A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Description Pin Assignments NEW PRODUCT The ZXCT1107/09/10 are high side unipolar current sense monitors. These devices eliminate the need to disrupt the ground plane when sensing a load current. The wide common-mode input voltage range and low quiescent current coupled with SOT23 packages make them suitable for a range of applications; including adapters, automotive and systems operating from industrial 24V rails. ZXCT1107 Top View OUT • • • • Applications • • • • • S+ 2 S+ OUT Wide supply and common-mode voltage range: 2.5V to 36V SOT23 packages o 3-pin ZXCT1107/09 o 5-pin ZXCT1110 Low quiescent current (3µA). Extended industrial temperature range -40 to 125°C AEC-Q100 Grade1 Automotive qualified variants 3 ZXCT1109 Top View Quiescent current is only 3µA thereby minimising current sensing error. One external gain setting resistor increases versatility by permitting wide gain ranges. • S- 1 The device is line powered and as such doesn’t need a separate supply rail. Features 2 1 3 S- ZXCT1110 Top View NC 1 GND 2 OUT 3 5 S- 4 S+ Automotive current measurement Industrial applications current measurement Battery management Over current monitor Power Management Typical Application Circuit ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 1 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Pin Descriptions Package Name NEW PRODUCT OUT SOT23 ZXCT1107 ZXCT1109 11 11 SOT25 ZXCT1110 3 Output pin. Current output. This is the positive input of the current monitor and has a wide common-mode input range. This also acts as the analog supply and provides power to internal circuitry. The current through this pin varies with differential sense voltage. S+ 3 2 4 S- 2 3 5 GND NC - - 2 1 Notes. Description This is the negative input of the current monitor and has a wide common-mode input range. Ground pin and substrate connection. No connection 1. For the ZXCT1107 and ZXCT1109 pin 1 (OUT) acts as both the output pin and substrate connection. This means that for the ZXCT1107 and ZXCT1109 the minimum rail voltage that can be used is 2.5V + VOUT (see applications section for more details). Absolute Maximum Ratings Description Rating Unit Voltage on S- and S+ relative to OUT (ZXCT1107/9) Voltage on S- and S+ relative to GND (ZXCT1110) -0.3 to 40 -0.3 to 40 V V Voltage on OUT to GND (ZXCT1110) -0.3 to VS+ V Differential Sense Voltage, VSENSE2,3 -0.3 to 0.8 V ±8.5 -55 to 150 150 mA °C °C 300 (De-rate to Zero at 150°C) 300 (De-rate to Zero at 150°C) mW 1000 150 V V 3 Current into S+ and SStorage Temperature Maximum Junction Temperature Package Power Dissipation (TA = 25°C) SOT23 SOT25 ESD Ratings Human Body Model Machine Model Operation above the absolute maximum rating may cause device failure. Operation at the absolute maximum ratings, for extended periods, may reduce device reliability. Notes: 2. VSENSE = VS+ - VS3. The differential input voltage limit, VS+ - VS-, may be exceeded provided that the input current limit into S+ or S- is not exceeded. ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 2 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Recommended Operating Conditions Symbol NEW PRODUCT Common-mode input range : VSENSE VOUT Notes. Min Max ZXCT1110 2.5 36 ZXCT1107/9 VOUT(MAX) + 2.5 36 0 0.5 ZXCT1110 0 VS- - 1 ZXCT1107/9 0 VS+ - 2.5 -40 125 4 VS+ TA Parameter Differential Sense Input voltage range (VS+-VS-) Output voltage range (0 ≤ VSENSE ≤ 100mV) Ambient temperature range Unit V V V °C 4. For the ZXCT1107 and ZXCT1109 pin 1 (OUT) acts as both the output pin and substrate connection. This means that for the ZXCT1107 and ZXCT1109 the minimum rail voltage that can be used is 2.5V + VOUT (see applications section for more details). Electrical Characteristics (TA = 25°C, VS+ = 20V, VSENSE5 = 100mV, RGAIN = 0 unless otherwise stated) ZXCT1107, ZXCT1109 Symbol IS- Parameter S- input current Conditions VSENSE5 = 0V 5 VSENSE = 0mV 5 VSENSE = 10mV 5 VSENSE = 30mV IOUT Output current6 TA Min 25°C -40°C 125°C 10 25°C -40°C 125°C 37 45 42 49 54 25°C 115 124 134 -40°C 119 125°C 129 394 25°C 787 VSENSE5 = 200mV -40°C 25°C BW Common-Mode Sense rejection VS+ = 2.5V to 36V -3dB Small Signal Bandwidth VSENSE5 (AC) = 10mVPP RGAIN = 2.5kΩ ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 3 of 16 www.diodes.com Units nA 3 2.2 5.5 µA 408 396 420 422 810 832 785 125°C CMSR 100 1 25°C -40°C 125°C IOUT -TC Output current temperature coefficient Max 19 16 35 25°C -40°C 125°C VSENSE5 = 100mV VSENSE5 = 500mV Typ 832 1.965 2.015 2.064 -40°C 125°C 1.965 2.065 mA full range 370 ppm/ºC 25°C 0.1 -40°C 125°C 0.13 0.05 0.4 µA/V 25°C 0.65 MHz JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Electrical Characteristics (TA = 25°C, VS+ = 20V, VSENSE5 = 100mV, RGAIN = 0 unless otherwise stated) (cont.) ZXCT1110 Symbol NEW PRODUCT IQ Parameter Conditions GND pin current VSENSE5 = 0V IS- S- input current CMSR Common-Mode Sense rejection 6,7 VS+ = 2.5V to 36V VSENSE5 = 10mV IOO Output Offset current GT Transconductance 5 VSENSE = 10mV to 150mV GE Transconductance error 5 VSENSE = 10mV to 150mV IOUT GT-TC Transconductance temp.co Typ Max 25°C 3 5 -40°C 125°C 25°C 2.2 5.8 19 TA 16 35 25°C -40°C 125°C 0.1 0.13 0.05 0.4 25°C 0 ±4 -40°C 125°C 25°C -1.8 +2.5 4 BW Notes. -3dB Small Signal Bandwidth 3.928 25°C VSENSE5 (AC) = 10mVPP, RGAIN = 2.5kΩ nA µA/V µA 4.072 mA/V 3.9 4.08 -1.8 25°C Output relative to VS- 100 -40°C -40°C 125°C 1.8 265 -1 Units µA 125°C 25°C VOUTH Min % ppm/ºC -0.78 -40°C -0.88 125°C -0.63 25°C 0.65 V MHz 5. VSENSE = “VSENSE+” – “VSENSE-“ 6. Output current characteristic measured with low impedance ammeter connected to GND 7. Defined as difference between actual output current and 40µA; measured at VSENSE =10mV. This will include an error due to bias currents of the device. 8. For VSENSE > 10mV, the internal voltage-current converter is fully linear. This enables a true offset to be defined and used. ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 4 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Typical Characteristics 9.0 12 V OUT = 0V V SENSE = 0V TA = 125°C V SENSE = 0V V OUT = 0V 8.0 10 VS+ = 20V 7.0 IS+ (µA) IS+ (µA) 6.0 TA = 85°C 6 5.0 VS+ = 3.7V 4.0 TA = 25°C 4 3.0 2.0 2 TA = -40°C TA = 0°C 0 0 10 20 30 VS+ (V) Input Current vs. VS+ 1.0 0.0 -40 -25 -10 5 40 20 35 50 65 80 95 110 125 TEMPERATURE (°C) Input Current vs. Ambient Temperature 4.0 1.8 3.5 1.6 TA = 25°C VOUT = 0V VSENSE = 0V 1.4 3.0 1.2 IS- (nA) IS+ (µA) 2.5 2.0 1.5 1.0 0.8 0.6 1.0 0.4 TA = 25°C V OUT = 0V V SENSE = 0V 0.5 0.2 0.0 0.0 0 10 20 30 VS+ (V) IS+ Current vs. VS+ 40 0 10 20 30 VS+ (V) IS- Current vs. VS+ 40 450 2500 TA = 85°C V S+ = 20V V OUT = 0V 400 TA = 125°C 2000 1500 TA = 0°C TA = -40°C 1000 OUTPUT CURRENT (µA) 350 TA =25°C IOUT (µA) NEW PRODUCT 8 500 300 250 200 150 100 50 0 0 100 200 300 400 500 VSENSE (mV) Output Current vs. VSENSE ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 600 5 of 16 www.diodes.com 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 OUTPUT VOLTAGE (V) Output Current vs. Output Voltage 4.0 JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Typical Characteristics (cont.) 2500 700 600 2000 IOUT (µA) 1500 IOUT (µA) 400 300 1000 200 500 100 0 0 -40 -25 -10 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE(°C) Output Current vs. Ambient Temperature 20 35 50 65 80 95 110 125 TEMPERATURE(°C) Output Current vs. Ambient Temperature 700 5 2500 TA = 25°C VOUT = 0V 600 VSENSE = 500mV 2000 IOUT (µA) IOUT (µA) 500 400 300 1500 1000 V SENSE = 5mV V SENSE = 150mV V SENSE = 10mV VSENSE = 100mV 200 500 100 0 VSENSE = 30mV 0 4.20 10 20 30 VS+ (V) Output Current vs. VS+ 0 40 0 10 20 30 VS+ (V) Output Current vs. VS+ TA 85°C 4.05 TA = 25°C IOUT Error [VS+ = 20V] (%) 4.10 4.00 TA = 0°C 3.95 VSENSE = 500mV 0.10% V SENSE = 100mV 0.05% TA = -40°C 200 300 400 500 VSENSE (mV) Differential Gain vs. VSENSE -0.05% -0.10% ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 -0.20% 600 6 of 16 www.diodes.com VSENSE = 150mV 0.00% -0.15% 3.90 100 40 0.20% TA = 125°C 0.15% 3.85 0 V SENSE = 50mV 0.25% VS+ = 20V VOUT = 0V 4.15 DIFFERENTIAL GAIN (mA/V) NEW PRODUCT 500 -0.25% 0 VSENSE = 30mV TA = 25°C VOUT = 0V VSENSE = 50mV 10 20 30 VS+ (V) Output Current Error vs. VS+ 40 JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Typical Characteristics (cont.) 4.00% VSENSE = 100mV, VOUT = 0V TA = 125°C IOUT ERROR [VS+ = 20V] (%) NEW PRODUCT 3.00% TA = 85°C 2.00% 1.00% TA = 25°C 0.00% TA = 0°C -1.00% -2.00% TA = -40°C -3.00% -4.00% 0 10 20 30 VS+ (V) Output Current Error vs. VS+ ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 40 7 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Typical AC Characteristics -2 -2.5 Input -70 0 5 -3.5 10 15 20 25 30 35 40 45 50 TIME (µs) Small Signal Pulse Response 0 -200 5 -15 -94 Output -16 -96 -16.5 Input -18 Input -10 -19 -15 Output 5 -20 10 15 20 25 30 35 40 45 50 TIME (µs) Small Signal Pulse Response -15 VS+ = 0V, GND = -20V RGAIN = 10k -100 -15.5 -92 -25 10 15 20 25 30 35 40 45 50 TIME (µs) Large Signal Pulse Response 5 -98 VS+ = 0V, GND = -20V RGAIN = 10k -90 -21 VS+ = 0V, GND = -20V RGAIN = 10k -25 0 -20 10 15 20 25 30 35 40 45 50 TIME (µs) Large Signal Pulse Response -88 Input -20 -18 -250 0 -98 SENSE VOLTAGE (mV) Input SENSE VOLTAGE (mV) SENSE VOLTAGE (mV) -16 -150 -17 -5 -12 -14 -100 -150 0 OUTPUT VOLTAGE (V) Output -50 -13 -250 0 -10 VS+ = 0V, GND = -20V RGAIN = 10k -100 -200 -3 OUTPUT VOLTAGE (V) -40 -9 Output OUTPUT VOLTAGE (V) -1.5 -50 SENSE VOLTAGE (mV) -30 OUTPUT VOLTAGE (V) -1 -50 VS+ = 0V, GND = -20V RGAIN = 10k -0.5 OUTPUT VOLTAGE (V) SENSE VOLTAGE (mV) Output -20 -60 SENSE VOLTAGE (mV) NEW PRODUCT -10 -5 0 0 VS+ = 0V, GND = -3.7V RGAIN = 10k -102 -15.2 -15.4 -15.6 Output -104 -15.8 -16 -106 -16.2 Input -108 -16.4 OUTPUT VOLTAGE (V) 0 -16.6 -110 -100 -102 0 5 -17 10 15 20 25 30 35 40 45 50 TIME (µs) Small Signal Pulse Response ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 -112 8 of 16 www.diodes.com -16.8 0 5 -17 20 25 30 35 40 45 50 TIME (µs) Small Signal Pulse Response 10 15 JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS NEW PRODUCT Typical AC Characteristics (cont.) Test Circuit for Pulse Response 100 90 80 CMRR (dB) 70 60 50 40 30 20 10 1 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz) Common Mode Rejection Ratio CMRR Test circuit for CMRR 