The ADL5310 is a low-cost dual logarithmic amplifier that converts input current over a wide dynamic range to a linear-in-dB output voltage. It is optimized for the determination of optical power in wide-ranging optical communication system applications including control circuitry for lasers, optical switches, attenuators, and amplifiers, as well as general system monitoring. The device is equivalent to a dual AD8305 with enhanced dynamic range (120 dB). While the ADL5310 contains two independent signal channels with individually-configurable transfer function constants (slope and intercept), internal bias circuitry is shared between channels for improved power consumption and channel matching. Dual converters in a single compact LFCSP package yield space-efficient solutions for measuring gain or attenuation across optical elements. Only a single supply is required, while optional dual supply operation offers added flexibility.
The ADL5310 employs an optimized translinear structure, which utilizes the accurate logarithmic relationship between a bipolar transistor's base-emitter voltage and collector current, with appropriate scaling by precision currents to compensate the inherent temperature dependence. Input and reference current pins sink current ranging from 3 nA to 3 mA (limited to ±60 dB between input and reference) into a fixed voltage defined by the VSUM potential, which is internally set to 500 mV but may be externally-grounded for dual-supply operation and additional applications requiring voltage inputs.
|Title||Content Type||File Type|
|ADL5310: 120dB-range (3 nA - 3 mA) Dual Logarithmic Converter Data Sheet (Rev A, 09/2004) (pdf, 668 kB)||Data Sheets|
|AN-643: Closed-Loop Control Circuit Implementation of the ADuC832 MicroConverter®IC and the AD8305 Logarithmic Converter in a Digital Variable Optical Attenuator (pdf, 395 kB)||Application Notes|
|CN-0057: Interfacing the ADL5317 High Side Current Mirror to a Translinear Logarithmic Amplifier in an Avalanche Photodiode Power Detector Application (pdf, 107 kB)||Circuit Note|
|CN-0056: Interfacing the ADL5315 High Side Current Mirror to a Translinear Logarithmic Amplifier in a Photodiode Power Detector Application (pdf, 107 kB)||Circuit Note|
Log Amps and Directional Couplers Enable VSWR Detection
(pdf, 2223 kB)
by Anil Rachakonda and Larry Hawkins, Analog Devices, Inc. (RF Design, 1/1/2007)
Design a Logamp RF Pulse Detector
(pdf, 338 kB)
by Eamon Nash
(Microwaves & RF, January 1, 2000)
Logarithmic Processing Applied to Network Power Monitoring
(pdf, 593 kB)
by Eric Newman, Analog Devices, Inc.
Closed-Loop Control of Variable Optical Attenuators with Logarithmic Analog Processing
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Optical and High Speed Networking
(pdf, 2236 kB)
Analog Devices’ optical and high speed networking ICs solve a depth and breadth of challenges faced by today’s designers of datacom and telecom systems, optical modules, and subsystems. Analog Devices products address a wide range of networking applications from O/E/O conversion, clock recovery, and backplane transmission to monitoring and control of optical power, power management, and clock generation and distribution.
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