ADL5315ACPZ-R7

Data Sheet Precision Wide Range (3 nA to 3 mA) High-Side Current Mirror ADL5315 FEATURES FUNCTIONAL BLOCK DIAGRAM Accurately mirrors input current (1:1 ratio) over 6 decades Linearity 1% from 3 nA to 3 mA Stable mirror input voltage Voltage held 1 V below supply using internal reference or can be set externally Adjustable input current limit 2.7 V to 8 V single-supply operation Miniature 8-lead LFCSP (2 mm × 3 mm) ADL5315 VOLTAGE REFERENCE CURRENT LIMITING 4 5 RLIM COMM 20k 3 CURRENT MIRROR 1:1 6 SREF VPOS VSET NC 2 7 APPLICATIONS IOUT INPT 1 8 IPD IPD 05694-001 Optical power monitoring from a single photodiode 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 current mirror featuring a stable and user-adjustable input voltage. It is optimized for use with PIN photodiodes, but its flexibility and wide operating range make it suitable for a broad array of additional applications. Over the 3 nA to 3 mA range, the current sourced from the INPT pin is accurately mirrored with a 1:1 ratio and sourced from the IOUT output pin. In a typical photodiode application, the output drives a currentinput logarithmic amplifier to produce a linear-in-dB output representing the optical power incident upon the photodiode. For linear voltage output, a single resistor to ground is all that is required. The photodiode anode can be connected to a high speed transimpedance amplifier for the extraction of the data stream. The voltage at the INPT pin is temperature stable with 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 The VSET input has very low input current and can be driven as low as the bottom rail, facilitating nonloading voltage-tocurrent conversion as well as minimizing dark current in photodiode applications. The ADL5315 also features adjustable input current limiting using an external resistor from RLIM to VPOS. The maximum current sourced by INPT (and IOUT) can be set between 1 mA and 16 mA, beyond which the voltage at INPT falls rapidly from its setpoint. Connecting RLIM directly to VPOS provides basic input short-circuit protection with the default current limit of 16 mA typical. The ADL5315 is available in a 2 mm × 3 mm, 8-lead LFCSP and is specified for operation from −40°C to +85°C. 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 rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 ©2005–2017 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com ADL5315 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 9/2017—Rev. 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 10/2005—Revision 0: Initial Version Rev. A | Page 2 of 17 Data Sheet ADL5315 SPECIFICATIONS VPOS = 5 V, VSET = 4 V, IINPT = 3 µA, TA = 25°C, unless otherwise noted. Table 1. Parameter CURRENT MIRROR OUTPUT Current Gain from INPT to IOUT Current Gain from INPT to IOUT Nonlinearity Small Signal Bandwidth Wideband Noise at IPDM Specified Output Voltage Range IOUT × ROUT Product MIRROR INPUT, VOLTAGE CONTROL Specified Input Current Range, IINPT Specified VSET Voltage Range Incremental Gain from VSET to INPT Incremental Input Resistance at VSET Input Bias Current at VSET SREF Voltage, Relative to VPOS OVERCURRENT PROTECTION INPT Current Limit POWER SUPPLY Supply Voltage Range Quiescent Current Conditions IOUT (Pin 8) −40°C < TA < +85°C 3 nA < IPD < 3 mA IINPT = 3 nA IINPT = 3 µA IINPT = 3 µA, CSET = 2.2 nF Min Typ Max 0.99 0.97 1.00 1.00 0.25 1 1 20 1.01 1.03 1.00 0 IINPT = 3 µA INPT (Pin 1), VSET (Pin 2), SREF (Pin 3) Flows from INPT pin 2.7 V < VPOS < 6.5 V 6.5 V < VPOS < 8 V 0.2 V < VSET < 7.0 V VSET = 4.0 V VSET = 4.0 V 2.7 V < VPOS < 8 V VINPT drops to 0 V, RLIM = 0 Ω VINPT drops to 0 V, RLIM = 3 kΩ VPOS (Pin 6) VPOS − 1 900 3n 0 VPOS − 6.5 0.98 −0.97 16 8 9.6 mA mA 1.8 8.3 8 2.2 10.2 V mA mA −1.04 6.4 2.7 IINPT = 3 µA IINPT = 3 mA Rev. A | Page 3 of 17 A/A % kHz MHz nA rms V V A V V V/V GΩ pA V 1 >100