30 20 GAIN (dB) 10 0 -10 -20 -30 10 TA =25°C VS+ = 20V VSENSE DC = 100mV VSENSE AC = 10mVpp RGAIN = 2.5K 100 1k 10k 100k 1M FREQUENCY (Hz) Small Signal Bandwidth ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 10M Test circuit for Small signal bandwidth 9 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Application Information NEW PRODUCT Description The current monitor ICs ZXCT1107, ZXCT1109 and ZXCT1110 all use a similar application circuit topology for high-side current sensing, with small differences. The ZXCT1110 has a separate ground pin whereas the ZXCT1107 and ZXCT1109 do not. The use of ZXCT1110 allows reduction of the absolute current measurement error in some applications by providing a reduced output offset current. The ZXCT1107 provides a mirror image pin assignment of the ZXCT1109 to ease PCB layout in very small equipment designs. The basic application circuit for each device is shown in Figure 1. Two external resistors are required. The resistor RSENSE is connected in the path of the current to be monitored. The resistor RGAIN converts the device output current to a voltage for convenient processing by a further device, such as a comparator, amplifier or analog-to-digital converter within a microcontroller system. The current monitor output current is defined through the nominal transconductance of 4mA/V. IOUT = 0.004 * VSENSE Amp Equation 1 Then the resistors determine the output voltage as described below. VSENSE RSENSE VSUPPLY ZXCT1110 S+ S- GND OUT ILOAD LOAD OUTPUT VOUT RGAIN GND Figure 1. Basic Application Circuit Calculation of Resistor Values In order to select RSENSE, a choice of sense voltage is required. This often involves a compromise between power efficiency and accuracy for the given temperature range. The resistor must be small enough to avoid excessive volt drop between the power supply and the load. However, the resistor must be large enough to avoid excessive current measurement error, particularly random errors. In a typical application, a digital system, perhaps a microcontroller, is set up to monitor the current. At a certain threshold current level, ILOADT, the system is required to disconnect the load or report a fault. At this current level, the current measurement error must be limited to a known value. The total percentage error comprises the inherent error in the ZXCT1107/1109/1110 device and the tolerances of the two resistors RSENSE and RGAIN. The ZXCT1107/ZXCT1109 absolute error is shown in Table 1 with error limits drawn from the table of Electrical Characteristics above. This error varies with VSENSE. ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 10 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Application Information (cont.) The ZXCT1110 is highly linear and has a transconductance of 4mA/V ±1.8% and an output of 40µA ±4µA at VSENSE=10mV. The output current can therefore be calculated (Standard International Units) as: IOUT = (40 +/-4)*10-6 + (VSENSE-0.01)*(0.004 +/- 0.000072) Amp NEW PRODUCT The worst-case current error is then -6 IOUTERROR = IOUT – IOUTIDEAL = +/- { 4*10 or -6 IOUTERROR = +/- { 3.28*10 + (VSENSE-0.01) * 0.000072 } Amp + VSENSE * 0.000072 } A The percentage error is ε= IOUTERROR IOUTERROR * 100% = * 100% IOUTIDEAL VSENSE * 0.004 Then ε=± 3.28 * 10 −4 + VSENSE * 0.0072 % VSENSE * 0.004 or ε=± 0.082 ± 1.8% VSENSE Equation 2 This shows that the error is reduced with increasing VSENSE. Then the minimum