Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLinear ICsLinear IC - Op-amp Current sensor SOIC 8

Charger

load

+3.3V

24V

48V

Inductive

Load

Inductive

Load

+5V

LMP8601, LMP8601-Q1

www.ti.com

SNOSAR2E –SEPTEMBER 2008–REVISED MARCH 2013

60-V Common-Mode Bidirectional Precision Current Sensing Amplifier

Check for Samples: LMP8601, LMP8601-Q1

FEATURES

DESCRIPTION

The LMP8601 and LMP8601Q are fixed 20x gain

• Unless Otherwise Noted, Typical Values at T

precision amplifiers. The part will amplify and filter

= 25°C, V

= 5.0V, Gain = 20x

small differential signals in the presence of high

– TCV

10μV/°C Max

common mode voltages. The input common mode

– CMRR 90 dB Min

voltage range is –22V to +60V when operating from a

single 5V supply. With 3.3V supply, the input

– Input offset voltage 1 mV Max

common mode voltage range is from –4V to +27V.

– CMVR at V

= 3.3V -4V to 27V

The LMP8601 and LMP8601Q are members of the

– CMVR at V

= 5.0V -22V to 60V

Linear Monolithic Precision (LMP

) family and are

ideal parts for unidirectional and bidirectional current

– Operating Ambient Temperature Range -

sensing applications. All parameter values of the part

40°C to 125°C

that are shown in the tables are 100% tested and all

– LMP8601Q Available in Automotive AEC-

bold values are also 100% tested over temperature.

Q100 Grade 1 Qualified Version

The part has a precise gain of 20x which is adequate

– Single-Supply Bidirectional Operation

in most targeted applications to drive an ADC to its

– All Min / Max Limits 100% Tested

full scale value. The fixed gain is achieved in two

separate stages, a preamplifier with a gain of 10x and

APPLICATIONS

an output stage buffer amplifier with a gain of 2x. The

connection between the two stages of the signal path

• High-Side and Low-Side Driver Configuration

is brought out on two pins to enable the possibility to

Current Sensing

create an additional filter network around the output

• Bidirectional Current Measurement

buffer amplifier. These pins can also be used for

alternative configurations with different gain as

• Current Loop to Voltage Conversion

described in Application Information.

• Automotive Fuel Injection Control

• Transmission Control

• Power Steering

• Battery Management Systems

Typical Applications

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (29 pages)

