LTCMN

LTC6103 Dual High Voltage, High Side Current Sense Amplifier FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTION The LTC®6103 is a versatile, high voltage, high side, dual current sense amplifier. The two internal amplifiers are independent except that they share the same V– terminal. Design flexibility is provided by the excellent device characteristics: 450µV maximum offset, and only 275µA of current consumption (typical at 12V) for each amplifier. The LTC6103 operates on supplies from 4V to 60V. The LTC6103 monitors current via the voltage across an external sense resistor (shunt resistor). Internal circuitry converts input voltage to output current, allowing for a small sense signal on a high common mode voltage to be translated into a ground referenced signal. Low DC offset allows the use of a small shunt resistor and large gain-setting resistors. As a result, power loss in the shunt is minimal. The wide operating supply range and high accuracy make the LTC6103 ideal for an extensive variety of applications from automotive to industrial and power management. The fast response makes the LTC6103 the perfect choice for load current warnings and shutoff protection control. With very low supply current, the LTC6103 is suitable for power sensitive applications. The LTC6103 is available in an 8-lead MSOP package. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Two Independent Current Sense Amplifiers Wide Supply Range: 4V to 60V, 70V Absolute Maximum Low Offset Voltage: 450µV Maximum Fast Response: 1µs Response Time Gain Configurable with External Resistors Low Input Bias Current: 170nA Maximum PSRR: 110dB Minimum (6V to 60V) Output Current: 1mA Maximum Low Supply Current: 275µA per Amplifier, VS = 12V Specified for –40°C to 125°C Temperature Range Available in an 8-lead MSOP Package APPLICATIONS ■ ■ ■ ■ ■ Current Shunt Measurement Battery Monitoring Remote Sensing Power Management High Voltage Level Translator TYPICAL APPLICATION Two 16-Bit Current Sense Channels Connected Directly to the LTC2436-1 ADC ILOAD LOAD 8 +INA 7 –INA – VA+ VSENSE + VB+ VSENSE Step Response ILOAD LOAD 5 + – VSENSE– ∆VSENSE– = 100mV 5.5V 5V RIN 100Ω 6 RIN 100Ω –INB +INB 5V 1µF +– VSA –+ VSB 7 OUTB 2 4 5 CH0 3,8,9,10,14,15,16 6103 TA01a 2 6 CH1 LTC2436-1 1 13 12 11 TO µP IOUT = 100µA LTC6103 OUTA 1 4 V – 0.5V 0V VOUT IOUT = 0µA 500ns/DIV TA = 25°C V+ = 12V RIN = 100Ω ROUT = 5k VSENSE+ = V+ 6103 TA01b ROUT 4.99k ROUT 4.99k 6103f 1 LTC6103 ABSOLUTE MAXIMUM RATINGS (Note 1) PACKAGE/ORDER INFORMATION TOP VIEW OUTA OUTB NC V– 1 2 3 4 8 7 6 5 +INA –INA –INB +INB Total Supply Voltage (+INA/+INB to V–) ....................70V Maximum Applied Output Voltage (OUTA/OUTB) ........9V Input Current........................................................±10mA Output Short-Circuit Duration (to V–)............... Indefinite Operating Temperature Range LTC6103C ............................................ –40°C to 85°C LTC6103I ............................................. –40°C to 85°C LTC6103H .......................................... –40°C to 125°C Specified Temperature Range (Note 2) LTC6103C ................................................ 0°C to 70°C LTC6103I ............................................. –40°C to 85°C LTC6103H .......................................... –40°C to 125°C Storage Temperature Range................... –65°C to 150°C Lead Temperature (Soldering, 10 sec) .................. 