User manual INTERSIL CA3140T DATASHEET

[. . . ] CA3140, CA3140A Data Sheet September 1998 File Number 957. 4 4. 5MHz, BiMOS Operational Amplifier with MOSFET Input/Bipolar Output The CA3140A and CA3140 are integrated circuit operational amplifiers that combine the advantages of high voltage PMOS transistors with high voltage bipolar transistors on a single monolithic chip. The CA3140A and CA3140 BiMOS operational amplifiers feature gate protected MOSFET (PMOS) transistors in the input circuit to provide very high input impedance, very low input current, and high speed performance. The CA3140A and CA3140 operate at supply voltage from 4V to 36V (either single or dual supply). These operational amplifiers are internally phase compensated to achieve stable operation in unity gain follower operation, and additionally, have access terminal for a supplementary external capacitor if additional frequency roll-off is desired. [. . . ] This technique is necessary because the voltage follower configuration approaches unity gain rather than the zero gain required to shape the sine wave at the two extremes. Meter Driver and Buffer Amplifier Figure 11 shows the CA3140 connected as a meter driver and buffer amplifier. Low driving impedance is required of the CA3080A current source to assure smooth operation of the Frequency Adjustment Control. This low-driving impedance requirement is easily met by using a CA3140 connected as a voltage follower. Moreover, a meter may be 9 CA3140, CA3140A CENTERING -15V 10k 62k 5 2 11k 11k 10k 0. 1 µF EXTERNAL OUTPUT 3 +15V 7. 5k 360 3 360 2 2M SYMMETRY -15V +15V 100k FROM BUFFER METER DRIVER (OPTIONAL) 39k -15V + +15V 7 15k 6 7-60 pF HIGH FREQ. SHAPE 4 5 -15V 51 pF 3 2 +15V 0. 1 µF 6 7 + CA3140 HIGH FREQUENCY LEVEL 910k 7-60pF 10k EXTERNAL OUTPUT 6 2. 7k -15V TO OUTPUT AMPLIFIER CA3080A - - 7 4 -15V 2k CA3080 + 4 13k 120 10k +15V FREQUENCY ADJUSTMENT 5. 1k TO SINE WAVE SHAPER THIS NETWORK IS USED WHEN THE OPTIONAL BUFFER CIRCUIT IS NOT USED OUTPUT AMPLIFIER 1N914 FIGURE 10A. CIRCUIT FREQUENCY ADJUSTMENT Top Trace: Output at junction of 2. 7 and 51 resistors; 5V/Div. , 500ms/Div. Center Trace: External output of triangular function generator; 2V/Div. , 500ms/Div. Bottom Trace: Output of "Log" generator; 10V/Div. , 500ms/Div. FIGURE FUNCTION GENERATOR SWEEPING METER DRIVER AND BUFFER AMPLIFIER FUNCTION GENERATOR +15V M POWER SUPPLY ±15V -15V SINE WAVE SHAPER WIDEBAND LINE DRIVER 51 GATE DC LEVEL SWEEP ADJUST OFF INT. EXTERNAL INPUT FINE RATE SWEEP GENERATOR 1V/Div. , 1s/Div. Three tone test signals, highest frequency 0. 5MHz. Note the slight asymmetry at the three second/cycle signal. This asymmetry is due to slightly different positive and negative integration from the CA3080A and from the PC board and component leakages at the 100pA level. FUNCTION GENERATOR WITH FIXED FREQUENCIES SWEEP LENGTH V- FIGURE 10D. FUNCTION GENERATOR 10 CA3140, CA3140A FREQUENCY CALIBRATION MAXIMUM 620k 7 51k 3 + CA3140 3M 2 6 4. 7k 4 2k +15V 0. 1µF 12k FREQUENCY 2. 4k CALIBRATION MINIMUM 2. 5 k 510 8 2k 6 7 METER POSITION ADJUSTMENT 12 3. 6k 13 500k FREQUENCY ADJUSTMENT 10k SWEEP IN - TO CA3080A OF FUNCTION CA3080A GENERATOR (FIGURE 10) 4 5 METER SENSITIVITY ADJUSTMENT 620 1k 200µA M METER 11 9 510 10 14 +15V -15V 0. 1µF 3 5. 1k 2 + 7 6 5. 6k 7. 5k SUBSTRATE OF CA3019 TO WIDEBAND OUTPUT AMPLIFIER 10k EXTERNAL OUTPUT CA3140 - 4 0. 1µF +15V 100 k -15V 1M D1 9. 1k 6 D3 R1 10k 7 -15V R3 10k D4 5 D6 9 1 8 D2 2 430 R2 1k 3/ OF CA3086 5 -15V 3 4 D CA3019 5 DIODE ARRAY FIGURE 11. METER DRIVER AND BUFFER AMPLIFIER FIGURE 12. SINE WAVE SHAPER 750k "LOG" SAWTOOTH 18M 1N914 1M 22M SAWTOOTH SYMMETRY 100k 100k FINE RATE 8. 2k 1N914 0. 47µF 0. 047µF 4700pF 470pF +15V SAWTOOTH AND RAMP LOW LEVEL SET (-14. 5V) 50k 75k COARSE RATE 2 3 - 7 +15V 0. 1 µF 6 0. 1 µF SAWTOOTH "LOG"+15V TRIANGLE 30k 50k LOG RATE ADJUST 10k -15V 36k 3 100k TO OUTPUT 2 AMPLIFIER 51k +15V CA3140 + 4 - 7 6 10k GATE PULSE OUTPUT CA3140 + 4 -15V 43k -15V 10k EXTERNAL OUTPUT TO FUNCTION GENERATOR "SWEEP IN" SWEEP WIDTH +15V 3 2 LOGVIO + CA3140 7 6 4 51k 6. 8k 91k 1 25k 3. 9 -15V 5 10k TRIANGLE 5 4 3 2 1 TRANSISTORS FROM CA3086 ARRAY SAWTOOTH "LOG" 100 390 FIGURE 13. SWEEPING GENERATOR 11 CA3140, CA3140A This circuit can be adjusted most easily with a distortion analyzer, but a good first approximation can be made by comparing the output signal with that of a sine wave generator. The initial slope is adjusted with the potentiometer R1, followed by an adjustment of R2. The final slope is established by adjusting R3, thereby adding additional segments that are contributed by these diodes. Because there is some interaction among these controls, repetition of the adjustment procedure may be necessary. Sweeping Generator Figure 13 shows a sweeping generator. [. . . ] Bottom Trace: Input Signal; 5V/Div. , 2µs/Div. LARGE SIGNAL RESPONSE AND SETTLING TIME SAMPLING RESPONSE Top Trace: Output; 100mV/Div. , 500ns/Div. Bottom Trace: Input; 20V/Div. , 500ns/Div. SAMPLE AND HOLD SYSTEM DYNAMIC CHARACTERISTICS WAVEFORMS 16 CA3140, CA3140A R2 5k +15V 0. 1µF R1 2 10k 3 0. 1µF 10k INPUT 3 2 10k R3 100k OFFSET ADJUST PEAK ADJUST 10k + CA3140 6 4 1N914 6 100pF 2k 7 SIMULATED LOAD +15V CA3140 + 8 1 5 7 4 0. 1µF -15V 2k 0. 05µF BW (-3dB) = 4. 5MHz SR = 9V/µs R2 R3 GAIN = ------ = X = ---------------------------R1 R1 R2 + R3 X+X R 3 = ---------------- R 1 1­X R2 5k FOR X = 0. 5 -------------- = -----10k R1 0. 75 R 3 = 10k ---------- = 15k 0. 5 2 FIGURE 28A. [. . . ]