Datasheet AD8215 Datasheet (ANALOG DEVICES)

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Page 1

Current Shunt Monitor

Data Sheet

AD8215

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

Trademarks and registered trademarks are the property of their respective owners.

07203-001

IN+

V+

OUT

G = +20

AD8215

PROPRIETARY

OFFSET

CIRCUITRY

IN–

GND

FEATURES

±4000 V HBM ESD High common-mode voltage range

−2 V to +65 V operating

−3 V to +68 V survival Buffered output voltage Wide operating temperature range

8-Lead SOIC_N: −40°C to +125°C

Excellent ac and dc performance

6 µV/°C typical offset drift

−8 ppm/°C typical gain drift

120 dB typical CMRR at dc

High Voltage,

FUNCTIONAL BLOCK DIAGRAM

APPLICATIONS

High-side current sensing

Motor controls Transmission controls Engine management Suspension controls Vehicle dynamic controls DC-to-dc converters

Qualified for automotive applications

GENERAL DESCRIPTION

The AD8215 is a high voltage, precision current shunt monitor. It features a set gain of 20 V/V, with a maximum ±0.3% gain error over the entire temperature range. The buffered output voltage directly interfaces with any typical converter. Excellent commonmode rejection from −2 V to +65 V is independent of the 5 V supply. The AD8215 performs unidirectional current measurements across a shunt resistor in a variety of industrial and automotive applications, such as motor controls, solenoid controls, or battery management.

Figure 1.

Special circuitry is devoted to output linearity being maintained throughout the input differential voltage range of 0 mV to 250 m V, regardless of the common-mode voltage present. The AD8215 has an operating temperature range of −40°C to +125°C and is offered in a small 8-lead SOIC_N package.

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700

www.analog.com

Page 2

AD8215 Data Sheet

TABLE OF CONTENTS

Features .............................................................................................. 1

Applications ....................................................................................... 1

Functional Block Diagram .............................................................. 1

General Description ......................................................................... 1

Revision History ............................................................................... 2

Specifications ..................................................................................... 3

Absolute Maximum Ratings ............................................................ 4

ESD Caution .................................................................................. 4

Pin Configuration and Function Descriptions ............................. 5

Typical Performance Characteristics ............................................. 6

Theory of Operation ...................................................................... 10

REVISION HISTORY

10/11—Rev. 0 to Rev. A

Change to Applications Section ...................................................... 1

Updated Outline Dimensions ....................................................... 13

Changes to Ordering Guide .......................................................... 13

Added Automotive Products Section .......................................... 13

1/08—Revision 0: Initial Version

Application Notes ........................................................................... 11

Output Linearity ......................................................................... 11

Applications Information .............................................................. 12

High-Side Current Sensing with a Low-Side Switch ............. 12

High-Side Current Sensing ....................................................... 12

Low-Side Current Sensing ........................................................ 12

Outline Dimensions ....................................................................... 13

Ordering Guide .......................................................................... 13

Automotive Products ................................................................. 13

Rev. A | Page 2 of 16

Page 3

Data Sheet AD8215

Drift

−15

+18

µV/°C

Output Voltage Range Low

0.03 V

SPECIFICATIONS

= −40°C to +125°C, TA = 25°C, VS = 5 V, RL = 25 kΩ (RL is the output load resistor), unless otherwise noted.

OPR

Table 1.

Parameter Min Typ Max Unit Conditions GAIN

Initial 20 V/V

Accuracy ±0.15 % VO ≥ 0.1 V dc, TA Accuracy Over Temperature ±0.3 % T Drift 0 −8 −15 ppm/°C T

VOLTAGE OFFSET

Offset Voltage, RTI ±1 mV TA Over Temperature, RTI ±2.5 mV T

INPUT

Input Impedance

Differential 5 kΩ Common Mode 5 MΩ Common-mode voltage > 5 V

3.5 kΩ Common-mode voltage < 5 V Common-Mode Input Voltage Range −2 +65 V Common-mode continuous Differential Input Voltage Range 250 mV Differential input voltage Common-Mode Rejection Ratio 100 120 dB T 80 90 dB T

