Texas Instruments LM306P

Overview

LM306P from Texas Instruments is a high-speed voltage comparator with differential inputs, dual strobe control, and a 100 mA high-sink-current open-collector output. It operates with dual supplies (VCC+ = up to 15 V, VCC− = −3 V to −12 V), delivers 40 ns low-to-high response time, and supports fanout to 10 TTL loads. It directly drives lamps, relays, or digital logic in industrial timing and analog threshold detection circuits.

For engineers reviewing the LM306P datasheet, LM306P pinout, LM306P application, or LM306P equivalent, this page provides verified functional specifications, strobe-controlled comparator behavior, absolute maximum ratings, thermal derating data, and validated alternative options for legacy system maintenance and replacement design.

Technical Context

The LM306P implements a bipolar transistor-based differential pair input stage with active load and a Darlington-connected output stage capable of sinking 100 mA. Its two independent strobe inputs force high-impedance output high-state when either is pulled low, enabling synchronized comparison gating in multiplexed systems.

It requires dual asymmetric supplies: positive rail (VCC+) referenced to ground and negative rail (VCC−) down to −12 V, with common-mode input range of ±5 V relative to ground. Input offset voltage is specified at 5 mV max (25°C) and 6.5 mV over full temperature range (0°C to 70°C), and large-signal voltage gain exceeds 40 V/mV.

Key Specifications

Pinout & Package

LM306P is supplied in an 8-pin plastic dual in-line package (PDIP) with 0.3-inch body width and standard 0.1-inch pin pitch. Pin 1 is located at the left end of the top row when viewing the top marking side with notch or dot oriented left.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM306P, LM311P offers better offset performance and single-supply flexibility but removes critical strobe functionality; LM393N reduces cost and power but sacrifices 33× slower response and 6× lower output drive-making LM306P irreplaceable in strobe-gated, high-current, high-speed comparator roles.

Availability

LM306P is available at Aetrix Electronics and suitable for industrial motor control, legacy power supply monitoring, analog sensor interface, and retro-TTL logic interfacing requiring stable component supply and long-term obsolescence mitigation.

Supply support for LM306P 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 U.S.-based semiconductor company founded in 1930, specializing in analog ICs, embedded processors, and high-reliability components for industrial, automotive, and aerospace markets.

The LM306P belongs to TI's legacy analog comparator product line, designed specifically for high-speed, high-drive, strobe-synchronized threshold detection in commercial-grade industrial control and instrumentation systems.

FAQ

What is the maximum allowable supply voltage for LM306P?

The LM306P supports VCC+ up to +15 V and VCC− down to −15 V. Exceeding these absolute maximum ratings risks permanent device damage. For reliable operation, use VCC+ between 5 V and 12 V and VCC− between −3 V and −12 V, as specified in recommended operating conditions. The LM306P datasheet confirms these limits in the Absolute Maximum Ratings table on page 3.

Does LM306P require both positive and negative supplies to operate?

Yes, the LM306P requires dual supplies: a positive rail (VCC+) referenced to ground and a negative rail (VCC−) typically between −3 V and −12 V. Its input common-mode range and internal biasing depend on this configuration. Operation with VCC− = GND is not supported - unlike LM311P, the LM306P lacks single-supply capability per its electrical characteristics and functional description.

Can LM306P drive a 12 V relay coil directly?

Yes, the LM306P can drive a 12 V relay coil directly when configured with an external pull-up to 12 V on the OUT pin and the relay coil connected between +12 V and OUT. Its 100 mA sink capability exceeds typical 12 V relay coil currents (20–80 mA). Ensure VCC− is set to −6 V or −12 V to maintain output saturation voltage below 1 V at full load, as verified in the VOL specification table on page 4 of the LM306P datasheet.

How do the strobe inputs on LM306P function in practice?

Either STROBE 1 or STROBE 2 pulled low (≤0.9 V) forces the LM306P output high regardless of the IN+ and IN− differential voltage. When both strobes are open or high (≥2.2 V), the output responds normally to input differential voltage. This OR-gated strobe behavior allows flexible external timing control - for example, synchronizing comparison to a master clock edge or disabling during system reset. The LM306P functional block diagram and truth table on page 1 confirm this behavior.

Is LM306P RoHS compliant and lead-free?

Yes, the LM306P is RoHS compliant and lead-free. According to TI's Package Option Addendum (February 2020), LM306P carries "Green (RoHS & no Sb/Br)" eco plan and "NIPDAU" lead finish. Its MSL rating is "N/A for Pkg Type", consistent with through-hole PDIP packaging. TI confirms active status and RoHS compliance for LM306P in its official packaging documentation.