IXYS IXI848A High-Side Current Monitor Features: General Description • High-Side Current Sense Amplifier The IXI848A is a precision high side current sense monitor. High side power-line monitoring offers the advantage of allowing the ground plane to remain undisturbed when sensing load currents. • 2.7V to 60V Input Range • 0.7% Typical Full Scale Accuracy • Scalable Output Voltage An external sense resistor sets the range of the amplified ground-referenced output monitoring voltage. The output voltage is amplified by a selectable fixed gain of either 10 or 50. With an input voltage range up to 60V, and output gain of up to 50, the IXI848A is designed to address a wide variety of current sense applications. • SOIC Package Applications: • Power Management Systems • Smart Battery Packs • Battery Chargers The IXI848A operates over a temperature range of -40°C to +85°C. The IXI848A is available in an 8Lead SOIC package. • Battery Powered Portable Equipment • DC Motor Control IXI848A Functional Block Diagram and General Application Circuit IXI848A SOIC PIN Configuration Rs 5 4 IN LOAD GND 1 8 R50 R10 2 7 N/C VOUT 3 6 N/C IN 4 5 LOAD R IL - + LOAD SOIC-8 3 10R RG 40R RG 2 8 1 VOUT R10 R50 GND Copyright © IXYS CORPORATION 2005 Zm Ordering Information Part No. Description Package Quantity IXI848AS1 98 (Tube) High Side Current SOIC-8 XI848AS1T/R Sense Monitor SOIC-8 2500 (T&R) 08/01/05 IXYS IXI848A Absolute Maximum Ratings Parameter Rating Voltage to IN (pin 4) Differential Input Voltage (VSENSE) Input Current to any pin Operating Ambient Temp Range Operating Junction Temp Range θJA θJC Storage Temp Range Lead Temperature (Soldering, 10 sec) -0.3V to +65V ±0.4V ±10mA -40°C to +85°C -40°C to +125°C 150°C/W 40°C/W -65°C to +150°C +300°C Absolute Maximum Ratings are stress ratings. Stresses in excess of these ratings can cause permanent damage to the device. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this data sheet is not implied. Exposure of the device to the absolute maximum ratings for an extended period may degrade the device and affect its reliability. ESD Warning ESD (electrostatic discharge) sensitive device. Although the IXI848A feature proprietary ESD protection circuitry, permanent damage may be sustained if subjected to high energy electrostatic discharges. Proper ESD precautions are recommended to avoid performance degradation or loss of functionality. Electrical Characteristics TA = 25°C, VIN = 2.7V to 40V, unless otherwise noted Parameter Symbol Operating Voltage Range VIN Supply Current IIN Full Scale Sense Voltage Input Offset Voltage Full Scale Accuracy Min VOS Gain Accuracy (Note 2) RG Typ 2.7 VIN = 20V, VSENSE = 0V, ILOAD = 0A .065 Max Unit 60 V .130 mA 150 VSENSE Total OUT Voltage Error (Note 1, Note 2) Gain Setting Resistance Conditions VIN = 12V -2.0 VSENSE = 100mV, VIN = 12V TA = +25°C VSENSE = 100mV TA = +25°C VIN = 12V ∆ @ TA = -40° to +85°C VSENSE = 100mV TA = +25°C VIN = 40V ∆ @ TA = -40° to +85°C VSENSE = 20mV TA = +25°C to 100mV ∆ @ TA = -40° to +85°C VIN = 12V, 40V VIN = 12V Gain = 10V/V VSENSE = 100mV Gain = 50V/V ±0.5 mV 2.0 ±0.7 % ±0.7 ±0.3 ±0.8 ±0.4 % % ±0.5 23 115 ±0.1 33 165 mV % 43 215 kΩ kΩ Note 1: Total OUT voltage error is the sum of gain and offset voltage errors. Note 2: Production Tested at TA =25°C. www.ixys.com 2 08/01/05 IXYS IXI848A Pin Description and Configuration SOIC Name Description 1 GND Ground 2 R10 Connecting R10 to GND, (R50=N/C) selects a VOUT voltage that is 10X the voltage across RSENSE. 