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19-4186; Rev 0; 7/08
KIT ATION EVALU BLE AVAILA
Remote Antenna Current-Sense Amplifier and Switches
General Description Features
Switch Phantom Power-On/-Off Under C Control Analog Current Measurement Output Adjustable Current Limiting (340mA Maximum) Detect Open-Load and Short-Circuit Conditions Provide Open-Drain Fault Signals (SC and OL) Overcurrent Blanking During Startup Thermal Shutdown AEC-Q100 Qualified (/V Versions Only) -40C to +105C Operating Temperature Range
MAX16913/MAX16913A
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. 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 +150C (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 -40C to +105C temperature range.
Typical Operating Circuits
BATTERY INPUT TO PROTECTED LOAD (LNA)
IN
SENS OUT REF
3.3V TO 5V
MAX16913
OLT
SC OL SHDN GND AOUT TO ADC INPUT
Applications
Remote LNA Phantom Power Automotive Safety and Infotainment
BATTERY INPUT
Ordering Information
PART MAX16913GEE+ MAX16913GEE/V+* MAX16913AGEE+ MAX16913AGEE/V+* TEMP RANGE -40C to +105C -40C to +105C -40C to +105C -40C to +105C PINOPEN-LOAD PACKAGE THRESHOLD 16 QSOP 16 QSOP 16 QSOP 16 QSOP Internally Set Internally Set
SC IN SENS OUT REF 3.3V TO 5V
TO PROTECTED LOAD (LNA)
MAX16913A
OLT
Externally Adjustable Externally Adjustable
OL SHDN GND AOUT TO ADC INPUT
+Denotes a lead(Pb)-free/RoHS-compliant package. */V denotes an automotive qualified part.
Pin Configuration appears at end of data sheet.
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________________________________________________________________ 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.
Remote Antenna Current-Sense Amplifier and Switches MAX16913/MAX16913A
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 = +70C) 16-Pin QSOP (derate 18.2mW/C above +70C)....1454.5mW Junction-to-Case Thermal Resistance (JC) (Note 1) ......25C/W Junction-to-Ambient Thermal Resistance (JA) (Note 1) .....55C/W Operating Temperature Range .........................-40C to +105C Junction Temperature........................................-40C to +150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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 = +25C.)
PARAMETER GENERAL Operating Input Voltage Range Quiescent Supply Current Shutdown Supply Current (VIN - VSENS) to VAOUT Gain AOUT Maximum Voltage AOUT Zero-Current Output Voltage AOUT Voltage AOUT Output Impedance Switch Dropout Voltage Thermal Shutdown Threshold Thermal Shutdown Hysteresis Reference Output Voltage Reference Output Impedance THRESHOLDS Open-Load Current Threshold Nominal Open-Load Threshold Setting Range Short-Circuit Voltage Threshold Voltage between IN and SENS Overvoltage Shutdown Threshold Overcurrent Blanking Time Retry Time IOL VOLR VSC VLIM VOVLO tBLANK tRETRY RSENSE = 1 (VOLT = 0.66V for the MAX16913 only) (MAX16913A only) RSENSE = 1 At current limit, VIN = 14V VIN rising 10 10 87 173 18 100 1500 100 200 21 200 3000 20 30 50 110 225 24 mA mV mV mV V ms ms ZAOUT VD TSHDN THYST VREF ZREF 2.7 Measured between SENS and OUT while sourcing 100mA Temperature rising +150 +164 15 3 5 3.3 VIN ICC ISD Av VSHDN < 0.4V VSHDN > 1.7V, TA = +25C VAOUT/(VIN - VSENS) (VIN - VSENS) > 300mV (VIN - VSENS) = 0 ILOAD = ISC, (VIN - VSENS) = 100mV ILOAD = 2 x ISC, (VIN - VSENS) = 200mV 340 1.5 2.7 13 4.3 400 1.7 3 5 0.6 460 1.9 3.3 5 0.6 18 1.2 5 V mA A V/V V mV V k V C C V k SYMBOL CONDITIONS MIN TYP MAX UNITS
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Remote Antenna Current-Sense Amplifier and Switches
ELECTRICAL CHARACTERISTICS (continued)
(VIN = +9V to +18V, TA = TJ = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.)
