LOG114 Series
Precision High-Speed Logarithmic Amplifier with 2.5V Reference and Uncommitted Output Op Amps
Manufacturer: Texas Instruments
Catalog
Precision High-Speed Logarithmic Amplifier with 2.5V Reference and Uncommitted Output Op Amps
Key Features
• Advantages:Tiny for high density systemsPrecision on one supplyFast over eight decadesFully-tested functionTwo scaling amplifiersWide input dynamic range: eight decades, 100pA to 10mA2.5V referenceStable over temperatureLow quiescent current: 10mADual or single supply: ±5V, 5VPackage: Small QFN-16 (4mm × 4mm)Specified temperature range: −5°C to 75°CAdvantages:Tiny for high density systemsPrecision on one supplyFast over eight decadesFully-tested functionTwo scaling amplifiersWide input dynamic range: eight decades, 100pA to 10mA2.5V referenceStable over temperatureLow quiescent current: 10mADual or single supply: ±5V, 5VPackage: Small QFN-16 (4mm × 4mm)Specified temperature range: −5°C to 75°C
Description
AI
The LOG114 is specifically designed for measuring low-level and wide dynamic range currents in communications, lasers, medical, and industrial systems. The device computes the logarithm or log-ratio of an input current or voltage relative to a reference current or voltage (logarithmic transimpedance amplifier).
High precision is ensured over a wide dynamic range of input signals on either bipolar (±5V) or single (5V) supply. Special temperature drift compensation circuitry is included on-chip. In log-ratio applications, the signal current may be from a high impedance source such as a photodiode or resistor in series with a low impedance voltage source. The reference current is provided by a resistor in series with a precision internal voltage reference, photo diode, or active current source.
The output signal at VLOGOUT has a scale factor of 0.375V/decade of input current, which limits the output so that it fits within a 5V or 10V range. The output can be scaled and offset with one of the available additional amplifiers, so it matches a wide variety of ADC input ranges. Stable DC performance allows accurate measurement of low-level signals over a wide temperature range. The LOG114 is specified over a −5°C to 75°C temperature range and can operate from −40°C to 85°C.
The LOG114 is specifically designed for measuring low-level and wide dynamic range currents in communications, lasers, medical, and industrial systems. The device computes the logarithm or log-ratio of an input current or voltage relative to a reference current or voltage (logarithmic transimpedance amplifier).
High precision is ensured over a wide dynamic range of input signals on either bipolar (±5V) or single (5V) supply. Special temperature drift compensation circuitry is included on-chip. In log-ratio applications, the signal current may be from a high impedance source such as a photodiode or resistor in series with a low impedance voltage source. The reference current is provided by a resistor in series with a precision internal voltage reference, photo diode, or active current source.
The output signal at VLOGOUT has a scale factor of 0.375V/decade of input current, which limits the output so that it fits within a 5V or 10V range. The output can be scaled and offset with one of the available additional amplifiers, so it matches a wide variety of ADC input ranges. Stable DC performance allows accurate measurement of low-level signals over a wide temperature range. The LOG114 is specified over a −5°C to 75°C temperature range and can operate from −40°C to 85°C.