300°C MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 300°C/W ORDER PART NUMBER LTC6103CMS8 LTC6103IMS8 LTC6103HMS8 MS8 PART MARKING* LTCMN LTCMN LTCMN Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. ELECTRICAL CHARACTERISTICS SYMBOL +INA(VSA)/ +INB(VSB) VOS ΔVOS/ΔT IB PSRR PARAMETER Supply Voltage Range Input Offset Voltage CONDITIONS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. RIN = 100Ω, ROUT = 5k, 4V ≤ +INA/+INB ≤ 60V, V– = 0V unless otherwise noted. MIN ● TYP MAX 60 UNITS V µV µV µV µV/°C nA nA dB dB dB dB V V V 4 ±85 VSENSE = 5mV, LTC6103 VSENSE = 5mV, LTC6103C, LTC6103I VSENSE = 5mV, LTC6103H VSENSE = 5mV RIN = 1M to –INA and –INB +INA/+INB = 6V to 60V, VSENSE = 5mV +INA/+INB = 4V to 60V, VSENSE = 5mV ● ● ● ● ● ● ● ● ● ● ● ● ● ±450 ±600 ±700 170 245 Input Offset Voltage Drift Input Bias Current Power Supply Rejection Ratio ±1.5 100 110 106 105 98 8 3 1 0 22.5 30 35 120 115 VOUT(MAX) Maximum Output Voltage 12V ≤ +INA/+INB ≤ 60V, VSENSE = 88mV, ROUT = 10k +INA/+INB = 6V, VSENSE = 66mV, ROUT = 5k +INA/+INB = 4V, VSENSE = 55mV, ROUT = 2k VSENSE = 0V, LTC6103 VSENSE = 0V, LTC6103C, LTC6103I VSENSE = 0V, LTC6103H 6V ≤ +INA/+INB ≤ 60V, VSENSE = 110mV, ROUT = 2k +INA/+INB = 4V, VSENSE = 55mV, ROUT = 2k, Gain = 20 ΔVSENSE = 100mV Step, 6V ≤ +INA/+INB ≤ 60V +INA/+INB = 4V (1V Output Step), ROUT = 1k IOUT = 200µA, RIN = 100Ω, ROUT = 5k IOUT = 1mA, RIN = 100Ω, ROUT = 5k VOUT(O) Minimum Output Voltage (Note 3) Maximum Output Current Input Step Response (to 50% of Output Step) Signal Bandwidth mV mV mV mA mA IOUT(MAX) tr BW 1 0.5 1 1.5 120 140 µs µs kHz kHz 6103f 2 LTC6103 ELECTRICAL CHARACTERISTICS SYMBOL I+INA, I+INB PARAMETER Supply Current per Amplifier CONDITIONS +INA/+INB = 4V, IOUT = 0, RIN = 1M +INA/+INB = 6V, IOUT = 0, RIN = 1M +INA/+INB = 12V, IOUT = 0, RIN = 1M +INA/+INB = 60V, IOUT = 0, RIN = 1M LTC6103I, LTC6103C LTC6103H Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC6103C is guaranteed to meet specified performance from 0°C to 70°C. The LTC6103C is designed, characterized and ● ● ● ● ● The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. RIN = 100Ω, ROUT = 5k, 4V ≤ +INA/+INB ≤ 60V, V– = 0V unless otherwise noted. MIN TYP 220 255 275 390 MAX 450 475 475 525 500 590 640 690 720 UNITS µA µA µA µA µA µA µA µA µA expected to meet specified performance from –40°C to 85°C but is not tested or QA sampled at these temperatures. LTC6103I is guaranteed to meet specified performance from –40°C to 85°C. The LTC6103H is guaranteed to meet specified performance from –40°C to 125°C. Note 3: This parameter is not tested in production and is guaranteed by the VOS test. TYPICAL PERFORMANCE CHARACTERISTICS Input VOS vs Temperature 200 150 INPUT OFFSET VOLTAGE (µV) INPUT OFFSET VOLTAGE (µV) 100 50 0 –50 RIN = 100Ω ROUT = 5k VIN = 5mV 0 20 40 60 80 TEMPERATURE (°C) 100 120 6103 G01 Input VOS vs Supply Voltage 200 150 100 50 0 –50 TA = 45°C TA = 0°C TA = –40°C RIN = 100Ω ROUT = 5k VIN = 5mV 0 10 40 50 30 VSUPPLY AT +INA OR +INB (V) 20 60 6103 G02 Input Sense Range 5.0 RIN = 5k 4.5 ROUT = 2.5k MAXIMUM VSENSE (V) 4.0 3.5 3.0 2.5 2.0 1.5 1.0 4 5 6 7 8 V+ (V) 6103 G03 3 REPRESENTATIVE UNITS TA = 85°C TA = 125°C –100 –150 –200 –40 –20 –100 –150 –200 9 10 11 12 6103f 3 LTC6103 TYPICAL PERFORMANCE CHARACTERISTICS VOUT Maximum vs Temperature 12 VS = 60V 10 MAXIMUM OUTPUT (V) VS = 12V MAXIMUM IOUT (mA) 8 6 VS = 6V 4 VS = 4V 2 0 –40 –20 7 6 5 4 VS = 6V 3 2 1 0 –40 –20 0.01 0 20 40 60 80 TEMPERATURE (°C) 100 120 6103 G05 IOUT Maximum vs Temperature 100 VS = 12V 10 OUTPUT ERROR (%) VS = 60V Calculated Output Error Due to Input Offset vs Input Voltage TA = 25°C GAIN =10 1 VS = 4V 0.1 0 20 40 60 80 TEMPERATURE (°C) 100 120 6103 G04 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 INPUT VOLTAGE (V) 6103 G06 Gain vs Frequency 40 35 30 GAIN (dB) 25 IOUT = 200µA 20 15 10 TA = 25°C 5 RIN = 100Ω ROUT = 5k 0 1k 100k 10k INPUT FREQUENCY (Hz) IOUT = 1mA IB (nA) 160 140 Input Bias Current vs Temperature 450 400 