Precision Wide Range (3 nA to 3 mA) High-Side Current Mirror Data Sheet ADL5315 FEATURES FUNCTIONAL BLOCK DIAGRAM Accurately mirrors input current (1:1 ratio) over 6 decades ADL5315 Linearity 1% from 3 nA to 3 mA VOLTAGE CURRENT Stable mirror input voltage REFERENCE LIMITING Voltage held 1 V below supply using internal reference 4 5 COMM RLIM or can be set externally 20k CURRENT Adjustable input current limit MIRROR 3 6 1:1 2.7 V to 8 V single-supply operation SREF VPOS Miniature 8-lead LFCSP (2 mm 3 mm) VSET NC 2 7 APPLICATIONS IOUT INPT 1 8 Optical power monitoring from a single photodiode I I PD PD General voltage biasing with precision current monitoring Voltage-to-current conversion Figure 1. GENERAL DESCRIPTION The ADL5315 is a wide input current range, precision high-side The VSET input has very low input current and can be driven current mirror featuring a stable and user-adjustable input as low as the bottom rail, facilitating nonloading voltage-to- voltage. It is optimized for use with PIN photodiodes, but its current conversion as well as minimizing dark current in flexibility and wide operating range make it suitable for a broad photodiode applications. array of additional applications. Over the 3 nA to 3 mA range, The ADL5315 also features adjustable input current limiting the current sourced from the INPT pin is accurately mirrored using an external resistor from RLIM to VPOS. The maximum with a 1:1 ratio and sourced from the IOUT output pin. In a current sourced by INPT (and IOUT) can be set between 1 mA typical photodiode application, the output drives a current- and 16 mA, beyond which the voltage at INPT falls rapidly input logarithmic amplifier to produce a linear-in-dB output from its setpoint. Connecting RLIM directly to VPOS provides representing the optical power incident upon the photodiode. basic input short-circuit protection with the default current For linear voltage output, a single resistor to ground is all that is limit of 16 mA typical. required. The photodiode anode can be connected to a high speed transimpedance amplifier for the extraction of the data The ADL5315 is available in a 2 mm 3 mm, 8-lead LFCSP and stream. The voltage at the INPT pin is temperature stable with is specified for operation from 40C to +85C. respect to the voltage at the VSET input pin, which it tracks. A temperature stable reference voltage is provided at the SREF pin, which, when tied to VSET, fixes the voltage at INPT 1.0 V below VPOS. VSET can also be driven from an external source. Rev. A Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20052017 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. 05694-001ADL5315 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Noise Performance ..................................................................... 10 Applications ....................................................................................... 1 Mirror Response Time............................................................... 10 Functional Block Diagram .............................................................. 1 Input Current Limiting .............................................................. 10 General Description ......................................................................... 1 Applications ..................................................................................... 11 Revision History ............................................................................... 2 Average Power Monitoring ....................................................... 11 Specifications ..................................................................................... 3 Translinear Log Amp Interfacing ............................................. 12 Absolute Maximum Ratings ............................................................ 4 Extended Operating Range ....................................................... 13 ESD Caution .................................................................................. 4 Using RLIM as a Secondary Monitor ...................................... 13 Pin Configuration and Function Descriptions ............................. 5 Characterization Methods ........................................................ 14 Typical Performance Characteristics ............................................. 6 Evaluation Board ............................................................................ 16 Theory of Operation ........................................................................ 9 Outline Dimensions ....................................................................... 17 Bias Control Interface .................................................................. 9 Ordering Guide .......................................................................... 17 REVISION HISTORY 9/2017Rev. 0 to Rev. A Changed CP-8-1 to CP-8-23 ........................................ Throughout Changes to Figure 2 .......................................................................... 5 Updated Outline Dimensions ....................................................... 17 Changes to Ordering Guide .......................................................... 17 10/2005Revision 0: Initial Version Rev. A Page 2 of 17