3 4 5 6 7 VOUT IN LOAD N/C N/C 8 R50 Output voltage proportional to the voltage across RSENSE. Positive supply terminal and power connection for the external Sense Resistor. Load-side connection to the external Sense Resistor. No Connect No Connect Connecting R50 to GND, (R10=N/C) selects a VOUT voltage that is 50X the voltage across RSENSE. Detailed Circuit Description the error component associated with the input offset voltage of the internal op amp. The IXI848A is a precision high side current sense monitor featuring an input voltage range of 2.7V to 60V, and a selectable ground referenced fixed gain output of either 10 or 50. The IXI848A can be configured to measure a wide selection of currents by using different RSENSE values. Some common values for typical operation of the IXI848A are listed in the following table. A small voltage developed across an external sense resistor (RS), is converted to an amplified ground referenced voltage output at VOUT, (Figure 1). The amplifier’s non-inverting input is high impedance making the voltage at that terminal equal to VIN – (IL) (RS). The amplifier forces the high impedance inverting terminal to equal the non-inverting input voltage by turning on the P-Channel MOS FET. Full-Scale IL (A) 0.15 1.5 5 100 As the P-Channel MOS FET is biased on by the amplifier output, current is sourced through RG (10R or 10R+40R), to produce a voltage equal to VIN – (IL) (RS) at the inverting input of the amplifier. This develops a voltage across the inverting input resistor, R that matches the sense voltage across RS, plus any associated input offset voltage, (VIO). Consequently, the voltage at VOUT corresponds to RG / R. Gain (V/V) 10 10 50 50 VOUT (V) VSENSE = 150mV 1.5 1.5 2.5 5 Output Impedance The VOUT output is a current source driving a 33kΩ resistance to ground for a gain of 10, or a 165kΩ resistance to ground for a gain of 50. Output gain is reduced by resistive loading of the VOUT terminal. The impedance of the external monitor load (ZM) should be chosen high enough to maintain the desired accuracy. Buffering of the VOUT terminal with a high-impedance input stage may be required to minimize output errors. Output: VOUT = G [ (IL) (RS) + VIO ] Gain: RSENSE RS (Ω) 1.0 0.1 0.01 0.001 G = (RG) (ZM) / R (RG (RG + ZM)) The following formulas quantify the percent error introduced by output loading: RG = 10R or 50R selectable Temperature coefficient: (all on-chip resistors) R = 700ppm / °C typical For a Gain of 10 %ERROR = 100 [RLOAD / (33kΩ + RLOAD) – 1] RSENSE Component Selection The RSENSE value should be selected such that the voltage across RSENSE is at full-scale for the load current to be monitored. Operating the IXI848A at or near the full-scale sense voltage will minimize For a Gain of 50 %ERROR = 100 [RLOAD / (165kΩ + RLOAD) – 1] www.ixys.com RLOAD = the external load applied to VOUT 3 08/01/05 IXYS IXI848A .125 .080 .105 .075 Supply Current (mA) Supply Current (mA) Typical Performance Characteristics .085 .065 .045 .025 .005 2.7 5 10 15 20 25 30 Supply Voltage (Vin) 35 Vin=20V .070 .065 .060 .055 .050 -40 40 Fig 3. Supply Current vs. Voltage -15 60 85 Fig 4. Supply Current vs. Temperature Gain=10 Gain=10 CL=8pF Vin=12V CL=8pF 10 35 Ta (°C) 100mV Vsense 100mV Vsense 5mV/Div Vin=12V 45mV/Div 95mV 6mV 1V Vout 1V Vout 0.95V 20mV/Div 0.06V 500mV/Div 2uS/Div 2uS/Div Fig 5. Small Signal Transient Response 10X Fig 6. Large Signal Transient Response 10X Gain=50 Gain=50 CL=8pF CL=8pF Vin=12V 45mV/Div 95mV 6mV 5V 5v Vout Vout 2V/Div 4.75V 100mV/Div 0.3V 10uS/Div 10uS/Div Fig 7. Small Signal Transient Response 50X www.ixys.com 100mV Vsense 100mV Vsense 5mV/Div Vin=12V Fig 8. Large Signal Transient Response 50X 4 08/01/05 IXYS IXI848A Package Outline 8-LEAD SOIC IXYS Corporation makes no representations or warranties with respect to the accuracy or completeness of the contents of this publication and reserves the right to make changes to specifications and product descriptions at any time without notice. Neither circuit patent licenses nor indemnity are expressed or implied. Except as set forth in IXYS’ Standard Terms and Conditions of Sale, IXYS Corporation assumes no liability whatsoever, and disclaims any expressed or implied warranty, relating to its products including, but not limited to, the implied warranty of merchantability, fitness for a particular purpose, or infringement of any intellectual property right. www.ixys.com 5 08/01/05