LT199G1XC6/R6

LT199G1, LT199G2, LT199G3 P-1 General Description The LT199 series of bidirectional zero-drift current sense amplifier can sense drops across shunts at common-mode voltages from -0.3V to 26V, independent of the supply voltage. Unidirectional operation allows the LT199 series to measure currents through a resistive shunt in one direction, while bidirectional operation allows the device to measure currents through a resistive shunt in two directions. The low offset of the zerodrift architecture enables current sensing with maximum drops across the shunt as low as 10mV full-scale. The LT199 series operates from a single +2.5V to +18V power supply, drawing a maximum of 100μA of supply current. The device is specified from –40℃ to +105℃, and offered in SC70-6L and TQFN-10L packages. Features and Benefits ◼ Wide common-mode range: -0.3V to 26V ◼ Maximum 180μV Offset voltage (LT199G2/G3) Enable Shunt Drops of 10mV Full-scale ◼ Accuracy – Maximum ±0.5% Gain Error – Maximum 0.5μV/℃ Offset Drift – Maximum 10ppm/℃ Gain Drift ◼ Choice of Gains: – LT199G1: 50V/V – LT199G2: 100V/V – LT199G3: 200V/V ◼ Quiescent Current: Maximum 100μA ◼ Package: SC70-6L, TQFN-10L Applications ◼ ◼ ◼ ◼ ◼ ◼ ◼ Power Management Battery Chargers Electrical Cigarette Smart Phones and Tablets Notebook Computers Telecom Equipments Welding Equipments Block Diagram and Pin Configuration (Top View) +2.5V to +18V CBYPASS (0.01μF to 0.1μF) VSUPPLY IN+ VSHUNT VS R4 R2 RSHUNT R1 VOUT IN– Load SC70-6L REF OUT R3 LT199G1/G2/G3 VREF GND High-side Sensing Application CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Linearin and designs are registered trademarks of Linearin Technology Corporation. © Copyright Linearin Technology Corporation. All Rights Reserved. All other trademarks mentioned are the property of their respective owners. REF 1 6 OUT GND 2 5 IN– VS 3 4 IN+ FN1618-31.1 — Data Sheet Bi-directional, Zero-Drift Current Sense Amplifiers LT199G1, LT199G2, LT199G3 P-2 Pin Description Symbol Description IN– Inverting input of the amplifier. IN+ Non-inverting input of the amplifier. OUT Amplifier output. The voltage range extends to within millivolt of each supply rail. REF Reference voltage VS Positive power supply. Typically, the voltage is from +2.5V to +18V. A bypass capacitor of 0.1μF as close to the part as possible should be used between power supply pin and ground pin. GND Negative power supply. Ordering Information Orderable Type Number Package Name Package Quantity Eco Class(1) Marking Code LT199G1XC6/R6 SC70-6L 3 000 Green (RoHS & no Sb/Br) 9G1 LT199G1XF10/R10 Thin QFN-10L 5 000 Green (RoHS & no Sb/Br) 9G1 LT199G2XC6/R6 SC70-6L 3 000 Green (RoHS & no Sb/Br) 9G2 LT199G2XF10/R10 Thin QFN-10L 5 000 Green (RoHS & no Sb/Br) 9G2 LT199G3XC6/R6 SC70-6L 3 000 Green (RoHS & no Sb/Br) 9G3 LT199G3XF10/R10 Thin QFN-10L 5 000 Green (RoHS & no Sb/Br) 9G3 (1) Eco Class - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & Halogen Free). (2) Please contact to your Linearin representative for the latest availability information and product content details. Limiting Value In accordance with the Absolute Maximum Rating System (IEC 60134). Parameter Absolute Maximum Rating Supply Voltage, VS to GND +20V Analog Input (IN+, IN–), Differential (VIN+ – VIN–) –26V to +26V Analog Input (IN+, IN–), Common-Mode (GND – 0.3V) to +26V REF Input (GND – 0.3V) to (V+ + 0.3V) Output (GND – 0.3V) to (V+ + 0.3V) Input Current Into All Pins 5mA Storage Temperature Range –65℃ to +150℃ Junction Temperature 150℃ Lead Temperature Range (Soldering 10 sec) 260℃ CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Linearin and designs are registered trademarks of Linearin Technology Corporation. © Copyright Linearin Technology Corporation. All Rights Reserved. All other trademarks mentioned are the property of their respective owners. FN1618-31.1 — Data Sheet Bi-directional, Zero-Drift Current Sense Amplifiers LT199G1, LT199G2, LT199G3 P-3 ESD Rating Parameter Electrostatic Discharge Voltage Item Value Human body model (HBM), per MIL-STD-883J / Method 3015.9 (1) ±4 000 Charged device model (CDM), per ESDA/JEDEC JS-002-2014 (2) ±2 000 Machine model (MM), per JESD22-A115C ±400 (1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. (2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Linearin and designs are registered trademarks of Linearin Technology Corporation. © Copyright Linearin Technology Corporation. All Rights Reserved. All other trademarks mentioned are the property of their respective owners. Unit V FN1618-31.1 — Data Sheet Bi-directional, Zero-Drift Current Sense Amplifiers LT199G1, LT199G2, LT199G3 P-4 Electrical Characteristics TA = +25℃, VS = +5.0V, VIN+ = 12V, VSENSE = VIN+ – VIN–, and VREF = VS/2, unless otherwise noted. Boldface limits apply over the specified temperature range, TA = −40 to +105 ℃. Symbol Parameter Conditions Min. Typ. Max. –250 +50 +300 ±50 ±180 0.5 Unit INPUT CHARACTERISTICS VOS Referred-to-input offset voltage VSENSE = 0mV, LT199G1 VOS TC Offset voltage drift over Temperature 0.1 IB Input bias current VSENSE = 0mV 25 μA IOS Input offset current VSENSE = 0mV 0.02 μA VCM Common-mode input voltage range CMRR Common-mode rejection ratio VSENSE = 0mV, LT199G2 / LT199G3 –0.3 26 VIN+ = 0 V to +24V, VSENSE = 0mV, LT199G1 91 105 VIN+ = 0 V to +26V, VSENSE = 0mV, LT199G2 / LT199G3 96 110 μV μV/℃ V dB OUTPUT CHARACTERISTICS G Gain LT199G1 50 LT199G2 100 LT199G3 200 EG Gain error VSENSE = –5mV to 5mV EG TC Gain error drift Over Temperature Nonlinearity Error VSENSE = –5mV to 5mV CL Maximum Capacitive Load No sustained oscillation VOH Swing to VS rail VOL Swing to GND RL = 10kΩ to GND VS–200 V/V ±0.03 ±0.5 % 3 10 ppm/℃ ±0.01 % 1 nF VS–50 VGND+5 VGND+50 mV DYNAMIC PERFORMANCE BW SR Bandwidth LT199G1, CLOAD = 10pF 80 LT199G2, CLOAD = 10pF 30 LT199G3, CLOAD = 10pF 14 Slew rate kHz 0.65 V/μs 25 nV/√Hz NOISE PERFORMANCE en Voltage noise density Referred-to-input POWER SUPPLY VS PSR IQ Operating supply voltage Input vs power supply Quiescent current over Temperature +2.5 VS = +2.5V to +18V, VIN+ = +18V, VSENSE = 0mV +18 μV/V ±0.1 70 VSENSE = 0mV V 100 115 μA THERMAL CHARACTERISTICS TA Operating temperature θJA Package Thermal Resistance -40 +105 SC70-6L 250 TQFN-10L 80 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Linearin and designs are registered trademarks of Linearin Technology Corporation. © Copyright Linearin Technology Corporation. All Rights Reserved. All other trademarks mentioned are the property of their respective owners. ℃ ℃/W FN1618-31.1 — Data Sheet Bi-directional, Zero-Drift Current Sense Amplifiers LT199G1, LT199G2, LT199G3 P-5 Typical Performance Characteristics 80 70 60 60 40 50 Gain (dB) Offset Voltage (μV) At TA = +25℃, VS = +5.0V, VIN+ = 12V, and VREF = VS /2, unless otherwise noted. 20 0 -20 40 30 20 -40 10 -60 0 -80 G = 100 -10 -50 -25 0 25 50 75 100 125 1 Temperature (℃) 100 1M Gain vs. Frequency Offset Voltage vs. Temperature 60 Quiescent Current (μA) 25 Input Bias Current (μA) 10k Frequency (Hz) 24 23 22 21 20 58 56 54 52 50 -50 -25 0 25 50 75 100 125 -50 Temperature (℃) -25 0 25 50 75 100 Temperature (℃) Input Bias Current vs. Temperature Quiescent Current vs. Temperature Input Voltage Output Voltage (5mV/div) (0.5V/div) Quiescent Current (μA) 125 100 75 50 25 0 2.5 5 7.5 10 12.5 15 17.5 2VPP Output 10mVPP Input 20 Supply Voltage (V) Quiescent Current vs. Supply Voltage Time (50μs/div) Step Response (10mVPP Input Step) CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Linearin and designs are registered trademarks of Linearin Technology Corporation. © Copyright Linearin Technology Corporation. All Rights Reserved. All other trademarks mentioned are the property of their respective owners. 