ata5749-6dq ATMEL Corporation, ata5749-6dq Datasheet - Page 7

• Manufacturer Part Number: ata5749-6dq
• Description: Fractional-n Pll Transmitter Ic
• Manufacturer: ATMEL Corporation

4. Application
4.1
Figure 4-1.
9128D–RKE–01/09
controller
Typical Application
Micro-
Typical Application Circuit
antenna
Loop
CLK
IO1
IO2
IO3
C2
Figure 4-1
value of 68 nF X7R is recommended. C2 and C3 are NPO capacitors used to match the loop
antenna impedance to the power amplifier optimum load impedance. They are based on the
PCB trace antenna and are 20 pF NPO capacitors. C1 (typically 1 nF X7R) is needed for the
supply blocking of the PA. In combination with L1 (200 nH to 300 nH), they prevent the power
amplifier from coupling to the supply voltage and disturbing PLL operation. They should be
placed close to pin 5. L1 also provides a low resistive path to V
ANT1.
SDIN_TXDIN
VS
C3
L1
ANT2
ANT1
SCK
CLK
shows the typical application circuit. For C6, the supply-voltage blocking capacitor,
C1
1
2
3
4
5
CLK_ON
CLK_DRV
Registers
Control
Digital
1
and
PA
4 or 8
FREQ[0:14]
PWR[0:3]
DIV_CNTRL
433_N315
ASK_mod
XTO_RDY
XTO Signal
FSEP[0:7]
FSK_mod
Fractional-N-PLL
ATA5749
Frac.
VCO
PFD
Div.
CP
LP
ATA5749 [Preliminary]
(FOX)
XTO
up/down
Power
S
to deliver the DC current to
10
9
8
7
6
EN
GND
VS
XTO1
XTO2
XTAL
VS
C4
C5
C6
7