PAGE 1
LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 60-V Common-Mode Bidirectional Precision Current Sensing Amplifier Check for Samples: LMP8601, LMP8601-Q1 FEATURES DESCRIPTION • The LMP8601 and LMP8601Q are fixed 20x gain precision amplifiers. The part will amplify and filter small differential signals in the presence of high common mode voltages. The input common mode voltage range is –22V to +60V when operating from a single 5V supply. With 3.
PAGE 2
LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 www.ti.com DESCRIPTION (CONTINUED) The mid-rail offset adjustment pin enables the user to use these devices for bidirectional single supply voltage current sensing. The output signal is bidirectional and mid-rail referenced when this pin is connected to the positive supply rail. With the offset pin connected to ground, the output signal is unidirectional and groundreferenced .
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LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 3.3V Electrical Characteristics (1) Unless otherwise specified, all limits ensured at TA = 25°C, VS = 3.3V, GND = 0V, -4V ≤ VCM ≤ 27V, and RL = ∞, Offset (Pin 7) is grounded, 10nF between VS and GND. Boldface limits apply at the temperature extremes.
PAGE 4
LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 www.ti.com 3.3V Electrical Characteristics (1) (continued) Unless otherwise specified, all limits ensured at TA = 25°C, VS = 3.3V, GND = 0V, -4V ≤ VCM ≤ 27V, and RL = ∞, Offset (Pin 7) is grounded, 10nF between VS and GND. Boldface limits apply at the temperature extremes.
PAGE 5
LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 5V Electrical Characteristics (1) (continued) Unless otherwise specified, all limits ensured for at TA = 25°C, VS = 5V, GND = 0V, -22V ≤ VCM ≤ 60V, and RL = ∞, Offset (Pin 7) is grounded, 10nF between VS and GND. Boldface limits apply at the temperature extremes. Parameter Test Conditions Min (2) Typ (3) Max (2) Unit -2 -2.5 ±0.5 2 2.5 mV 2 2.
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LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 www.ti.com DEVICE INFORMATION Block Diagram OFFSET VS 7 6 +IN Level shift 8 + Preamplifier Gain = 10 -IN Output Buffer Gain = K2 5 OUT - 1 100 k: 2 3 GND 4 A1 A2 K2 = 2 Figure 1. Block Diagram Connection Diagram Top View -IN 1 GND 2 A1 3 A2 4 LMP8601 LMP8601Q 8 +IN 7 OFFSET 6 VS 5 OUT Figure 2. 8-Pin SOIC Package see package number D0008A Table 1. Pin Descriptions 6 Name Pin No.
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LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 Table 1. Pin Descriptions (continued) Name Pin No. OUT 5 Description Output Single ended output Automotive Grade (Q) product incorporates enhanced manufacturing and support processes for the automotive market, including defect detection methodologies. Reliability qualification is compliant with the requirements and temperature grades defined in the AEC Q100 standard.
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LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics Unless otherwise specified, all limits ensured for at TA = 25°C, VS = 5V, GND = 0V, -22 ≤ VCM ≤ 60V, and RL = ∞, Offset (Pin 7) connected to VS, 10nF between VS and GND. VOS vs. VCM at VS = 3.3V 1.0 0.8 0.8 0.6 125°C 85°C 0.6 VOFFSET (mV) 0.4 VOFFSET (mV) VOS vs. VCM at VS = 5V 1.0 0.2 0 -0.2 25°C -0.4 -0.6 0.4 0.2 0 -0.2 -0.4 -40°C 25°C -40°C -0.6 -0.8 125°C 85°C -0.
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LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 Typical Performance Characteristics (continued) Unless otherwise specified, all limits ensured for at TA = 25°C, VS = 5V, GND = 0V, -22 ≤ VCM ≤ 60V, and RL = ∞, Offset (Pin 7) connected to VS, 10nF between VS and GND. Input Referred Voltage Noise vs. Frequency PSRR vs. Frequency 1.5 100 1.2 80 VS = 5V PSRR (dB) VOLTAGE NOISE (PV/ Hz) VS = 5V 0.9 0.6 VS = 3.3V 0.3 VS = 3.3V 60 40 20 0 0.
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LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) Unless otherwise specified, all limits ensured for at TA = 25°C, VS = 5V, GND = 0V, -22 ≤ VCM ≤ 60V, and RL = ∞, Offset (Pin 7) connected to VS, 10nF between VS and GND. INPUT SIGNAL (200 mV/DIV) Step Response at VS = 5V OUTPUT SIGNAL (1V/DIV) OUTPUT SIGNAL (1V/DIV) INPUT SIGNAL (100 mV/DIV) Step Response at VS = 3.3V VS = 3.
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LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 Typical Performance Characteristics (continued) Unless otherwise specified, all limits ensured for at TA = 25°C, VS = 5V, GND = 0V, -22 ≤ VCM ≤ 60V, and RL = ∞, Offset (Pin 7) connected to VS, 10nF between VS and GND. Positive Swing vs. RLOAD at VS = 3.3V Negative Swing vs. RLOAD at VS = 3.3V 60 VS = 3.3V VIN = 0V VCM = VS/2 50 3.28 OUTPUT VOLTAGE (mV) OUTPUT VOLTAGE (V) 3.30 3.26 3.24 3.22 10k 30 20 10 VS = 3.
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LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 www.ti.com Typical Performance Characteristics (continued) Unless otherwise specified, all limits ensured for at TA = 25°C, VS = 5V, GND = 0V, -22 ≤ VCM ≤ 60V, and RL = ∞, Offset (Pin 7) connected to VS, 10nF between VS and GND. TCVOS Distribution Gain Drift Distribution 30 30 1300 parts 1300 parts VS = 3.
