UMA1005 Ver la hoja de datos (PDF) - Philips Electronics
Número de pieza
componentes Descripción
Fabricante
UMA1005 Datasheet PDF : 24 Pages
| |||
Philips Semiconductors
Dual low-power frequency synthesizer
Preliminary specification
UMA1005T
Table 2 Selection of prescaler ratio
COUNTER
STATUS
FB1
FB2
(−NM1 − 1) to 0
1
0
(−NM1 − 1) to −1
1
0
1 to NM2
0
0
0 to NM2
0
0
0 to NM3
0
1
0 to NM4
1
1
Notes
1. X = don’t care.
2. When the fractional accumulator overflows.
PRESCALER RATIO(1)
R1
R1(2)
R2
R2(2)
R3; if PR = 1X
R4; if PR = 11 or 00
The total division ratio from prescaler to the phase detector expressions are given in Table 3.
Table 3 Total division from prescaler to phase detector expressions
CONDITION
PR = 01
PR = 10
PR = 11
PR = 00
EXPRESSION
N = (NM1 + 2) × R1 + NM2 × R2
N′ = (NM1 + 1) × R1 + (NM2 + 1) × R2; note 1
N = (NM1 + 2) × R1 + NM2 × R2 + (NM3 + 1) × R3
N′ = (NM1 + 1) × R1 + (NM2 + 1) × R2 + (NM3 + 1) × R3; note 1
N = (NM1 + 2) × R1 + NM2 × R2 + (NM3 + 1) × R3 + (NM4 + 1) × R4
N′ = (NM1 + 1) × R1 + (NM2 + 1) × R2 + (NM3 + 1) × R3 + (NM4 + 1) × R4; note 1
N = (NM1 + 2) × R1 + NM2 × R2 + (NM4 + 1) × R4
N′ = (NM1 + 1) × R1 + (NM2 + 1) × R2 + (NM4 + 1) × R4; note 1
Note
1. When the fractional accumulator overflows.
When the prescaler ratio is R2 = R1 + 1 the total division ratio N′ = N + 1.
Table 4 Modulus prescaler
PR
MODULUS PRESCALER
00
4
01
2
10
3
11
4
NM1
12
12
12
12
BIT CAPACITY
NM2
4
8
4
4
NM3
−
−
4
4
NM4
4
−
−
4
November 1994
9
Share Link: 