PARAMETER LOGIC LEVELS SC, OL Output-Voltage Low SC, OL Output-Leakage Current SHDN Input Low Voltage SHDN Input High Voltage TIMING Startup Response Time tST SHDN falling edge to 90% of VIN, no load 100 s VOL ILEAK VIL VIH 1.7 Sink current = 1mA VSC = VOL = 5V 0.01 0.4 0.4 V A V V SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX16913/MAX16913A
Typical Operating Characteristics
(VIN = 14V, RSENSE = 1, TA = +25C, unless otherwise noted.)
OPERATING SUPPLY CURRENT vs. TEMPERATURE
MAX16913/3A toc01
OPERATING SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX16913/3A toc02
SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE
VIN = 14V
MAX16913/3A toc03
700 650 600 ICC (A)
800 700 600 ICC (A) 500 400 300 200
5
4
550 500 450 400 -40
ISD (A)
3
2
1
0 4 6 8 10 12 14 16 18 -40 -15 10 35 60 85 105 VIN (V) TEMPERATURE (C)
-15
10
35
60
85
105
TEMPERATURE (C)
AOUT GAIN vs. TEMPERATURE
MAX16913/3A toc04
(VSENSE - VOUT) vs. TEMPERATURE
MAX16913/3A toc04
(VSENSE - VOUT) vs. VIN
IOUT = 90mA
MAX16913/3A toc06
14.0
0.8
IOUT = 90mA
0.8
13.5 AV (V/V)
0.6 VSENSE - VOUT (V)
0.6 VSENSE - VOUT (V)
13.0
0.4
0.4
12.5
0.2
0.2
12.0 -40 -15 10 35 60 85 105 TEMPERATURE (C)
0 -40 -15 10 35 60 85 105 TEMPERATURE (C)
0 4 6 8 10 12 14 16 18 VIN (V)
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Remote Antenna Current-Sense Amplifier and Switches MAX16913/MAX16913A
Typical Operating Characteristics (continued)
(VIN = 14V, RSENSE = 1, TA = +25C, unless otherwise noted.)
TOTAL CURRENT MEASUREMENT ERROR vs. (VIN - VSENSE)
MAX16913/3A toc07
OVERCURRENT BLANKING TIME vs. TEMPERATURE
MAX16913/3A toc08
OVERCURRENT BLANKING TIME vs. VIN
MAX16913/3A toc09
4 TOTAL CURRENT MEASUREMENT ERROR (%)
300 250 200 tBLANK (ms) 150 100
300 250 200 tBLANK (ms) 150 100 50 0
3
2
1
0
50 0 -40
-1 10 20 30 40 50 60 70 80 90 100 VIN - VSENSE (mV)
-15
10
35
60
85
105
4
6
8
10
12
14
16
18
TEMPERATURE (C)
VIN (V)
OVERCURRENT SHUTDOWN
MAX16913/3A toc10
TURN-ON INTO CAPACITIVE LOAD (OUTPUT STAYS ON) (CLOAD = 1000F)
MAX16913/3A toc11
SHDN
5V/div SHDN 5V/div
SC
5V/div
100mA/div IOUT 400ms/div IOUT 20ms/div
100mA/div
CURRENT-LIMIT VOLTAGE vs. VIN
MAX16913/3A toc12
250
200 VIN - VSENSE (mV)
150
100
50
0 4 6 8 10 12 14 16 18 VIN (V)
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Remote Antenna Current-Sense Amplifier and Switches
Pin Description
PIN 1, 8, 9, 16 2 3, 4 5, 6 7 10 11 12 13 14 15 NAME GND IN SENS OUT SHDN N.C. OLT REF AOUT OL SC Ground Input Voltage. Bypass IN to GND with a low-ESR ceramic capacitor with a minimum value of 0.1F. Input to Current-Sense Amplifier. Connect the sense resistor between SENS and IN. Switch Output Active-High Control Input. Drive SHDN low to turn on the device. No Connection. Not internally connected. 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. +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 5k. Current-Monitor Voltage Output. AOUT can be used to measure the load current by means of an external ADC. The output impedance is 5k. 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 10k pullup resistor. See Table 1. 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 10k pullup resistor. See Table 1. FUNCTION
MAX16913/MAX16913A
MAX16913 Functional Diagram
SENS
MAX16913A Functional Diagram
SENS
MAX16913
IN CURRENT SENSE SHDN CHARGE PUMP
OUT IN
MAX16913A
CURRENT SENSE SHDN CHARGE PUMP
OUT
FET DRIVER AND CONTROL
AOUT OT REF VREF REF
FET DRIVER AND CONTROL
AOUT OT REF VREF REF
SC VREF2 OL
SC VREF2 OL
OLT
GND
OLT
GND
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Remote Antenna Current-Sense Amplifier and Switches MAX16913/MAX16913A
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. 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).
