ADI ADL5315ACPZ-R7

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 current - input 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. The VSET input has very low input current and can be driven as low as the bottom rail, facilitating nonloading voltage - to - current 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.

• Accurately mirrors input current (1:1 ratio) over 6 decades
• Linearity ±7% 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)

• Optical power monitoring from a single photodiode
• General voltage biasing with precision current monitoring
• Voltage - to - current conversion