19-4186; Rev 0; 7/08 KIT ATION EVALU E L B AVAILA Remote Antenna Current-Sense Amplifier and Switches Features The MAX16913/MAX16913A high-voltage high-side current-sense switches feature internal current limiting to prevent system damage due to fault conditions. The MAX16913/MAX16913A input voltage range extends from 5V to 18V, making them ideal for providing phantom power to remote radio-frequency low-noise amplifiers (LNAs) in automotive applications. ♦ Switch Phantom Power-On/-Off Under µC Control The MAX16913/MAX16913A monitor the load current and provide an analog output voltage proportional to the sensed load current. In addition to current sensing, accurate internal current-limiting circuitry protects the input supply against both overload and short-circuit conditions. Two open-drain fault indicator outputs notify the microprocessor when a short circuit, an open-load condition, or a short-to-battery condition exists. For the MAX16913A, the open-load threshold is externally adjustable using a resistive divider. A fault-blanking feature enables the circuit to ignore momentary faults, such as those caused by the initial charging of a capacitive load when hot swapping, preventing false alarms to the system. Built-in thermaloverload protection turns off the switch when the die temperature exceeds +150°C (min). The MAX16913/ MAX16913A also feature a short-to-battery detection every time the internal switch turns on. These devices provide an active-high control input to put the devices in low-power shutdown mode. The MAX16913/MAX16913A are available in the 16-pin QSOP package and operate over the -40°C to +105°C temperature range. ♦ Overcurrent Blanking During Startup ♦ Analog Current Measurement Output ♦ Adjustable Current Limiting (340mA Maximum) ♦ Detect Open-Load and Short-Circuit Conditions ♦ Provide Open-Drain Fault Signals (SC and OL) ♦ Thermal Shutdown ♦ AEC-Q100 Qualified (/V Versions Only) ♦ -40°C to +105°C Operating Temperature Range Typical Operating Circuits TO PROTECTED LOAD (LNA) BATTERY INPUT IN SENS OUT REF 3.3V TO 5V MAX16913 OLT SC OL Applications SHDN GND AOUT TO ADC INPUT Remote LNA Phantom Power Automotive Safety and Infotainment TO PROTECTED LOAD (LNA) BATTERY INPUT Ordering Information TEMP RANGE PART PINOPEN-LOAD PACKAGE THRESHOLD MAX16913GEE+ -40°C to +105°C 16 QSOP MAX16913GEE/V+* -40°C to +105°C 16 QSOP Internally Set MAX16913AGEE+ -40°C to +105°C 16 QSOP Externally Adjustable MAX16913AGEE/V+* -40°C to +105°C 16 QSOP Externally Adjustable IN SENS OUT REF 3.3V TO 5V Internally Set MAX16913A OLT SC +Denotes a lead(Pb)-free/RoHS-compliant package. */V denotes an automotive qualified part. OL SHDN GND AOUT TO ADC INPUT Pin Configuration appears at end of data sheet. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX16913/MAX16913A General Description MAX16913/MAX16913A Remote Antenna Current-Sense Amplifier and Switches ABSOLUTE MAXIMUM RATINGS IN to GND ............................................….…………-0.3V to +42V OUT to GND ...........................................................-0.3V to +42V SENS to IN.............................................................-0.3V to +0.3V SC, OL, SHDN, OLT, AOUT to GND..................…-0.3V to +6.0V Current into Any Pin Except OUT and SENS....................±20mA Current into SENS and OUT ...........................................±340mA Continuous Power Dissipation (TA = +70°C) 16-Pin QSOP (derate 18.2mW/°C above +70°C)....1454.5mW Junction-to-Case Thermal Resistance (θJC) (Note 1) ......25°C/W Junction-to-Ambient Thermal Resistance (θJA) (Note 1) .....55°C/W Operating Temperature Range .........................-40°C to +105°C Junction Temperature........................................-40°C to +150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. 