MAX7032ATJ+ Maxim Integrated Products, MAX7032ATJ+ Datasheet - Page 27

• Manufacturer Part Number: MAX7032ATJ+
• Description: RF Transceiver IC TXRX ASK/FSK PROG MHz Crystal-Based, P
• Manufacturer: Maxim Integrated Products

Specifications of MAX7032ATJ+

• Number Of Receivers: 1
• Number Of Transmitters: 1
• Wireless Frequency: 300 MHz to 450 MHz
• Output Power: 6.7 dBm
• Operating Supply Voltage: 2.7 V, 5 V
• Maximum Operating Temperature: + 125C
• Mounting Style: SMD/SMT
• Maximum Supply Current: 12.5 mA
• Minimum Operating Temperature: - 40 C
• Modulation: ASK/OOK.FSK
• Package / Case: TQFN-32 EP
• Data Rate: 33Kbps
• Supply Voltage Range: 2.1V To 3.6V, 4.5V To 5.5V
• Logic Case Style: QFN
• No. Of Pins: 32
• Operating Temperature Range: -40°C To +125°C
• Filter Terminals: SMD
• Rohs Compliant: Yes
• Data Rate Max: 66Kbps
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The on timer, t
is configured through register 0x0B for the upper byte,
register 0x0C for the lower byte (Table 15). The infor-
mation stored in this timer provides an additional way to
control the duration of the on time of the receiver.
The CPU must begin driving DIO low any time during
t
low at the end of t
internal pullup resistor and the time sequence is restart-
ed, leaving the MAX7032 powered down. Any time the
DIO line is driven high while the DRX = 1, the DRX
sequence is initiated, as defined in Figure 10. In the
event that the CPU is processing data, after t
expires, the CPU should keep the MAX7032 awake by
holding the DIO line low.
The data written to the t
register 0x0C) are multiplied by the t
(Table 15) to give the total t
the Off Timer ( t
register is reset to zero and must be written before
using DRX mode.
The TxLOW register sets the divider information of the
fractional-N synthesizer for the lower transmit frequency
in FSK mode. See the example given in the Fractional-N
PLL section. In ASK mode, TxLOW determines the carri-
er frequency.
The TxHIGH register sets the divider information of the
fractional-N synthesizer for the upper transmit frequency
in the FSK mode. In ASK mode, the content of TxHIGH
is not used. The 16-bit register contains the binary rep-
resentation of the TX PLL divider ratio, which is shown in
the example in the Fractional-N PLL section.
Table 15. On-Timer (t
LOW
ONPS1
= t
Transmitter High-Frequency Register (TxHIGH)
Transmitter Low-Frequency Register (TxLOW)
0
0
1
1
CPU
ASK/FSK Transceiver with Fractional-N PLL
+ t
ON
OFF
RF
Low-Cost, Crystal-Based, Programmable,
______________________________________________________________________________________
(see Figure 10), is a 16-bit timer that
) section. On power-up, the on-timer
ON
+ t
, DIO is pulled high through the
ON
ON
ONPS0
. If the CPU fails to drive DIO
0
1
0
1
ON
ON
register (register 0x0B and
time. See the example in
) Configuration
On Timer (t
ON
t
ON
time base
TIME BASE
1920µs
7680µs
120µs
480µs
ON
ON
)
When matched to a 50Ω system, the MAX7032’s PA is
capable of delivering +10dBm of output power at V
= +2.7V. The output of the PA is an open-drain transis-
tor that requires external impedance matching and
pullup inductance for proper biasing. The pullup induc-
tance from the PA to PAV
es: it resonates the capacitive PA output, provides
biasing for the PA, and becomes a high-frequency
choke to prevent RF energy from coupling into V
The network also forms a bandpass filter that provides
attention for the higher order harmonics.
In most applications, the MAX7032 must be impedance
matched to a small-loop antenna. The antenna is usual-
ly fabricated out of a copper trace on a PCB in a rec-
tangular, circular, or square pattern. The antenna has
an impedance that consists of a lossy component and
a radiative component. To achieve high radiating effi-
ciency, the radiative component should be as high as
possible, while minimizing the lossy component. In
addition, the loop antenna has an inherent loop induc-
tance associated with it (assuming the antenna is termi-
nated to ground). For example, in a typical application,
the radiative impedance is less than 0.5Ω, the lossy
impedance is less than 0.7Ω, and the inductance is
approximately 50nH to 100nH.
A properly designed PCB is an essential part of any
RF/microwave circuit. On high-frequency inputs and
outputs, use controlled-impedance lines and keep
them as short as possible to minimize losses and radia-
tion. At high frequencies, trace lengths that are on the
order of λ/10 or longer act as antennas, where λ is the
wavelength.
Output Matching to PCB Loop Antenna
REG 0x0B = 0x00
REG 0x0C = 0x01
MIN t
1.92ms
7.68ms
120µs
480µs
Applications Information
ON
Output Matching to 50 Ω Ω
DD
Layout Considerations
serves three main purpos-
REG 0x0B = 0xFF
REG 0x0C = 0xFF
MAX t
8min 23s
2min 6s
31.46s
7.86s
ON
DD
DD
27
.