OUTPUT

OPR

, f = dc to 50 kHz, VCM > 5 V

OPR

, f = dc to 40 kHz, VCM < 5 V

OPR

0.10 V T

OPR

Output Voltage Range High 4.95 V TA

4.90 V T

OPR

Output Impedance 2 Ω

DYNAMIC RESPONSE

Small Signal −3 dB Bandwidth 450 kHz T

OPR

Slew Rate 4.5 V/µs TA

NOISE

0.1 Hz to 10 Hz, RTI 7 µV p-p Spectral Density, 1 kHz, RTI 70 nV/√Hz

POWER SUPPLY

Operating Range 4.5 5.5 V Quiescent Current Over Temperature 1.3 2.2 mA VCM > 5 V1, T Power Supply Rejection Ratio 75 dB T

OPR

TEMPERATURE RANGE

For Specified Performance −40 +125 °C

When the input common-mode voltage is less than 5 V, the supply current increases, which can be calculated by IS = −0.275 (VCM) + 2.5.

OPR

Rev. A | Page 3 of 16

Page 4

AD8215 Data Sheet

Storage Temperature Range

−65°C to +150°C

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

Supply Voltage 12.5 V Continuous Input Voltage −3 V to +68 V Continuous Differential Input Voltage 0.5 V Reverse Supply Voltage −0.3 V Human Body Model (HBM) ESD Rating ±4000 V Charged Device Model (CDM) ESD Rating ±1000 V Operating Temperature Range −40°C to +125°C

Output Short-Circuit Duration Indefinite

Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

ESD CAUTION

Rev. A | Page 4 of 16

Page 5

Data Sheet AD8215

07203-002

–IN

GND

+IN

V+

OUT

NC = NO CONNECT

AD8215

TOP VIEW

(Not to Scale)

07203-003

V+

+273

−266

Supply.

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

Figure 2. Metallization Diagram

Table 3. Pin Function Descriptions

Pin No. Mnemonic X Y Description

1 −IN −228 +519 Inverting Input. 2 GND −273 −251 Ground. 3, 4, 7 NC N/A N/A No Connect. 5 OUT +265 −466 Buffered Output.

8 +IN +229 +519 Noninverting Input.

Figure 3. Pin Configuration

Rev. A | Page 5 of 16

Page 6

AD8215 Data Sheet

–1.2

–1.0

–0.8

–0.6

–0.4

–0.2

0.4

0.2

0.6

0.8

1.0

1.2

–40 –20 0 20

40 60 80 100 120

07203-017

TEMPERATURE (°C)

OSI

(mV)

07203-024

FREQUENCY ( Hz )

CMRR (dB)

100

110

120

130

140

10 100 1k 10k 100k 1M

COMMON-MODE VOLTAGE >5V

COMMON-MODE VOLTAGE <5V

–2500

–2000

–1500

–1000

–500

500

1000

1500

2000

2500

–40 –20 0 20 40 60 80 100 120

07203-016

TEMPERATURE (°C)

GAIN ERROR ( ppm)

–40

–35

–30

–25

–20

–15

–10

–5

10k 100k 1M 10M

07203-018

FREQUENCY ( Hz )

GAIN (dB)

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95

DIFFERENTIAL INPUT VOLTAGE (mV)

TOTAL OUTPUT ERROR (%)

250

07203-022

–570

–560

–550

–540

–530

–520

–510

–500

–490

–480

IN+

IN–

0 25 50 75 100 125 150 175 200 225 250

07203-007

DIFFERENTIAL INPUT VOLTAGE (mV)

INPUT BIAS CURRE NT (µA)

TYPICAL PERFORMANCE CHARACTERISTICS

Figure 4. Typical Offset Drift vs. Temperature

Figure 5. Typical CMRR vs. Frequency

Figure 7. Typical Small Signal Bandwidth (V

= 200 mV p-p)