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 (VIN = +9V to +18V, TA = TJ = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 18 V 0.6 1.2 mA GENERAL Operating Input Voltage Range VIN Quiescent Supply Current ICC VSHDN < 0.4V Shutdown Supply Current ISD VSHDN > 1.7V, TA = +25°C (VIN - VSENS) to VAOUT Gain Av VAOUT/(VIN - VSENS) 13 V/V AOUT Maximum Voltage (VIN - VSENS) > 300mV 4.3 V AOUT Zero-Current Output Voltage (VIN - VSENS) = 0 340 400 460 ILOAD = ISC, (VIN - VSENS) = 100mV 1.5 1.7 1.9 ILOAD = 2 x ISC, (VIN - VSENS) = 200mV 2.7 3 3.3 AOUT Voltage AOUT Output Impedance Switch Dropout Voltage 5 5 ZAOUT VD Thermal Shutdown Threshold TSHDN Thermal Shutdown Hysteresis THYST Reference Output Voltage VREF Reference Output Impedance ZREF 5 Measured between SENS and OUT while sourcing 100mA Temperature rising 2.7 mV V kΩ 0.6 +150 µA V +164 °C 15 °C 3 3.3 5 V kΩ THRESHOLDS RSENSE = 1Ω (VOLT = 0.66V for the MAX16913 only) 10 VOLR (MAX16913A only) 10 VSC RSENSE = 1Ω 87 VLIM At current limit, VIN = 14V VIN rising Open-Load Current Threshold IOL Nominal Open-Load Threshold Setting Range Short-Circuit Voltage Threshold Voltage between IN and SENS 20 30 mA 50 mV 100 110 mV 173 200 225 mV 18 21 24 Overvoltage Shutdown Threshold VOVLO Overcurrent Blanking Time tBLANK 100 200 ms Retry Time tRETRY 1500 3000 ms 2 _______________________________________________________________________________________ V Remote Antenna Current-Sense Amplifier and Switches (VIN = +9V to +18V, TA = TJ = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS LOGIC LEVELS SC, OL Output-Voltage Low VOL SC, OL Output-Leakage Current Sink current = 1mA ILEAK SHDN Input Low Voltage VIL SHDN Input High Voltage VIH 0.4 VSC = VOL = 5V V 0.01 µA 0.4 V 1.7 V TIMING Startup Response Time tST SHDN falling edge to 90% of VIN, no load 100 µs Typical Operating Characteristics (VIN = 14V, RSENSE = 1Ω, TA = +25°C, unless otherwise noted.) 650 700 4 550 500 500 400 450 300 10 35 60 85 105 4 6 8 10 12 14 16 -15 10 35 60 TEMPERATURE (°C) AOUT GAIN vs. TEMPERATURE (VSENSE - VOUT) vs. TEMPERATURE (VSENSE - VOUT) vs. VIN MAX16913/3A toc04 0.8 0.4 0.2 12.5 10 35 60 TEMPERATURE (°C) 85 105 105 16 18 IOUT = 90mA 0.6 0.4 0.2 0 12.0 0.8 VSENSE - VOUT (V) 0.6 VSENSE - VOUT (V) 13.0 IOUT = 90mA 85 MAX16913/3A toc06 VIN (V) 13.5 -15 -40 18 TEMPERATURE (°C) 14.0 -40 2 0 200 -15 3 1 MAX16913/3A toc04 400 -40 ISD (μA) ICC (μA) ICC (μA) VIN = 14V 600 600 AV (V/V) 5 MAX16913/3A toc02 800 MAX16913/3A toc01 700 SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE OPERATING SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX16913/3A toc03 OPERATING SUPPLY CURRENT vs. TEMPERATURE 0 -40 -15 10 35 60 TEMPERATURE (°C) 85 105 4 6 8 10 12 14 VIN (V) _______________________________________________________________________________________ 3 MAX16913/MAX16913A ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (VIN = 14V, RSENSE = 1Ω, TA = +25°C, unless otherwise noted.) 250 250 200 1 0 20 30 40 50 60 70 80 150 90 100 150 100 100 50 50 0 -40 -1 10 200 tBLANK (ms) tBLANK (ms) 2 MAX16913/3A toc09 3 300 MAX16913/3A toc08 300 MAX16913/3A toc07 4 OVERCURRENT BLANKING TIME vs. VIN OVERCURRENT BLANKING TIME vs. TEMPERATURE TOTAL CURRENT MEASUREMENT ERROR vs. (VIN - VSENSE) TOTAL CURRENT MEASUREMENT ERROR (%) 0 -15 VIN - VSENSE (mV) 10 35 60 85 105 4 6 8 10 TEMPERATURE (°C) MAX16913/3A toc11 MAX16913/3A toc10 5V/div SHDN 5V/div SHDN 5V/div SC 100mA/div 100mA/div IOUT IOUT 20ms/div 400ms/div CURRENT-LIMIT VOLTAGE vs. VIN MAX16913/3A toc12 250 200 150 100 50 0 4 6 8 10 12 14 16 18 VIN (V) 4 12 VIN (V) TURN-ON INTO CAPACITIVE LOAD (OUTPUT STAYS ON) (CLOAD = 1000µF) OVERCURRENT SHUTDOWN VIN - VSENSE (mV) MAX16913/MAX16913A Remote Antenna Current-Sense Amplifier and Switches _______________________________________________________________________________________ 14 16 18 Remote Antenna Current-Sense Amplifier and Switches PIN NAME FUNCTION 1, 8, 9, 16 GND 2 IN 3, 4 SENS Input to Current-Sense Amplifier. Connect the sense resistor between SENS and IN. 5, 6 OUT Switch Output 7 SHDN 10 N.C. No Connection. Not internally connected. 11 OLT Open-Load Threshold Setting Input. A resistive divider between REF, OLT, and GND sets the open-load current threshold (MAX16913A). For the MAX16913, connect OLT to GND. 12 REF +3V Nominal Reference Output. Use a resistive divider between REF, OLT, and ground to set the open-load current threshold (MAX16913A). The output impedance of this voltage regulator is 5kΩ. 13 AOUT 14 OL Open-Drain Open-Load Indicator Output. OL goes low when the load current is lower than the open-load current threshold, or when there is a short-to-battery fault. Connect OL to a 10kΩ pullup resistor. See Table 1. 