Rainbow Electronics MAX9920 User Manual

General Description

The MAX9918/MAX9919/MAX9920 are single-supply,
high-accuracy current-sense amplifiers with a high
input common-mode range that extends from -20V to
+75V. These amplifiers are well suited for current moni­toring of inductive loads such as motors and solenoids,
where common-mode voltages can become negative
due to inductive kickback, reverse-battery conditions,
or transient events.

The MAX9918/MAX9920 feature adjustable gain set by
an external resistive-divider network. The MAX9919 fea­tures fixed gains of 45V/V (MAX9919F) and 90V/V
(MAX9919N). The MAX9918/MAX9919/MAX9920 oper­ate as unidirectional amplifiers when V

REFIN

= GND

and as bidirectional amplifiers when V

REFIN

= VCC/2.
The MAX9920 attenuates the input signal by a factor of
4 at the input level-shifting stage allowing the device to
sense voltages up to 200mV (unidirectional operation)
or ±100mV (bidirectional operation).

The MAX9918/MAX9919/MAX9920 operate with a sin­gle 5V supply voltage, are fully specified over the -40°C
to +125°C automotive temperature range, and are
available in an 8-pin SOIC package.

Applications

H-Bridge Motor Current Sensing

Solenoid Current Sensing

Current Monitoring of Inductive Loads

High- and Low-Side Precision Current Sensing

4x4 Transmission Control

Electronic Throttle Control

Super-Capacitor Charge/Discharge Monitoring in
Hybrid Cars

Precision High-Voltage Current Monitoring

Features

♦ -20V to +75V Input Common-Mode Voltage Range

♦ 400µV (max) Input Offset Voltage

♦ 0.6% (max) Gain Accuracy Error

♦ Uni- or Bidirectional Current Sensing

♦ Reference Input for Bidirectional OUT

♦ 120kHz, -3dB Bandwidth (MAX9919N)

♦ Single-Supply Operation (4.5V to 5.5V)

♦ 1mA Supply Current

♦ 0.5µA (typ) Shutdown Current

♦ Rail-to-Rail Output

♦ -40°C to +125°C Automotive Temperature Range

MAX9918/MAX9919/MAX9920

-20V to +75V Input Range, Precision

Uni-/Bidirectional, Current-Sense Amplifiers

________________________________________________________________

Maxim Integrated Products

1

19-5015; Rev 1; 1/10

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

EVALUATION KIT

AVAILABLE

Typical Operating Circuit

Ordering Information/

Selector Guide

Note: All devices operate over the -40°C to +125°C tempera­ture range.

+

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

*

EP = Exposed pad.

V

BATT

V

PART

MAX9918ASA+ ±50 Adjustable 8 SOIC-EP*

MAX9919FASA+ ±50 45 8 SOIC-EP*

MAX9919NASA+ ±50 90 8 SOIC-EP*

MAX9920ASA+ ±200 Adjustable 8 SOIC-EP*

SENSE

(mV)

GAIN

(V/V)

PIN-PACKAGE

V

V

CC

CC

φ1A

φ2B

R

SENSE

M

φ2B

RS+

RS-

φ1B

MAX9918
MAX9920

INPUT STAGE

LEVEL SHIFTER

SHDN

A

ADJUSTABLE GAIN

GND

OUT

R2

FB

R1

REFIN

REF

ADC

μC

GND

MAX9918/MAX9919/MAX9920

-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= 5V, V

RS+

= V

RS-

= +14V, V

SENSE

= (V

RS+

- V

RS-

) = 0V, V

SHDN

= V

GND

= 0V, V

REFIN

= VCC/2, RL= 100kΩ; for MAX9918, AV=

90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A

V

= 20V/V, R2/R1 = 79kΩ/1kΩ; TA= -40°C to +125°C, unless otherwise noted. Typical val-

ues are at T

A

= +25°C.) (Note 1)

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.

