATE(UP) and ΔVGATE specs across voltage and temperature ranges.

What determines the fault timer duration in the LT4356CS-1#PBF?

The fault timer duration in the LT4356CS-1#PBF is set by the capacitor value on the TMR pin and the instantaneous VCC–OUT voltage. During overvoltage, TMR current scales from ~2µA (at 0.5V VDS) to 50µA (at 75V VDS); during overcurrent, it scales from ~4µA to 260µA (at 80V VDS). Total fault time = tFLT + tWARNING, where tWARNING = CTMR × 100mV / 5µA (fixed after FLT assertion). This adaptive scheme ensures MOSFET SOA compliance.

Is the LT4356CS-1#PBF pin-compatible with other package variants like DFN or MSOP?

No-the LT4356CS-1#PBF uses a 16-lead SOIC package with specific pin assignments including four NC (no-connect) pins (3, 6, 12, 14), whereas the DFN-12 and MSOP-10 variants have different pin counts, layouts, and functions (e.g., AOUT and IN+ are absent in MSOP). Pin compatibility exists only within the same package family (e.g., LT4356CS-1#PBF ↔ LT4356IS-1#PBF), not across packages.