15 SC Open-Drain Short-Circuit Indicator Output. SC goes low when the load current is greater than the short-circuit current threshold or when there is a short-to-battery fault. Connect SC to a 10kΩ pullup resistor. See Table 1. Ground Input Voltage. Bypass IN to GND with a low-ESR ceramic capacitor with a minimum value of 0.1µF. Active-High Control Input. Drive SHDN low to turn on the device. Current-Monitor Voltage Output. AOUT can be used to measure the load current by means of an external ADC. The output impedance is 5kΩ. MAX16913 Functional Diagram MAX16913A Functional Diagram SENS SENS OUT MAX16913 OUT MAX16913A IN IN CURRENT SENSE CURRENT SENSE SHDN SHDN CHARGE PUMP FET DRIVER AND CONTROL CHARGE PUMP FET DRIVER AND CONTROL AOUT AOUT OT OT REF REF VREF VREF REF REF SC SC VREF2 VREF2 OL OL OLT GND OLT GND _______________________________________________________________________________________ 5 MAX16913/MAX16913A Pin Description MAX16913/MAX16913A Remote Antenna Current-Sense Amplifier and Switches Detailed Description The MAX16913/MAX16913A high-voltage, high-side, current-sense switches feature internal current limiting to prevent system damage due to fault conditions. The MAX16913/MAX16913A input voltage range extends from 5V to 18V, making them ideal for providing phantom power to remote radio-frequency low-noise amplifiers (LNAs) in automotive applications. High-side current monitoring does not interfere with the ground path of the load being measured, making these devices particularly useful in a wide range of high-voltage battery-powered systems. The MAX16913/MAX16913A monitor the load current by means of a high-side current-sense amplifier and provide an analog output voltage proportional to that current at AOUT. The devices combine a high-side current-sense amplifier, an internal switch, a +3V bandgap reference, and two open-drain fault indicator outputs. These features enable the design of remote power circuits with shortcircuit, short-to-battery, and thermal protection. For the MAX16913A, the open-load threshold is externally adjustable using a resistive divider. A fault-blanking feature enables the circuit to ignore momentary faults, such as those caused by initial charging of a capacitive load at turn-on, preventing false alarms to the system. The MAX16913/MAX16913A provide an active-high control input (SHDN) to put the devices in low-power shutdown mode. Current-Sense Amplifier The integrated current-sense amplifier is a differential amplifier that amplifies the voltage between VIN and VSENS. A sense resistor (0.65Ωmin, 4.7Ωmax), RSENSE, is connected across VIN and VSENS. When the load current passes through the sense resistor, a voltage drop develops across it. The current-sense amplifier amplifies this voltage. The current-sense amplifier features an internally fixed gain of 13V/V (typ). The following equations show the relationship between the current-sense amplifier output voltage (AOUT) and load current: I LOAD (A) = (VIN - VSENS )(V) RSENSE (Ω) VAOUT (V) = [A V (V/V) × (VIN - VSENS )(V)] + 0.4V AOUT is the output of an internal buffer with a 5kΩ output impedance. 6 The AOUT voltage is clamped to typically 4.3V in order to avoid damage to external circuitry. Load Protection The MAX16913/MAX16913A monitor the load current through an external sense resistor and perform the following actions: • If the monitored current is lower than the open-load current, the device signals open load (see the Open Load section). • If the monitored current is higher than the short-circuit current (ISC), the device enters the short-circuit mode (see the Short Circuit section). The devices also perform a short-to-battery detection every time the internal switch turns on (see the Short-toBattery Detection section). In addition, thermal shutdown protects the MAX16913/MAX16913A from overheating (see the Thermal Shutdown section). Two open-drain outputs (OL and SC) indicate the device status (see Table 1). Open Load If the load current drops below the open-load current threshold, the OL output asserts low. An open-load condition does not turn off the internal switch. The MAX16913 provides an internally fixed open-load threshold, while the MAX16913A features an adjustable open-load threshold. For the MAX16913, when (VIN - VSENS) drops below 20mV (typ), the device signals open load. For the MAX16913A, using a resistive divider between REF, the open-load threshold adjustment pin (OLT), and GND sets the open-load threshold (see the OpenLoad Threshold Selection section). Short Circuit If the load current reaches the short-circuit current threshold (I SC ), the t BLANK timer begins counting. During this period, the load current