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LOG112

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Precision logarithmic and log ratio amplifier with on-chip 2.5-V voltage reference

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LOG200 ACTIVE High-speed precision logarithmic amplifier with photodiode bias and dark-current correction Upgraded performance with smaller package option

LOG112

ACTIVE
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Product details

Scale factor (V/decade) 0.5 Input current range (min) (nA) 1 Input current range (max) (mA) 3.5 Offset voltage (input amplifiers) (max) (mV) 1.5 Vs (±) (min) (V) 4.5 Vs (±) (max) (V) 18 Iq (max) (mA) 1.75 Dynamic range (typ) (dB) 150 Reference type Internal Auxiliary op amps 1 Full-scale output voltage (min) (±V) -3.8 Full-scale output voltage (max) (±V) 3.5 Conformity error (initial 5 decades) (max) (%) 0.2 Conformity error (initial 5 decades) (typ. over temp) (%/°C) 0.0001 Operating temperature range (°C) -40 to 85 Specified voltage (±V) 5 Rating Catalog
Scale factor (V/decade) 0.5 Input current range (min) (nA) 1 Input current range (max) (mA) 3.5 Offset voltage (input amplifiers) (max) (mV) 1.5 Vs (±) (min) (V) 4.5 Vs (±) (max) (V) 18 Iq (max) (mA) 1.75 Dynamic range (typ) (dB) 150 Reference type Internal Auxiliary op amps 1 Full-scale output voltage (min) (±V) -3.8 Full-scale output voltage (max) (±V) 3.5 Conformity error (initial 5 decades) (max) (%) 0.2 Conformity error (initial 5 decades) (typ. over temp) (%/°C) 0.0001 Operating temperature range (°C) -40 to 85 Specified voltage (±V) 5 Rating Catalog
SOIC (D) 14 51.9 mm² (8.65 mm × 6 mm)
  • EASY-TO-USE COMPLETE FUNCTION
  • OUTPUT SCALING AMPLIFIER
  • ON-CHIP 2.5V VOLTAGE REFERENCE
  • HIGH ACCURACY: 0.2% FSO Over 5 Decades
  • WIDE INPUT DYNAMIC RANGE:
       7.5 Decades, 100pA to 3.5mA
  • LOW QUIESCENT CURRENT: 1.75mA
  • WIDE SUPPLY RANGE: ±4.5V to ±18V
  • PACKAGES: SO-14 (narrow) and SO-16
  • APPLICATIONS
    • LOG, LOG RATIO:
         Communication, Analytical, Medical, Industrial, Test, General Instrumentation
    • PHOTODIODE SIGNAL COMPRESSION AMP
    • ANALOG SIGNAL COMPRESSION IN FRONT OF ANALOG-TO-DIGITAL (A/D) CONVERTER
    • ABSORBANCE MEASUREMENT
    • OPTICAL DENSITY MEASUREMENT

All trademarks are the property of their respective owners.
  • EASY-TO-USE COMPLETE FUNCTION
  • OUTPUT SCALING AMPLIFIER
  • ON-CHIP 2.5V VOLTAGE REFERENCE
  • HIGH ACCURACY: 0.2% FSO Over 5 Decades
  • WIDE INPUT DYNAMIC RANGE:
       7.5 Decades, 100pA to 3.5mA
  • LOW QUIESCENT CURRENT: 1.75mA
  • WIDE SUPPLY RANGE: ±4.5V to ±18V
  • PACKAGES: SO-14 (narrow) and SO-16
  • APPLICATIONS
    • LOG, LOG RATIO:
         Communication, Analytical, Medical, Industrial, Test, General Instrumentation
    • PHOTODIODE SIGNAL COMPRESSION AMP
    • ANALOG SIGNAL COMPRESSION IN FRONT OF ANALOG-TO-DIGITAL (A/D) CONVERTER
    • ABSORBANCE MEASUREMENT
    • OPTICAL DENSITY MEASUREMENT

All trademarks are the property of their respective owners.

The LOG112 and LOG2112 are versatile integrated circuits that compute the logarithm or log ratio of an input current relative to a reference current. VLOGOUT of the LOG112 and LOG2112 are trimmed to 0.5V per decade of input current, ensuring high precision over a wide dynamic range of input signals.

The LOG112 and LOG2112 features a 2.5V voltage reference that may be used to generate a precision current reference using an external resistor.

Low DC offset voltage and temperature drift allow accurate measurement of low-level signals over the specified temperature range of –5°C to +75°C.

The LOG112 and LOG2112 are versatile integrated circuits that compute the logarithm or log ratio of an input current relative to a reference current. VLOGOUT of the LOG112 and LOG2112 are trimmed to 0.5V per decade of input current, ensuring high precision over a wide dynamic range of input signals.

The LOG112 and LOG2112 features a 2.5V voltage reference that may be used to generate a precision current reference using an external resistor.

Low DC offset voltage and temperature drift allow accurate measurement of low-level signals over the specified temperature range of –5°C to +75°C.
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* Data sheet Precision Logarithmic and Log Ratio Amplifier datasheet (Rev. D) Apr 4, 2005

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Simulation model

LOGx112 PSpice Model (Rev. B)

SBOC044B.ZIP (26 KB) - PSpice model
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