Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsLinear IC - Op-amp Current sensor SC 70 5

Pin Configuration appears at end of data sheet.

General Description

The MAX9937 is a tiny current-sense amplifier designed

for unidirectional high-side current-sense applications.

This device addresses major areas of concern for various

applications including load-dump protection up to +40V,

reverse-battery protection, and filtering for EMI and tran-

sient performance.

The MAX9937 also features a low input offset voltage of

±1.2mV (max) at +25°C with a low temperature drift of just

1µV/°C (typ).

The MAX9937 is available in a 5-pin SC70 package and is

rated over the -40°C to +125°C temperature range.

Applications

● Battery Current Sense

● Fuse Box Current Sense

● ECU Current Monitor

Features

● Reverse Battery and Load-Dump Protection

-20V to +40V

● +4V to +28V Input Common-Mode Range

● Flexible EMI Filtering

● Low V

: ±1.2mV (max)

● Low V

Drift : 1µV/°C (typ)

● 20µA Supply Current

● 350kHz, 3dB Small-Signal Bandwidth

+Denotes a lead(Pb)-free/RoHS-compliant package.

T = Tape and reel.

PART TEMP RANGE

PIN-

PACKAGE

TOP

MARK

MAX9937AXK+T -40°C to +125°C 5 SC70 +ATB

LOAD

MICROCONTROLLER

ADC

SENSE

GND

OUT

RS+

RS-

RSN

499Ω

RSP

499Ω

OUT

10kΩ

RSP

RSN

BIAS

BLOCK

BAT

= 4V

TO 28V

MAX9937

GAIN =

OUT

SENSE

OUT

RSP

MAX9937 Current-Sense Amplier with

Reverse-Battery Protection

19-4233; Rev 1; 9/14

Typical Application Circuit

Ordering Information

Summary of content (11 pages)

PAGE 1
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection General Description The MAX9937 is a tiny current-sense amplifier designed for unidirectional high-side current-sense applications. This device addresses major areas of concern for various applications including load-dump protection up to +40V, reverse-battery protection, and filtering for EMI and transient performance. The MAX9937 also features a low input offset voltage of ±1.
PAGE 2
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection Absolute Maximum Ratings RSP, RSN to GND Voltage Continuous.................-0.3V to +30V RSP, RSN to GND Load-Dump Voltage Duration (VBAT = 40V) with Typical Application Circuit....................... 1s RSP, RSN to GND Reverse-Battery Voltage Duration (VBAT = -20V) with Typical Application Circuit.......Continuous Differential Input Voltage (RSP - RSN)...............................±0.3V VCC to GND..........................................
PAGE 3
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection Electrical Characteristics (continued) (VCC = 5V, VBAT = VRS+ = 12V, VSENSE = (VRS+ - VRS-) = 0V, RRSP = RRSN = 500Ω, ROUT = 10kΩ, TA = -40°C to +125°C. Typical values are at TA = +25°C, unless otherwise noted. See the Typical Application Circuit.) (Note 2) PARAMETER Maximum Output Current SYMBOL IOUT Output-Voltage Compliance (Note 6) CONDITIONS RRSN = 500W, RRSP = 0, VOUT = 0V MIN TYP MAX UNITS 2 7.
PAGE 4
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection Typical Operating Characteristics (VCC = 5V, VBAT = VRSP = 12V, VSENSE = VRS+ - VRS- = 0V, RRSP = RRSN = 500Ω, ROUT = 10kΩ, TA = +25°C, unless otherwise noted. See the Typical Application Circuit.) OFFSET VOLTAGE HISTOGRAM 25 20 15 10 80 120 OFFSET VOLTAGE vs.
PAGE 5
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection Typical Operating Characteristics (continued) (VCC = 5V, VBAT = VRSP = 12V, VSENSE = VRS+ - VRS- = 0V, RRSP = RRSN = 500Ω, ROUT = 10kΩ, TA = +25°C, unless otherwise noted. See the Typical Application Circuit.) GAIN ERROR HISTOGRAM 20 15 10 0.4 0.3 0.2 0.1 0 -0.1 5 -0.2 -0.3 -0.115 -0.105 -0.095 -0.085 -0.090 -0.100 -0.110 GAIN ERROR (%) GAIN ERROR (%) 0.6 TA = -40°C 0.4 0.2 TA = +25°C 0 -0.2 TA = +125°C -0.4 4 8 1.5 1.0 0.
PAGE 6
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection Typical Operating Characteristics (continued) (VCC = 5V, VBAT = VRSP = 12V, VSENSE = VRS+ - VRS- = 0V, RRSP = RRSN = 500Ω, ROUT = 10kΩ, TA = +25°C, unless otherwise noted. See the Typical Application Circuit.) INPUT BIAS CURRENT MISMATCH vs. COMMON-MODE VOLTAGE INPUT BIAS CURRENT vs. SUPPLY VOLTAGE 1.2 0.8 0.4 8 12 16 20 24 0 28 3.0 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) INPUT BIAS CURRENT MISMATCH vs.
PAGE 7
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection Typical Operating Characteristics (continued) (VCC = 5V, VBAT = VRSP = 12V, VSENSE = VRS+ - VRS- = 0V, RRSP = RRSN = 500Ω, ROUT = 10kΩ, TA = +25°C, unless otherwise noted. See the Typical Application Circuit.
PAGE 8
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection Pin Description PIN NAME 1 VCC Power Supply. Bypass to GND with a 0.1µF capacitor. 2 GND Ground 3 OUT Current Output 4 RSN Load-Side Connection Through External RRSN Resistor RSP Supply-Side Connection Through External RRSP Resistor 5 FUNCTION Detailed Description The MAX9937 unidirectional high-side, current-sense amplifier features a 4V to 28V input common-mode voltage range that is independent of supply voltage (VCC = 2.
PAGE 9
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection RSENSE RS+ CIN* 220nF RRSP 499Ω RS- RSN RSP LOAD RRSN 499Ω 5V VCC GND VBAT = 4V TO 28V BIAS BLOCK MICROCONTROLLER MAX9937 OUT ADC GAIN = VOUT = ROUT VSENSE RRSP ROUT 10kΩ COUT* 1nF *FILTER CAPACITORS ARE OPTIONAL. Figure 1. Typical Application Circuit with Optional External Filtering In this case, RRS = RRSP = RRSN, ∆RRS depends on the tolerance of the RRS resistors used, and ∆IB = input offset current of the amplifier.
PAGE 10
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection At frequencies below the output corner frequency, the MAX9937 itself provides excellent 100dB (DC) common-mode rejection. At higher frequencies, as the CMRR of the MAX9937 degrades, the output filter formed by ROUT and COUT helps boost the common-mode rejection of the circuit.
PAGE 11
MAX9937 Current-Sense Amplifier with Reverse-Battery Protection Revision History REVISION NUMBER REVISION DATE 0 8/08 Initial release 1 9/14 Removed automotive reference from data sheet DESCRIPTION PAGES CHANGED — 1, 8 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.