Electrical characteristics (continued) – Rainbow Electronics ATA5757 User Manual
Page 16
16
ATA5756/ATA5757 [Preliminary]
4702D–RKE–02/04
Imaginary part of XTO1
Impedance in stady state
oscillation
Since pulling P is
P = -IM
XTO
×
C
M
×
π ×
f
XTO
∆
f
XTO
can be calculated out of IM
XTO
with C
M
= 4.37 fF
IM
XTO
j20
j110
j200
Ω
Real part of XTO1 impedance in
small signal oscillation
This value is important for crystal
oscillator start-up
RE
XTO
-650
-1100
Ω
Crystal oscillator start-up time
Time between ENABLE of the IC with
FSK = H and activation of the CLK
output. The CLK is activated
synchronously to the output frequency
if the current through the XTAL has
reached 35% to 80% of its maximum
amplitude. Crystal parameters:
C
M
=
4.37
fF,
C
0
=
1.3
pF,
C
LNOM
=
18
pF,
C
4
=
10
pF,
C
5
=
15
pF,
R
S
≤
60
Ω
∆
T
XTO
0.6
1.4
ms
XTO drive current
Current flowing through the crystal in
steady state oscillation (peak-to-peak
value)
I
DXTO
300
µApp
Locking time of the PLL
Time between the activation of CLK
and when the PLL is locked
(transmitter ready for data
transmission)
∆Τ
PLL
250
µs
PLL loop bandwidth
f
Loop_PLL
250
kHz
In loop phase noise PLL
25 kHz distance to carrier
L
PLL
-85
-76
dBc/Hz
Phase noise VCO
at 1 MHz
at 36 MHz
L
at1M
L
at36M
-90
-121
-84
-115
dBc/Hz
dBc/Hz
Frequency range of VCO
ATA5756
ATA5757
f
VCO
310
432
317
448
MHz
MHz
Clock output frequency (CMOS
microcontroller compatible)
ATA5756
ATA5757
f
CLK
f
0
/192
f
0
/256
MHz
Clock output minimum High and
Low time
C
Load
≤
20 pF, High = 0.8
×
Vs,
Low = 0.2
×
V
S
, f
CLK
< 1.7 MHz
T
CLKLH
125
ns
Series resonance resistance of
the resonator seen from pin
XTO1
For proper detection of the XTO
amplitude
R
s_max
150
Ω
Capacitive load at Pin XTO1
C
L_max
5
pF
FSK modulation frequency rate
This corresponds to 20 kBaud in
Manchester coding and 40 kBaud in
NRZ coding
f
MOD_FSK
0
20
kHz
FSK switch OFF resistance
High Z
R
SWIT_OFF
50
k
Ω
FSK switch OFF capacitance
High Z capacitance
C
SWIT_OFF
0.75
0.9
1.1
pF
FSK switch ON resistance
Low Z
R
SWIT_ON
130
175
Ω
ASK modulation frequency rate
Duty cycle of the modulation signal =
50%, this corresponds to 20 kBaud in
Manchester coding and 40 kBaud in
NRZ coding
f
MOD_ASK
0
20
kHz
Electrical Characteristics (Continued)
V
S
= 2.0 V to 3.6 V, T
amb
= -40°C to 125°C unless otherwise specified.
Typical values are given at V
S
= 3.0 V and T
amb
= 25°C. All parameters are referred to GND (Pin 9).
C
M
=
4.37
fF,
C
0
=
1.3
pF,
C
LNOM
=
18
pF,
C
4
=
10
pF,
C
5
=
15
pF and
R
S
≤
60
Ω
Parameters
Test Conditions
Symbol
Min.
Typ.
Max.
Unit