DIO2388ASC6

Rev 1.1 DIO2388A/B Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor Features Descriptions Wide common-mode range: -0.3V to 26V The DIO2388x series of voltage output current Offset voltage: 90µV (Max) shunt monitors can sense drops across shunts at (Enable shunt drops of 10mV full-scale) common-mode Accuracy independent of the supply voltage. Two fixed gains – ±1.5% Gain error (Max over temperature) are available: 50V/V and 100V/V. The low offset of – 0.5µV/℃ Offset drift (Typ) the Zero-Drift architecture enables current sensing – 10ppm/℃ Gain drift (Max) with maximum drops across the shunt as low as voltages from -0.3V to 26V, 10mV full-scale. Choice of Gains: – DIO2388A: 50V/V – DIO2388B: 100V/V These devices operate from a single +2.7V to +26V power supply, drawing a maximum of 100µA of Quiescent current: 100µA (Max) supply current. All versions are specified from Packages: SC70-6, thin DQFN-10 -40℃ to +105℃, and offered in both SC70-6 and thin DQFN-10 packages. Applications Block Diagram Notebook Computers Cell Phones Supply Reference Voltage Telecom Equipment RSHUNT Load Power Management REF Battery Chargers OUT Output Welding Equipment GND +2.7V to +26V Order Part Number Top Marking R3 R2 R4 ININ+ V+ CBYPASS 0.01µF To 0.1µF Ordering Information R1 TA Package DIO2388ASC6 YWZX Green -40 to +85°C SC70-6 Tape & Reel, 3000 DIO2388BSC6 YWZX Green -40 to +85°C SC70-6 Tape & Reel, 3000 Green -40 to +85°C DQFN-10 Tape & Reel, 3000 Green -40 to +85°C DQFN-10 Tape & Reel, 3000 DIO2388ALP10 DIO2388BLP10 www.dioo.com YW ZX YW ZX © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 DIO2388A/B Pin Assignments SC70-6 DQFN-10 Figure 1 Pin Assignment Pin Description www.dioo.com Pin name Description REF Reference voltage GND Ground V+ Positive supply IN+ Positive Input IN- Negative Input OUT Output NC No connection © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor Marking Definition DIO2388A/B Stresses beyond those listed under “Absolute Maximum Rating” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other condition beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maxim rating conditions for extended periods may affect device reliability. Parameter Rating Unit +26 V -26 to +26 V GND-0.3 to +26 V ERF Input GND-0.3 to (V+)+0.3 V Output GND-0.3 to (V+)+0.3 V 5 mA Operating Temperature -40 to +105 ℃ Storage Temperature -65 to +150 ℃ Junction Temperature +150 ℃ SC70-6 250 ℃/W DQFN-10 80 ℃/W Supply Voltage Differential (VIN+) – (VIN-) Analogy Inputs, VIN+, VINCommon-mode Input Current Into All Pins Thermal Resistance θJA ESD HBM V 3000 Electrical Characteristics Typical value: TA = 25°C, VS=+5V, VIN+=12V, VSENSE=VIN+-VIN-, and VREF=VS/2, unless otherwise specified. Symbol Parameter Conditions Min. Typ. Max. Unit 26 V Input VCM Common-Mode Input Range CMR Common-Mode Rejection VOS dVOS/dT www.dioo.com -0.3 VIN+=0V to +26V, VSENSE=0mV 100 120 dB VSENSE=0mV, Vcom=VDD/2 ±5 ±40 µV VSENSE=0mV, Vcom=12V ±5 ±90 µV Offset Voltage, RTI Input vs Temperature 0.5 µV/°C © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor Absolute Maximum Ratings DIO2388A/B VS=+2.7V to +18V, VIN+=+18V, VSENSE=0mV IB Input Bias Current IOS Input Offset Current ±0.1 µV/V VSENSE=0mV 28 µA VSENSE=0mV ±0.02 µA Output G DIO2388A 50 DIO2388B 100 V/V Gain Gain Error VSENSE=-8mV to 8mV Output vs Temperature Nonlinearity Error VSENSE=-8mV to 8mV Maximum Capacitive Load No Sustained Oscillation ±0.03 ±1.5 % 3 10 ppm/°C ±0.01 % 1 nF Voltage Output Swing to V+ Power-Supply Rail Swing to GND RL=10kΩ to GND RL=10kΩ to GND (V+) (V+) - - 0.05 0.2 (VGND) (VGND) + + 0.005 0.05 V V Frequency Response BW SR CLOAD=10pF, DIO2388A 5 CLOAD=10pF, DIO2388B 5 kHz f (-3dB) Bandwidth 0.007 Slew Rate V/µs Power Supply VS Operating Voltage Range IQ Quiescent Current +2.7 VSENSE=0mV 65 Over Temperature +26 V 100 µA 125 µA Noise, RTI Voltage Noise Density 25 nV/√Hz Notes: RTI = Referred-to-input Specifications subject to change without notice. www.dioo.com © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor Input vs Power Supply PSR DIO2388A/B Typical value: TA = 25°C, VS=+5V, VIN+=12V, VSENSE=VIN+-VIN-, and VREF=VS/2, unless otherwise