U4256BM Datasheet, PDF (7/14 Pages) TEMIC Semiconductors – Frequency Synthesizer for Radio Tuning

U4256BM
Bus Control
The charge pump current can be choosen by setting the The gain of DAC1 has a range of 0.7 x V(PDO) to
Bits IPD1, 2 (Bit 71) and IPD3, 4 (Bit 70) as following: 2.15 x V(PDO). V(PDO) is the PLL tuning voltage
IPD (µA)
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 25
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ¹⁰⁰
500
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ₂₀₀₀
IPD1, 2
0
0
1
1
IPD3, 4
0
1
0
1
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{The oscillator buffer output can be switched by the OSCB}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{Bit as following (Bit 69):}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{MX2LO AC Voltage}
OSCB
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _ON
0
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ OFF
1
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{The DAC3 output voltage can be controlled by the}
output. This range is divided into 256 steps. So one step
is approximately (2.15–0.7)/256 = 5.664 m. The gain can
be controlled by the Bits 36 to 43 (G–2⁰ to G–2⁷) as
following:
Gain B43 B42 B41 B40 B39 B38 B37 B36
DAC1
Approx.
0.7
00000000
0.70566 0 0 0 0 0 0 0 1
0.71133 0 0 0 0 0 0 1 0
0.71699 0 0 0 0 0 0 1 1
...
... ... ... ... ... ... ... ...
1.00019 0 0 1 1 0 1 0 1
...
... ... ... ... ... ... ... ...
2.1386 1 1 1 1 1 1 0 1
2.14434 1 1 1 1 1 1 1 0
2.15 m 1 1 1 1 1 1 1 1
Bits P-2⁰ to P-2² (Bits 66 to 68) as following:
DAC3 Offset Approx.
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{0.5 V}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{1.1 V}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{1.8 V}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{2.4 V}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 3.1 V
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ 3.7 V
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ^{4.4 V}
5.0 V
Bit68
0
0
0
0
1
1
1
1
Bit67
0
0
1
1
0
0
1
1
Bit66
0
1
0
1
0
1
0
1
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{The FM/AM function can be controlled by setting the}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{FM/AM Bit 34 as following:}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _FM/AM
Bit 34
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _FM
0
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _AM
1
The offset of DAC1 has a range of 0.5 to –0.6. This range
is divided into 64 steps. So one step is approximately
1.1V/63 = 17.2 m. The offset can be controlled by the Bits
44 to 49 (O–2⁰ to O–2⁵) as following:
Offset DAC1 B49 B48 B47 B46 B45 B44
Approx.
0.5
0
0
0
0
0
0
0.4828
0
0
0
0
0
1
0.4656
0
0
0
0
1
0
0.4484
0
0
0
0
1
1
...
... ... ... ... ... ...
–0.0156
0
1
1
1
1
0
...
... ... ... ... ... ...
0.5656
1
1
1
1
0
1
–0.5828
1
1
1
1
1
0
–0.6
1
1
1
1
1
1
The tuning capacity for the crystal oscillator has a range
of 0.5 pF to 71.5 pF. The values are coded binary. The
tuning can be controlled by the Bits 78 to 85 as following:
The switching output SWO1 to SWO4 can be controlled
as following (Bits 30 to 33):
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{Switch Output}
Bit
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{SWOx = ON}
0
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{SWOx = OFF}
1
C B85 B84 B83 B82 B81 B80 B79 B78
(pF)
0 11111111
0.5 1 1 1 1 1 1 1 0
1.0 1 1 1 1 1 1 0 1
1.5 1 1 1 1 1 1 0 0
... ... ... ... ... ... ... ... ...
63.5 1 0 0 0 0 0 0 0
71.5 0 0 0 0 0 0 0 0
Rev. A2, 03-Nov-98
7 (14)
Preliminary Information