AD8203YRZ Analog Devices Inc, AD8203YRZ Datasheet - Page 14

• Manufacturer Part Number: AD8203YRZ
• Description: IC,Differential Amplifier,SINGLE,BIPOLAR,SOP,8PIN,PLASTIC
• Manufacturer: Analog Devices Inc
• Type: Single Supplyr

Specifications of AD8203YRZ

• Amplifier Type: Differential
• Number Of Circuits: 1
• Slew Rate: 0.330 V/µs
• Gain Bandwidth Product: 60kHz
• Current - Input Bias: 40nA
• Voltage - Input Offset: 1000µV
• Current - Supply: 250µA
• Voltage - Supply, Single/dual (±): 3.5 V ~ 12 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Bandwidth: 60 kHz
• Common Mode Rejection Ratio: 82
• Current, Input Bias: 40 nA
• Current, Supply: 0.25 mA
• Package Type: SOIC-8
• Resistance, Input: 320 Kilohms (Differential), 160 Kilohms (Common-Mode)
• Temperature, Operating, Range: -40 to +125 °C
• Voltage, Gain: 14 V/V
• Voltage, Input: -6 to +30 V
• Voltage, Input Offset: -1 to +1 mV
• Voltage, Noise: 300 nV/sqrt Hz
• Voltage, Output Swing: 0.02 to 4.8 V
• Voltage, Supply: 3.5 to 12 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• Current - Output / Channel: -
• -3db Bandwidth: -
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

AD8203
APPLICATIONS
The AD8203 difference amplifier is intended for applications
that require extracting a small differential signal in the presence
of large common-mode voltages. The input resistance is nominally
320 kΩ, and the device can tolerate common-mode voltages
higher than the supply voltage and lower than ground.
The open collector output stage sources current to within
20 mV of ground and to within 200 mV of V .
CURRENT SENSING
High Line, High Current Sensing
Basic automotive applications making use of the large common-
mode range are shown in Figure 2 and Figure 3. The capability
of the device to operate as an amplifier in primary battery sup-
ply circuits is shown in
of the device to withstand voltages below system ground.
Low Current Sensing
The AD8203 is also used in low current sensing applications,
such as the 4 to 20 mA current loop shown in Figure 42. In such
applications, the relatively large shunt resistor can degrade the
common-mode rejection. Adding a resistor of equal value on the
low impedance side of the input corrects this error.
GAIN ADJUSTMENT
The default gain of the preamplifier and buffer are ×7 and ×2,
respectively, resulting in a composite gain of ×14. With the
addition of external resistor(s) or trimmer(s), the gain can be
lowered, raised, or finely calibrated.
Gains Less Than 14
Since the preamplifier has an output resistance of 100 kΩ, an
external resistor connected from Pin 3 and Pin 4 to GND
decreases the gain by a factor R
in Figure 43.
+
Figure 42. 4 to 20 mA Current Loop Receiver
Figure 2. Figure 3 illustrates the ability
10Ω
1%
10Ω
1%
EXT
+IN
–IN
/(100 kΩ + R
AD8203
GND
+V
5V
S
NC
A1
NC = NO CONNECT
S
OUT
A2
EXT
), as shown
OUTPUT
Rev. B | Page 14 of 20
The overall bandwidth is unaffected by changes in gain by using
this method, although there may be a small offset voltage due to
the imbalance in source resistances at the input to the buffer.
This can often be ignored, but if desired, it can be nulled by
inserting a resistor equal to 100 kΩ minus the parallel sum of
R
R
offset nulling resistor is 50 kΩ.
Gains Greater Than 14
Connecting a resistor from the output of the buffer amplifier to
its noninverting input, as shown in Figure 44, increases the
gain. The gain is now multiplied by the factor R
100 kΩ); for example, the gain is doubled for R
Overall gains as high as 50 are achievable this way. Note that the
accuracy of the gain becomes critically dependent on the
resistor value at high gains. Also, the effective input offset
voltage at Pin 1 and Pin 8 (about six times the actual offset of
A1) limits the part’s use in high gain, dc-coupled applications.
V
V
CM
EXT
EXT
CM
and 100 kΩ, in series with Pin 4. For example, with
= 100 kΩ (yielding a composite gain of ×7), the optional
V
V
DIFF
DIFF
V
V
2
2
NC = NO CONNECT
DIFF
DIFF
2
2
NC = NO CONNECT
Figure 43. Adjusting for Gains < 14
Figure 44. Adjusting for Gains > 14
AD8203
+IN
–IN
100kΩ
10kΩ
AD8203
+IN
100kΩ
–IN
10kΩ
GND
+V
+V
S
S
GND
+V
+V
10kΩ
NC
A1
S
S
10kΩ
NC
A1
OUT
A2
OUT
A2
R
R
EXT
EXT
GAIN =
R
EXT
GAIN =
R
OUT
EXT
EXT
EXT
= 100kΩ
OUT
R
= 100kΩ
/(R
= 200 kΩ.
EXT
R
14R
EXT
EXT
14R
+ 100kΩ
14 – GAIN
EXT
– 100kΩ
GAIN – 14
−
EXT
GAIN
GAIN