VS = 6V TO 100V VS = 4V SUPPLY CURRENT (µA) 350 300 250 200 150 100 50 0 20 40 60 80 TEMPERATURE (°C) 100 120 6103 G09 Supply Current vs Supply Voltage TA = 125°C TA = 85°C TA = 70°C 120 100 80 60 40 20 0 –40 –20 TA = 25°C TA = –40°C TA = 0°C VIN = 0V RIN = 1M 0 20 30 10 40 50 VSUPPLY AT +INA OR +INB (V) 60 1M 6103 G08 0 6103 G10 Step Response 0mV to 10mV V+ + V -10mV 0.5V VSENSE– V+-10mV V -20mV TA = 25°C V+ = 12V RIN = 100Ω ROUT = 5k VSENSE+ = V+ 1V + Step Response 10mV to 20mV VSENSE– TA = 25°C V+ = 12V RIN = 100Ω ROUT = 5k VSENSE+ = V+ 0V VOUT TIME (10µs/DIV) 0.5V VOUT TIME (10µs/DIV) 6103 G11 6103 G12 6103f 4 LTC6103 TYPICAL PERFORMANCE CHARACTERISTICS Step Response 0mV to 100mV VSENSE – Step Response 0mV to 100mV V+ VSENSE – Step Response Rising Edge VSENSE– ∆VSENSE– =100mV 5.5V 5V TA = 25°C V+ = 12V RIN = 100Ω ROUT = 5k VSENSE+ = V+ IOUT = 100µA ∆VSENSE– =100mV 5V CLOAD = 10pF ∆VSENSE– =100mV 5V CLOAD = 1000pF TA = 25°C V+ = 12V RIN = 100Ω ROUT = 5k VSENSE+ = V+ 0V VOUT TIME (10µs/DIV) 6103 G13 TA = 25°C V+ = 12V CLOAD = 2200pF RIN = 100Ω ROUT = 5k VSENSE+ = V+ VOUT 0V VOUT TIME (100µs/DIV) 6103 G14 0.5V 0V IOUT = 0µA TIME (500ns/DIV) 6103 G15 Step Response Falling Edge 140 V+ VOUT TA = 25°C V+ = 12V RIN = 100Ω ROUT = 5k VSENSE+ = V+ IOUT = 0µA 0.5V 0V TIME (500ns/DIV) 6103 G16 PSRR vs Frequency 120 100 PSRR (dB) VS = 12V 80 VS = 4V 60 RIN = 100Ω 40 ROUT = 5k COUT = 5pF 20 GAIN = 50 IOUTDC = 100µA VINAC = 50mVP-P 0 0.1 1 10 100 1k 10k FREQUENCY (Hz) ∆VSENSE– =100mV 5.5V 5V IOUT = 100µA 100k 1M 6103 G17 6103f 5 LTC6103 PIN FUNCTIONS OUTA (Pin 1): Current Output of Amplifier A. OUTA will source a current that is proportional to the sense voltage of amplifier A into an external resistor. OUTB (Pin 2): Current Output of Amplifier B. OUTB will source a current that is proportional to the sense voltage of amplifier B into an external resistor. NC (Pin 3): No Connect. V– (Pin 4): Negative Supply (or Ground for Single Supply Operation). Common to both amplifiers. +INB/VSB (Pin 5): The Positive Input of the Internal Sense Amplifier B. Must be tied to the system load end of the sense resistor. It also works as the positive supply for amplifier B. Supply current of amplifier B is drawn through this pin. The LTC6103 supply current is monitored along with the system load current. –INB (Pin 6): The Negative Input of the Internal Sense Amplifier B. The internal sense amplifier will drive –INB to the same potential as +INB. A resistor (RIN) tied from VB+ to –INB sets the output current IOUT = VSENSE/ RIN. VSENSE is the voltage developed across the external RSENSE (Figure 1). –INA (Pin 7): The Negative Input of the Internal Sense Amplifier A. The internal sense amplifier will drive –INA to the same potential as +INA. A resistor (RIN) tied from VA+ to –INA sets the output current IOUT = VSENSE/ RIN. VSENSE is the voltage developed across the external RSENSE (Figure 1). +INA/VSA (Pin 8): The Positive Input of the Internal Sense Amplifier A. Must be tied to the system load end of the sense resistor. It also works as the positive supply for amplifier A. Supply current of amplifier A is drawn through this pin. The LTC6103 supply current is monitored along with the system load current. BLOCK DIAGRAM VA+ ILOAD LOAD VSENSE VB+ VSENSE – + RIN + – ILOAD LOAD RSENSE RSENSE RIN 6 –INA –INB 5k 5k 5 8 +INA 5k 5k 7 +INB ISA +– VSA 10V 10V OUTA 1 IOUT ROUT 4 V– 2 OUTB –+ VSB ISB 6103 F01 IOUT VOUT = VSENSE • ROUT ROUT RIN Figure 1. LTC6103 Block Diagram and Typical Connection 6103f 6 LTC6103 THEORY OF OPERATION An internal sense amplifier loop forces –IN to have the same potential as +IN. Connecting an external resistor, RIN, between –IN and V+ forces a potential across