Diodes ZXCT1081 User Manual

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ZXCT1081

HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR

Description

The ZXCT1081 is a high side current sense monitor with a
gain of 10 and a voltage output. Using this device
eliminates the need to disrupt the ground plane when
sensing a load current.

The wide input voltage range of 40V d own to as low as 3V
make it suitable for a range of applications; including
systems operating from industrial 24-28V rails and power
supplies.

Features

• 3V to 40V continuous high side voltage

• Accurate high-side current sensing

• Output voltage scaling x10

• 4.5V to 12V V

• Low quiescent current:

o 80 μA supply pin
o 30 μA I

• SOT23-5 package

• -40°C to 125°C ambient temperature range

CC

SENSE

range

+

Pin Assignments

1

V

CC

5

SENSE-

GND

2

OUT

3

4

SENSE+

Applications

• Automotive current measurement

• Industrial applications current measurement

• Battery management

• Over current monitor

• Power management

• Power adapters

Typical Application Circuit

V

IN

SENSE+

V

CC

1

V

cc

ZXCT1081

Document number: DS32102 Rev. 1 - 2

R

SENSE

4

ZXCT1081

GND

2

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5

SENSE-

OUT

3

V

OUT

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ZXCT1081

Pin Description

Pin Name Description

1 VCC This is the analogue supply and provides power to internal circuitry
2 GND Ground pin
3 OUT Output voltage pin. NMOS source follower with 20μA bias to ground

This is the positive input of the current monitor and has an input range from 40V

4 SENSE+

(60V transient) down to 3V. The current through this pin varies with differential sense
voltage

5 SENSE-

This is the negative input of the current monitor and has an input range from 40V
(60V transient) down to 3V

Absolute Maximum Ratings

Parameter Rating Unit

Continuous Voltage on SENSE+ and SENSE- -0.6 and 45 V
Transient Voltage on SENSE+ and SENSE- -0.6 and 65 V
Voltage On All Other Pins -0.6 and 14 V

Differential Sense Voltage, V

SENSE

Operating Temperature -40 to 125 °C
Storage Temperature -55 to 150 °C
Maximum Junction Temperature 125 °C

Package Power Dissipation

Operation above the absolute maximum rating may cause device failure. Operation at the absolute maximum ratings, for extended periods, may reduce
device reliability

(de-rate to zero at 125°C)

800 mV

300 @ T

= 25°C

A

mW

Recommended Operating Conditions

Symbol Parameter Min Max Units

VIN

VCC

V

SENSE

V

OUT

TJ

ZXCT1081

Document number: DS32102 Rev. 1 - 2

Common-Mode Sense+ Input Range 3 40 V
Supply Voltage Range 4.5 12 V
Differential Sense Input Voltage Range 0 0.15 V
Output Voltage Range 0 1.5 V
Ambient Temperature Range -40 125 °C

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V

V

V

)

V

V

)

V

Δ

V

V

V

A

V

V

V

V

V

V

(AC)

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ZXCT1081

Electrical Characteristics (Test conditions: T

= 25°C, VIN = 12V, VCC = 5V, V

A

Symbol Parameter Condition Min. Typ. Max. Unit

ICC
I

SENSE

I

SENSE

Zero V

O(0
O(10

Gain

TC

OUT
CC

IOH
IOL
PSRR
CMRR Common-Mode Sense Rejection Ratio
BW -3dB Small Signal Bandwidth

Notes: (a) VSENSE = "V

ZXCT1081

Document number: DS32102 Rev. 1 - 2

CC Supply Current

SENSE+ Input Current 15 30 60 µA

+

SENSE- Input Current 10 40 80 nA

-

Output Offset Voltage

V

OUT

(d)

OUT

SENSE

/ΔV

SENSE

(a)

error

(a)

(b)

(c)

Variation with Temperature

= 12V

CC

SENSE
SENSE
SENSE

(a)

= 0V

(a)

= 10mV

(a)

= 10mV to 150mV

Total Output Error -3 3 %
Output Source Current
Output Sink Current

CC Supply Rejection Ration

+" - "V
(b) The ZXCT1081 operates from a positive power rail and the internal voltage-current converter current flow is unidirectional; these result in the
output offset voltage for V
(c) For V
the variance about an output voltage of 100mV>.
(d)Temperature dependent measurements are extracted from characterization and simulation results.

SENSE

> 10mV, the internal voltage-current converter is fully linear. This enables a true offset to be defined and used. V

SENSE

-"

SENSE

= 0V always being positive.

SENSE

= 30mV

OUT

= +30mV

OUT

= 4.5V to 12V

CC

+ 40V to 3V

IN

(a)

SENSE

= 10mVpp

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(a)

SENSE

= 100mV unless otherwise stated)

40 80 120 µA

0 35 mV

-30 +30 mV

9.95 10 10.05
30 ppm/°C

1 mA
20 µA

54 60 dB
60 75 dB

50 kHz

is expressed as

O(10)

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ZXCT1081

Typical Operating Conditions (Test conditions: T

= 25°C, VCC = 5V, V

A

= 12V, VSENSE = 100mV)

SENSE+

ZXCT1081

Document number: DS32102 Rev. 1 - 2

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