19-2742; Rev 1; 5/03 High-Accuracy, High-Side Current Monitors in SOT23 Applications Photodiode Current-Monitoring Systems Features ♦ Wide Reference Current Dynamic Range Guaranteed 250nA to 2.5mA with 5% Accuracy Extended 10nA to 10mA with 10% Monitor Accuracy ♦ Current (MAX4004) or Voltage (MAX4006) Monitor Output ♦ Reference Current-Limit Protection (20mA, typ) ♦ Voltage Clamp Protects Subsequent Output Circuitry ♦ +2.7V to +22V Wide Voltage Range Operation ♦ 6-Pin SOT23 Packages Ordering Information TOP MARK PART TEMP RANGE PIN-PACKAGE MAX4004EUT-T -40°C to +85°C 6 SOT23-6 ABNL MAX4006EUT-T -40°C to +85°C 6 SOT23-6 ABNN Portable Instrumentation Medical Instrumentation Laboratory Instrumentation Consumer Electronics Current-to-Voltage Conversion Pin Configuration Level Translation Selector Guide INTERNAL TYPICAL RESISTOR ACCURACY PART PIN-PACKAGE MAX4004EUT-T 6 SOT23-6 None 5% MAX4006EUT-T 6 SOT23-6 10kΩ 1% TOP VIEW CLAMP 1 GND 2 MAX4004 MAX4006 OUT 3 Typical Operating Circuit appears at end of data sheet. 6 BIAS 5 N.C. 4 REF SOT23 ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX4004/MAX4006 General Description The MAX4004/MAX4006 precision, high-side, current monitors are specifically designed for monitoring photodiode current in fiber applications. They offer a connection point for the reference current and a monitor output that produces a signal proportional to the reference current. The monitor output of the MAX4004 is a current proportional to the reference current. The monitor output of the MAX4006 is a voltage proportional to the reference current. The current monitors have six decades of dynamic range and monitor reference current of 250nA to 2.5mA with better than 5% accuracy. The photodiode current can be monitored from 10nA to 10mA with reduced accuracy. The MAX4004/MAX4006 accept a +2.7V to +22V supply voltage, suitable for PIN photodiode applications. (For higher voltage applications, refer to the MAX4007/ MAX4008 data sheet.) Internal current limiting (20mA, typ) protects the device against short-circuit-to-ground or excessive current conditions. A clamp diode protects the monitor output from overvoltage. Additionally, these devices feature thermal shutdown if the die temperature reaches +150°C. The MAX4004/MAX4006 are available in tiny, spacesaving 6-pin SOT23 packages, and operate over the extended temperature range of -40°C to +85°C. MAX4004/MAX4006 High-Accuracy, High-Side Current Monitors in SOT23 ABSOLUTE MAXIMUM RATINGS CLAMP to GND ......................................................-0.3V to +25V BIAS, REF to GND ..................................................-0.3V to +25V OUT to GND .........................................-0.3V to (VCLAMP + 0.6V) Short-Circuit, REF to GND..........................................Continuous Current into any Pin ..........................................................±30mA Continuous Power Dissipation (TA = +70°C) 6-Pin SOT23 (derate 8.7mW/°C above +70°C)............696mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C 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 (VBIAS = 5V, GND = 0V, REF = Open, VOUT = 0V (MAX4004), CLAMP = Open, TA = -40°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL Bias Voltage Range VBIAS Bias Quiescent Current IBIAS Reference Voltage VREF CONDITIONS Inferred from power-supply rejection test TYP 2.7 MAX UNITS 22 V IREF = 250nA 40 100 µA IREF = 2.5mA 3.6 4 mA VBIAS - 0.8 V TSHDN REF shorted to GND, junction temperature rising 150 °C Trip-Point Temperature Hysteresis THYS REF shorted to GND, junction temperature falling 5 °C Input Current Limit ILIM VREF = VBIAS - 5V 20 mA Thermal Shutdown Engage Temperature IREF = 2.5mA f = 0.1Hz to 10Hz MAX4004 Output Current Noise iNOUT f = 0.1Hz to 10kHz f = 0.1Hz to 10Hz MAX4006 Output Voltage Noise eNOUT f = 0.1Hz to 10kHz Output Resistance ROUT Output Leakage Output Voltage Range 2 MIN