Texas Instruments LM13700N/NOPB

Overview

LM13700N/NOPB 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 6-decade gm adjustability (5 μA–500 μA), <0.3 dB gm tracking between channels, ±14.4 V peak buffered output swing, and 10-dB SNR improvement over non-linearized OTAs in audio-grade applications such as stereo volume control and VCOs.

For engineers reviewing the LM13700N/NOPB datasheet, LM13700N/NOPB pinout, LM13700N/NOPB application, or LM13700N/NOPB equivalent, key selection criteria include transconductance linearity under IABC control, diode-bias-dependent distortion reduction, dual-channel matching for stereo/PLL use, and buffer output current capability up to 20 mA without external drivers.

Technical Context

The LM13700N/NOPB implements two independent current-controlled transconductance stages, each with differential NPN input pairs biased by dedicated IABC pins (pins 1 & 16) and linearizing diodes (pins 2 & 15) that reduce THD by enabling higher input signal levels while maintaining <0.1% distortion at 60 mV_PP differential input. Its output current is directly proportional to IABC and VIN, with gm ≈ 19.2 × IABC (μS) at 25°C.

Each channel integrates a Darlington-buffered output stage (pins 8 & 9 for Amp A; pins 7 & 10 for Amp B) providing 20 mA sink/source capability, DC-level independence from IABC, and sustained short-to-ground tolerance. The device operates from ±4.75 V to ±16 V dual supplies or 9.5–32 V single supply, with 0°C to 70°C industrial temperature range and PDIP-16 package thermal resistance of 43.8°C/W.

Key Specifications

Pinout & Package

LM13700N/NOPB uses a 16-pin PDIP package (6.35 mm × 19.304 mm) with through-hole mounting and industry-standard lead pitch. Pin functions are electrically isolated per channel, supporting independent configuration of both OTAs.

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 LM13700N/NOPB uniquely combines dual-channel integration, on-die linearizing diodes, IABC-independent buffer DC levels, and 0.3 dB gm tracking-making it the only option among the three capable of high-fidelity stereo VCA and low-THD sinusoidal VCO implementation without external compensation.

Availability

LM13700N/NOPB is available at Aetrix Electronics and suitable for stereo audio systems, voltage-controlled oscillators, analog synthesizers, and industrial AGC circuits requiring stable component supply and long-term manufacturability.

Supply support for LM13700N/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 is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision analog IC design and manufacturing.

The LM13700 series belongs to TI's legacy analog signal processing portfolio, engineered specifically for voltage-controlled analog functions-including VCAs, filters, oscillators, and multipliers-in professional audio, test equipment, and industrial control systems.

FAQ

What is the maximum recommended diode bias current (ID) for LM13700N/NOPB?

The absolute maximum diode bias current for LM13700N/NOPB is 2 mA per channel, as specified in the Absolute Maximum Ratings table. Operating at 1 mA is recommended for optimal linearizing action and minimal junction resistance, especially in audio applications where distortion below 0.1% THD is required. Exceeding 2 mA risks exceeding package power dissipation limits and degrading long-term reliability.

Can LM13700N/NOPB operate from a single 12-V supply?

Yes, LM13700N/NOPB supports single-supply operation from 9.5 V to 32 V. When powered from +12 V and ground, the V– pin must be tied to GND, and input common-mode range shifts to 0 V to +10.5 V. Output swing remains asymmetric (≈+10.5 V positive, ≈–1.5 V negative due to PNP/NPN asymmetry), so AC coupling or level-shifting may be needed for bipolar signal handling in single-supply mode.

How does the LM13700N/NOPB buffer output differ from the LM13600N?

The LM13700N/NOPB buffer output features DC bias independence from IABC-its output level remains stable even as transconductance is adjusted-whereas the LM13600N buffer output DC level shifts with IABC changes. This makes LM13700N/NOPB superior in audio applications requiring consistent DC operating points across gain settings, such as in stereo volume controllers or AGC loops where offset drift would cause audible artifacts.

What is the minimum IABC required for stable operation of LM13700N/NOPB?

The minimum recommended amplifier bias current (IABC) for LM13700N/NOPB is 5 μA per channel, as validated in Electrical Characteristics tables across the full temperature range. At IABC = 5 μA, transconductance remains functional (≥6700 μS), gm tracking holds within 0.3 dB, and input offset voltage stays within 0.3–4 mV. Operation below 5 μA risks degraded linearity, increased noise, and potential instability in high-gain configurations.

Does LM13700N/NOPB require external compensation capacitors?

No, LM13700N/NOPB does not require external compensation capacitors for unity-gain stable operation. Its internal architecture is unity-gain compensated, with a specified slew rate of 50 V/μs and open-loop bandwidth of 2 MHz. However, external RC networks are necessary in application circuits-such as VCO integrators or filter feedback paths-to set time constants; these are functional, not stability-compensation, components.