IC213 Datasheet, PDF (5/11 Pages) IC-Haus GmbH – PROGRAMMABLE OSCILLATOR MODULE

iC213
preliminary
PROGRAMMABLE OSCILLATOR MODULE
SETTING THE FREQUENCY
Rev A1, Page 5/11
Using the I²C interface arbitrary output frequencies
in the range 39.0625 kHz to 1417.5 MHz can be pro-
grammed. The intrinsic oscillator allows frequencies in
the ranges 10 to 945 MHz, 970 to 1134 MHz, and 1213
to 1417.5 MHz to be programmed.
To this end the oscillator utilises a so called DCO (Dig-
itally Controlled Oscillator), consisting of a reference
clock oscillator with f_XTAL and a multiplier R_FREQ follow-
ing a high-speed divider HS_DIV as well as the output
divider N1:
f_out
=
f_XTAL ∗ RFREQ
HS_DIV ∗ N1
HS_DIV and further reduced by divider N1 to the re-
quired output frequency.
RFREQ
RFREQ it the multiplier for the Digitally Controlled Os-
cillator. Multiplying it with the referecnyl clock f_XTAL =
114.3363533 MHz yields the output frequency of the
DCO. Hence the multiplier RFREQ is determined as
follws:
f_DCO = f_XTAL ∗ RFREQ
⇒ RFREQ = ^fDCO
f_XTAL
f_out
Ouptut Frequency
f_XTAL Reference Clock (= 114,3363533 MHz)
HS_DIV High-Speed Divider
N1
Output Divider N1
RFREQ Multiplier
Using a PLL the reference clock in the DCO is multi-
plier with RFREQ. The operatign frequency of this PLL
is between 4.85 and 5.67 GHz. The thus generated
RF signal is divided by means of the high-sped divider
f_DCO DCO Output Frequency
f_XTAL Reference Clock (= 114.3363533 MHz)
RFREQ Multiplier
RFREQ it a 38 bit number with the upper 10 Bit repre-
senting the digits to the left of the decimal point and the
lower 28 bit the digits to the right of the decimal point.
Example: RFREQ = 02E0B04CE0
Hex
Binary
Decimal
02E
00 0010 1110
46
0B04CE0
0000 1011 0000 0100 1100 1110 0000
: 2²⁸
0,043042064
46,043042064
Table 2: RFREQ Conversion
HS_DIV
The high-speed divider is coded as a 3 bit digit as
shown in Table 3.
N1
The output divider N1 only allows even values between
1 and 128 to be set, except for the division factor 1. N1
calculates as:
HS_DIV[2:0]
000
001
010
011
100
101
110
111
Divider
4
5
6
7
not used
9
not used
11
Table 3: Values for HS_DIV
Value in the register N1 = Divider N1 − 1
So to set a division factor of e.g. 10, 0001001b (deci-
mal 9) must be programmed.
N1[6:0]
0000000
0010011
1111111
Divider
1
36
128
Table 4: Values for output divider N1