specified. Figure 2. Quiescent Current Vs. Supply Voltage Figure 4. Offset Voltage Vs. Supply Voltage Figure 6. Offset Voltage Vs. Common-Mode Voltage www.dioo.com Figure 3. Quiescent Current Vs. Temperature Figure 5. Offset Voltage Vs. Temperature Figure 7. Offset Voltage Vs. Common-Mode Voltage © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor Typical Performance Characteristics DIO2388A/B Typical value: TA = 25°C, VS=+5V, VIN+=12V, VSENSE=VIN+-VIN-, and VREF=VS/2, unless otherwise specified. Figure 8. PSRR Vs. Frequency www.dioo.com Figure 9. CMRR Vs. Frequency © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor Typical Performance Characteristics (Continuted) DIO2388A/B Supply Reference Voltage RSHUNT REF GND +2.7V to +26V CBYPASS 0.01µF To 0.1µF OUT R1 R3 R2 R4 Load Output ININ+ V+ Figure 10. Input and Output AC-Coupling Application Figure 10 shows the basic connections for the DIO2388x. 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. On the RSW package, two pins are provided for each input. These pins should be tied together (that is, tie IN+ to IN+ and tie IN– to IN–). Power Supply The input circuitry of the DIO2388x can accurately measure beyond its power-supply voltage, V+. For example, the V+ power supply can be 5V, whereas the load power-supply voltage can be as high as +26V. However, the output voltage range of the OUT terminal is limited by the voltages on the power-supply pin. Note also that the DIO2388x 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 DIO2388x 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 shunt monitors typically require a full-scale range of 100mV. The DIO2388x series of current-shunt monitors give 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 DIO2388x 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. www.dioo.com © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor Typical Application DIO2388A/B 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 DIO2388x 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 11 shows a filter placed at the inputs pins. Figure 11. Filter at Input Pins The addition of external series resistance, however, creates an additional error in the measurement so the value of these series resistors should be kept to 10Ω or less if possible to reduce impact to accuracy. The internal bias network shown in Figure 11 present at the input pins creates a mismatch in input bias currents when a differential voltage is applied between the input pins. If additional external series filter resistors are added to the circuit, the mismatch in bias currents results in a mismatch of voltage drops across the filter resistors. This mismatch creates a differential error voltage that subtracts from the voltage developed at the shunt resistor. This error results in a voltage at the device input pins that is different than the voltage developed across the shunt resistor. Without the additional series resistance, the mismatch in input bias currents has little effect on device operation. The amount of error these external filter resistor add to the measurement can be calculated using Equation 2 where the gain error factor is calculated using Equation 1. The amount of variance in the differential voltage present at the device input relative to the voltage developed at the shunt resistor is based both on the external series resistance value as well as the internal input resistors, R3 and R4 (or RINT as shown in Figure 11). The reduction of the shunt voltage reaching the device input pins appears as a gain error when comparing the output voltage relative to the voltage across the shunt resistor. A factor can be calculated to determine the amount of gain error that is introduced by the addition of external series resistance. The equation used to calculate the expected deviation from the shunt voltage to what is seen at the www.dioo.com © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor A less frequent case of unipolar output biasing is to bias the output by connecting the REF pin to the supply; in DIO2388A/B Gain Error Factor = (1250 × RINT ) (1250 × RS ) + (1250 × RINT ) + (RS × RINT ) (1) Where: RINT is the internal input