ROHM BA3121F Technical data
Audio Accessory IC Series
Ground Isolation
Amplifier
BA3121F, BA3123F
No.09092EAT01
●Description
The BA3121F/BA3123F are ground isolation amplifiers deve loped for use in car audio applications.
This IC efficiently eliminate problems caused by wiring resistance, and remove noise generated by the electrical devices
used in automobiles. The capacitance values of the external capacitors required for the ICs are small to allow compact
and reliable set design.
●Features
1) Large capacitors not required
2) High common-mode rejection ratio (57dB typ. at f = 1kHz).
3) Low noise (VNO = 3.5μVrms T yp.).
4) Low distortion (THD = 0.002% Typ.).
5) Two channels.
●Applications
Car audio systems
●Line up matrix
BA3121F BA3123F
Operation temperature
●Absolute maximum ratings (Ta = 25C)
Parameter Symbol Limits Unit
Power supply voltage Vcc 18 V
Power dissipation Pd 450* mW
Operation
temperature
Storage temperature Tstg －55～＋125 ℃
＊Reduced by 4.5mW in Ta of 1C over 25C.
●Recommended operating conditions (Ta = 25C)
Parameter Symbol Min. Typ. Max. Unit
Power supply voltage Vcc 4 12 18 V
BA3121F
BA3123F －40～＋85 ℃
－30～＋85C －40～＋85C
Topr
－30～＋85 ℃
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.08 - Rev.A
BA3121F, BA3123F
●Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 12V, f = 1kHz, Rg = 1.8k)
Parameter Symbol Min. Typ. Max. Unit Conditions
Quiescent current IQ 5.6 9.0 14.0 mA VIN＝0V
Output noise voltage VNO － 3.5 8.0 μV
BPF＝20Hz-20kHz
rms
rms
Voltage gain GV -1.5 -0.04 1.5 dB VO＝－10dBm, Rg＝0Ω
Maximum output voltage VOM 1.8 2.0 － V
THD＝0.1％, Vcc＝8V
rms
Total harmonic distortion THD － 0.002 0.02 ％ VO＝0.7V
Common-mode rejection ratio CMRR 41 57 － dB
Common-made voltage VCM 2.5 3.75 － V
Ripple rejection ratio RR 72 80 － dB
Channel separation CS － 82 － dB
Vcc＝8V,CMRR＝40dB
rms
fRR＝100Hz,VRR＝－10dBm,
＝0Ω
R
g
VIN＝－10dBm,
Rg＝1.8kΩ/OPEN
Slew rate SR － 2.0 － V/μS
Input resistance RIN 44 55 66 kΩ
◎Not designed for radiation resistance
●Electrical characteristics curves
Fig.1 Quiescent current
vs. power supply voltage
Fig.2 Maximum output voltage
vs. power supply voltage
Fig.3 Output noise voltage
vs. power supply voltage
Fig.4 Voltage gain
vs. power supply voltage
Fig.5 Voltage gain vs. frequency
Fig.6 Channel separation
rms
Technical Note
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.08 - Rev.A
BA3121F, BA3123F
Fig.7 Ripple rejection ratio
Fig.10 Common-mode rejection ratio
vs. frequency
vs. frequency
Fig.8 Total harmonic distortion
vs. output voltage
Fig.11Common-mode rejection ration
vs. input voltage
Technical Note
Fig.9 Total harmonic distortion
vs. frequency
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© 2009 ROHM Co., Ltd. All rights reserved.
2009.08 - Rev.A
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