OUT

Figure 8. Total Output Error vs. Differential Input Voltage

Figure 6. Typical Gain Error vs. Temperature

Figure 9. Input Bias Current vs. Differential Input Voltage, VCM = 0 V

Rev. A | Page 6 of 16

Page 7

Data Sheet AD8215

100

110

120

0 25 50 75 100 125 150 175 200 225 250

IN+

IN–

07203-006

DIFFERENTIAL INPUT VOLTAGE (mV)

INPUT BIAS CURRE NT (µA)

–2.4

–2.0

–1.6

–1.2

–0.8

–0.4

0.4

0.8

–4 –2 0 2 4 6 8 65

07203-004

INPUT COMMON-MODE VOLTAGE (V)

INPUT BIAS CURRE NT (mA)

1.0

1.5

2.0

2.5

3.0

3.5

4.0

–4 –2 0 2 4 6 8 65

07203-005

INPUT COMMON-MODE VOLTAGE (V)

SUPPLY CURRENT (mA)

TIME (400ns/DIV)

07203-012

100mV/DIV

INPUT

OUTPUT

1V/DIV

TIME (400ns/DIV)

07203-015

100mV/DIV

INPUT

OUTPUT

1V/DIV

TIME (1µs/DIV)

07203-013

200mV/DIV

INPUT

OUTPUT

2V/DIV

Figure 10. Input Bias Current vs. Differential Input Voltage, VCM = 5 V

Figure 11. Input Bias Current vs. Input Common-Mode Voltage

Figure 13. Fall Time

Figure 14. Rise Time

Figure 12. Supply Current vs. Common-Mode Voltage

Figure 15. Differential Overload Recovery (Falling)

Rev. A | Page 7 of 16

Page 8

AD8215 Data Sheet

TIME (1µs/DIV)

07203-014

200mV/DIV

INPUT

OUTPUT

2V/DIV

TIME (4µs/DIV)

07203-019

2V/DIV

0.01%/DIV

TIME (4µs/DIV)

07203-020

2V/DIV

0.01%/DIV

–40 –20 0 20 40 60 80 100 120 140

07203-010

TEMPERATURE (°C)

MAXIMUM O UTPUT SINK CURRENT (mA)

–40 –20 0 20 40 60 80 100 120 140

07203-011

TEMPERATURE (°C)

MAXIMUM O UTPUT SOURCE CURRE NT (mA)

1.0

1.4

1.8

2.2

2.6

3.0

3.4

3.8

4.2

4.6

5.0

0 1 2 3 4 5 6 7 8 9

07203-008

OUTPUT S OURCE CURRENT (mA)

OUTPUT VOLTAGE RANGE (V)

Figure 16. Differential Overload Recovery (Rising)

Figure 17. Settling Time (Falling)

Figure 19. Maximum Output Sink Current vs. Temperature

Figure 20. Maximum Output Source Current vs. Temperature

Figure 18. Settling Time (Rising)

Figure 21. Output Voltage Range vs. Output Source Current

Rev. A | Page 8 of 16

Page 9

Data Sheet AD8215

0.4

0.8

1.2

1.6

2.0

0 1 2 3 4 5 6 7 8 9 10

11 12

07203-009

OUTPUT S INK CURRENT (mA)

OUTPUT VOLTAGE RANGE (V)

07203-021

VOS (mV)

COUNT

–2 0–1 1 2

500

1000

1500

2000

2500

3000

3500

+125°C +25°C –40°C

07203-023

GAIN DRIFT (ppm/°C)

COUNT

–2–4–6–8–10–12–14–16 0

300

600

900

1200

1500

1800

2100

2400

07203-030

OFFSET DRIFT (µV/°C)

