HD155101BF Datasheet, PDF (12/50 Pages) Hitachi Semiconductor – RF Single-chip Linear IC for GSM and EGSM Systems

HD155101BF
IFVCO Operation
The HD155101BF incorporates an IFVCO circuit. The IFVCO circuit consists of an IFVCO transistor and
a bias circuit for it, whose current are 2.0 mA and 0.5 mA respectively. If an internal IFVCO is used, treat
pin 23 (IFVCOO), pin 24 (IFVCOI) and pin 21 (IFLO) as shown figure 3-(a).
Using an external IFVCO, pin 23 (IFVCOO) and pin 24 (IFVCOI) cannot be connected any pattern and
component, and any component to feed direct current must be also removed from pin 21 (IFLO).
If pin 23 (IFVCOO), pin 24 (IFVCOI) and pin 21 (IFLO) are treated as shown figure 3-(b), current
consumption will decrease 2.0 mA.
IFVCO
bias circuit
21 23 24 ^HD155101BF
IFVCO
bias circuit
21 23 24 ^HD155101BF
Vtune
Vcc
PLL
IFLO ^synth.
External
IFVCO
Vtune
PLL
IFLO ^synth.
(a) using an internal IFVCO
(b) using an external IFVCO
Figure 3 Control Diagram for Operating Mode Selection