ATA8401-6AQY Atmel, ATA8401-6AQY Datasheet - Page 4

• Manufacturer Part Number: ATA8401-6AQY
• Description: IC XMITTER ASK/FSK UHF 8-TSSOP
• Manufacturer: Atmel

Specifications of ATA8401-6AQY

• Frequency: 310MHz ~ 350MHz
• Applications: Alarm, ISM, Telemetry
• Modulation Or Protocol: UHF, ASK, FSK
• Data Rate - Maximum: 50 kBaud
• Power - Output: 8dBm
• Current - Transmitting: 9mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 2 V ~ 4 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-TSSOP
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (typ): 2.5/3.3V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -
• Lead Free Status / Rohs Status: Compliant

3. General Description
4. Functional Description
4.1
4.2
4
ASK Transmission
FSK Transmission
Atmel ATA8401
This fully integrated PLL transmitter allows particularly simple, low-cost RF miniature transmit-
ters to be assembled. The VCO is locked to 32 f
needed for a 315MHz transmitter. All other PLL and VCO peripheral elements are integrated.
The XTO is a series resonance oscillator so that only one capacitor together with a crystal
connected in series to GND are needed as external elements.
The crystal oscillator together with the PLL typically needs < 3ms until the PLL is locked and
the CLK output is stable. There is a wait time of
troller and the PA is switched on.
The power amplifier is an open-collector output delivering a current pulse, which is nearly
independent from the load impedance. The delivered output power is therefore controllable via
the connected load impedance.
This output configuration enables a simple matching to any kind of antenna or to 50 . A high
power efficiency of = P
load impedance of Z
If ENABLE = L and the PA_ENABLE = L, the circuit is in standby mode, consuming only a
very small amount of current, so that a lithium cell used as power supply can work for several
years.
With ENABLE = H the XTO, PLL, and the CLK driver are switched on. If PA_ENABLE remains
L, only the PLL and the XTO are running, and the CLK signal is delivered to the microcon-
troller. The VCO locks to 32 times the XTO frequency.
With ENABLE = H and PA_ENABLE = H the PLL, XTO, CLK driver, and the power amplifier
are on. The power amplifier can be switched on and off with PA_ENABLE. This is used to per-
form the ASK modulation.
The Atmel
typically
power can be modulated by means of the PA_ENABLE pin. After transmission, PA_ENABLE
is switched to L and the microcontroller switches back to internal clocking. The Atmel
ATA8401 is switched back to standby mode with ENABLE = L.
The Atmel ATA8401 is activated by ENABLE = H. PA_ENABLE must remain L for
typically
amplifier is switched on with PA_ENABLE = H. The chip is then ready for FSK modulation.
The microcontroller starts to switch on and off the capacitor between the XTAL load capacitor
and GND with an open-drain output port, thus changing the reference frequency of the PLL. If
the switch is closed, the output frequency is lower than if the switch is open. After transmis-
sion, PA_ENABLE is switched to L, and the microcontroller switches back to internal clocking.
The Atmel ATA8401 is switched back to standby mode with ENABLE = L.
The accuracy of the frequency deviation with XTAL pulling method is about ±25% when the
following tolerances are considered.
3 ms, then the CLK signal can be taken to clock the microcontroller and the output
3ms, then the CLK signal can be taken to clock the microcontroller, and the power
®
ATA8401 is activated by ENABLE = H. PA_ENABLE must remain L for
Load
out
= (255 + j192) is used at 3V supply voltage.
/(I
S,PA
V
S
) of 40% for the power amplifier results when an optimized
XTAL
3ms until the CLK is used for the microcon-
, and therefore a 9.8438MHz crystal is
4984D–INDCO–12/10