MIRIN CURRENT LIMIT DS3920 R AGC ROSA

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1 General Description The DS39 precision current mirror is designed for avalanche photodiode (APD) and PIN photodiode biasing and monitoring applications. The device offers a current clamp to limit current through the APD and a current mirror output that produces a signal proportional (5:) to the APD current. A diode is also provided to limit the voltage at the current mirror output. The device accepts a +.97V to +76V current mirror supply voltage. Internal current limiting (4.4mA or ma, typ) protects the monitored device from a short circuit to ground. The provided internal clamp diode protects the current mirror output from overvoltage. Additionally, the device features thermal shutdown if the die temperature reaches +5NC. The device is available in a 6-pin SOT3 package, and operates over the -4NC to +85NC extended temperature range. Features S Wide Voltage Input Range:.97V to 76V S Current Monitor Wide 5nA to ma Range 5: Mirror Ratio Fast 5ns Time Constant S Current Clamp (4.4mA or ma, typ) S Voltage Clamp Protects Subsequent Output Circuitry S 6-Pin SOT3 (MAX47 Compatible) Applications Avalanche Photodiode (APD) Biasing PIN Photodiode Monitoring GEPON, GPON, GEPON, XGPON: ONU and OLT Ordering Information appears at end of data sheet. Typical Application Circuit APD BIAS 3.3V DIODE CURRENT MONITOR R FILTER Ω Ω C FILTER.μF I MIROUT I MIROUT /5 GND THERMAL SHUTDOWN MIROUT CURRENT LIMIT DS39 MIR I MIROUT /5 V OUT R OUT kω R AGC 499Ω ROSA APD TIA For related parts and recommended products to use with this part, refer to: For pricing, delivery, and ordering information, please contact Maxim Direct at , or visit s website at ; Rev ; /

2 ABSOLUTE MAXIMUM RATINGS Voltage Range on, MIROUT, and DIODE Relative to GND...-.3V to +8 Voltage Range on MIR Relative to GND V to (V DIODE +.6V) Continuous Power Dissipation (T A = +7NC) SOT3 (derate 3.4mW/NC above +7NC)...7.4mW Operating Junction Temperature Range... -4NC to +5NC Storage Temperature Range NC to +35NC Lead Temperature (soldering, s)...+3nc Soldering Temperature (reflow)...+6nc Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V =.97V to 76V, T A = -4NC to +85NC, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Voltage V V Current I I MIROUT =.5mA 4.4 ma Diode Forward Current I DF 5 ma I DF = FA, T A = +5NC.6 Diode Forward Voltage V DF I DF = 5mA, T A = +5NC.5 V DS39T- version, T A = +5NC 4 MIROUT Current Limit I MIROUT DS39T- version, T A = +5NC ma MIROUT Series Resistance R AGC (Note ) W FA to.5ma.9.. MIR to MIROUT Ratio K MIR I MIROUT >.5mA.8.. A/A Power-Supply Rejection Ratio (DI MIR /I MIR ) V = 3V (Note ) 48 5, /DV V = 3 or 6 (Notes, 3) 5 ppm/v MIR Current Rise Time (%/8%) t RC (Note 4) 3 ns Thermal Shutdown Temperature T SHDN (Note 3) +5 NC Thermal Shutdown Hysteresis T HYST (Note 3) NC Note : See the Typical Application Circuit. Note : V DC change applied to ; FA at MIROUT; 4.99kI load to ground on MIR. Note 3: Guaranteed by design; not production tested. Note 4: Rising MIROUT transition from FA to ma; 5V < V OUT < 76V.

3 Typical Operating Characteristics (T A = +5 C, unless otherwise noted.) CURRENT vs. VOLTAGE I MIROUT =.5mA DS39 toc CURRENT vs. MIROUT CURRENT V = 4 DS39 toc I (ma) I (ma). I MIROUT = µa V (V).... I MIROUT (ma) I (ma) CURRENT vs. TEMPERATURE I MIROUT =.5mA. I MIROUT = µa V = TEMPERATURE ( C) DS39 toc3 GAIN ERROR (%) GAIN ERROR vs. MIROUT CURRENT 5 V = I MIROUT (ma) DS39 toc4 GAIN ERROR (%) GAIN ERROR vs. TEMPERATURE 5 4 I MIROUT = µa 3 I MIROUT =.5mA - I MIROUT = 5µA - I MIROUT = ma -3-4 V = TEMPERATURE ( C) DS39 toc5 GAIN ERROR (%) GAIN ERROR vs. VOLTAGE I MIROUT = µa I MIROUT =.5mA I MIROUT = 5mA I MIROUT = ma V (V) DS39 toc6 3

