1 Features
• Ultra-fast transient response to low current levels:
– Settling time for 10nA to 100nA step:
240ns rising, 620ns falling (typ)
– Settling time for 100nA to 1μA step:
60ns rising, 150ns falling (typ)
• Wide dynamic range: 10pA to 10mA (180dB)
– Specified from 100pA to 10mA (160dB)
• High signal bandwidth:
– 20MHz at 10μA to 10mA
– 6.3MHz at 1μA
– 90kHz at 1nA
• High-accuracy transfer function:
– 0.2% max log conformity error (10nA to 100μA)
• Integrated reference current (1μA) and reference
voltages (2.5V and 1.65V)
• Additional auxiliary high-speed op amp for
differential ADC drive, single-ended gain or filter
blocks, and other peripheral functions
• Single supply (4.5V to 12.6V) or
dual supply (±2.25V to ±6.3V) operation
• Specified temperature range: –40°C to +125°C
• Small package options:
– 3mm × 3mm VQFN
– 1.6mm x 1.6mm DSBGA (Preview)

2 Applications
• Optical modules
• Inter-DC interconnect
• Optical network terminal unit
• Chemistry/gas analyzer
• Erbium-doped fiber optic amplifier (EDFA)

3 Description
The LOG200 is a wide-dynamic-range current-tovoltage
amplifier specifically designed to optimize
current measurements across 160dB of dynamic
range with unparalleled accuracy and speed
for optical communications, medical diagnostics,
and industrial process-control measurements. The
LOG200 features two logarithmic amplifiers followed
by a high-accuracy differential amplifier that convert
current signals into a voltage representing the logcompressed
ratio of the two currents. The current
inputs are designed to feature a high-speed response
from one input, and a highly accurate reference
signal on the other input, allowing for a unique
combination of fast transient response and high
logarithmic conformity.
The LOG200 ratio is internally set to 250mV/
decade of current-to-voltage conversion. The device
integrates an uncommitted high-speed amplifier to
allow the output to be configured for differential or
filtered responses, with a fast settling time to drive
successive approximation analog-to-digital converters
(SAR ADCs). The LOG200 also features a separate
reference current and reference voltage designed to
configure the device for optimized input current and
common-mode voltages.
The LOG200 can be powered in a single-supply
(4.5V to 12.6V) or dual-supply (±2.25V to ±6.3V)
configuration and is specified from –40°C to +125°C.