ATA5746-PXQW Atmel, ATA5746-PXQW Datasheet - Page 15

• Manufacturer Part Number: ATA5746-PXQW
• Description: IC RCVR ASK/FSK UHF 24-QFN
• Manufacturer: Atmel

Specifications of ATA5746-PXQW

• Frequency: 315MHz
• Sensitivity: -114dBm
• Data Rate - Maximum: 10 kbps
• Modulation Or Protocol: ASK, FSK
• Applications: Alarm and Security Systems, RKE, TPMS
• Current - Receiving: 6.7mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 2.7 V ~ 3.3 V, 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 105°C
• Package / Case: 24-VQFN Exposed Pad, 24-HVQFN, 24-SQFN, 24-DHVQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -

4596B–RKE–06/07
Figure 3-1.
With C
P ±1 ppm.
The C
not enter the steep region of pulling versus load capacitance where there is risk of an unstable
oscillation.
To ensure proper start-up behavior, the small signal gain and the negative resistance provided
by this XTO at start is very large. For example, oscillation starts up even in the worst case with a
crystal series resistance of 1.5 k at C
approximately given by
with Z
Z
Z
Z
XTAL2, with typically 20 mS at 25°C.
With f
tance of about 2 k . The worst case for technology, supply voltage, and temperature variations
is then always higher than 1.4 k for C
Due to the large gain at start, the XTO is able to meet a very low start-up time. The oscillation
start-up time can be estimated with the time constant .
After 10 to 20
High if the amplitude is large enough; this activates the CLK_OUT output if it is enabled via the
pins CLK_OUT_CTRL0 and CLK_OUT_CTRL1. Note that the necessary conditions of the
DVCC voltage also have to be fulfilled.
It is recommended to use a crystal with C
C
Re Zxtocore
1
3
3
0
=
= –j / (2
consists of crystal C
= –j / (2
= 1.0 pF to 2.2 pF.
------------------------------------------------------------------------------------------------------------------ -
4
XTO
1
0
and Z
m
of the XTAL has to be lower than C
2
= 13.5 MHz, gm = 20 mS, C
10 fF, C
f
=
2
p
XTAL
p
Crystal Equivalent Circuit
as complex impedances at pins XTAL1 and XTAL2, hence
Re
2
f
f
XTO
XTO
an amplitude detector detects the oscillation amplitude and sets XTO_OK to
Z
---------------------------------------------------------------------------------------- -
0
C
1
C
L1
Z
m
1
0
1.0 pF, C
2
Z
+
C
C
in parallel with an internal 110-k resistor, hence
XTAL
3
Z
L1
0
+
) / 110 k , gm is the internal transconductance between XTAL1 and
Re Z
2
) + 5 and Z
Z
+
2
Z
3
xtocore
Z
+
LN
ATA5745/ATA5746 [Preliminary]
3
Z
+
1
= 9 pF and C
Z
C
L
+
1
0
L2
Z
= 9 pF, and C
R
2
2
2.2 pF.
0
m
= –j / (2
Z
Lmin
3
2.2 pF with this XTO. The negative resistance is
gm
m
gm
/ 2 = 7.9 pF for a Pierce oscillator type in order to
= 3.0 fF to 10 fF, C
L1,2
C
p
Crystal Equivalent Circuit
L
0
= C
= 16 pF ±1%, the pulling amounts to
= 2.2 pF, this results in a negative resis-
L
f
m
XTO
L1
C
C
L2
m
C
/ (C
C
L2
0
L1
) + 5 .
R
+ C
LN
m
L2
= 9 pF, R
)
m
< 120
and
15