PAGE 13
LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 APPLICATION INFORMATION GENERAL The LMP8601 and LMP8601Q are fixed gain differential voltage precision amplifiers with a gain of 20x and a 22V to +60V input common mode voltage range when operating from a single 5V supply or a -4V to +27V input common mode voltage range when operating from a single 3.3V supply.
PAGE 14
LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 www.ti.com ADDITIONAL SECOND ORDER LOW PASS FILTER The LMP8601/LMP8601Q has a third order Butterworth low-pass characteristic with a typical bandwidth of 60 kHz integrated in the preamplifier stage of the part. The bandwidth of the output buffer can be reduced by adding a capacitor on the A1 pin to create a first order low pass filter with a time constant determined by the 100 kΩ internal resistor and the external filter capacitor.
PAGE 15
LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 Note that the frequency response achieved using this procedure will only be accurate if the cut-off frequency of the second order filter is much smaller than the intrinsic 60 kHz low-pass filter. In other words, to have the frequency response of the LMP8601/LMP8601Q circuit chosen such that the internal poles do not affect the external second order filter.
PAGE 16
LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 Gr = www.ti.com 20 Rr Rr + 100 k: (8) Given a desired value of the reduced gain Gr, using this equation the required value for Rr can be calculated with: Rr = 100 k: X Gr 20 - Gr (9) Increase Gain Figure 36 shows the configuration that can be used to increase the gain of the LMP8601/LMP8601Q. Ri creates positive feedback from the output pin to the input of the buffer amplifier. The positive feedback increases the gain.
PAGE 17
LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 With the offset pin connected to the supply pin (VS) the operation of the amplifier will be fully bidirectional and symmetrical around 0V differential at the input pins. The signal at the output will follow this voltage difference multiplied by the gain and at an offset voltage at the output of half VS. Example: With 5V supply and a gain of 20x, a differential input signal of +10mV will result in 2.7V at the output pin.
PAGE 18
LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 www.ti.com LMP8601/ LMP8601Q ADC Figure 40. Reduce Error When Driving ADCs The external capacitor absorbs the charge that flows when the ADC sampling capacitor is connected. The external capacitor should be much larger than the sample and hold capacitor at the input of the ADC and the RC time constant of the external filter should be such that the speed of the system is not affected.
PAGE 19
LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 HIGH SIDE CURRENT SENSING APPLICATION Figure 42 illustrates the application of the LMP8601/LMP8601Q in a high side sensing application. This application is similar to the low side sensing discussed above, except in this application the common mode voltage on the shunt drops below ground when the driver is switched off.
PAGE 20
LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 www.ti.com BATTERY CURRENT MONITOR APPLICATION This application example shows how the LMP8601/LMP8601Q can be used to monitor the current flowing in and out a battery pack. The fact that the LMP8601/LMP8601Q can measure small voltages at a high offset voltage outside the parts own supply range makes this part a very good choice for such applications.
PAGE 21
LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 ADVANCED BATTERY CHARGER APPLICATION The above circuit can be used to realize an advanced battery charger that has the capability to monitor the exact net current that flows in and out the battery as show in Figure 44. The output signal of the LMP8601/LMP8601Q is digitized with the A/D converter and used as an input for the charge controller.
PAGE 22
LMP8601, LMP8601-Q1 SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 www.ti.com CURRENT LOOP RECEIVER APPLICATION Many industrial applications use 4 to 20 mA transmitters to send a sensor’s analog value to a central control room. The LMP8601/LMP8601Q can be used as a current loop receiver as shown in Figure 45. VS OFFSET 7 +IN 8 4 mA to 20 mA CURRENT LOOP RSENSE 1 -IN + Level shift Output Buffer Gain = K2 Preamplifier Gain = 10 - 5 OUT Internal Resistor 100 k: 3 4 A2 A1 C1 K2 = 2 Figure 45.
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LMP8601, LMP8601-Q1 www.ti.com SNOSAR2E – SEPTEMBER 2008 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision D (March 2013) to Revision E • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LMP8601MAX/NOPB SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LMP8601QMAX/NOPB SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMP8601MAX/NOPB SOIC D 8 2500 367.0 367.0 35.0 LMP8601QMAX/NOPB SOIC D 8 2500 367.0 367.0 35.
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