NJM2795 Ground noise isolation Amplifier with Adjustable Differential Gain GENERAL DESCRIPTION The NJM2795 is a ground noise isolation amplifier. It contains dual channel differential amplifier with Adjustable Differential Gain. It is developed for those car audio applications where long connections between head unit and other components are necessary and ground noise has to be eliminated. Further the NJM2795 allow the user to alter the gain to optimize the signal-to-noise ratio of their system. It is useful in microphone amplifier applications. PACKAGE OUTLINE NJM2795V FEATURES l Dual Channel Differential Amplifier l Adjustable Differential Gain +6dB to +52dB l Operating Voltage 4.3 to 20V l Operating Current 7mA typ. l Maximum Output Voltage 2Vrms min., @ THD=1% l Common mode rejection ratio80dB typ. l Supply Voltage Rejection Ratio 65dB typ. l Total Harmonic Distortion 0.005% typ. l Equivalent Input Noise Voltage 2µVrms typ. @ Gv=+20dB l Bipolar Technology l Package Outline SSOP14 BLOCK DIAGRAM V+ RG1IN1OUT1 IN1+ RG1+ VREF RG2+ IN2+ OUT2 IN2RG2GND Ver .2.2E –1– PIN CONFIGURATION –2– 1 14 7 8 No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Symbol OUT1 RG1+ GND VREF V+ RG2+ OUT2 IN2+ RG2IN2NC IN1RG1IN1+ Function Output1 Gain Ajustment 1+ Ground Reference Voltage Power Supply Gain Ajustment 2+ Output2 +Input2 Gain Ajustment 2-Input2 No Connect -Input1 Gain Ajustment 1+Input1 Ver .2.2E NJM2795 ABSOLUTE MAXIMUM RANGES (Ta=25°C) PARAMETER SYMBOL RANGE UNIT +22 V + Supply Voltage V +( ) Maximum Input Voltage VIM Power Dissipation PD NOTE: EIA/JEDEC STANDARD Test board (76.2x114.3x1.6mm, 2layer, FR-4) mounting mW Operating Temperature Topr -40 to +85 °C Storage Temperature Tstg -40 to +150 °C V 0 to V SSOP14 : 555* ( ) For the maximum input voltage less than 0 toV ELECTRICAL CHARACTERRISTIC (V+=9V, Ta=25°C) PARAMETER TEST CONDITION SYMBOL MIN. TYP. MAX. UNIT 4.3 9 20 V - 7 10 mA 4.0 4.5 5.0 V DC CHARACTERRISTIC Operating Voltage V+ Operating Current ICC Reference Voltage VREF No Signal AC CHARACTERRISTIC (Non-inverting circuit, f=1kHz, Vin=100mVrms, Rg=0Ω, RG=10kΩ, RL=10kΩ unless otherwise specified) GV1 Voltage Gain 1 RG=91kΩ +4.0 +6.0 +8.0 dB Voltage Gain 2 GV2 RG=10kΩ +18.0 +20.0 +22.0 dB Voltage Gain 3 GV3 RG=220Ω, Vin=2.5Vrms +50.0 +52.0 +54.0 dB Channel Separation CS VO=2Vrms, A-weighted 90 100 - dB Channel Balance BAL - - 0.5 dB 100 - - kHz Roll-off High Frequency fRH Input Resistance RIN 160 200 240 kΩ Output Resistance ROUT - 200 - Ω Maximum Output Voltage 1 VOM1 THD=1% 2 2.5 - Vrms Maximum Output Voltage 2 Equivalent Input Noise Voltage VOM2 Inverting, THD=1% - 2.5 - Vrms Rg=600Ω, A-weighted, Gv=+20dB - 2 3 µVrms Total Harmonic Distortion THD VO=1Vrms, BW=400Hz to 30kHz - 0.005 0.05 % VICM=1Vrms 70 80 - dB f=100Hz , Vripple=100mVrms 55 65 - dB Common Mode Rejection Ratio (*) Supply Voltage Rejection Ratio VNI CMRR SVR -3dB Note (*): CMRR = GV 2 , Where GV 2 is the Differential Mode Gain and GVCM is the Common Mode Gain. GVCM ⎛V GVCM = 20 * log⎜⎜ OCM ⎝ VICM Ver .2.2E ⎞ ⎟⎟ , Where VOCM is the Common Mode Output and V ICM is the Common Mode Input. ⎠ –3– + TERMINAL DESCRIPTION PIN NO. SYMBOL FUNCTION V+ V+ V+ 1 7 OUT1 OUT2 Output1 Output2 200Ω + V x 0.5 V+ V+ 2 6 9 13 RG1RG2RG2+ RG1+ TERMINAL DC VOLTAGE EQUIVALENT CIRCUIT Gain Adjustment 1Gain Adjustment 2Gain Adjustment 2+ Gain Adjustment 1+ + V x 0.5 750Ω 200kΩ V+ 8 10 12 14 IN2+ IN2IN1IN1+ +Input2 -Input2 -Input1 +Input1 V+ V+ 750Ω + V x 0.5 45kΩ V+ V+ 4 VREF Reference Voltage V+ 240kΩ 750Ω + V x 0.5 240kΩ –4– Ver .2.2E NJM2795 APPLICATION CIRCUIT RG OUT1 3.3µF 1 + 14 RG1- 1µF + IN1+ 1µF + IN1- 1µF + IN2- RG1+ 2 200kΩ 13 GND 3 22µF + 200kΩ NC VREF 4 11 V+ 200kΩ 10 5 + 12 47µF RG2- RG2+ 200kΩ 6 OUT2 9 3.3µF + 7 8 1µF + IN2+ RG Ver .2.2E –5– APPLICATION BLOCK DIAGRAM (1) Non-inverting line input IN+ OUT NJM2795 IN- IC GND Vref VN (2) Inverting line input OUT IN- NJM2795 IN+ IC GND Vref VN (3) Non-inverting line output IN+ OUT NJM2795 IN- IC GND Vref VN (4) Inverting line output OUT IN- NJM2795 IN+ IC GND Vref VN [CAUTION] The specifications on this databook are only given for information , without any guarantee as regards either mistakes or omissions. The application circuits in this databook are described only to show representative usages of the product and not intended for the guarantee or permission of any right including the industrial rights. –6– Ver .2.2E