VCCto GND..............................................................-0.3V to +6V

RS+, RS- to GND (V

CC

= 5V) ..................................-30V to +80V

RS+, RS- to GND (V

CC

= 0V) .............-15V to +80V (15 minutes)

Differential Input Voltage (V

RS+

- V

RS-

)

(MAX9918/MAX9919).................................±15V (Continuous)

Differential Input Voltage

(V

RS+

- V

RS-

) (MAX9920) .............................±5V (Continuous)

REFIN, FB, OUT to GND.............................-0.3V to (V

CC

+ 0.3V)

SHDN to GND.........................................................-0.3V to +20V

Output Short Circuit to V

CC

or GND...........................Continuous

Continuous Current into Any Pin

(Not to exceed package power dissipation) ................±20mA

Continuous Power Dissipation (T

A

= +70°C)

8-Pin SOIC-EP (derate 24.4mW/°C above +70°C) .1951.2mW**

SOIC Package Junction-to-Ambient

Thermal Resistance (θ

JA

) (Note 1)...............................41°C/W

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Reflow Soldering Temperature ........................................+260°C

Lead Temperature (soldering, 10s) .................................+300°C

Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-

layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial

.

**

As per JEDEC51 Standard (multilayer board).

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

MAX9918

Input Offset Voltage (Note 2) V

OS

MAX9919_

MAX9920

V

= V

RS+

+14V, V
= 0V

V

= V

RS+

-2V, V
0V

V

= V

RS+

+14V, V
= 0V

V

= V

RS+

-2V, V
0V

V

= V

RS+

+14V, V
= 0V

V

= V

RS+

-2V, V
0V

REFIN

REFIN

REFIN

RS-

REFIN

RS-

RS-

REFIN

RS-

RS-

REFIN

RS-

TA = +25°C ±0.14 ±0.4

=

T

A

= -40°C

to +125°C

TA = +25°C ±0.08 ±0.4

=

=

T

= -40°C

A

to +125°C

TA = +25°C ±0.18 ±0.4

=

= -40°C

T

A

to +125°C

TA = +25°C ±0.11 ±0.4

=

=

T

= -40°C

A

to +125°C

TA = +25°C ±0.48 ±1.2

=

= -40°C

T

A

to +125°C

TA = +25°C ±0.10 ±0.9

=

=

= -40°C

T

A

to +125°C

±0.7

±1.3

±0.9

±1.0

±3.0

±3.5

mV

MAX9918/MAX9919/MAX9920

-20V to +75V Input Range, Precision

Uni-/Bidirectional, Current-Sense Amplifiers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 5V, V

RS+

= V

RS-

= +14V, V

SENSE

= (V

RS+

- V

RS-

) = 0V, V

SHDN

= V

GND

= 0V, V

REFIN

= VCC/2, RL= 100kΩ; for MAX9918, AV=

90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A

V

= 20V/V, R2/R1 = 79kΩ/1kΩ; TA= -40°C to +125°C, unless otherwise noted. Typical val-

ues are at T

A

= +25°C.) (Note 1)

Input Offset Voltage Drift
(Note 3)

Common-Mode Range V

Common-Mode Rejection Ratio
(Note 3)

Input Bias Current I

Input Offset Current ( I

Input Leakage Current in
Shutdown

Input Leakage Current V

Input Resistance

Full-Scale Sense Voltage (Note 4) V

Minimum Adjustable Gain G

PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS

MAX9918

V

OSD

MAX9919_

MAX9920

CM

Inferred from CMRR tests -20 +75 V

M AX 9918, M AX 9919

CMRR

MAX9920

, I

RS+

RS +

-20V ≤ VCM ≤ +75V

RS-

- I

) 0 ±8 μA

RS -

-20V ≤ V

RS+

≤ +75V, V

CM

= V

= +14V, +75V, V

RS-

MAX9918,
MAX9919_

MAX9920

SENSE

Inferred from gain
error test

MAX9918, MAX9920 Adj

MAX9919F 45Gain (Notes 2, 4) G

MAX9919N 90

ADJ

MAX9918 30

MAX9920 7.5

V

V

V

V

V

V

RS+

RS+

RS+

RS+

RS+

RS+

= V

RS-

= V

RS-

= V

RS-

= V

RS-

= V

RS-

= V

RS-

= +14V ±1.2

= -2V ±3.3

= +14V ±1.8

= -2V ±1.8

= +14V ±2.4

= -2V ±8.8

-2V ≤ VCM ≤ +14V 80

-20V ≤ V

≤ +75V 96

CM

-2V ≤ VCM ≤ +14V 72

-20V ≤ V

≤ +75V 86

CM

TA = +25°C ±175

= -40°C to +125°C ±250

T

A

= V

SHDN

= 5V ±30 μA

CC

= 0V ±30 μA

CC

Common mode 300 kΩ
Differential 715 Ω
Common mode 330 kΩ
Differential 224 Ω

MAX9918, MAX9919_ 50

MAX9920 200

μV/°C

dB

μA

mV

V/V

V/V

MAX9918/MAX9919/MAX9920

-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 5V, V

RS+

= V

RS-

= +14V, V

SENSE

= (V

RS+

- V

RS-

) = 0V, V

SHDN

= V

GND

= 0V, V

REFIN

= VCC/2, RL= 100kΩ; for MAX9918, AV=

90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A

V

= 20V/V, R2/R1 = 79kΩ/1kΩ; TA= -40°C to +125°C, unless otherwise noted. Typical val-

