experiment with sample circuit, voltage source ADR433, resistor connected between VOUT and VIN 1kΩ and the feedback resistor 1kΩ to calibrate the gain factor.internal crystal oscillator ,excitation frequency 30Khz , 1Vpp.
| 1K | 2K | 3K | 5.1K | 6.8K | 7.5K | 8.2K | 10K | real |
|---|---|---|---|---|---|---|---|---|
| 1000 | 1806 | 2617 | 4316 | 5689 | 6263 | 6861 | 8316 | measure(Ω) |
only the integer part is given.
external crystal oscillator 163.84Mhz ,excitation frequency 30Khz , 1Vpp or 2Vpp ,the result is similar to the above.
questions:
1.why so big errors?
2.the chip pin 12(DGND) 13(AGND) 14(AGND) is short measured by multimeter . the chip designed or my chip is broken?