125 FN1618-31.1 — Data Sheet Bi-directional, Zero-Drift Current Sense Amplifiers LT199G1, LT199G2, LT199G3 P-6 Typical Performance Characteristics (continued) At TA = +25℃, VS = +5.0V, VIN+ = 12V, and VREF = VS /2, unless otherwise noted. VIN+ VS = 5V, VCM = 12V, VREF = 2.5V 2V/div 2V/div Inverting Input Overload VIN– Output Output 0V 50μs/div Inverting Differential Input Overload VS = 5V, VCM = 12V, VREF = 2.5V 50μs/div Noninverting Differential Input Overload CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Linearin and designs are registered trademarks of Linearin Technology Corporation. © Copyright Linearin Technology Corporation. All Rights Reserved. All other trademarks mentioned are the property of their respective owners. FN1618-31.1 — Data Sheet Bi-directional, Zero-Drift Current Sense Amplifiers LT199G1, LT199G2, LT199G3 P-7 Application Notes BASIC CONNECTIONS Figure 1 shows the basic connections for the LT199. The input pins, IN+ and IN–, should be connected as closely as possible to the shunt resistor to minimize any resistance in series with the shunt resistance. Power-supply bypass capacitors are required for stability. Applications with noisy or high-impedance power supplies may require additional decoupling capacitors to reject power-supply noise. Connect bypass capacitors close to the device pins. +2.5V to +18V CBYPASS (0.01μF to 0.1μF) VSUPPLY IN+ VSHUNT VS VREF R4 R2 R3 R1 RSHUNT REF OUT VOUT IN– GND Load High-side Sensing Application Figure 1. Typical Application POWER SUPPLY The input circuitry of the LT199 can accurately measure beyond its power-supply voltage, VS. For example, the VS power supply can be 5V, whereas the load power-supply voltage can be as high as +18V. However, the output voltage range of the OUT terminal is limited by the voltages on the power-supply pin. Note also that the LT199 can withstand the full –0.3V to +26V range in the input pins, regardless of whether the device has power applied or not. SELECTING RS The zero-drift offset performance of the LT199 offers several benefits. Most often, the primary advantage of the low offset characteristic enables lower full-scale drops across the shunt. For example, non-zero-drift current sense amplifiers typically require a full-scale range of 100mV. The LT199 of current sense amplifier gives equivalent accuracy at a full-scale range on the order of 10mV. This accuracy reduces shunt dissipation by an order of magnitude with many additional benefits. Alternatively, there are applications that must measure current over a wide dynamic range that can take advantage of the low offset on the low end of the measurement. Most often, these applications can use the lower gain of 100 to accommodate larger shunt drops on the upper end of the scale. UNIDIRECTIONAL OPERATION Unidirectional operation allows the LT199 to measure currents through a resistive shunt in one direction. The most frequent case of unidirectional operation sets the output at ground by connecting the REF pin to ground. In unidirectional applications where the highest possible accuracy is desirable at very low inputs, bias the REF pin to a convenient value above 50mV to get the device output swing into the linear range for zero inputs. A less frequent case of unipolar output biasing is to bias the output by connecting the REF pin to the supply; in this case, the quiescent output for zero input is at quiescent supply. This configuration would only respond to negative currents (inverted voltage polarity at the device input). BIDIRECTIONAL OPERATION Bidirectional operation allows the LT199 to measure currents through a resistive shunt in two directions. In this case, the output can be set anywhere within the limits of what the reference inputs allow (that is, between 0V to V+). Typically, it is set at half-scale for equal range in both directions. In some cases, however, it is set at a voltage other than half-scale when the bidirectional current is nonsymmetrical. The quiescent output voltage is set by applying voltage to the reference input. Under zero differential input conditions the output assumes the same voltage that is applied to the reference input. INPUT FILTERING An obvious and straightforward filtering location is at the device output. However, this location negates the advantage of the low output impedance of the internal buffer. The only other filtering option is at the device input pins. This location, though, does require consideration of the ±30% tolerance of the internal resistances. Figure 2 shows a filter placed at the inputs pins. VS VCM RINT RS