MICROCHIP ATA8402C-6AQY-66

The ATA8402 is a PLL transmitter IC, which has been developed for the demands of RF low-cost transmission systems for industrial applications at data rates up to 50kBaud ASK and 32kBaud FSK modulation scheme. The transmitting frequency range is 429MHz to 439MHz. It can be used in both FSK and ASK systems. This fully integrated PLL transmitter allows particularly simple, low-cost RF miniature transmitters to be assembled. The VCO is locked to 32 f_XTAL, and therefore a 13.56MHz crystal is needed for a 433.92MHz transmitter. All other PLL and VCO peripheral elements are integrated. The crystal oscillator together with the PLL typically needs <1 ms until the PLL is locked and the CLK output is stable. There is a wait time of ≥1 ms until the CLK is used for the microcontroller 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 50Ω. A high power efficiency of η = P_out/(I_S,PA V_S) of 36% for the power amplifier results when an optimized load impedance of Z_Load = (166 + j223)Ω is used at 3V supply voltage. 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 microcontroller. 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 perform the ASK modulation.

• Integrated PLL loop filter
• ESD protection (3kV HBM/150V MM)
• High output power (7.5dBm) with low supply current (9.0mA)
• Modulation scheme ASK/FSK ● FSK modulation is achieved by connecting an additional capacitor between the XTAL load capacitor and the open drain output of the modulating microcontroller
• Easy to design-in due to excellent isolation of the PLL from the PA and power supply
• Single Li-cell for power supply
• Supply voltage 2.0V to 4.0V in the temperature range of -40°C to +85°C
• Package TSSOP8L
• Single-ended antenna output with high efficient power amplifier
• CLK output for clocking the microcontroller
• One-chip solution with minimum external circuitry

• Industrial/aftermarket remote keyless entry systems
• Alarm, telemetering, and energy metering systems
• Remote control systems for consumer and industrial markets
• Access control systems
• Home automation
• Home entertainment
• Toys