U2896B Datasheet, PDF (6/13 Pages) TEMIC Semiconductors – Modulation PLL for GSM, DCS and PCS Systems

U2896B
Supply Current of the Charge Pump I_VSP vs. Time
Due to the pulsed operation of the charge pump, the
current into the charge-pump supply pin VSP is not
constant. Depending on I (see figure 5) and the phase
difference at the phase detector inputs, the current I_VSP
over time varies. Basically, the total current is the sum of
the quiescent current, the charge-/discharge current, and
– after each phase comparison cycle – a current spike (see
figure 3).
Internal current |I_CPC| vs. R_CPC
19.2 kW
9.6 kW
4.8 kW
2.4 kW
R_CPC
(typical values)
|I_CPCO|
0.5 mA
1 mA
2 mA
4 mA
Up
Down
2.5 I_CPCO
I_{VSP 1.5 ICPCO}
I
I_CPO
I_CPCO
–I_CPCO
t
t
14913
Figure 3. Supply current of the charge pump
Mode Selection
The device can be programmed to different modes via an external resistor RMODE (including short, open) from Pin
MC to VS2. The mode is distinguished from specific N-, R-divider ratios, and the polarity of the charge-pump selection.
Mode Selection
N-Divider R-Divider CPO Current Polarity ⁴⁾ Application
Mode Resistance
between Pin MC
and Pin VS2
1 0 (<50 W)
1:1
W 2 2.7 k (±5%)
1:1
W 3 10 k (±5%)
1:1
W 4 47 k (±5%)
2:1
5 ∞ (> MW)
2:1
f_n < f_R ¹⁾ f_n > f_R ¹⁾
1:1
sink
source
t.b.d.
1:1
source
sink
t.b.d.
2:1
source
sink
t.b.d.
2:1
source
sink PCN/ PCS ²⁾
2:1
sink
source
GSM ³⁾
CPCH
active
x
x
CPCL
active
x
x
x
1) _{Frequencies referred to PFD input}
2) _{LO frequencies below VCO frequency}
3) _{LO frequencies above VCO frequency}
4_{) Sink current into Pin CPO. Source: current out from Pin CPO.}
6 (13)
Rev. A1, 18-Sep-98
Preliminary Information