U2896B Datasheet, PDF (7/13 Pages) TEMIC Semiconductors – Modulation PLL for GSM, DCS and PCS Systems

Equivalent Circuits at the IC’s Pins
I,Q
NI, NQ
V_{Bias_MDLO}
MDLO
2230 Ω
2230 Ω
V_{Ref_input}
V_{Ref_MDLO}
Baseband inputs
LO input
Figure 4. I/Q modulator
U2896B
2 x 615 W
VS1
MDO
NMDO
V_{Ref_output}
Output
GND
14893
RF
NRF
1 kΩ
V_{Bias_RF}
890 Ω
890 Ω
MIXLO
1 kΩ
V_{Bias_LO}
1.6 kΩ
1.6 kΩ
650 W
NMIXO
VS3
650 W
MIXO
V_{Ref_RF}
V_{Ref_LO}
RF input
LO output
Figure 5. Mixer
Output
GND
14894
CPCL
CPCH
V_Ref
Ref
n
up
Ref
n
n ^{= Transistor with an emitter area–factor of “n”}
Figure 6. Charge pump
4
down
VSP
4
I
CPO
I
GNDP
14896
Rev. A1, 18-Sep-98
7 (13)
Preliminary Information