ues are at T

A

= +25°C.) (Note 1)

Gain Error
(Note 2)

FB Input Bias Current I

Output-Voltage High (Note 4) VCC - V

Output-Voltage Low (Note 4) V

Short-Circuit Current I

Output Resistance R

REFIN Voltage Range

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

GE

FB

OL

SC

OUT

TA = +25°C,
V

= 0V

REFIN

=

= -40°C to

T

A

+125°C,

= 0V

V

REFIN

TA = +25°C ±0.02 ±0.6

=

=

T

= -40°C to

A

+125°C

TA = +25°C ±0.13 ±0.45

=

=

T

= -40°C to

A

+125°C

TA = +25°C ±0.10 ±0.45

=

=

= -40°C to

T

A

+125°C

TA = +25°C ±0.16 ±0.6

=

=

= -40°C to

T

A

+125°C

TA = +25°C ±0.11 ±0.6

=

=

T

= -40°C to

A

+125°C

TA = +25°C ±0.29 ±1.0

=

=

T

= -40°C to

A

+125°C

TA = +25°C ±0.24 ±1.0

=

=

= -40°C to

T

A

+125°C

MAX9918

MAX9919F

MAX9919N

MAX9920

V

= V

RS+

+14V

V

= V

RS+

-2V, V
0V

V

= V

RS+

+14V, V
0V

= V

V

RS+

-2V, V
0V

V

= V

RS+

+14V, V
0V

V

= V

RS+

-2V, V
0V

V

= V

RS+

+14V, V
0V

V

= V

RS+

-2V, V
0V

RS-

RS-

REFIN

RS-

REFIN

RS-

REFIN

RS-

REFIN

RS-

REFIN

RS-

REFIN

RS-

REFIN

MAX9918, MAX9920 5 15 nA

V

= 200mV for

SENSE

MAX9918, MAX9919_,

OH

V

= 400mV for

SENSE

MAX9920
V

= -200mV for

SENSE

MAX9918, MAX9919_,
V

= -400mV for

SENSE

MAX9920

OUT shorted to V

RL = 100kΩ to GND 3 10

R

= 10kΩ to GND 12 40

L

CC

RL = 100kΩ to V

R

= 10kΩ to V

L

CC

CC

OUT shorted to GND 41

M AX 9918, M AX9919_ 0

Inferred from REFIN
CMRR test

MAX9920 0

±0.08 ±0.6

310

10 40

44

0.1 Ω

V

CC

/2

V

CC

/2

±1.2

±1.0

±1.2

±0.9

±1.2

±1.0

±1.7

±1.7

V

CC

1.9

V

CC

2.4

%

mV

mV

mA

-

V

-

MAX9918/MAX9919/MAX9920

-20V to +75V Input Range, Precision

Uni-/Bidirectional, Current-Sense Amplifiers

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 5V, V

RS+

= V

RS-

= +14V, V

SENSE

= (V

RS+

- V

RS-

) = 0V, V

SHDN

= V

GND

= 0V, V

REFIN

= VCC/2, RL= 100kΩ; for MAX9918, AV=

90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A

V

= 20V/V, R2/R1 = 79kΩ/1kΩ; TA= -40°C to +125°C, unless otherwise noted. Typical val-

ues are at T

A

= +25°C.) (Note 1)

REFIN Common-Mode Rejection
Ratio

REFIN Current I

SHDN Logic-High V

SHDN Logic-Low V
SHDN Logic Input Current 0 ≤ V

Supply Voltage Range V

Power-Supply Rejection Ratio
(Note 3)