VOUT MAX4004 VBIAS - 1.1 IREF = 250nA 0.3 IREF = 2.5mA 63 IREF = 250nA 9.2 IREF = 2.5mA 1240 IREF = 250nA 0.041 IREF = 2.5mA 0.63 IREF = 250nA 1.3 pARMS µVRMS IREF = 2.5mA 12.5 IREF = 250nA 50 GΩ IREF = 2.5mA 5 MΩ MAX4006 10 kΩ REF = open 1 pA 0 to VBIAS - 0.85 V VBIAS = 2.7V to 22V, IREF = 0 to 1mA, MAX4004: ∆IOUT/IOUT = ±1%, MAX4006: ∆VOUT/IOUT = ±1% 0 to VBIAS - 1.5 _______________________________________________________________________________________ High-Accuracy, High-Side Current Monitors in SOT23 (VBIAS = 5V, GND = 0V, REF = Open, VOUT = 0V (MAX4004), CLAMP = Open, TA = -40°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER Output Clamp Voltage SYMBOL MIN VOUT VCLAMP Output Clamp Leakage MAX4004 Current Gain CONDITIONS VOUT/IREF 1 0.099 0.11 IREF = 2.5mA 0.094 0.095 0.106 0.9 0.995 1.1 IREF = 2.5mA 0.95 0.998 1.05 Power-Up Settling Time MAX4004: VBIAS = 2.7V to 22V (∆VOUT/VOUT) /∆VBIAS MAX4006: VBIAS = 2.7V to 22V tS V/mA 0.992 IREF = 250nA 50 1000 IREF = 1mA 50 1000 IREF = 1mA 50 1000 IOUT settles within 0.1%, IREF = 250nA CIN = 10nF between IREF = 2.5mA REF and GND mA/mA 0.098 IREF = 250nA IREF = 10mA, VBIAS = 12V Power-Supply Rejection Ratio (PSRR) pA 0.09 (∆IOUT/IOUT) /∆VBIAS UNITS V IREF = 250nA IREF = 10mA, VBIAS = 12V MAX4006 Transimpedance Gain MAX 0.6 VCLAMP = 0 to 22V IOUT/IREF TYP ppm/V 7.5 ms 90 µs Note 1: All devices are 100% tested at room temperature (TA = +25°C). All temperature limits are guaranteed by design. _______________________________________________________________________________________ 3 MAX4004/MAX4006 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) 1 IREF = 250nA 10 BIAS CURRENT (mA) VBIAS = 5V BIAS CURRENT (mA) IREF = 2.5mA MAX4004/6 toc02 10 MAX4004/6 toc01 10 1 0.1 0.01 8 14 26 20 100n 1µ 10µ 100µ 0.1 10m 1m -40 -15 IREF (A) VBIAS = 5V 4 3 60 GAIN ERROR vs. TEMPERATURE 1 0 -1 VBIAS = 5V IREF = 10nA 0.5 0 GAIN ERROR (%) 2 -0.5 -1.0 IREF = 250nA -1.5 IREF = 2.5µA -2.0 -2 -2.5 -3 -3.0 -4 -3.5 -5 IREF = 250µA IREF = 2.5A IREF = 5mA -4.0 10n 100n 1µ 10µ 100µ 1m 10m -40 -15 10 35 60 IREF (A) TEMPERATURE (°C) GAIN ERROR vs. BIAS VOLTAGE TRANSIENT RESPONSE (VBIAS = 5V) 85 MAX4004/6 toc07 MAX4004/6 toc06 0.2 0 -0.2 IREF = 250nA -0.4 IREF = 25µA IREF 1.0mA/div 0A -0.6 -0.8 IREF = 2.5mA IOUT 0.1mA/div -1.0 0A -1.2 IREF = 5mA -1.4 2 7 12 17 22 400ns/div VBIAS (V) 4 35 1.0 MAX4004/6 toc04 5 10 TEMPERATURE (°C) GAIN ERROR vs. REFERENCE CURRENT GAIN ERROR (%) 1 0.01 10n SUPPLY VOLTAGE (V) GAIN ERROR (%) VBIAS = 5V IREF = 250nA 0.01 2 IREF = 2.5mA MAX4004/6 toc05 0.1 BIAS CURRENT vs. TEMPERATURE BIAS CURRENT vs. REFERENCE CURRENT MAX4004/6 toc03 BIAS CURRENT vs. SUPPLY VOLTAGE BIAS CURRENT (mA) MAX4004/MAX4006 High-Accuracy, High-Side Current Monitors in SOT23 _______________________________________________________________________________________ 85 High-Accuracy, High-Side Current Monitors in SOT23 MAX4004/6 toc09 STARTUP DELAY (VBIAS = 5V, IREF = 2.5mA) MAX4004/6 toc08 STARTUP DELAY (VBIAS = 5V, IREF = 250nA) CH1 CH1 0V CH1 0V VBIAS BIAS D.U.T. REF OUT VBIAS CH1 BIAS D.U.T. REF OUT R1 CH2 CH2 R1 CH2 RREF 13pF CH2 RREF RTEST 13pF 0V RTEST 0V 40ms/div 4ms/div RREF = 1.68kΩ R1 = 0Ω RTEST = 14.0kΩ CH1: 2V/div CH2: 1V/div STARTUP DELAY (VBIAS = 2.7V, IREF = 250nA) CH1 SHORT-CIRCUIT RESPONSE (VBIAS = 5V) MAX4004/6 toc11 MAX4004/6 toc10 STARTUP DELAY (VBIAS = 2.7V, IREF = 2.5mA) MAX4004/6 toc12 RREF = 16.8MΩ R1 = 118MΩ RTEST = 1.67MΩ CH1: 2V/div CH2: 10mV/div TA = +148°C CH1 A 0V CH1 0V VBIAS CH1 CH2 RREF CH2 CH2 RREF 13pF 13pF 0A RTEST RTEST 0V CH1 R1 R1 CH2 C BIAS D.U.T. REF OUT BIAS D.U.T. REF OUT B VBIAS 0V 10ms/div RREF = 8.8MΩ R1 = 0Ω RTEST = 8.1MΩ CH1: 1V/div CH2: 50mV/div 10ms/div RREF = 794Ω R1 = 0Ω RTEST = 4.01kΩ CH1: 1V/div CH2: 200mV/div 20ms/div CH1: IBIAS, 10mA/div A: REF SHORTS TO GND B: CURRENT LIMIT ACTIVE C: THERMAL SHUTDOWN _______________________________________________________________________________________ 