Texas Instruments SN75468N

Overview

SN75468N from Texas Instruments is a 7-channel NPN Darlington transistor array in a 16-pin PDIP package, rated for 500 mA per channel and 100 V collector-emitter voltage, with integrated common-cathode clamp diodes and 2.7 kΩ input base resistors-designed for direct TTL/CMOS interfacing to drive relays, lamps, and solenoids in industrial control systems.

For engineers reviewing the SN75468N datasheet, SN75468N pinout, SN75468N application, or SN75468N equivalent, key selection criteria include per-channel sink current capability, flyback diode integration, thermal derating at elevated ambient temperatures, and compatibility with 3.3 V/5 V logic inputs without external biasing.

Technical Context

The SN75468N implements seven independent Darlington pairs, each with cascaded NPN transistors yielding current gain up to 10,000 A/A, enabling high output current drive from low-input GPIO current (e.g., 350 µA typical at 5 V). Its 2.7 kΩ series base resistor ensures direct interface with TTL and 3.3 V/5 V CMOS logic.

All channels share a common emitter (Pin 7) and common cathode clamp node (Pin 8), supporting simultaneous inductive load switching with built-in suppression of back-EMF via internal diodes-eliminating need for external flyback components in relay and solenoid applications.

Key Specifications

Pinout & Package

SN75468N uses a 16-pin plastic dual in-line package (PDIP-N) with 19.30 mm × 6.35 mm body size and 2.54 mm lead pitch. Pin 1 is located at the top-left corner adjacent to the notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Darlington array applications.

Compared with ULN2003A and SN75468NSR, the SN75468N offers identical Darlington performance and pin compatibility in a through-hole PDIP package-making it ideal for breadboarding, field repair, and legacy board upgrades where footprint and assembly method constrain alternatives.

Availability

SN75468N is available at Aetrix Electronics and suitable for relay driver modules, industrial lamp control systems, and electromechanical actuator interfaces requiring stable component supply across extended product lifecycles.

Supply support for SN75468N 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 is a global semiconductor leader founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial and automotive qualification.

The SN75468N belongs to TI's legacy Darlington transistor array family-designed specifically for robust, low-complexity interface between digital logic and high-voltage/high-current electro-mechanical loads in factory automation and control systems.

FAQ

What is the maximum operating temperature for the SN75468N?

The SN75468N has a specified junction temperature range of –40°C to 125°C and a recommended operating ambient temperature of 0°C to 70°C. Its thermal resistance (R_θJA) is 73°C/W in the PDIP package, so sustained operation above 70°C ambient requires derating based on power dissipation and heatsinking-verified in Figure 5 of the SLRS023E datasheet.

Can the SN75468N drive inductive loads without external diodes?

Yes-the SN75468N integrates seven common-cathode clamp diodes connected between each collector output and the COM pin (Pin 8). When COM is tied to the inductive load's positive supply rail, these diodes provide complete flyback current recirculation-eliminating the need for external flyback diodes in relay, solenoid, and hammer driver applications.

Is the SN75468N pin-compatible with the ULN2003A?

Yes-the SN75468N and ULN2003A share identical pin numbering, electrical characteristics (500 mA per channel, 100 V V_CE, 2.7 kΩ input resistors), and functional behavior. Both devices use the same 16-pin PDIP footprint and can be substituted one-for-one in existing designs without layout or firmware changes.

What logic families can directly drive the SN75468N inputs?

The SN75468N inputs are compatible with TTL, 3.3 V CMOS, and 5 V CMOS logic families due to its integrated 2.7 kΩ base resistors. At 5 V input, typical input current is 1.85 mA; at 3.3 V, it drops to ~1.22 mA-well within the drive capability of standard microcontroller GPIOs and logic buffers without additional buffering.

How does the SN75468N handle multiple channels driven simultaneously?

When multiple channels operate concurrently, total power dissipation must remain within thermal limits. The SN75468N's maximum per-channel dissipation is ~1.05 W at 350 mA and 3 V V_CE(sat). Figure 5 in the datasheet shows maximum allowable duty cycle vs. number of active channels-e.g., all 7 channels can operate continuously at ≤100 mA each in free-air conditions.