| 9 | LOIN | 50 Q LO input port. This pin has an internal l kQ resistor to Vcc, hence an external DC blocking capacitor is recommended. | |
| 10 | VCC1 | Power supply pin for the first TX LO amplifier. An external RF decou- pling capacitor should be placed as close to the pin as possible. | |
| 1 1 | RFIN- | Complementary input of pin l. Normally this pin has an external RF | IfIRF.N |
| 12 | GND | decoupling capacitor. Ground connection. | |
| 13 | GND | Ground connection. | |
| 14 | MODIN | Modulation input. This pin has an internal 6 kQ resistor to ground. The | |
| 15 | TX ENABLE | allowed DC voltage at this input is -1 V to +1 V An external DC blocking capacitor is recommended to maintain a DC level of OV. Enables the TX circuits (TX LO buffer amplifier, modulator, output amplifier) when high. | Same as pin 2. |
| 16 | RF OUT | Open collector RF output. This pin requires an external inductor to Vcc for biasing. | 7 |
| | | |
| | mm | inch |
| DIM | MIN | TYP | MAX | MIN | TYP | MAX |
| A | | | 1.75 | | | 0.068 |
| al | 0.1 | | 0.2 | 0.003 | | 0.007 |
| a2 | | | 1.65 | | | 0.064 |
| b | 0.35 | | 0.46 | 0.013 | | 0.018 |
| bl | 0.19 | | 0.25 | 0.007 | | 0.010 |
| c | | 0.5 | | | 0.019 | |
| c1 | 450 | ltyp.) |
| D | 8.55 | | 8.75 | 0.336 | | 0.344 |
| E | 5.8 | | 6.2 | 0.228 | | 0.244 |
| e | | 1.27 | | | 0.050 | |
| e3 | | 7.62 | | | 0.300 | |
| F | 3.8 | | 4.0 | 0.149 | | 0.157 |
| G | 4.6 | | 5.3 | 0.181 | | 0.208 |
| L | 0.5 | | 1.27 | 0.019 | | 0.050 |
| M | | | 0.68 | | | 0.026 |
| S | 8fr | iax1 |
| | | | | | |
Current feedback amplifiers want resistive feedback from the output to the inve rting input for stable operation. Take care to minimize the stray capacitance between the output and the inve rting input. Capacitance on the inve rting input to ground will cause peaking in the frequency response (and overshoot in the transient response), but it does not degrade the stability of the amplifier. The amount of capacitance that is necessary to cause peaking is a func- tion of the closed-loop gain taken. The higherthe gain,the more capacitance is required to cause peaking. We can add capacitance from the inverting input to ground to increase the bandwidth in high gain applications. For example,in this gain of100 application,the bandwidth can be increased from 10MHz t0 17MHz by adding a 2200pF capacitor.