4 Typical Operating Characteristics (continued) (T A = +5 C, unless otherwise noted.) TRANSIENT RESPONSE (V = 4) DS39 toc7 (V BIAS = 4, I MIROUT = µa) DS39 toc8 (V = 4, I MIROUT =.5mA) DS39 toc9 A 4 R R 38MΩ 4 R R 5.6kΩ 4 B kω 5ns/div A:, V/div, I MIROUT = 375µA TO 7.5mA A: ; 5V/div, I MIR = 75µA TO.5mA : /div : /div : /div : /div (V = 5V, I MIROUT = µa) DS39 toc (V = 5V, I MIROUT =.5mA) DS39 toc 5V R R 4.6MΩ 5V R R.7kΩ : V/div : V/div : V/div : V/div 4

5 Typical Operating Characteristics (continued) (T A = +5 C, unless otherwise noted.) A SHORT-CIRCUIT RESPONSE (V = 4) DS39 toc T A = +4 C A B C D E F A SHORT-CIRCUIT RESPONSE (V = 76V) DS39 toc3 T A = +4 C A B C D E F V - VMIROUT (V) VOLTAGE DROP vs. MIROUT CURRENT V =.97V T A = -4 C T A = +5 C T A = + C DS39 toc4 ms/div : I MIROUT, 5mA/div A: MIROUT SHORTS TO GND THROUGH Ω B: CURRENT LIMIT ACTIVE C: THERMAL SHUTDOWN D: POST COOL-DOWN REENTRY E: THERMAL SHUTDOWN F: POST COOL-DOWN REENTRY ms/div : I MIROUT, 5mA/div A: MIROUT SHORTS TO GND THROUGH Ω B: CURRENT LIMIT ACTIVE C: THERMAL SHUTDOWN D: POST COOL-DOWN REENTRY E: THERMAL SHUTDOWN F: POST COOL-DOWN REENTRY. T A = +85 C... I MIROUT (ma) TOP VIEW DIODE GND MIR Pin Configuration + 6 DS39 5 N.C. 3 4 MIROUT SOT3 PIN NAME FUNCTION Pin Description DIODE Protection Diode. External potential used for voltage clamping of V MIR. If unused, this pin can be left unconnected. GND Ground 3 MIR Mirror Current Monitor Output, 5: Ratio 4 MIROUT Current Mirror Voltage Output. Connect to photodiode bias pin. Photodiode provides reference current for the mirror. 5 N.C. No Connection. Not internally connected. 6 Current Voltage Bias 5

6 Detailed Description The DS39 provides a fast, precision current mirror for photodiode-monitoring applications. The current mirror is accurate across a large dynamic range. The mirror response time is fast enough to comply with GPON Rx burst-mode monitoring requirements. The device has a built-in current limiting feature to protect photodiodes from large signal inputs, and an included thermal shutdown. A diode is provided to limit the voltage at the MIR output. Current Mirror The mirror output is typically connected to an analogto-digital converter (ADC) using a resistor to convert the mirrored current into a voltage. The resistor to ground should be selected so that the ADC s full-scale voltage is reached when the maximum mirrored current is reached. For example, given that the maximum monitored current through the APD is ma,.5v ADC full scale, and a 5: mirror ratio, the correct resistor is approximately 3.kI. The mirror response time is dominated by the amount of capacitance placed on the output. Current Clamp The device features a current clamping circuit to protect the photodiode by limiting the amount of current from MIROUT to no more than I MIROUT. See the Ordering Information for available current clamp options. Diode Protection A diode is internally connected from the MIR to DIODE pins. This enables an external voltage applied to DIODE to limit the voltage on MIR. The voltage applied to DIODE should be equal to the desired V MIR limit minus the diode forward voltage drop, or V MIR - V DF. Thermal Shutdown As a safety feature, the device has a thermal shutdown circuit that turns off the MIROUT and MIR currents when the internal die temperature exceeds T SHDN. The thermal shutdown mechanism has a built-in hysteresis of T HYST. Thus, the MIROUT and MIR currents resume once the device has cooled to T SHDN - T HYST. Ordering Information PART TEMP RANGE TYP CURRENT LIMIT (ma) PIN-PACKAGE DS39T-+ -4NC to +85NC 6 SOT3 DS39T-+T -4NC to +85NC 6 SOT3 DS39T-+ -4NC to +85NC SOT3 DS39T-+T -4NC to +85NC SOT3 +Denotes a lead(pb)-free/rohs-compliant package. T = Tape and reel. Package Information For the latest package outline information and land patterns (footprints), go to Note that a +, #, or - in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 6 SOT3 U6SN

7 REVISION NUMBER REVISION DATE DESCRIPTION Revision History PAGES CHANGED 3/ Initial release 8/ Changed the MIROUT - version current limit value from.9ma (typ) to 4.4mA (typ); updated the Electrical Characteristics I MIROUT values for - version from ma (min),.9ma (typ), 4.4mA (max) to.8ma (min), 4.4mA (typ), 8mA (max) and added T A = +5 C test conditions / Added R FILTER and R OUT resistor values to the Typical Application Circuit,, 6 cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a product. No circuit patent licenses are implied. reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. 6 Rio Robles, San Jose, CA 9534 USA Products, Inc. and the logo are trademarks of Products, Inc.