SNAS730A March 2018 – November 2018 LMX8410L
PRODUCTION DATA.
When using External LO mode, the integrated synthesizer may be powered down and bypassed. The internal state machine clock is derived by dividing down the LO input. Since the frequency range of the LO circuit is bounded below the operational frequency of the divide-by-2 path, I/Q generation must be done using the polyphase filter path.
In External LO mode, some pins must be configured differently than in Internal LO mode. Even when the synthesizer circuitry is bypassed, VCC should be applied to all power pins (though bypass capacitors are no longer required). Table 5 contains a summary of the External LO requirements.
PIN NO. | NAME | I/O | EXTERNAL LO REQUIREMENTS |
---|---|---|---|
2 | VBIAS_VCO2 | Bypass | Floating (no connection) or same configuration with internal LO mode |
3 | VBIAS_VCO1 | Bypass | Floating (no connection) or same configuration with internal LO mode |
5 | SYNC | Input | Grounded |
8 | OSCINP | input | Grounded |
9 | OSCINM | input | Grounded |
10 | VREG_OSCIN | Bypass | Floating (no connection) or same configuration with internal LO mode |
13 | CP | Output | Floating (no connection) or same configuration with internal LO mode |
17 | LO_M | Input | Matching network recommended. No pull-up resisters / inductors. (1) |
18 | LO_P | Input | Matching network recommended. No pull-up resisters / inductors. (1) |
42 | VBIAS_VARAC | Bypass | Floating (no connection) or same configuration with internal LO mode |
44 | VTUNE | Input | Grounded |
47 | VREF_VCO | Bypass | Floating (no connection) or same configuration with internal LO mode |