BU7461G_10 Datasheet, PDF (27/37 Pages) Rohm – Ground Sense Low Voltage Operation CMOS Operational Amplifiers

BU7461/BU7461S family, BU7441/BU7441S family, BU7462/BU7462S family, BU7442/BU7442S family
BU7464/BU7464S family, BU7444/BU7444S family, BU7465/BU7465S family, BU7445/BU7445S family Technical Note
●Test circuit 1 NULL method
Parameter
VDD, VSS, EK, Vicm Unit:[V]
VF S1 S2 S3 VDD VSS EK Vicm Calculation
Input Offset Voltage
VF1 ON ON OFF 3
0 -1.5 1.8
1
Large Signal Voltage Gain
VF2
-0.5
ON ON ON 3
0
0.9
2
VF3
-2.5
Common-mode Rejection Ratio
(Input Common-mode Voltage Range)
VF4
ON ON OFF 3
VF5
0
0 -1.5
1.8
3
Power Supply Rejection Ratio
VF6
1.7
ON ON OFF
0 -0.9 0
4
VF7
5.5
－ Calculation－
1. Input Offset Voltage (Vio)
Vio = ^|VF1| [V]
1 +Rf/Rs
2. Large Signal Voltage Gain(Av)
Av = 20Log ^{2 × (1 + Rf/Rs)} [dB]
|VF2-VF3|
3. Common-mode Rejection Ratio (CMRR)
1.8 × (1+Rf/Rs)
CMRR= 20Log
[dB]
|VF4 - VF5|
4. Power Supply Rejection Ratio (PSRR)
PSRR = 20Log ^{3.8 × (1 + Rf/Rs)} [dB]
|VF6 - VF7|
0.1[µF]
Vicm
SW1
VDD
RS=50[Ω] Ri=1[MΩ]
0.015[µF] 0.015[µF] ^DUT
RS=50[Ω] ^Ri=1[MΩ]
50[kΩ]
SW2
VSS
Rf=50[kΩ]
500[kΩ]
EK
Vo
500[kΩ]
SW3
RL
VRL
1000[pF]
0.01[µF]
15[V]
NULL
VF
-15[V]
Fig.185 Test circuit 1 (one channel only)
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27/36
2010.12 - Rev.A