MAX472 Maxim Integrated Products, MAX472 Datasheet
MAX472
Available stocks
Related parts for MAX472
MAX472 Summary of contents
Page 1
... The MAX471 has an internal 35mΩ current-sense resis- tor and measures battery currents up to ±3A. For appli- cations requiring higher current or increased flexibility, the MAX472 functions with external sense and gain-set- ting 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 volt- ages and currents ...
Page 2
... Current into SHDN, GND, OUT, RG1, RG2, V Current into SIGN.................................................+10mA, -50mA 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 ...
Page 3
... ELECTRICAL CHARACTERISTICS—MAX472 (V = +3V to +36V, RG1 = RG2 = 200Ω PARAMETER SYMBOL Supply Voltage V Supply Current Input Offset Voltage V (Note 2) Input Bias Current I RG1 Input Bias-Current Matching OUT Current Accuracy I RG No-Load OUT Error Low-Level OUT Error Power-Supply Rejection Ratio PSRR SIGN Threshold (V ...
Page 4
... T = +85° +25°C A 1.2 1.0 0.8 0 (V) RS+ MAX471 RS+ TO RS- RESISTANCE vs. TEMPERATURE -40 - TEMPERATURE (°C) 4 _______________________________________________________________________________________ = 2kΩ (MAX472), T OUT SHUTDOWN CURRENT vs. SUPPLY VOLTAGE 2 -40°C A 2.0 1 +25° +85° (V) RS+ MAX471 ERROR vs. LOAD CURRENT FROM RS- TO RS+ LOAD FROM RS+ TO RS- ...
Page 5
... LOAD OUT _______________________________________________________________________________________ Precision, High-Side Current-Sense Amplifiers 100 1000 0A LOAD CURRENT 50mA/div V OUT 50mV/div V OUT 500mV/div V SHDN 5V/div = 2kΩ (MAX472 +25°C, unless OUT A MAX471 NOISE vs. LOAD CURRENT 0.5 0.4 0.3 0.2 0 1mA 10mA 100mA I SENSE MAX471 -100mA to +100mA TRANSIENT RESPONSE 50mA/div ...
Page 6
... An open-collector logic output. For the MAX471, a low level indicates current is flowing from 5 5 SIGN RS- to RS+. For the MAX472, a low level indicates a negative V high impedance when SHDN is high. Leave open if SIGN is not needed. Load side of the internal current-sense resistor. The “-” indicates direction of flow for SIGN 6, 7 — ...
Page 7
... RS+ Q1 MAX471 Figure 1. MAX471 Functional Diagram POWER SOURCE OR BATTERY Q1 MAX472 Figure 2. MAX472 Functional Diagram _______________________________________________________________________________________ Precision, High-Side Current-Sense Amplifiers R SENSE RG1 A1 R SENSE V SENSE RG1 RG2 RS- RG2 OUT 5 COMP SIGN TO LOAD/CHARGER OUT 5 COMP SIGN 7 ...
Page 8
... CHARGER V OUT 1k Figure 4. MAX472 Standard Application Circuit When SHDN is high, the MAX471/MAX472 are shut down and consume less than 18µA. In shutdown mode, SIGN is high impedance and OUT turns off. __________Applications Information SIGN Output The MAX471 obtains its power from the RS- pin. This includes MAX471 current consumption in the total sys- tem current measured by the MAX471 ...
Page 9
... CC load/charge or power-source/battery side of the sense resistor. Connect V to the load/charge side you want to include the MAX472 current drain SENSE in the measured current. Suggested Component Values for Various Applications The general circuit of Figure 4 is useful in a wide variety of applications. It can be used for high-current applica- tions (greater than 3A), and also for those where the full- scale load current is less than the 3A of the MAX471 ...
Page 10
... POWER SOURCE OR BATTERY RG1 and RG2 /RG). Choose SENSE . Figure 6. MAX472 Connections Showing Use of PC Board gets larger for a Trace is not OUT make sure RG is small enough that I not add any appreciable errors. The full-scale error is given by: is limit- OUT % Error = / 1 ...
Page 11
... If the noise at OUT caused by these transients is a problem, you may want to place a 1µF capacitor at the OUT pin to ground. You can also place a large capaci- tor at the RS- terminal (or “load” side of the MAX472) to OUT decouple the load and, thereby, reduce the current transients ...
Page 12
... Precision, High-Side Current-Sense Amplifiers ____Pin Configurations (continued) SHDN 1 2 N.C. MAX472 3 RG1 GND 4 DIP/SO Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. ...