The Tektronix 178 is a specialized test fixture for linear integrated circuit characterization that operates as a plug-in module to the Tektronix 577 Curve Tracer System. It employs closed-loop measurement techniques to deliver enhanced stability and precision when testing high-gain devices such as operational amplifiers, comparators, differential amplifiers, and voltage regulators. Unlike conventional open-loop curve tracing, the 178’s closed-loop approach provides controlled stimulus and response measurement for accurate IC parameter extraction.
Technical Specifications
Sweep Generation
• Internal frequency range: 0.01 Hz to 1 kHz
• Sinusoidal output with five calibrated steps (0.1, 1, 10, 100, 1000 Hz) plus variable fine adjustment (0.1–1.0× decade)
• Frequency accuracy: ±5% at x1 calibrated position
Power Supplies
• Two regulated supplies (positive and negative): 0 to 30 V adjustment range
• Minimum current capability: 150 mA per supply
• Current-limit protection on device card with overload indication
Load Resistors
• Selectable internal: 100 Ω, 1 kΩ, 2 kΩ, 5 kΩ, 10 kΩ, 20 kΩ, or 50 kΩ
• External position allows external resistance or parallel connection with internal 50 kΩ
Vertical Measurement System
• Selectable current or voltage measurement via FUNCTION switch
• Current deflection (unmagnified): 50 pA/div to 2 mA/div
• Voltage deflection (unmagnified): 10 µA/div to 50 mA/div
• With 10× magnifier — current: 5 pA/div to 20 µA/div; voltage: 1 µA/div to 5 mA/div
• Current accuracy: ±3% ±50 pA (unmagnified); ±4% ±50 pA (10× magnifier)
• Voltage accuracy: ±3% (unmagnified); ±4% (10× magnifier)
– Key Features
• Closed-loop testing architecture for stability in high-gain IC measurement
• Dual independent regulated supplies with current limiting and overload indication
• Wide deflection factor range covering picoampere to milliampere current measurement
• Fine-resolution sweep control across five calibrated frequency decades
– Typical Applications
Single, dual, and quad operational amplifier characterization; comparator and differential amplifier testing; voltage regulator parameter measurement.
– Compatibility & Integration
Designed as a plug-in module for the Tektronix 577 Curve Tracer System with D1/D2 Display Units.
