Texas Instruments DS3668N/NOPB

Overview

DS3668N/NOPB from Texas Instruments (formerly National Semiconductor) is a quad open-collector peripheral driver IC with fault-protected outputs, TTL-compatible inputs, 70V output breakdown voltage, 600 mA sink current per channel, and integrated 800 mA clamp diodes for inductive fly-back protection. It serves as a high-voltage, high-current interface between logic controllers and electromechanical loads such as relays and solenoids.

For engineers reviewing the DS3668N/NOPB datasheet, DS3668N/NOPB pinout, DS3668N/NOPB application, or DS3668N/NOPB equivalent, key selection considerations include per-output fault shutdown (1.0 A threshold, 12 µs delay), fail-safe high-impedance state on open input, glitch-free power sequencing, and compatibility with 5 V TTL logic sources driving MOS devices directly.

Technical Context

The DS3668N/NOPB integrates four independent NPN sink drivers, each with dedicated overcurrent protection that disables only the affected channel without disrupting others. Protection activation requires sustained >1.0 A load current for ≥12 µs, preventing false triggering by turn-on surges.

Its TTL/LS-compatible inputs draw only 1 µA typical, enabling direct drive from CMOS or MOS logic. Outputs feature open-collector architecture with 70 V breakdown rating and on-chip clamp diodes rated for 800 mA, supporting safe switching of inductive loads clamped to ≤35 V to avoid latch-up.

Key Specifications

Pinout & Package

Molded dual-in-line package (MDIP), 16-pin, NS package number N16E. Four ground pins (pins 4, 5, 12, 13) are directly bonded to the die via copper lead frame to enhance thermal dissipation and support 2 W power handling when PCB-mounted.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar peripheral driver applications.

Compared with SN75437N and ULN2803ADWR, DS3668N/NOPB uniquely delivers per-output fault isolation and resettable shutdown-critical for systems where single-point failures must not cascade across multiple actuators-while maintaining TTL compatibility and 600 mA drive strength in a 16-pin DIP.

Availability

DS3668N/NOPB is available at Aetrix Electronics and suitable for relay drivers, solenoid drivers, and stepping motor phase drivers requiring stable component supply, long-term industrial lifecycle support, and guaranteed traceable sourcing.

Supply support for DS3668N/NOPB 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

Texas Instruments acquired National Semiconductor in 2011 and maintains its legacy analog and interface product lines with full technical documentation and long-term support.

The DS3668N/NOPB belongs to National Semiconductor's peripheral driver family, engineered for robust interfacing between digital logic and high-current, high-voltage electromechanical loads in industrial control, instrumentation, and automation systems.

FAQ

What is the fault protection mechanism in DS3668N/NOPB?

The DS3668N/NOPB implements per-output overcurrent protection that disables an individual channel when load current exceeds approximately 1.0 A for more than 12 µs. This prevents thermal runaway without affecting other outputs. The latched state persists until the corresponding input is toggled or the EN pin is pulled low for ≥1.0 µs. DS3668N/NOPB's protection is fully self-contained and requires no external components.

Does DS3668N/NOPB require external fly-back diodes for inductive loads?

No, DS3668N/NOPB integrates a dedicated 800 mA clamp diode at each output specifically for inductive fly-back suppression. When used with loads clamped to ≤35 V, these on-die diodes eliminate the need for external diodes. This reduces bill-of-materials count and PCB footprint while ensuring consistent clamping performance across all four channels.

Is DS3668N/NOPB pin-compatible with SN75437N?

Yes, DS3668N/NOPB is pin-for-pin compatible with SN75437N and shares identical pinout, package (16-pin MDIP), and core electrical specifications including 600 mA sink current and 70 V output breakdown. However, DS3668N/NOPB adds per-output fault protection and fail-safe open-input behavior not present in SN75437N.

What is the maximum ambient temperature for continuous operation of DS3668N/NOPB?

DS3668N/NOPB is rated for continuous operation from −40 °C to +125 °C ambient temperature. Its thermal design-including four dedicated ground pins bonded directly to the die-supports reliable performance at elevated temperatures when mounted on a properly designed PCB with adequate copper pour for heat spreading.

Can DS3668N/NOPB be driven directly by a microcontroller GPIO?

Yes, DS3668N/NOPB accepts standard 5 V TTL logic levels and draws only 1 µA typical input current, making it compatible with most microcontroller GPIO pins without buffer stages. Its high-impedance NPN inputs ensure minimal loading, and the fail-safe feature forces outputs to high-impedance if the GPIO signal is disconnected or floating-enhancing system robustness.