Analog Devices Inc. LTC1153CS8#PBF

Overview

LTC1153CS8#PBF from Analog Devices (formerly Linear Technology) is an auto-reset electronic circuit breaker IC that drives external N-channel MOSFETs to protect sensitive loads from over-current, thermal, and short-circuit faults. It features programmable trip current (1mA–>20A), trip delay (15µs–>100ms), and auto-reset time (1ms–>10s), operates from 4.5V to 18V, and delivers 8µA standby quiescent current. It is used in SCSI termination power protection and battery short-circuit protection systems.

For engineers reviewing the LTC1153CS8#PBF datasheet, LTC1153CS8#PBF pinout, LTC1153CS8#PBF application, or LTC1153CS8#PBF equivalent, key selection criteria include drain sense threshold voltage (100mV typ), gate drive capability above supply rail (up to +25V), open-drain status output, thermal shutdown interface via PTC, and SOIC-8 package compatibility with surface-mount assembly.

Technical Context

The LTC1153CS8#PBF integrates a charge-pump-based gate driver that generates gate voltages up to 25V above VS without external capacitors, enabling robust turn-on of low-R_DS(ON) N-MOSFETs. Its analog comparator continuously monitors V_DS drop across an external sense resistor against a precision 100mV internal reference.

Auto-reset timing is controlled by an external capacitor charged at 4.2µA (typ), producing delays scalable from milliseconds to seconds. The device includes TTL/CMOS-compatible inputs with 1.3V thresholds and 100mV hysteresis, plus a dedicated shutdown input for thermal fault integration via PTC thermistor.

Key Specifications

Pinout & Package

Package: 8-pin plastic SOIC (S8), 150°C/W junction-to-ambient thermal resistance, RoHS-compliant lead-free finish (#PBF).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar electronic circuit breaker applications.

Compared with MAX16920ATC+ and TPS25982LMLR, the LTC1153CS8#PBF offers wider trip current range (1mA–>20A), true analog thermal shutdown integration, and lowest standby IQ (8µA), making it optimal for high-flexibility, low-power, and thermally coordinated protection designs.

Availability

LTC1153CS8#PBF is available at Aetrix Electronics and suitable for SCSI termination power protection, battery short-circuit protection, and DC motor stall protection requiring stable component supply across industrial and embedded design cycles.

Supply support for LTC1153CS8#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 acquired Linear Technology in 2017 and maintains its legacy precision analog and power management product lines.

The LTC1153CS8#PBF belongs to Linear's electronic circuit breaker family, designed specifically for high-reliability, programmable over-current protection in systems where fuse replacement is impractical and thermal coordination with load is essential.

FAQ

What is the minimum trip delay achievable with the LTC1153CS8#PBF?

The LTC1153CS8#PBF achieves a minimum trip delay of 5µs (typical) when configured with no external RC delay on the DS pin and operating at VS = 12V. This value is confirmed in the Electrical Characteristics table under parameter t_TD (Minimum Trip Delay). The internal comparator and latch architecture enable this fast response while maintaining immunity to sub-microsecond supply transients. The LTC1153CS8#PBF's 5µs capability makes it suitable for protecting MOSFETs against destructive short-circuit energy accumulation.

Can the LTC1153CS8#PBF drive logic-level MOSFETs directly?

Yes, the LTC1153CS8#PBF can directly drive logic-level N-channel MOSFETs. Its gate driver uses an on-chip charge pump to generate gate voltages up to +25V above VS (at VS = 12V), well exceeding the V_GS(th) requirements of common logic-level devices such as IRLZ24 or IRLR024. The datasheet confirms gate drive capability across the full 4.5V–18V supply range, and typical turn-on times of 20–100µs (depending on C_GATE) ensure reliable switching without external boost circuitry. The LTC1153CS8#PBF eliminates the need for discrete charge pumps or level shifters in these configurations.

How does the LTC1153CS8#PBF implement thermal shutdown using a PTC thermistor?

The LTC1153CS8#PBF implements thermal shutdown via its dedicated SHUTDOWN pin, which accepts a voltage divider output from a PTC thermistor. As temperature rises, the PTC's resistance increases sharply, raising the voltage at SHUTDOWN above the 2.0V threshold (V_SDH). This forces immediate gate discharge and latching-off of the MOSFET switch. The LTC1153CS8#PBF's SHUTDOWN input has ±1µA leakage and CMOS-compatible thresholds, enabling direct interface without op-amps or comparators. This analog thermal coordination is documented in the Applications Information section and Figure TA04/TA06 schematics.

Is the LTC1153CS8#PBF pin-compatible with the DIP-packaged LTC1153CN8?

No, the LTC1153CS8#PBF is not pin-compatible with the LTC1153CN8 despite identical functionality. The S8 (SOIC-8) and N8 (PDIP-8) packages have different pinouts: in the S8 package, pins are ordered VS–DS–G–SHUTDOWN–CT–STATUS–GND–IN (top view), whereas the N8 package sequences IN–CT–STATUS–GND–VS–DS–G–SHUTDOWN. This reversal of functional grouping means PCB layouts cannot be reused between packages. The LTC1153CS8#PBF requires its own footprint optimized for surface-mount assembly and thermal performance.

What is the purpose of the 100mV internal reference in the LTC1153CS8#PBF?

The 100mV internal reference in the LTC1153CS8#PBF serves as the precise trip threshold for the drain sense comparator. It compares the voltage drop across the external sense resistor (R_SENSE) to determine over-current conditions: when V_DS – V_SENSE > 100mV, the latch trips and disables the gate driver. This fixed, temperature-stable reference enables accurate current limiting independent of supply voltage variations. The LTC1153CS8#PBF's datasheet specifies 75mV–125mV tolerance over temperature, ensuring consistent trip points across 0°C–70°C operation.