Datasheet AD8304 (Analog Devices) - 3

AD8304 ABSOLUTE MAXIMUM RATINGS* PIN FUNCTION DESCRIPTIONS
Supply Voltage VP – VN . 8 V Input Current . 20 mA
Pin No. Mnemonic Function
Internal Power Dissipation . 270 mW 1 VNEG Optional Negative Supply, VN. This ␪JA . 150°C/W pin is usually grounded; for details of Maximum Junction Temperature . 125°C usage, see Applications section. Operating Temperature Range . –40°C to +85°C 2 PWDN Power-Down Control Input. Device is Storage Temperature Range . –65°C to +150°C active when PWDN is taken LOW. Lead Temperature Range (Soldering 60 sec) . 300°C 3, 5 VSUM Guard Pins. Used to shield the INPT *Stresses above those listed under Absolute Maximum Ratings may cause perma- current line. nent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational 4 INPT Photodiode Current Input. Usually section of this specification is not implied. Exposure to absolute maximum rating connected to photodiode anode (the conditions for extended periods may affect device reliability. photo current flows toward INPT). 6 VPDB Photodiode Biaser Output. May be connected to photodiode cathode to provide adaptive bias control.
PIN CONFIGURATION
7 VREF Voltage Reference Output of 2 V 8 VLOG Output of the Logarithmic Front-End
VNEG 1 14 ACOM
Processor; ROUT = 5 kΩ to ground.
PWDN 2 13 BFNG
9 BFIN Buffer Amplifier Noninverting Input
VSUM 3 12 VPS1 AD8304
(High Impedance)
INPT 4 TOP VIEW 11 VOUT (Not to Scale)
10 VPS2 Positive Supply, V
VSUM 10
P (3.0 V to 5.5 V)
5 VPS2 VPDB 9
11 VOUT Buffer Output; Low Impedance
6 BFIN VREF 7 8 VLOG
12 VPS1 Positive Supply, VP (3.0 V to 5.5 V) 13 BFNG Buffer Amplifier Inverting Input 14 ACOM Analog Ground
ORDERING GUIDE Model Temperature Range Package Description Package Option
AD8304ARU –40°C to +85°C Tube, 14-Lead TSSOP RU-14 AD8304ARU-REEL 13" Tape and Reel AD8304ARU-REEL7 7" Tape and Reel AD8304-EVAL Evaluation Board
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the
WARNING!
AD8304 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended
ESD SENSITIVE DEVICE
to avoid performance degradation or loss of functionality. REV. A –3– Document Outline FEATURES APPLICATIONS PRODUCT DESCRIPTION FUNCTIONAL BLOCK DIAGRAM SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION PIN FUNCTION DESCRIPTIONS ORDERING GUIDE Typical Performance Characteristics BASIC CONCEPTS Optical Measurements Decibel Scaling GENERAL STRUCTURE Bandwidth and Noise Considerations Chip Enable USING THE AD8304 Slope and Intercept Adjustments Low Supply Slope and Intercept Adjustment Using the Adaptive Bias Changing the Voltage at the Summing Node Implementing Low-Pass Filters Operation in Comparator Modes Using a Negative Supply APPLICATIONS Summing Node at Ground and Voltage Inputs Providing Negative Outputs and Rescaling Inverting the Slope Programmable Level Comparator with Hysteresis Programmable Multidecade Current Source Characterization Setups and Methods Evaluation Board OUTLINE DIMENSIONS Revision History