COUNT

151050–5–10–15–20 20

200

400

600

800

1000

1200

1400

1600

Figure 22. Output Voltage Range from GND vs. Output Sink Current

Figure 23. Offset Distribution

Figure 24. Gain Drift Distribution

Figure 25. Offset Drift

Rev. A | Page 9 of 16

Page 10

AD8215 Data Sheet

07203-025

V+

OUT = (I

SHUNT

× R

SHUNT

) × 20

G = +20

AD8215

OUT

PROPRIETARY

OFFSET

CIRCUITRY

GND

SHUNT

THEORY OF OPERATION

In typical applications, the AD8215 amplifies a small differential input voltage generated by the load current flowing through a shunt resistor. The AD8215 rejects high common-mode voltages (up to 65 V) and provides a ground-referenced, buffered output that interfaces with an analog-to-digital converter (ADC). Figure 26 shows a simplified schematic of the AD8215.

A load current flowing through the external shunt resistor produces a voltage at the input terminals of the AD8215. The input terminals are connected to A1 by R and R1. The inverting terminal, which has very high input impedance, is held to

) − (I

SHUNT

× R

SHUNT

)

because negligible current flows through R. A1 forces the noninverting input to the same potential. Therefore, the current that flows through R1 is equal to

= (I

This current (I

× R

SHUNT

) is converted back to a voltage via R

SHUNT

)/R1

OUT

. The output buffer amplifier has a gain of 20 V/V and offers excellent accuracy as the internal gain setting resistors are precision trimmed to within 0.01% matching. The resulting output voltage is equal to

OUT = (I

SHUNT

× R

SHUNT

) × 20

Figure 26. Simplified Schematic

Rev. A | Page 10 of 16

Page 11

Data Sheet AD8215

200

07203-

026

DIFFERENTIAL INPUT VOLTAGE (mV)

OUTPUT VOLTAGE (mV)

180

160

140

120

100

1 2 3 4 5 6 7 8 9

IDEAL V

OUT

(mV)

OUT

(mV) @ VCM= 0V

OUT

(mV) @ VCM= 65V

APPLICATION NOTES

OUTPUT LINEARITY

In all current sensing applications, and especially in automotive and industrial environments where the common-mode voltage can vary significantly, it is important that the current sensor maintain the specified output linearity, regardless of the input differential or common-mode voltage. The AD8215 contains specific circuitry on the input stage, which ensures that even when the differential input voltage is very small and the common-mode voltage is also low (below the 5 V supply), the input-to-output linearity is maintained. Figure 27 shows the differential input voltage vs. the corresponding output voltage at different common modes.

Regardless of the common mode, the AD8215 provides a correct output voltage when the differential input is at least 2 mV, which is due to the voltage range of the output amplifier that can go as low as 33 mV typical. The specified minimum output amplifier voltage is 100 mV to provide sufficient guardbands. The ability of the AD8215 to work with very small differential inputs, regardless of the common-mode voltage, allows for more dynamic range, accuracy, and flexibility in any current sensing application.

Figure 27. Gain Linearity Due to Differential and Common-Mode Voltage

Rev. A | Page 11 of 16

Page 12

AD8215 Data Sheet

07203-027

INDUCTIVE

LOAD

CLAMP DIODE

SHUNT

SWITCH

BATTERY

8 7 6

2 3

1 4

NC V+IN+

IN–

OUT

NCNCGND

AD8215

07203-028

OVERCURRENT

DETECTION (<100ns)

07203-029

INDUCTIVE LOAD

CLAMP

DIODE

SHUNT

BATTERY

SWITCH

5 6 7

3 2

4 1

NCV+ IN+

IN–

OUT

NC NC

GND

AD8215

APPLICATIONS INFORMATION

HIGH-SIDE CURRENT SENSING WITH A LOW-SIDE SWITCH

In such load control configurations, the PWM-controlled switch is ground referenced. An inductive load (solenoid) is tied to a power supply. A resistive shunt is placed between the switch and the load (see Figure 28). An advantage of placing the shunt on the high side is that the entire current, including the recirculation current, can be measured because the shunt remains in the loop when the switch is off. In addition, diagnostics can be enhanced because shorts to ground can be detected with the shunt on the high side. In this circuit configuration, when the switch is closed, the common-mode voltage moves down to near the negative rail. When the switch is opened, the voltage reversal across the inductive load causes the common-mode voltage to be held one diode drop above the battery by the clamp diode.

