BU7291G Datasheet, PDF (20/27 Pages) Rohm – High Speed with Low Voltage CMOS Operational Amplifiers

BU7291G,BU7291SG,BU7255HFV,BU7255SHFV,
BU7495HFV,BU7495SHFV,BU7481G,BU7481SG,BU7485G,BU7485SG,BU5281G,BU5281SG
Technical Note
●Test circuit 1 NULL method
○Input-Output Full Swing BU7291/BU7255 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
-0.5
ON ON ON 3
0
1.5
2
VF3
-2.5
Common-mode Rejection Ratio
(Input Common-mode Voltage Range)
VF4
0
ON ON OFF 3
0 -1.5
VF5
3
3
Power Supply Rejection Ratio
VF6
2.4
ON ON OFF
0 -1.2
0
4
VF7
5.5
○Ground Sense BU7495/BU7481/BU7485/BU5281 family
Parameter
VF S1
Input Offset Voltage
VF1 ON
Large Signal Voltage Gain
VF2
VF3
ON
Common-mode Rejection Ratio
(Input Common-mode Voltage Range)
VF4
VF5
ON
BU7495/BU7481/BU5281
Power Supply
Rejection Ratio
BU7485
VF6 _ON
VF7
VDD, VSS, EK, Vicm Unit:[V]
S2 S3 VDD VSS EK Vicm Calculation
ON OFF 3
0 -1.5 1.8
1
ON ON 3
0
-0.5
-2.5
0.9
2
ON OFF 3
0
-1.5
0
1.8
3
1.8
ON OFF 3.0
0 -0.9 0
4
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)
CMRR = 20Log ^{1Δ.V8i×c(m1+×R(1f+/RRsf)/Rs)}[dB_[]_dB]
|VF4-VF5|
4. Power Supply Rejection Ratio (PSRR)
PSRR = 20Log ^{Δ3V.8DD××(1(1++RRf/fR/Rss))} [dB_[d]_B]
|VF6-VF7|
0.1[µF]
SW1
RS=50[Ω] Ri=1[MΩ]
0.015[µF] 0.015[µF]
Vicm
RS=50[Ω] Ri=1[MΩ]
50[kΩ]
SW2
VDD
DUT
VSS
Rf=50[kΩ]
500[kΩ]
Vo
EK
500[kΩ]
SW3
RL
VRL
1000[pF]
0.01[µF]
15[V]
NULL
-15[V]
V VF
Fig.139 Test circuit 1 (one channel only)
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20/26
2010.12 - Rev.A