Texas Instruments LM306DRE4

Overview

LM306DRE4 from Texas Instruments is a high-speed voltage comparator with differential inputs, 100 mA high-sink-current open-collector output, dual strobe inputs, and operation from −3 V to −12 V negative supply (with +15 V max positive supply). It delivers 40 ns low-to-high response time, ±5 mV input offset voltage, and fanout to 10 TTL loads. It directly drives lamps, relays, or digital logic in industrial control signal conditioning.

For engineers reviewing the LM306DRE4 datasheet, LM306DRE4 pinout, LM306DRE4 application, or LM306DRE4 equivalent, this page provides verified functional identity, validated SOIC-8 pin mapping, confirmed strobe-controlled comparator behavior, and real-world design constraints including −15 V absolute VCC− rating and 464 mW derated power at 70°C.

Technical Context

The LM306DRE4 implements a bipolar transistor-based differential pair front-end with active load and high-current output stage, enabling fast propagation through internal 70 Ω pull-down and 300 Ω/600 Ω emitter-follower drive paths. Its dual strobe inputs operate as OR-gated enable: either low forces output high regardless of IN+/IN− differential voltage.

It supports asymmetric dual-supply operation - VCC+ referenced to ground (0 to +15 V), VCC− referenced to ground (−3 V to −12 V) - with common-mode input range of ±5 V and differential input range of ±5 V. Output can swing up to 24 V relative to ground when externally pulled up, with short-circuit protection limiting duration to 10 s.

Key Specifications

Pinout & Package

LM306DRE4 is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package per JEDEC MS-012 variation AA, 3.9 mm body width, 1.75 mm max height, with 1.27 mm pitch and RoHS-compliant NiPdAu finish. Moisture sensitivity level is Level-1 (unlimited floor life).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed comparator applications.

Compared with LM306DRE4, LM311DR sacrifices strobe control and negative-supply operation for single-rail simplicity, while LM393DR trades speed and drive strength for integrated output logic and lower quiescent current - neither matches the LM306DRE4's combination of 40 ns response, 100 mA sink, and dual strobe capability in legacy dual-rail systems.

Availability

LM306DRE4 is available at Aetrix Electronics and suitable for industrial control systems, legacy instrumentation upgrades, and relay-driving embedded applications requiring stable component supply across extended production lifecycles.

Supply support for LM306DRE4 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

The LM306DRE4 belongs to TI's legacy high-speed comparator product line, designed specifically for robust signal discrimination in industrial control, power supply monitoring, and relay-driving applications requiring fast response and high-output drive under dual-rail operation.

FAQ

What is the maximum allowable negative supply voltage for LM306DRE4?

The LM306DRE4 supports VCC− from −3 V to −12 V under normal operation, but its absolute maximum rating is −15 V. Exceeding −12 V may degrade performance parameters such as input offset voltage and response time, and operation beyond −15 V risks permanent damage. Always maintain VCC− within −3 V to −12 V for guaranteed specification compliance in designs using LM306DRE4.

Does LM306DRE4 require external pull-up resistors on its output?

Yes, LM306DRE4 features an open-collector NPN output stage that can only sink current. An external pull-up resistor to VCC+ (or another logic rail) is mandatory to establish a defined high-level output voltage. Typical values range from 1 kΩ to 10 kΩ depending on rise time and load requirements. Without a pull-up, the LM306DRE4 output remains floating and cannot drive TTL or CMOS logic reliably.

Can both strobe inputs of LM306DRE4 be left unconnected?

Yes - when both STROBE 1 and STROBE 2 pins are left open (high-impedance), the LM306DRE4 functions as a standard comparator controlled solely by the differential voltage at IN+ and IN−. The internal circuitry interprets open strobes as logic high, enabling normal comparison mode. However, for noise immunity in industrial environments, TI recommends tying unused strobes to VCC+ via 10 kΩ resistors rather than leaving them floating.

What is the power dissipation limit of LM306DRE4 at 60°C ambient?

LM306DRE4 has a 600 mW power rating at TA ≤ 25°C and a derating factor of 5.8 mW/°C for the SOIC-8 (D) package. At 60°C ambient, derating is (60 − 25) × 5.8 = 203 mW, so maximum allowable dissipation is 600 − 203 = 397 mW. This assumes adequate PCB copper area; actual thermal performance depends on board layout and airflow. Exceeding this limit risks thermal shutdown or parametric drift in LM306DRE4 operation.

Is LM306DRE4 pin-compatible with National Semiconductor's LM306?

Yes, LM306DRE4 is a Texas Instruments second-source replacement for National Semiconductor's LM306 and maintains identical pinout, electrical specifications, and functional behavior in SOIC-8 (D) packaging. TI explicitly states "Designed to Be Interchangeable With National Semiconductor LM306" in the official datasheet SLCS008A. No PCB layout changes are required when substituting LM306DRE4 for LM306 in existing designs.