resistor (R3 and R4), and RS is the external series resistance. With the adjustment factor equation including the device internal input resistance, this factor varies with each gain version, as shown in Table1. Each individual device gain error factor is shown in Table 2. Table 1. Input Resistance Product Gain RINT(kΩ) DIO2388A 50 20 DIO2388B 100 10 Table 2. Device Gain Error Factor Product Simplified Gain Error Factor DIO2388A 20， 000 (17 × RS ) + 20， 000 DIO2388B 20， 000 (9 × RS ) + 20， 000 The gain error that can be expected from the addition of the external series resistors can then be calculated based on Equation 2: Gain Error (%)= 100-(100*Gain Error Factor) (2) Shutting Down the DIO2388x Series While the DIO2388x series does not have a shutdown pin, the low power consumption allows powering from the output of a logic gate or transistor switch that can turn on and turn off the DIO2388x power-supply quiescent current. However, in current shunt monitoring applications. there is also a concern for how much current is drained from the shunt circuit in shutdown conditions. Evaluating this current drain involves considering the simplified schematic of the DIO2388x in shutdown mode shown in Figure 12. www.dioo.com © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor device input pins is given in Equation 1: DIO2388A/B Note that there is typically slightly more than 1MΩ impedance (from the combination of 1MΩ feedback and 5kΩ input resistors) from each input of the DIO2388x to the OUT pin and to the REF pin. The amount of current flowing through these pins depends on the respective ultimate connection. For example, if the REF pin is grounded, the calculation of the effect of the 1MΩ impedance from the shunt to ground is straightforward. However, if the reference or op amp is powered while the DIO2388x is shut down, the calculation is direct; instead of assuming 1MΩ to ground, however, assume 1MΩ to the reference voltage. If the reference or op amp is also shut down, some knowledge of the reference or op amp output impedance under shutdown conditions is required. For instance, if the reference source behaves as an open circuit when it is unpowered, little or no current flows through the 1MΩ path. Regarding the 1MΩ path to the output pin, the output stage of a disabled DIO2388x does constitute a good path to ground; consequently, this current is directly proportional to a shunt common-mode voltage impressed across a 1MΩ resistor. As a final note, when the device is powered up, there is an additional, nearly constant, and well-matched 25μA that flows in each of the inputs as long as the shunt common-mode voltage is 3V or higher. Below 2V commonmode, the only current effects are the result of the 1MΩ resistors. REF Input Impedance Effects As with any difference amplifier, the DIO2388x series common-mode rejection ratio is affected by any impedance present at the REF input. This concern is not a problem when the REF pin is connected directly to most references or power supplies. When using resistive dividers from the power supply or a reference voltage, the REF pin should be buffered by an op amp. In systems where the DIO2388x output can be sensed differentially, such as by a differential input analog-to-digital converter (ADC) or by using two separate ADC inputs, the effects of external impedance on the REF input can be cancelled. Figure 13 depicts a method of taking the output from the DIO2388x by using the REF pin as a reference. www.dioo.com © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor Figure 12. Basic Circuit for Shutting Down DIO2388x with Grounded Reference DIO2388A/B Using the DIO2388x with common-mode transients above 26V With a small amount of additional circuitry, the DIO2388x series can be used in circuits subject to transients higher than 26V, such as automotive applications. Use only zener diode or zener-type transient absorbers (sometimes referred to as Transzorbs); any other type of transient absorber has an unacceptable time delay. Start by adding a pair of resistors as shown in Figure 14 as a working impedance for the zener. It is desirable to keep these resistors as small