RIN that is the same as the sense voltage across RSENSE. A corresponding current, (ILOAD + IS) • RSENSE/RIN, will flow through RIN. The high impedance inputs of the sense amplifier will not conduct this input current, so the current will flow through an internal MOSFET to the OUT pin. In most application cases, IS 1.2A) 4 5 6 VLOGIC (3.3V TO 5V) 7 + – LTC1540 8 Q1 CMPT5551 4.7k R5 7.5k 6103 F03b (VLOGIC + 5V) ≤ VIN ≤ 60V 0A ≤ ILOAD ≤ 10A Figure 3b. The LTC6103 Allows High-Low Current Ranging Care should be taken when designing the printed circuit board layout to minimize input trace resistance (to Pins 5, 6, 7 and 8), especially for small RIN values. Trace resistance to the –IN terminals will increase the effective RIN value, causing a gain error. Trace resistance on +IN terminals will have an effect on offset error. These errors are described in more detail later in this data sheet. In addition, internal device resistance will add approximately 0.3Ω to RIN. Selection of External Output Resistor, ROUT The output resistor, ROUT, determines how the output current is converted to voltage. VOUT is simply IOUT • ROUT. In choosing an output resistor, the maximum output voltage must first be considered. If the circuit following is a buffer or ADC with limited input range, then ROUT must be chosen so that IOUT(MAX) • ROUT is less than the allowed maximum input range of this circuit. In addition, the output impedance is determined by ROUT. If the circuit to be driven has high enough input impedance, then almost any useful output impedance will be acceptable. However, if the driven circuit has relatively low input impedance or draws spikes of current, as an ADC might do, then a lower ROUT value may be required in order to preserve the accuracy of the output. As an example, if the input impedance of the driven circuit is 100 times ROUT, then the accuracy of VOUT will be reduced by 1% since: VOUT = IOUT • ROUT • RIN(DRIVEN) ROUT + RIN(DRIVEN) 100 = 0.99 • IOUT • ROUT 101 = IOUT • ROUT • 6103f 9 LTC6103 APPLICATIONS INFORMATION Error Sources The current sense system uses an amplifier and resistors to apply gain and level shift the result. The output is then dependent on the characteristics of the amplifier, such as bias current and input offset, as well as resistor matching. Ideally, the circuit output is: VOUT = VSENSE • ROUT RIN supply current can cause an output error if trace resistance between RSENSE and +IN is significant (Figure 4). EOUT(RT_+IN) = (IS • RT/RIN) • ROUT Trace resistance to the –IN pin will increase the effective RIN value, causing a gain error. In addition, internal device resistance will add approximately 0.3Ω to RIN. Minimizing the trace resistance is important and care should be taken in the PCB layout. Make the trace short and wide. Kelvin connection to the shunt resistor pad should be used. V+ ILOAD LOAD RT RSENSE VSENSE = RSENSE • ISENSE In this case, the only error is due to resistor mismatch, which provides an error in gain only. However, offset voltage, bias current and finite gain in the amplifier cause additional errors. Output Error, EOUT, Due to the Amplifier DC Offset Voltage, VOS EOUT( VOS) = VOS • ROUT RIN RIN RT +IN IS –IN +– VS The DC offset voltage of the amplifier adds directly to the value of the sense voltage, VSENSE. This is the dominant error of the system and it limits the available dynamic range. The paragraph, Selection of External Current Sense Resistor provides details. Output Error, EOUT, Due to Bias Currents The bias current IB(+) flows into the positive input of the internal op amp. IB(–) flows into the negative input. EOUT(IBIAS) = ROUT(IB(+) • (RSENSE/RIN) – IB(–)) Since IB(+) ≈ IB(–) = IBIAS, if RSENSE