HD155121F Datasheet, PDF (19/57 Pages) Hitachi Semiconductor – RF Transceiver IC for GSM and PCN Dual band cellular systems

HD155121F
Rx Gain Control Stage
The PGA amplifier of the HD155121F is the main Rx gain control stage. However, Mixer1 and Mixer2
gain level can switched as an optional function in order to optimize system performance.
LNA
bias
circuit
LNA
bias
circuit
Mixer1
Mixer1
Mixer2
PGA
Decoder
X7 X6 X5 X4 X3 X2 X1 X0
Serial data
X7 : for Mixer1 gain
X6 : for Mixer2 gain
X5 :
Bit allocation ^{X4 :}
X3 :
X2 :
for PGA gain
X1 :
X0 :
Figure 1
Table 2 First Mixer Gain Control Table (as optional function)
Item
Gain 1 (normal gain)
Gain 2 (low gain)
Band
GSM
PCN
GSM
PCN
Gain (typ)
9.5 dB
8.5 dB
–2.5 dB
–3.5 dB
I&Q
Demo.
X7
0
0
1
1
I
Q
CLK (26)
SDATA (27)
LE (28)
Table 3 Second Mixer Gain Control Table (as optional function)
Item
Gain (Typ)
X6
Gain 1 (normal gain)
13.0 dB
0
Gain 2 (low gain)
–3.0 dB
1
19