is limited to a value of twice the short-circuit current threshold (2 x ISC). If the short-circuit condition is present for tBLANK, SC asserts low and the internal switch turns off. The timer resets if the short-circuit condition disappears before the blanking time (tBLANK) has elapsed. If the switch is turned off at the end of tBLANK, a retry timer (tRETRY) starts immediately after the blanking time has elapsed. During that time, the switch stays off. At the end of tRETRY, the switch turns on again. If the fault still exists, the cycle repeats. If the fault has been removed, the switch stays on. During this cycle, SC stays low. During retry when the switch is off, the current through the _______________________________________________________________________________________ Remote Antenna Current-Sense Amplifier and Switches MAX16913/MAX16913A TURN-ON INTO A HARD SHORT CIRCUIT 2 x ISC ISC LOAD CURRENT tBLANK tRETRY RETRY SHDN SC TURN-ON INTO A TEMPORARY SHORT CIRCUIT 2 x ISC ISC LOAD CURRENT tBLANK tRETRY RETRY SHDN SC Figure 1. Short-Circuit Timing Diagram switch is zero (see Figure 1). If the load current is greater than ISC, but does not reach the 2 x ISC threshold, the tBLANK timer still begins counting (see Figure 2). The resistor across IN and SENS sets ISC to a typical value of 100mV/RSENSE (Ω). Blanking time and retry time have fixed values of 100ms (min) and 1500ms (min), respectively. Short-to-Battery Detection It may happen that OUT is shorted to the battery due to a fault in the system. The MAX16913/MAX16913A detect this failure by comparing the OUT voltage and the IN voltage before the switch turns on. Every time the switch turns on, such as at the end of the retry time, or once the thermal shutdown condition disappears, the short-to-battery detection is performed. At this point, if the device detects any failure, the switch stays off, and both SC and OL assert low (see Table 1). Thermal Shutdown Thermal shutdown circuitry protects the devices from overheating. The switch turns off immediately when the junction temperature exceeds +150°C (min) (see Table 1). The switch turns on again after the device temperature drops by approximately 15°C (typ). Shutdown (SHDN) The MAX16913/MAX16913A feature an active-high control input (SHDN) to put the devices in a low-power shutdown mode. The devices turn off and consume only 5µA (max) of shutdown current when SHDN is driven high. _______________________________________________________________________________________ 7 MAX16913/MAX16913A Remote Antenna Current-Sense Amplifier and Switches TURN-ON WITH A HEAVY LOAD 2 x ISC ISC tBLANK LOAD CURRENT tRETRY RETRY SHDN SC TURN-ON INTO A TEMPORARY HEAVY LOAD 2 x ISC ISC tBLANK LOAD CURRENT tRETRY RETRY SHDN SC Figure 2. Overcurrent Timing Diagram Undervoltage and Overvoltage Lockout The MAX16913/MAX16913A include undervoltage circuitry (UVLO) to prevent erroneous switch operation when the input voltage goes below approximately 4.25V during startup and brownout conditions. Input voltages of less than 4.25V inhibit operation of the Table 1. Status Truth Table 8 SC OL 0 0 0.4V OUT Short-to-Battery 0 1 Cycling While Autoretrying Short-Circuit Condition 1 0 0.4V Open-Load Condition 1 1 (VIN - VSENS) x 13 + 0.4V Normal Operation VAOUT DEVICE STATUS device by turning off the internal charge pump and the switch. These devices also feature an overvoltage lockout (OVLO) threshold of +21V (typ). When V IN is greater than VOVLO, the device immediately turns off the switch and the internal charge pump. Internal Reference The MAX16913/MAX16913A feature a +3V bandgap reference output, stable over supply voltage and temperature. For the MAX16913A, the reference output is connected to the resistive divider which sets the openload threshold. The output impedance of the internal reference is 5kΩ (typ). _______________________________________________________________________________________ Remote Antenna Current-Sense Amplifier and Switches Choosing the Sense Resistor Ideally, the maximum load current develops the fullscale sense voltage across the current-sense resistor. The current-sense amplifier output voltage is given by: REF R1 MAX16913 OLT VAOUT (V) = [(VIN - VSENS)(V) x AV(V/V)] + 0.4(V) where VAOUT is the output voltage of the current-sense amplifier, and AV is the gain of the current-sense amplifier of 13V/V (typ). Calculate the maximum