AD8212YRMZ Analog Devices Inc, AD8212YRMZ Datasheet - Page 9

• Manufacturer Part Number: AD8212YRMZ
• Description: IC CURRENT MONITOR 8MSOP
• Manufacturer: Analog Devices Inc
• Type: Current Shunt Monr

Specifications of AD8212YRMZ

• Function: Current Monitor
• Sensing Method: High-Side
• Voltage - Input: 7 ~ 65 V
• Current - Output: 500µA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Number Of Channels: 1
• Number Of Elements: 1
• Power Supply Requirement: Single
• Input Resistance: 5@15VMohm
• Input Offset Voltage: 2@15VmV
• Input Bias Current: 1000@15V@-40 TO 125CnA
• Single Supply Voltage (typ): 9/12/15/18/24/28V
• Dual Supply Voltage (typ): Not RequiredV
• Power Supply Rejection Ratio: 80dB
• Rail/rail I/o Type: No
• Single Supply Voltage (min): 7V
• Single Supply Voltage (max): 65V
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Operating Temp Range: -40C to 125C
• Operating Temperature Classification: Automotive
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: MSOP
• No. Of Amplifiers: 1
• Output Current Per Channel: 500µA
• Gain Db Max: 50dB
• Bandwidth: 1MHz
• Cmrr: 100dB
• Supply Voltage Range: 7V To 65V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Accuracy: -
• Lead Free Status / Rohs Status: Compliant

THEORY OF OPERATION
NORMAL OPERATION
(7 V TO 65 V SUPPLY (V+) RANGE)
In typical applications, the AD8212 measures a small
differential input voltage generated by a load current
flowing through a shunt resistor.
The operational amplifier (A1) is connected across the shunt
resistor (R
battery/supply side, and the noninverting input connected
to the load side of the system. Amplifier A1 is powered via
an internal series regulator (depicted as a Zener diode in
Figure 22). This regulator maintains a constant 5 V between
the battery/supply terminal of the AD8212 and COM (Pin 2),
which represents the lowest common point of the internal
circuitry.
A load current flowing through the external shunt resistor
produces a voltage at the input terminals of the AD8212.
Amplifier A1 responds by causing Transistor Q1 to conduct the
necessary current through Resistor R1 to equalize the potential
at both the inverting and noninverting inputs of Amplifier A1.
The current through the emitter of Transistor Q1 (I
proportional to the input voltage (V
load current (I
output current (I
external resistor, the value of which is dependent on the input
to output gain equation desired in the application.
The transfer function for the AD8212 is
where:
In normal voltage operation mode, the bias circuit is connected
to GND, as shown in Figure 22. In this mode, I
185 μA throughout the 7 V to 65 V (V+) range.
I
V
V
V
g
OUT
m
SENSE
OUT
OUT
= 1000 µA/V.
= (g
= I
= (V
SHUNT
= I
OUT
m
LOAD
LOAD
SENSE
× V
) with its inverting input connected to the
× R
OUT
× R
) through the shunt resistor (R
SENSE
× R
OUT
) is converted to a voltage by using an
SHUNT
)
OUT
)/1000
SENSE
), and, therefore, the
BIAS
SHUNT
is typically
OUT
). The
) is
Rev. B | Page 9 of 16
When using the AD8212 as described, the battery/supply
voltage in the system must be between 7 V to 65 V. The 7 V
minimum supply range is necessary to turn on the internal
regulator (shown as a Zener diode in Figure 22). This regulated
voltage then remains a constant 5 V, regardless of the supply
(V+) voltage. The 65 V maximum limit in this mode of
operation is due to the breakdown voltage limitation of the
AD8212 process.
Typically, a 1% resistor can be used to convert the output
current to a voltage. Table 4 provides suggested R
Table 4. Suggested R
Gain (V/V)
1
10
20
50
100
Figure 22. Typical Connection (7 V to 65 V Supply (Pin V+) Range)
VOUT
BATTERY
R
OUT
R1
Q1
1
5
I
OUT
OUT
2
CIRCUIT
Values
BIAS
AD8212
R
SHUNT
A1
3
R
1
10
20
49.9
100
COMPENSATION
OUT
CURRENT
OUTPUT
(kΩ)
I
LOAD
6
8
R2
OUT
AD8212
values.