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Part: MAX471
Category:
Analog & Mixed-Signal Processing
-> Amplifiers
-> Current Sense Amplifiers
Description: Precision, High-side Current-sense Amplifiers
Company: Maxim Integrated Products
Datasheet: Download MAX471 datasheet File size : 261 kB
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Datasheet text preview:
19-0335; Rev 2; 12/96
Precision, High-Side Current-Sense Amplifiers
_______________General Description
The MAX471/MAX472 are complete, bidirectional, highside current-sense amplifiers for portable PCs, telep h o n e s , and other systems where battery/DC power-line monitoring is critical. High-side power-line monitoring is especially useful in battery-powered systems, since it does not interfere with the ground paths o f the battery chargers or monitors often found in "smart" batteries. The MAX471 has an internal 35m current-sense resistor and measures battery currents up to ±3A. For applications requiring higher current or increased flexibility, the MAX472 functions with external sense and gain-setting resistors. Both devices have a current output that can be converted to a ground-referred voltage with a single resistor, allowing a wide range of battery voltages and currents. An open-collector SIGN output indicates current-flow direction, so the user can monitor whether a battery is being charged or discharged. Both devices operate from 3V to 36V, draw less than 100µA over temperature, and include a 18µA max shutdown mode.
____________________________Features
o Complete High-Side Current Sensing o Precision Internal Sense Resistor (MAX471) o 2% Accuracy Over Temperature o Monitors Both Charge and Discharge o 3A Sense Capability with Internal Sense Resistor (MAX471) o Higher Current-Sense Capability with External Sense Resistor (MAX472) o 100µA Max Supply Current o 18µA Max Shutdown Mode o 3V to 36V Supply Operation o 8-Pin DIP/SO Packages
MAX471/MAX472
______________Ordering Information
PART MAX471CPA MAX471CSA MAX471EPA MAX471ESA MAX472CPA MAX472CSA MAX472EPA MAX472ESA TEMP. RANGE 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C PIN-PACKAGE 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO
________________________Applications
Portable PCs: Notebooks/Subnotebooks/Palmtops Smart Battery Packs Cellular Phones Portable Phones Portable Test/Measurement Systems Battery-Operated Systems Energy Management Systems
__________Typical Operating Circuit
RS+ RS+ RSRSILOAD TO LOAD or CHARGER S LOGIC UPPLY 100k T 3V 3O 6V SHDN
________________Pin Configurations
TOP VIEW
SHDN
1
8 7
OUT RSRSSIGN
MAX471
GND
RS+ 2 DISCHARGE/CHARGE VOUT (1V/A) RS+ 3 GND 4
SIGN OUT I2 OAD L 000 2k
D AX471 M
6 5
IP/SO
_
MAX472 Pin Configuration continued on last page.
________________________________________________________________ Maxim Integrated Products 1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
Precision, High-Side Current-Sense Amplifiers MAX471/MAX472
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, RS+, RS-, VCC to GND...........-0.3V, +40V RMS Current, RS+ to RS- (MAX471 only)..±3.3A Peak Current, (RS+ to RS-) .....see Figure 5 Differential Input Voltage, RG1 to RG2 (MAX472 only) .....±0.3V Voltage at Any Pin Except SIGN MAX471 only ..........-0.3V to (RS+ - 0.3V) MAX472 only .........-0.3V to (VCC + 0.3V) Voltage at SIGN......-0.3V to +40V Current into SHDN, GND, OUT, RG1, RG2, VCC .......±50mA Current into SIGN.......+10mA, -50mA Continuous Power Dissipation (TA = +70°C) MAX471 (Note 1): Plastic DIP (derate 17.5mW/°C above +70°C) .........1.4W SO (derate 9.9mW/°C above +70°C) .....791mW MAX472 : Plastic DIP (derate 9.09mW/°C above +70°C) .....727mW SO (derate 5.88mW/°C above +70°C) ...471mW Operating Temperature Ranges MAX47_C_A ........0°C to +70°C MAX47_E_A .....-40°C to +85°C Junction Temperature Range ....-60°C to +150°C Storage Temperature Range .....-60°C to +160°C Lead Temperature (soldering, 10sec) .....+300°C
Note 1: Due to special packaging considerations, MAX471 (DIP, SO) has a higher power dissipation rating than the MAX472. RS+ and RS- must be soldered to large copper traces to achieve this dissipation rating.