VSENSE required to give the error ±ε % is VSENSE = 0.082 ε − 1 .8 V [only for ZXCT1110] Equation 3 In the application, the effect of the external resistor tolerances must also be taken into account. Table 1: ZXCT1107/ZXCT1109 Error VSENSE Mean IOUT Error Band Percent Error 10mV 45.5 µA ±8.5µA ±18.7% 30mV 100mV 200mV 124.5 µA 408 µA 809.5 µA ±9.5µA ±14µA ±22.5µA ±7.6% ±3.4% ±2.8% VSENSE Mean IOUT Error Band Percent Error 10mV 30mV 100mV 200mV 40µA 120µA 400µA 800µA ±4µA ±5.44µA ±10.48µA ±17.68µA ±10% ±4.53% ±2.62% ±2.21% Table 2: ZXCT1110 Error ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 11 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Application Information (cont.) Note that in order to avoid additional error, VSUPPLY must be at least 1.5V greater than VOUT. This margin depends on the value of VSENSE. For VSENSE = 100mV, this margin can be reduced to 1.0V. NEW PRODUCT RSENSE is chosen based on the threshold VSENSET of sense voltage selected as above, for the chosen threshold load current, ILOADT. R SENSE = VSENSET ILOADT Equation 4 RGAIN is chosen to give the required threshold output voltage, VOUTT. From Equation 1, the threshold output current is IOUTT = 0.004 * VSENSET or R GAIN = VOUTT IOUTT R GAIN = VOUTT 0.004 * VSENSET Equation 1a Equation 5 Design Example A current monitor is required to provide an output voltage of 2V ±6% when the load current of a 12V supply is 2A. Resistors are available with 1% tolerance. The sense and output resistors will contribute a total possible error of 2%, so the ZXCT11xx error must not exceed 4%. From Table 1, the error of ZXCT1107/1109 will be 3.4% if the sense voltage is 100mV. This satisfies the total error requirement of 6%. Equation 4 gives RSENSE = 100mV/2A = 50mΩ Equation 5 gives R GAIN = 2 = 5kΩ 0.004 * 0.1 A suitable preferred value is 5.1kΩ. This gives a systematic error of +2%, which can be compensated elsewhere in the system if desired. Figure 2 shows the resulting schematic. 50mΩ VSUPPLY ZXCT1107 or ZXCT1109 ILOAD S- S+ LOAD OUT OUTPUT VOUT 5k1 GND Figure 2. Example Circuit using ZXCT1107/ZXCT1109 ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 12 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS Application Information (cont.) Alternatively, the ZXCT1110 may be used with a reduced sense voltage if desired. From Equation 3, with ε=4%, NEW PRODUCT VSENSE = 0.082 = 0.082/(4-1.8) = 37.2mV ε − 1 .8 Equation 4 gives RSENSE = 37.2mV/2A = 18.6mΩ A suitable preferred value is 20mΩ. Then the sense voltage will be 2A * 20mΩ = 40mV. Equation 5 gives R GAIN = 2 = 12500Ω 0.004 * 0.04 A suitable preferred value is 13kΩ. The alternative example circuit using the ZXCT1110 with a sense voltage of 40mV is shown in Figure 3, giving the required overall accuracy of ±6%. 20mΩ VSUPPLY ZXCT1110 S+ S- GND OUT ILOAD LOAD OUTPUT VOUT 13k GND Figure 3. Example Circuit using ZXCT1110 Protection Against Load Short Circuit In the event of a load short circuit or overload, a large proportion of the supply voltage may appear between the sense terminals. The supply may be current limited, but there is normally a large reservoir capacitor which can deliver enough energy to damage the ZXCT11xx before the supply voltage falls to a safe level due to current limit activation. The ZXCT11xx is rated for a maximum sense voltage of +0.8V, but is safe if the input current is limited to ±8.5mA. In Figure 4, the resistor RPROT limits the current and therefore protects the current monitor device against load short circuit without introducing significant current measurement error. ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 13 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS NEW PRODUCT Application Information (cont.) Figure 4. Protection and EMC Filtering EMC Susceptibility In many applications, the circuit is required to operate in the presence of RF radiation. This radiation is coupled into the circuit via the supply or load connections and will often cause significant bias shift due to rectification within the integrated circuit. The bias shift may lead to erroneous operation of the integrated circuit. In Figure 4, a low pass filter, RPROT and C1, provides significant attenuation in the VHF and UHF regions. The value of C1 is recommended to be in the range of 10pF to 47pF, leadless ceramic type. PCB Layout Considerations It is necessary to take into account a small volt drop in the PCB copper and solder joints to RSENSE. Such volt drops can create noticeable error at currents of the order of 1A and greater. The PCB must be designed to provide the maximum possible copper carrying current via the sense resistor, and the traces from the S+ and S- pins must be connected only to the resistor pads. In this way, the effect of the copper is minimized. If used, the capacitor C1 should be placed very close the input pins S+ and S-. Application: High Voltage Current Monitor The schematic of Figure 5 shows how the current monitor may be used in a high voltage application such as a TV LED backlight system. In this configuration the 500V PNP transistor Q1 drops a large proportion of the supply voltage. Diode D2 limits the differential input voltage to a safe level under overload conditions. The voltage across U1 is limited by the zener diode D1. The output current of U1 is limited to about 3mA by the D2. As RGAIN is typically a few kΩ, the output voltage is therefore limited to a few volts. An additional output clamping diode may be required for higher gains. R1 is chosen to give a suitable bias current in D1 for the given supply voltage range. Figure 5. 450V Current Monitor ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 14 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS NEW PRODUCT Ordering Information Order Reference Package ZXCT1107SA-7 ZXCT1109SA-7 ZXCT1110W5-7 SOT23 SOT23 SOT25 Device Marking 1107 1109 1110 Reel Size 7”, 180mm 7”, 180mm 7”, 180mm Quantity Per Reel 3000 3000 3000 Tape Width (mm) 8 8 8 Package Outline Dimensions (All Dimensions in mm) Package type: SOT23 A B C H K M K1 D J F L G SOT23 Dim Min Max Typ A 0.37 0.51 0.40 B 1.20 1.40 1.30 C 2.30 2.50 2.40 D 0.89 1.03 0.915 F 0.45 0.60 0.535 G 1.78 2.05 1.83 H 2.80 3.00 2.90 J 0.013 0.10 0.05 K 0.903 1.10 1.00 K1 0.400 L 0.45 0.61 0.55 M 0.085 0.18 0.11 0° 8° α All Dimensions in mm Package type: SOT25 A SOT25 Dim Min Max Typ A 0.35 0.50 0.38 B 1.50 1.70 1.60 C 2.70 3.00 2.80 D ⎯ ⎯ 0.95 H 2.90 3.10 3.00 J 0.013 0.10 0.05 K 1.00 1.30 1.10 L 0.35 0.55 0.40 M 0.10 0.20 0.15 N 0.70 0.80 0.75 0° 8° α ⎯ All Dimensions in mm B C H K J M N D ZXCT1107/1109/1110 Document number: DS35033 Rev. 3 - 2 L 15 of 16 www.diodes.com JULY 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXCT1107/1109/1110 LOW POWER HIGH-SIDE CURRENT MONITORS IMPORTANT NOTICE NEW PRODUCT DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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