value for RSENSE so that the differential voltage across IN and SENS does not exceed the minimum full-scale sense voltage (87mV): RSENSE (Ω) = VDIFF(MIN) (V) I LOAD(FULL-SCALE)(A) where VDIFF(MIN) = VIN - VSENS = 87mV minimum at maximum load current. Use resistors specified for current-sensing applications with a minimum resistance value of 0.65Ω, and the maximum resistance value of 4.7Ω. Keep inductance low if ISENSE has a large high-frequency component. Wire-wound resistors have the highest inductance, while metal film is somewhat better. Low-inductance metal-film resistors are also available. Instead of being spiral wrapped around a core, as in metal-film or wirewound resistors, they are a straight band of metal and are available in values under 1Ω. Because of the high current that flows through RSENSE, avoid parasitic trace resistance from causing errors in the sense voltage. Open-Load Threshold Selection For the MAX16913A, a resistive divider between REF, OLT, and GND sets the open-load threshold. See Figure 3. Use the following formula to set the desired open-load threshold: (R (Ω) × I OL (A) × A V (V/V))+ 0.4V R2 (kΩ) = SENSE (R1 +R2 )(kΩ) VREF (V) where IOL is the desired open-load current threshold; AV is the current-sense amplifier gain (13V/V typ), and VREF is the reference voltage (+3V typ). The sum of R1 and R 2 should be large enough so that the output impedance of the internal reference (5kΩ) is negligible compared to the sum of R1 and R2, and has a minimum effect on the accuracy of the adjusted open-load threshold. R2 Figure 3. Open-Load Threshold Selection For example, to set the open-load threshold at 10mA, using a 1Ω sense resistor, use the following method to calculate the value of R1 and R2: (1(Ω) × 0.01(A) × 13(V/V))+ 0.4V R2 (kΩ) = = 0.177 (R1 +R2 )(kΩ) 3(V) Choose R1 = 470kΩ and calculate R2 as 101kΩ. Input Capacitor Connect a low-leakage ceramic capacitor from IN to GND to limit the input voltage drop during momentary output short-circuit conditions, and to protect the device against transients due to inductance in the IN line. For example, use at least a 0.1µF ceramic capacitor if the input inductance (including any stray inductance) is estimated to be 20µH. Larger capacitor values reduce the voltage undershoot at the input. Output Capacitor In an analogous fashion to the input capacitor, an output capacitor protects the device against transients due to any series inductance in the output. Under no conditions should the OUT pin voltage go below -0.3V as specified in the Absolute Maximum Ratings. If a capacitor alone is not sufficient to avoid large negative transients on OUT, then a Schottky diode should be used to clamp transients which go below ground. With a 100µH output series inductor, a 220µF output capacitor is needed to eliminate potential problems. With larger inductor values or smaller capacitors, a Schottky clamp diode will be necessary. Layout and Thermal Dissipation To optimize the switch response time to output shortcircuit condition, it is very important to keep all traces as short as possible to reduce the effect of undesirable parasitic inductance. Place input and output capacitors as close as possible to the device (no more than 5mm). _______________________________________________________________________________________ 9 MAX16913/MAX16913A Applications Information MAX16913/MAX16913A Remote Antenna Current-Sense Amplifier and Switches IN and OUT must be connected with wide short traces to the power bus. During normal operation, the power dissipation is small and the package temperature change is minimal. If the output is continuously shorted to ground at the maximum supply voltage, the devices are protected because the total power dissipated dur- ing the short is scaled down by the duty cycle imposed by the protection: P(MAX) = VIN(MAX) × I OUT(MAX)× tBLANK tRETRY + tBLANK Chip Information Pin Configuration PROCESS: BiCMOS TOP VIEW GND 1 + 16 GND IN 2 15 SC SENS 3 14 OL SENS 4 OUT 5 MAX16913 MAX16913A OUT 6 13 AOUT 12 REF Package Information 11 OLT SHDN 7 10 N.C. GND 8 9 QSOP For the latest package outline information, go to www.maxim-ic.com/packages. GND PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 16 QSOP E16-8F 21-0112 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 © 2008 Maxim Integrated Products SPRINGER is a registered trademark of Maxim Integrated Products, Inc.