5 MAX4004/MAX4006 Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) VOLTAGE DROP vs. REFERENCE CURRENT SHORT-CIRCUIT RESPONSE (VBIAS = 22V) TA = +120°C MAX4004/6 toc14 1.40 MAX4004/6 toc13 VBIAS = 2.7V 1.20 1.00 A B VBIAS - VREF (V) MAX4004/MAX4006 High-Accuracy, High-Side Current Monitors in SOT23 C CH1 0.80 A 0.60 B 0.40 0A C 0.20 A: TA = -40°C B: TA = +25°C C: TA = +85°C D: TA = +100°C D 0 100n 10ms/div 1µ 10µ 100µ 1m 10m REFERENCE CURRENT (A) CH1: IBIAS, 10mA/div A: REF SHORTS TO GND B: CURRENT LIMIT ACTIVE C: THERMAL SHUTDOWN Pin Description PIN 6 NAME FUNCTION MAX4004 MAX4006 1 1 CLAMP 2 2 GND Ground 3 — OUT Current-Monitor Output. OUT sources a current of 1/10th IREF. 4 4 REF Reference Current Output. REF provides the source current to the cathode of the photodiode. 5 5 N.C. No Connection. Not internally connected. 6 6 BIAS Bias Voltage Input. Bias voltage for photodiode. — 3 OUT Current-Monitor Output. OUT presents a voltage proportional to IREF at 1V/mA. An internal 10kΩ resistor connects OUT to GND (see Functional Diagram). Clamp Voltage Input. External potential used for voltage clamping of VOUT. _______________________________________________________________________________________ High-Accuracy, High-Side Current Monitors in SOT23 BIAS BIAS MAX4004 MAX4006 CURRENT MONITOR 10x CURRENT MONITOR 10x 1x 1x CLAMP CLAMP OUT CURRENT CLAMP REF REF GND OUT CURRENT CLAMP 10kΩ GND Detailed Description Applications Information The MAX4004/MAX4006 are versatile current monitors intended for monitoring DC photodiode current in fiber applications (see the Functional Diagram). The MAX4004 output is a current that is exactly one-tenth of the reference current. The MAX4006 outputs a voltage that is proportional to the reference current with a transimpedance gain of 1V/mA achieved by a factorytrimmed, internal 10kΩ resistor. CLAMP provides a means for diode clamping the voltage at OUT, thus VOUT is limited to VCLAMP + 0.6V. CLAMP can be connected to either an external supply, to BIAS, or can be left floating if voltage clamping is not required. Both current devices have six decades of dynamic range and monitor reference current ranging from 250nA to 2.5mA, the nominal operating range, with better than 5% accuracy across the entire reference current, bias voltage, and temperature ranges. The corresponding monitor outputs produce 25nA to 0.25mA (MAX4004) and 0.25mV to 2.5V (MAX4006). When the reference currents are extended to the broader range of 10nA to 10mA, an accuracy of less than 10% is maintained. Internal current limiting (20mA, typ) protects the device against short-circuit-to-ground conditions, and a thermal shutdown feature reduces both the reference current and the monitor current to zero if the die temperature reaches +150°C. The MAX4004/MAX4006 accept a +2.7V to +22V supply voltage, suitable for PIN photodiode applications. A clamping diode, shown in the Functional Diagram, is provided to protect subsequent output circuitry from an overvoltage condition. Clamping the Monitor Output Voltage Using PIN Photodiodes in Fiber Applications When using the MAX4004/MAX4006 to monitor PIN photodiode currents in fiber applications, several issues must be addressed. In applications where the photodiode must be fully depleted, keep track of voltages budgeted for each component with respect to the available supply voltage(s). The current monitor requires as much as 1.2V between BIAS and REF, which must be considered as part of the overall voltage budget. Additional voltage margin can be created if a negative supply is used in place of a ground connection, as long as the overall voltage drop experienced by the MAX4004/MAX4006 is less than or equal to 22V. For this type of application, the MAX4004 is suggested so the output can be referenced to “true” ground and not the negative supply. The MAX4004’s output current can be