LOG114 is a precision high speed logarithmic amplifier with 2.5V reference and non-dedicated output op amp

The LOG114 is designed for measuring low level and wide dynamic range currents in communication, laser, medical and industrial systems. The device calculates the logarithm or logarithmic ratio of an input current or voltage relative to a reference current or voltage (AQY210KS Logarithmic Transimpedance Amplifier).

Ensures high accuracy over a wide dynamic input signal range on bipolar (±5V) or single (+5V) supplies. A special temperature drift compensation circuit is included on-chip. In log-ratio applications, the signal current may come 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, a photodiode, or an active current source.

The output signal at V LOGOUT has a scale factor of 0.375V per decade of the input current, which limits the output to fit in the 5V or 10V range. The output can be scaled and offset by one of the additional amplifiers available, so it matches various ADC input ranges. Stable DC performance allows accurate measurement of low-level signals over a wide temperature range. The LOG114 is rated from -5°C to +75°C and operates from -40°C to +85°C.



— Tiny for high-density systems

- Precise one-time supply

- almost eight years

— Fully tested functionality

●Two zoom amplifiers

●Wide input dynamic range: eight decades, 100pA to 10mA

●2.5V reference

●Stable temperature

●Low quiescent current: 10mA

●Dual power supply or single power supply: ±5V, +5V

●Package: Small QFN-16 (4mm x 4mm)

●Specified temperature range: –5°C to +75°C


—ONET Erbium-Doped Fiber Amplifier (EDFA)

- Laser Optical Density Measurement

— Photodiode Signal Compression Amplifier

- logarithmic, logarithmic ratio functions

—Analog signal compression in front of analog-to-digital (ADC) converters

- Absorbance measurement


Scale Factor (V/decade): 0.375

Input current range (Min) (nA): 0.1

Input Current Range (Max) (mA): 10

Consistency Error (First 5 Decades) (Maximum) (%): 0.2

Conformance Error (First 5 Decades) (Typical Over Temperature) (%/degree Celsius): 0.1

Offset Voltage (Input Amp) (Max) (mV): 4

Vs (+/-) (min) (V): 4.8

Vs (+/-) (max) (V): 11

IQ (Max) (mA): 15

Dynamic Range (Typ) (dB): 160

Reference Type: Internal

Auxiliary Op Amp: 2

Full Scale Output Voltage (Min) (+/- V): -4.4

Full-scale output voltage (Max) (+/- V): 4.4

Operating temperature range (°C): 0 to 70

Specified Voltage (+/- V): 5