GND NC –INOUT

AD8214

REG

5 6 7

OUT

AD8215

NC NC GND

3 2

4 1

+IN V

NCV+ IN+

IN–

8765

123

SHUNT

CLAMP

DIODE

INDUCTIVE LOAD

SWITCH

BATTERY

HIGH-SIDE CURRENT SENSING

In this configuration, the shunt resistor is referenced to the battery. High voltage is present at the inputs of the current sense amplifier. In this mode, the recirculation current is again measured and shorts to ground can be detected. When the shunt is battery referenced, the AD8215 produces a linear ground-referenced analog output. An AD8214 can also be used to provide an over- current detection signal in as little as 100 ns (see Figure 29). This feature is useful in high current systems where fast shutdown in over-current conditions is essential.

Figure 28. Low-Side Switch

Figure 29. Battery-Referenced Shunt Resistor

LOW-SIDE CURRENT SENSING

In systems where low-side current sensing is preferred, the

AD8215 provides an integrated solution with great accuracy.

Ground noise is rejected, CMRR is typically higher than 90 dB, and output linearity is not compromised, regardless of the input differential voltage.

Figure 30. Ground-Referenced Shunt Resistor

Rev. A | Page 12 of 16

Page 13

Data Sheet AD8215

OUTLINE DIMENSIONS

5.00 (0.1968)

4.80 (0.1890)

4.00 (0.1574)

3.80 (0.1497)

0.25 (0.0098)

0.10 (0.0040)

COPLANARITY

0.10 SEATING

CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLYAND ARE NOT APPROPRIATE FOR USE IN DESIGN.

1.27 (0.0500)

PLANE

COMPLIANT TO JEDEC STANDARDS MS-012-AA

BSC

6.20 (0.2441)

5.80 (0.2284)

1.75 (0.0688)

1.35 (0.0532)

0.51 (0.0201)

0.31 (0.0122)

8° 0°

0.25 (0.0098)

0.17 (0.0067)

0.50 (0.0196)

0.25 (0.0099)

1.27 (0.0500)

0.40 (0.0157)

45°

012407-A

Figure 31. 8-Lead Standard Small Outline Package [SOIC_N]

Narrow Body

(R-8)

Dimensions shown in millimeters and (inches)

ORDERING GUIDE

1, 2

Model

AD8215YRZ −40°C to +125°C 8-Lead SOIC_N R-8 AD8215YRZ-RL −40°C to +125°C 8-Lead SOIC_N, 13” Tape and Reel R-8 AD8215YRZ-R7 −40°C to +125°C 8-Lead SOIC_N, 7” Tape and Reel R-8 AD8215WYRZ −40°C to +125°C 8-Lead SOIC_N R-8 AD8215WYRZ-R7 −40°C to +125°C 8-Lead SOIC_N, 7” Tape and Reel R-8 AD8215WYRZ-RL −40°C to +125°C 8-Lead SOIC_N, 13” Tape and Reel R-8

Z = RoHS Compliant Part.

W = Qualified for Automotive Applications.

Temperature Range Package Description Package Option

AUTOMOTIVE PRODUCTS

The AD8215WYRZ models are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. Note that these automotive models may have specifications that differ from the commercial models; therefore designers should review the Specifications section of this data sheet carefully. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for these models.

Rev. A | Page 13 of 16

Page 14

AD8215 Data Sheet

NOTES

Rev. A | Page 14 of 16

Page 15

Data Sheet AD8215

NOTES

Rev. A | Page 15 of 16

Page 16

AD8215 Data Sheet

NOTES

registered trademarks are the property of their respective owners. D07203-0-10/11(A)

Rev. A | Page 16 of 16