Texas Instruments LM13700M

Overview

LM13700M from Texas Instruments is a dual operational transconductance amplifier (OTA) with linearizing diodes and high-impedance output buffers, designed for voltage-controlled analog signal processing. It delivers gm adjustable over 6 decades (5400–13000 μS), 0.3 dB gm tracking between channels, ±14.4 V peak buffered output swing, and supports ±16 V dual-supply operation in stereo audio amplifiers and voltage-controlled filters.

For engineers reviewing the LM13700M datasheet, LM13700M pinout, LM13700M application, or LM13700M equivalent, key selection considerations include its 110°C/W junction-to-ambient thermal resistance (SOIC package), independent IABC-controlled transconductance per channel, linearizing diode biasing for <0.1% THD at 60 mVpp differential input, and Darlington-buffered 20 mA output drive capability.

Technical Context

The LM13700M implements two fully independent current-controlled transconductance stages, each with differential NPN input pairs biased by dedicated IABC pins (pins 1/16) to set gm ∝ IABC. Linearizing diodes (pins 2/15) reduce distortion by enabling higher input signal levels while maintaining 0.3 dB gm matching across temperature.

Each channel integrates a Darlington-pair buffer (pins 7–10, 8–9) with 0.5–2 μA input bias current independent of IABC - a key distinction from LM13600 - enabling stable DC operating points in AC-coupled audio paths. The unbuffered outputs (pins 5/12) support continuous short-to-ground operation.

Key Specifications

Pinout & Package

LM13700M is packaged in a 16-pin SOIC (3.91 mm × 9.90 mm) with standard JEDEC MS-012AC footprint and 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar operational transconductance amplifier applications.

Compared with LM13600N and CA3080E, the LM13700M provides superior audio performance via on-chip linearizing diodes and IABC-independent buffers, while its 110°C/W SOIC thermal rating demands careful PCB copper pour design - making it optimal for high-fidelity, dual-channel analog signal conditioning where distortion and channel matching are critical.

Availability

LM13700M is available at Aetrix Electronics and suitable for stereo audio amplifiers, voltage-controlled filters, voltage-controlled oscillators, automatic gain control circuits, and analog synthesizer modules requiring stable component supply and long-term obsolescence management.

Supply support for LM13700M 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 and embedded processing solutions, with over 90 years of innovation in precision analog ICs.

The LM13700M belongs to TI's legacy analog signal processing portfolio, engineered specifically for voltage-controlled analog functions in audio synthesis, test instrumentation, and industrial control systems.

FAQ

What is the maximum allowable differential input voltage for LM13700M?

The LM13700M specifies a maximum differential input voltage of ±5 V across pins 3–4 and 13–14. Exceeding this risks zenering the input transistors. When using linearizing diodes (pins 2/15 biased ≥1 mA), the effective linear input range extends to ±60 mVpp for <0.1% THD - verified in Figure 13 of the SNOSBW2F datasheet.

How does the LM13700M differ from the LM13600 in buffer behavior?

The LM13700M buffer input bias current is independent of IABC, whereas the LM13600 buffer bias varies with IABC. This makes LM13700M's DC output offset stable across gain adjustments - critical in audio volume control. The LM13700M also integrates linearizing diodes absent in LM13600, reducing distortion by 10 dB at equivalent signal levels.

Can LM13700M operate from a single 12-V supply?

Yes. The LM13700M supports single-supply operation from +9.5 V to +32 V (V+ pin 11), with V− (pin 6) tied to ground. Input common-mode range extends to ±12 V referenced to V−, so AC-coupled inputs centered at 6 V are valid. Buffer output swing reaches +12 V (typical) under these conditions, as confirmed in Section 6.4 of SNOSBW2F.

What is the purpose of pins 2 and 15 on the LM13700M?

Pins 2 and 15 are diode bias inputs for the internal linearizing diodes at each amplifier's input stage. Biasing these pins with ≥1 mA (e.g., via 13-kΩ resistor to V+) reduces harmonic distortion by compensating transistor nonlinearities - enabling 60 mVpp differential input at <0.1% THD. Omitting bias degrades THD to >0.5% at same input level.

Is LM13700M pin-compatible with LM13700N?

Yes. LM13700M (SOIC) and LM13700N (PDIP) share identical 16-pin functional mapping and electrical specifications. The only difference is package type and thermal resistance: LM13700M has θ_JA = 110°C/W (SOIC), while LM13700N has θ_JA = 90°C/W (PDIP). Both use the same pinout shown in Figure 1 of SNOSBW2F.