Current-Sense Amplifier
The integrated current-sense amplifier is a differential amplifier that amplifies the voltage between VIN and VSENS. A sense resistor (0.65min, 4.7max), 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 ()
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
VAOUT (V) = [A V (V/V) x (VIN - VSENS )(V)] + 0.4V AOUT is the output of an internal buffer with a 5k output impedance.
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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 (). Blanking time and retry time have fixed values of 100ms (min) and 1500ms (min), respectively.
point, if the device detects any failure, the switch stays off, and both SC and OL assert low (see Table 1).
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
Thermal Shutdown Thermal shutdown circuitry protects the devices from overheating. The switch turns off immediately when the junction temperature exceeds +150C (min) (see Table 1). The switch turns on again after the device temperature drops by approximately 15C (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 5A (max) of shutdown current when SHDN is driven high.
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Remote Antenna Current-Sense Amplifier and Switches MAX16913/MAX16913A
TURN-ON WITH A HEAVY LOAD 2 x ISC
ISC LOAD CURRENT tBLANK tRETRY
RETRY SHDN
SC
TURN-ON INTO A TEMPORARY HEAVY LOAD 2 x ISC
ISC LOAD CURRENT tBLANK 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
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 5k (typ).
Table 1. Status Truth Table
SC 0 0 1 1 OL 0 1 0 1 0.4V Cycling While Autoretrying 0.4V (VIN - VSENS) x 13 + 0.4V VAOUT DEVICE STATUS OUT Short-to-Battery Short-Circuit Condition Open-Load Condition Normal Operation
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Remote Antenna Current-Sense Amplifier and Switches
Applications Information
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: 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 () = VDIFF(MIN) (V) I LOAD(FULL-SCALE)(A)
R2 REF R1 OLT
MAX16913/MAX16913A
MAX16913
Figure 3. Open-Load Threshold Selection
For example, to set the open-load threshold at 10mA, using a 1 sense resistor, use the following method to calculate the value of R1 and R2:
(1() x 0.01(A) x 13(V/V))+ 0.4V R2 (k) = = 0.177 (R1 +R2 )(k) 3(V)
where VDIFF(MIN) = VIN - VSENS = 87mV minimum at maximum load current. Use resistors specified for current-sensing applications with a minimum resistance value of 0.65, and the maximum resistance value of 4.7. 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 1. Because of the high current that flows through RSENSE, avoid parasitic trace resistance from causing errors in the sense voltage.
Choose R1 = 470k and calculate R2 as 101k.
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 0.1F ceramic capacitor if the input inductance (including any stray inductance) is estimated to be 20H. Larger capacitor values reduce the voltage undershoot at the input.
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 () x I OL (A) x A V (V/V))+ 0.4V R2 (k) = SENSE (R1 +R2 )(k) VREF (V)
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 100H output series inductor, a 220F output capacitor is needed to eliminate potential problems. With larger inductor values or smaller capacitors, a Schottky clamp diode will be necessary.
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 (5k) is negligible compared to the sum of R1 and R2, and has a minimum effect on the accuracy of the adjusted open-load threshold.
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).
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Remote Antenna Current-Sense Amplifier and Switches MAX16913/MAX16913A
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 during the short is scaled down by the duty cycle imposed by the protection: P(MAX) = VIN(MAX) x I OUT(MAX)x tBLANK tRETRY + tBLANK
Pin Configuration
PROCESS: BiCMOS
TOP VIEW
GND 1 IN 2 SENS 3 SENS 4 OUT 5 OUT 6 SHDN 7 GND 8
Chip Information
+
16 GND 15 SC 14 OL
MAX16913 MAX16913A
13 AOUT 12 REF 11 OLT 10 N.C. 9 GND
Package Information
For the latest package outline information, go to www.maxim-ic.com/packages. PACKAGE TYPE PACKAGE CODE E16-8F DOCUMENT NO. 21-0112
QSOP
16 QSOP
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 (c) 2008 Maxim Integrated Products
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is a registered trademark of Maxim Integrated Products, Inc.

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