referenced as desired with either a resistor to ground or a transimpedance amplifier. Take care to ensure that output voltage excursions do not interfere with the required margin between BIAS and OUT. _______________________________________________________________________________________ 7 MAX4004/MAX4006 Functional Diagrams MAX4004/MAX4006 High-Accuracy, High-Side Current Monitors in SOT23 In many fiber applications, OUT is connected directly to an ADC that operates from a supply voltage that is less than the voltage at BIAS. Connecting the MAX4004/MAX4006’s clamping diode output, CLAMP, to the ADC power supply helps avoid damage to the ADC. Without this protection, voltages can develop at OUT that can destroy the ADC. This protection is less critical when OUT is connected directly to subsequent transimpedance amplifiers (linear or logarithmic) that have low-impedance, near-ground-referenced inputs. If a transimpedance amp is used on the low side of the photodiode, its voltage drop must also be considered. Leakage from the clamping diode is most often insignificant over nominal operating conditions, but grows with temperature. To maintain low levels of wideband noise, lowpass filtering the output signal is suggested in applications where only DC measurements are required. Determining the required filtering components is straightforward, as the MAX4004 exhibits a very high output impedance (>5MΩ), while the MAX4006 exhibits an output resistance of 10kΩ. In some applications where pilot tones are used to identify specific fiber channels, higher bandwidths are desired at OUT to detect these tones. Consider the minimum and maximum currents to be detected, then consult the frequency response and noise typical operating curves. If the minimum current is too small, insufficient monitor bandwidth could result, while too high of a current could result in excessive monitor noise across the desired bandwidth. See the MAX4009 family for devices intended for fiber applications using pilot tones. 8 Bypassing and External Components In applications where power-supply noise can interfere with DC diode measurements, additional filtering is suggested. Such noise is commonly seen when switching power supplies are used to generate the photodiode bias voltage. As shown in the typical operating circuit, a pi filter (two 0.22µF capacitors and one 2.2µH inductor) greatly suppress power-supply switching noise. If such a filter is already present in the bias-generating circuit, only a simple bypass capacitor at the BIAS pin is suggested. The output lowpass filter, a 10kΩ resistor and a 10nF capacitor, further reduce permeating power-supply noise as well as other wideband noise that might otherwise restrict measurements at low signal levels. Again, reducing the bandwidth of the OUT signal can affect performance of pilot-tone systems. To restrict high-frequency photodiode signals from affecting the current monitor and BIAS power supply, an RF choke and 10nF capacitor can be added. The capacitance presented to REF should not exceed 10nF; larger values increase startup time and could cause the thermal shutdown circuit to activate during startup. _______________________________________________________________________________________ High-Accuracy, High-Side Current Monitors in SOT23 +2.7V TO +22V 2.2µH 0.22µF 0.22µF BIAS +5V CURRENT MONITOR 10x 1x CLAMP CURRENT CLAMP REF +5V OUT ADC 10kΩ MAX4004 10nF GND PIN PHOTODIODE TIA TO LIMITING AMPLIFIER HIGH-SPEED DATA PATH Chip Information TRANSISTOR COUNT: 195 PROCESS: BiCMOS _______________________________________________________________________________________ 9 MAX4004/MAX4006 Typical Operating Circuit Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) 6LSOT.EPS MAX4004/MAX4006 High-Accuracy, High-Side Current Monitors in SOT23 PACKAGE OUTLINE, SOT-23, 6L 21-0058 F 1 1 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.