BU7261G Datasheet, PDF (23/33 Pages) Rohm – Low Voltage Operation CMOS Operational Amplifiers

BU7261G,BU7261SG,BU7241G,BU7241SG,BU7262F/FVM,BU7262SF/FVM,BU7242F/FVM,BU7242SF/FVM
BU7461G,BU7461SG,BU7441G,BU7441SG,BU7462F/FVM,BU7462SF/FVM,BU7442F/FVM,BU7442SF/FVM
Technical Note
●Test circuit1 NULL method
○Input-Output Full Swing BU7261/BU7241 family , BU7262/BU7242 family
VDD,VSS,EK,Vicm Unit : [V]
Parameter
VF
S1
S2
S3 VDD VSS EK Vicm Calculation
Input Offset Voltage
VF1 ON ON OFF
3
0
-1.5
3
1
Large Signal Voltage Gain
VF2
VF3
ON
ON
ON
3
0
-0.5
-2.5
1.5
2
Common-mode Rejection Ratio
(Input Common-mode Voltage Range)
VF4
VF5
ON
ON OFF
3
0
-1.5
0
3
3
Power Supply Rejection Ratio
VF6
VF7
ON
ON OFF
1.8
5.5
0
-0.9
0
4
○Ground Sense BU7461/BU7441 family , BU7462/BU7442 family
VDD,VSS,EK,Vicm Unit : [V]
Parameter
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
VF3
ON
ON
ON
3
0
-0.5
-2.5
0.9
2
Common-mode Rejection Ratio
(Input Common-mode Voltage Range)
VF4
VF5
ON
ON OFF
3
0
-1.5
0
1.8
3
Power Supply Rejection Ratio
VF6
ON
ON
OFF
1.7
0
-0.9
0
4
VF7
5.5
-Calculation-
1. Input Offset Voltage (Vio)
2. Large Signal Voltage Gain (Av)
Vio =
|VF1|
1+Rf /Rs
[V]
Av = 20Log ^{2×(1+Rf/Rs)} [dB]
|VF2-VF3|
3. Common-mode Rejection Ratio (CMRR) ^{CMRR = 20Log 1.8×(1+Rf/Rs) [dB]}
|VF4-VF5|
4. Power Supply Rejection Ratio (PSRR)
PSRR = 20Log ^{3.8×(1+Rf/Rs)} [dB]
|VF6-VF7|
0.1[μF]
SW1
VDD
RS＝50[Ω] Ri=1[MΩ]
0.015[μF] 0.015[μF] DUT
Vicm
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. 185Test circuit 1 (one channel only)
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2009.05 - Rev.A