Analog Devices Inc. LTC1255IS8#PBF

Overview

LTC1255IS8#PBF from Analog Devices (formerly Linear Technology) is a dual high-side N-channel MOSFET driver IC designed for industrial and automotive 9V–24V systems. It integrates an on-chip charge pump to generate gate drive ≥7.5V above VS, delivers 5–23µA gate drive current, features independent overcurrent sensing with 100mV threshold, and draws only 12µA standby current. It enables robust solenoid and DC motor control in harsh environments.

For engineers reviewing the LTC1255IS8#PBF datasheet, LTC1255IS8#PBF pinout, LTC1255IS8#PBF application, or LTC1255IS8#PBF equivalent, key selection criteria include its dual-channel high-side architecture, built-in short-circuit shutdown (5–16µs response), adjustable overcurrent delay via external RC, compatibility with TTL/CMOS logic, and SOIC-8 packaging suitable for space-constrained automotive modules.

Technical Context

The LTC1255IS8#PBF implements two independent high-side driver channels, each with CMOS-compatible input latches, adaptive charge pump circuitry, and fast gate discharge paths. Its internal 100mV reference comparator monitors drain-source voltage drop across an external sense resistor to trigger automatic shutdown during overcurrent events.

Each channel supports controlled turn-on (30–500µs) and turn-off (10–60µs) times with load-dependent timing, includes ESD-protected high-impedance inputs (±1µA leakage), and operates across –40°C to +85°C. The device requires no external charge pump components and uses Kelvin-connected VS for accurate current sensing.

Key Specifications

Pinout & Package

The LTC1255IS8#PBF is housed in an 8-pin SOIC (S8) package with standard JEDEC outline, 1.27mm pitch, and gull-wing leads. Thermal resistance θ_JA = 150°C/W enables operation at full load in compact PCB layouts without forced airflow.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS2812D and LM5050-1MMX/NOPB, the LTC1255IS8#PBF uniquely combines dual-channel high-side drive, self-contained overcurrent protection with user-adjustable delay, and integrated charge pump - making it the only option requiring zero external components for standalone 24V solenoid or motor control.

Availability

LTC1255IS8#PBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial solenoid control, and DC motor driver designs requiring stable component supply, long-term lifecycle support, and AEC-Q100-aligned reliability.

Supply support for LTC1255IS8#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 high-reliability analog portfolio. Linear pioneered precision power management ICs for demanding industrial and automotive markets.

The LTC1255 product line was engineered specifically for high-side N-MOSFET replacement in 9–24V automotive and industrial systems, emphasizing ultra-low quiescent current, integrated fault protection, and simplified layout.

FAQ

What is the maximum supply voltage the LTC1255IS8#PBF can withstand during transients?

The LTC1255IS8#PBF is rated for transient supply voltages up to 40V for durations less than 10ms. This specification allows it to survive load-dump events common in 12V automotive systems. During such transients, the device remains functional and resumes normal operation once voltage returns within the 9V–24V operating range. The internal protection circuitry does not latch off unless triggered by overcurrent or input conditions - the LTC1255IS8#PBF itself does not incorporate overvoltage shutdown.

Can the LTC1255IS8#PBF drive logic-level MOSFETs directly without external Zener clamping?

No - the LTC1255IS8#PBF requires a 12V Zener diode (e.g., MMBZ5242A) clamped across the gate-source of the external MOSFET. This is mandatory because the internal charge pump drives the gate up to VS + 12V, which exceeds the V_GS(max) rating of most logic-level MOSFETs. The Zener prevents gate oxide damage and ensures safe, repeatable turn-on. The LTC1255IS8#PBF datasheet explicitly specifies this requirement in Note 3 of the Electrical Characteristics table.

How does the drain sense pin (DS1/DS2) interface with the external current-sense resistor?

The DS1 and DS2 pins connect directly to the source-side terminal of the external sense resistor (typically 0.002Ω–0.1Ω), forming a Kelvin connection that references the VS pin. The internal comparator detects when the voltage drop across the resistor exceeds 100mV - indicating overcurrent. To avoid false triggering during in-rush, an RC network (e.g., 100kΩ + 0.01µF) may be added between DSx and the resistor's drain-side node. This configuration is validated in LTC1255IS8#PBF typical application circuits TA02 and F04.

Is the LTC1255IS8#PBF pin-compatible with other variants like LTC1255CN8 or LTC1255IN8?

Yes - all LTC1255 variants (C-grade, I-grade, N8 DIP, S8 SOIC) share identical pinouts and electrical functionality. The LTC1255IS8#PBF differs only in temperature grade (–40°C to +85°C) and package (SOIC-8). Pin-for-pin replacement is supported across the family, allowing direct substitution in existing designs when upgrading from commercial to industrial temperature range or DIP to surface-mount assembly.

Does the LTC1255IS8#PBF support PWM operation, and what are the practical frequency limits?

The LTC1255IS8#PBF supports PWM operation up to approximately 10kHz, as confirmed in Application Note TA09 ("Bootstrapped Gate Driver, 100Hz < f_O < 10kHz"). Its turn-on time ranges from 30µs to 500µs and turn-off from 10µs to 60µs depending on supply voltage and gate capacitance. For reliable 10kHz PWM, total switching time must remain <50µs - achievable with low-C_iss MOSFETs (e.g., IRLR024) and optimized layout. The LTC1255IS8#PBF does not include dedicated PWM control logic but functions as a robust gate driver within externally generated PWM systems.