MAX7030HATJ+ Maxim Integrated Products, MAX7030HATJ+ Datasheet - Page 16

• Manufacturer Part Number: MAX7030HATJ+
• Description: RF Receiver IC TRANSCVR ASK 5MHz, and 433.92MHz
• Manufacturer: Maxim Integrated Products
• Type: Transceiverr

Specifications of MAX7030HATJ+

• Package / Case: TQFN-32 EP
• Operating Frequency: 433.92 MHz
• Operating Supply Voltage: 2.7 V, 5 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

only and connect AVDD, PAVDD, and DVDD together.
In both cases, bypass DVDD, HVIN, and PAVDD to
GND with 0.01µF and 220pF capacitors and bypass
AVDD to GND with 0.1µF and 220pF capacitors.
Bypass T/R, ENABLE, DATA, and AGC0-2 with 10pF
capacitors to GND. Place all bypass capacitors as
close as possible to the respective pins.
The MAX7030 features an internal SPST RF switch that,
when combined with a few external components, allows
the transmit and receive pins to share a common
antenna (see the Typical Application Circuit) . In receive
mode, the switch is open and the power amplifier is
shut down, presenting a high impedance to minimize
the loading of the LNA. In transmit mode, the switch
closes to complete a resonant tank circuit at the PA
output and forms an RF short at the input to the LNA. In
this mode, the external passive components couple the
output of the PA to the antenna and protect the LNA
input from strong transmitted signals.
The switch state is controlled by the T/R pin (pin 22).
Drive T/R high to put the device in transmit mode; drive
T/R low to put the device in receive mode.
The XTAL oscillator in the MAX7030 is designed to pre-
sent a capacitance of approximately 3pF between the
XTAL1 and XTAL2 pins. In most cases, this corre-
sponds to a 4.5pF load capacitance applied to the
external crystal when typical PCB parasitics are added.
It is very important to use a crystal with a load
capacitance that is equal to the capacitance of the
MAX7030 crystal oscillator plus PCB parasitics. If a
crystal designed to oscillate with a different load
capacitance is used, the crystal is pulled away from its
stated operating frequency, introducing an error in the
reference frequency. Crystals designed to operate with
higher differential load capacitance always pull the ref-
erence frequency higher.
Low-Cost, 315MHz, 345MHz, and 433.92MHz
ASK Transceiver with Fractional-N PLL
16
______________________________________________________________________________________
Transmit/ Receive Antenna Switch
Crystal Oscillator (XTAL)
In actuality, the oscillator pulls every crystal. The crys-
tal’s natural frequency is really below its specified fre-
quency, but when loaded with the specified load
capacitance, the crystal is pulled and oscillates at its
specified frequency. This pulling is already accounted
for in the specification of the load capacitance.
Additional pulling can be calculated if the electrical
parameters of the crystal are known. The frequency
pulling is given by:
where:
f
C
C
C
C
When the crystal is loaded as specified, i.e.,
C
f
p
P
m
CASE
SPEC
LOAD
LOAD
is the amount the crystal frequency is pulled in ppm.
=
is the motional capacitance of the crystal.
TOP VIEW
C
2
m
is the specified load capacitance.
is the case capacitance.
is the actual load capacitance.
= C
⎛
⎜
⎝
25
26
27
28
29
30
31
32
C
SPEC
+
CASE
24
1
, the frequency pulling equals zero.
23
2
+
1
C
22
3
LOAD
THIN QFN
MAX7030
21
4
Pin Configuration
20
5
−
C
19
6
CASE
18
7
17
8
1
+
C
SPEC
16
15
14
13
12
11
10
9
⎞
⎟
⎠
x
10
6