as possible, most often around 10Ω. Larger values can be used with an effect on gain that is discussed in the section on input filtering. Because this circuit limits only short-term transients, many applications are satisfied with a 10Ω resistor along with conventional zener diodes of the lowest power rating that can be found. This combination uses the least amount of board space. RSHUNT Supply RPROTECT 10Ω Load RPROTECT 10Ω Reference Voltage GND Shutdown Control Output OUT REF 1MΩ V+ R3 IN- R4 IN+ 1MΩ CBYPASS Figure 14. DIO2388x Transient Protection Using Dual Zener Diodes In the event that low-power zeners do not have sufficient transient absorption capability and a higher power transzorb must be used, the most package-efficient solution then involves using a single transzorb and back-toback diodes between the device inputs. This method is shown in Figure 15. The most space-efficient solutions are dual series-connected diodes in a single SOT-523 or SOD-523 package. In both examples shown in Figure 14 and Figure 15, the total board area required by the DIO2388x with all protective components is less than that of an SO-8 package, and only slightly greater than that of an MSOP-8 package. www.dioo.com © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor Figure 13. Sensing DIO2388x to Cancel Effects of Impedance on the REF Input DIO2388A/B RPROTECT 10Ω Load RPROTECT 10Ω Reference Voltage REF GND Shutdown Control OUT 1MΩ V+ R3 IN- R4 IN+ Output 1MΩ CBYPASS Figure 15. DIO2388x Transient Protection Using a Single Transzorb and Input Clamps Improving transient robustness Applications involving large input transients with excessive dV/dt above 2kV per microsecond present at the device input pins may cause damage to the internal ESD structures on version A devices. This potential damage is a result of the internal latching of the ESD structure to ground when this transient occurs at the input. With significant current available in most current-sensing applications, the large current flowing through the input transient-triggered, ground-shorted ESD structure quickly results in damage to the silicon. External filtering can be used to attenuate the transient signal prior to reaching the inputs to avoid the latching condition. Care must be taken to ensure that external series input resistance does not significantly impact gain error accuracy. For accuracy purposes, these resistances should be kept under 10Ω if possible. Ferrite beads are recommended for this filter because of their inherently low dc ohmic value. Ferrite beads with less than 10Ω of resistance at dc and over 600Ω of resistance at 100MHz to 200MHz are recommended. The recommended capacitor values for this filter are between 0.01µF and 0.1µF to ensure adequate attenuation in the high-frequency region. This protection scheme is shown in Figure 16. Figure 16. Transient Protection To minimize the cost of adding these external components to protect the device in applications where large transient signals may be present, version B devices are now available with new ESD structures that are not susceptible to this latching condition. Version B devices are incapable of sustaining these damage causing latched conditions so they do not have the same sensitivity to the transients that the version A devices have, thus making the version B devices a better fit for these applications. www.dioo.com © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor RSHUNT Supply DIO2388A/B Dioo is a professional design and sales corporation for high-quality and performance analog semiconductors. The company focuses on industry markets, such as, cell phone, handheld products, laptop, and medical equipment and so on. Dioo’s product families include analog signal processing and amplifying, LED drivers and charger IC. Go to http://www.dioo.com for a complete list of Dioo product families. For additional product information, or full datasheet, please contact with our Sales Department or Representatives. www.dioo.com © 2017 DIOO MICROCIRCUITS CO., LTD DIO2388A/B• Rev. 1.1 Voltage Output, High or Low Side Measurement, Bi-Directional Zero-Drift Series Current Shunt Monitor CONTACT US