Supply Current I

Shutdown Supply Current I

Small Signal -3dB Bandwidth BW

Slew Rate SR

1% Settling Time from V
Step

PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS

MAX9918, MAX9919_

RE FIN

C M R R

MAX9920

REFIN

CC

PSRR

CC

CC_SHDNVSHDN

M AX 9918, M AX 9919_, V

MAX9920, V

IH

IL

SHDN

≤ V

RS+

= V

CC

Inferred from PSRR test 4.5 5.5 V
MAX9918, MAX9919_ 4.5V ≤ V
MAX9920 4.5V ≤ V

V

= V

= V

RS-

RS-

= +14V

= -2V

V

RS+

RS+

= VCC = 5V 0.5 10 μA

MAX9918, V

MAX9919F, V

MAX9919N, V

MAX9920, V

SENSE

SENSE

SENSE

SENSE

MAX9918 0.6

MAX9919F 0.9

MAX9919N 3.0

MAX9920 1.5

V

MAX9918

MAX9919F

SENSE

MAX9919N

MAX9920

SENSE

V

SENSE

V

SENSE

V

SENSE

V

SENSE

V

SENSE

V

S E N S E

V

S E N S E

0V ≤ V

REFIN

- 1.9V)

0V ≤ V

REFIN

- 2.4V)

= V

RS +

RS -

= ±200mV ±100

RS-

≤ (V

≤ (V

CC

CC

82 103

75 90

= ± 50m V ±100

2.0 V

≤ 5.5V 74 103

CC

≤ 5.5V 68 100

CC

TA = +25°C 0.7 1.2

T

= - 40°C to + 125°C 1.5

A

TA = +25°C 1.0 1.6

T

= - 40°C to + 125°C 2.2

A

= 50mV 75

= 50mV 250

= 50mV 120

= 200mV 230

= 5mV to 50mV step 12

= 50mV to 5mV step 7

= 5mV to 50mV step 3.5

= 50mV to 5mV step 2.5

= 5mV to 50mV step 3.5

= 50mV to 5mV step 3

= 20m V to 200m V step 5

= 200m V to 20m V ste p 3

dB

μA

0.8 V

5μA

dB

mA

kHz

V/μs

μs

MAX9918/MAX9919/MAX9920

-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers

6 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 5V, V

RS+

= V

RS-

= +14V, V

SENSE

= (V

RS+

- V

RS-

) = 0V, V

SHDN

= V

GND

= 0V, V

REFIN

= VCC/2, RL= 100kΩ; for MAX9918, AV=

90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A

V

= 20V/V, R2/R1 = 79kΩ/1kΩ; TA= -40°C to +125°C, unless otherwise noted. Typical val-

ues are at T

A

= +25°C.) (Note 1)

Note 1: All devices are 100% production tested at TA= +25°C. All temperature limits are guaranteed by design.
Note 2: V

OS

is extrapolated from two point gain error tests. Measurements are made at V

SENSE

= 5mV and 50mV for

MAX9918/MAX9919N/MAX9919F, and V

SENSE

= 20mV and 200mV for MAX9920.

Note 3: Extrapolated V

OS

as described above in Note 2 is used to calculate VOSdrift, CMRR, and PSRR.

Note 4: OUT should be 100mV away from either rail to achieve rated accuracy, or limited by a V

SENSE

of 50mV for the

MAX9918/MAX9919N/MAX9919F and 200mV for the MAX9920.

Note 5: Not production tested. Guaranteed by design.

1% Settling Time from VCM Step

Power-Up Time

Max Capacitive Load Stability No sustained oscillations (Note 5) 50 pF

Input Referred Noise Voltage
Density

PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS

e

n

MAX9918,
V

= 50mV

SENSE

MAX9919F,
V

= 50mV

SENSE

MAX9919N,
V

= 50mV

SENSE

MAX9920,
V

= 200mV

SENSE

MAX9918, V

MAX9919F, V

MAX9919N, V

MAX9920, V

10kHz

VCM = -2V to +14V step 2.5

V

VCM = -2V to +14V step 2.5

V

VCM = -2V to +14V step 3.5

V

VCM = -2V to +14V step 0.25

V

= 50mV, 1% settling 4.5

SENSE

= 50mV, 1% settling 5

SENSE

= 50mV, 1% settling 6

SENSE

= 200mV, 1% settling 5

SENSE

MAX9918, MAX9919_ 60

MAX9920 174

= +14V to -2V step 0.5

CM

= +14V to -2V step 0.5

CM

= +14V to -2V step 3.5

CM

= +14V to -2V step 2.5

CM

μs

μs

nV/√Hz