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS--MAX471
(RS+ = +3V to +36V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Supply Voltage Supply Current Sense Current Sense Resistor Current-Sense Ratio No-Load OUT Error Low-Level OUT Error Power-Supply Rejection Ratio SIGN Threshold (ILOAD required to switch SIGN) SIGN Output Leakage Current SIGN Sink Current Shutdown Supply Current SHDN Input Low Voltage SHDN Input Low Current SHDN Input High Voltage SHDN Input High Current OUT Output Voltage Range OUT Output Resistance OUT Rise, Fall Time OUT Settling Time to 1% of Final Value 2 IOL PSRR SYMBOL VRS+ IRS+ ILOAD RSENSE IOUT/ ILOAD MAX471C ILOAD = 1A, RS+ = 10V MAX471E MAX471C ILOAD = 0A, RS+ = 10V MAX471E MAX471C ILOAD = 30mA, RS+ = 10V MAX471E 3V RS+ 36V, ILOAD = 1A MAX471C MAX471E VSIGN = 36V VSIGN = 0.3V 0.1 1.5 18.0 0.3 1.0 2.4 VSHDN = 2.4V 0 ILOAD = 3.0A, VOUT = 0V to (VRS+ - 1.5V) ILOAD = 50mA to 3.0A, ROUT = 2k, COUT = 50pF, 10% to 90% ILOAD = 100mA to 3.0A, ROUT = 2k, COUT = 50pF 1 3 4 15 1.0 VRS+ - 1.5 IRS+(SHDN) VSHDN = 2.4V; VCC = 3V to 20V VIL IIL VIH IIH VOUT ROUT tR, tF ts VSHDN = 0V 0.490 0.4875 35 0.500 0.500 ILOAD = 0A, excludes ISIGN CONDITIONS MIN 3 50 TYP MAX 36 113 ±3 70 0.510 0.5125 2.5 3.0 ±2.5 ±3.0 0.1 ±6.0 ±7.0 1.0 UNITS V µA ARMS m mA/A µA µA %/V mA µA mA µA V µA V µA V M µs µs
±4.0
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Precision, High-Side Current-Sense Amplifiers
ELECTRICAL CHARACTERISTICS--MAX472
(VCC = +3V to +36V, RG1 = RG2 = 200, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Supply Voltage Supply Current Input Offset Voltage (Note 2) Input Bias Current Input Bias-Current Matching OUT Current Accuracy No-Load OUT Error Low-Level OUT Error Power-Supply Rejection Ratio SIGN Threshold (VSENSE required to switch SIGN) SIGN Output Leakage Current SIGN Output Sink Current Shutdown Supply Current SHDN Input Low Voltage SHDN Input Low Current SHDN Input High Voltage SHDN Input High Current OUT Output Voltage Range OUT Output Resistance OUT Rise, Fall Time OUT Settling Time to 1% of Final Value Maximum Output Current ICC(SHDN) VIL IIL VIH IIH VOUT ROUT tR, tF ts IOUT IOUT = 1.5mA VSENSE = 5mV to 150mV, ROUT = 2k, COUT = 50pF, 10% to 90% VSENSE = 5mV to 150mV, ROUT = 2k, COUT = 50pF 1.5 VSHDN = 2.4V 0 1 3 4 15 VSHDN = 0V 2.4 1.0 VCC - 1.5 PSRR SYMBOL VCC ICC VOS IRG1, IRG2 IOS IRG/IOUT IRG1 - IGR2 VSENSE = 100mV, VCC = 10V (Note 3) VCC = 10V, VSENSE = 0V VCC = 10V, VSENSE = 3mV MAX472C MAX472E MAX472C MAX472E MAX472C MAX472E MAX472C MAX472E 0.1 1.5 18.0 0.3 1.0 60 60 ILOAD = 0A, excludes ISIGN; VCC = 3V to 20V MAX472C MAX472E 20 ±0.4 CONDITIONS MIN 3 20 TYP MAX 36 48 120 140 35 ±3.0 ±2 ±2.5 2.5 3 ±2.5 ±3.0 0.1 120 140 1.0 UNITS V µA µV µA µA % µA µA %/V µV µA mA µA V µA V µA V M µs µs mA
MAX471/MAX472
3V VCC 36V, VSENSE = 100mV VCC = 10V VSIGN = 36V VSIGN = 0.3V VSHDN = 2.4V; VCC = 3V to 20V
Note 2: VOS is defined as the input voltage (VSENSE) required to give minimum IOUT. Note 3: VSENSE is the voltage across the sense resistor.
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