LM13700M: High-Performance Transconductance Amplifier - Features, Specs & Applications
LM13700M: Texas Instruments' High-Performance Dual Transconductance Amplifier
The LM13700M from Texas Instruments represents a pinnacle of analog design, offering engineers a versatile solution for precision current-controlled applications. This comprehensive guide delves into every aspect of this remarkable IC, from its electrical characteristics to real-world implementation strategies that maximize performance.
In-Depth Technical Analysis
Architectural Overview
Housed in a space-efficient 16-pin SOIC package (3.90mm width), the LM13700M integrates two independent operational transconductance amplifiers (OTAs) with linearizing diode inputs. This dual-channel configuration provides exceptional design flexibility while minimizing PCB footprint.
Key Performance Metrics
- Transconductance Range: Programmable from 0 to 10,000 mhos
- Bandwidth: 2MHz gain-bandwidth product ensures stable operation across audio and RF spectra
- Dynamic Performance: 50V/ s slew rate enables crisp signal reproduction
- Precision Characteristics: 300 V input offset voltage and 400nA bias current
Advanced Application Circuits
1. Voltage-Controlled Filters
The LM13700M excels in state-variable filter designs, where its current-mode operation enables precise Q control. Typical implementations include:
- 24dB/octave voltage-controlled low-pass filters for analog synthesizers
- Tunable bandpass filters for biomedical instrumentation
2. Professional Audio Systems
Audio designers leverage the OTA's unique characteristics for:
- VCA (Voltage Controlled Amplifier) modules in mixing consoles
- Dynamic range compressors with exponential control laws
- Parametric equalizer sections
Design Considerations
Thermal Management
While operating across the industrial temperature range (0 C to 70 C), proper PCB layout is essential:
- Maintain minimum 0.5mm clearance between adjacent pins
- Use thermal relief patterns for power supply pins
- Consider copper pours for heat dissipation in high-current applications
Power Supply Configurations
The 10V-36V operating range supports multiple configurations:
- 5V to 18V split supplies for maximum headroom
- Single +24V supply for industrial control systems
- Battery-powered operation down to 10V total supply
Comparison with Modern Alternatives
While marked "Not for New Designs", the LM13700M offers unique advantages over newer OTAs:
| Feature | LM13700M | Modern Alternatives |
|---|---|---|
| Supply Range | 10-36V | Typically 3-5.5V |
| Output Current | 500 A | Often limited to 100 A |
| Package Options | SOIC-16 | Smaller CSP packages |
Purchasing Guide
When sourcing LM13700M devices:
- Verify Texas Instruments' date codes for fresh inventory
- Consider tape-and-reel packaging for production runs
- Evaluate alternative part numbers for drop-in replacements
For engineers requiring the unique performance characteristics of transconductance amplifiers, the LM13700M remains an excellent choice despite its legacy status. Its combination of analog precision, flexible supply requirements, and dual-channel integration continues to make it relevant in specialized applications where modern ICs may fall short.