U4313B

· Usable for amplitude- and frequency-modulated transmission systems
· Extremely low quiescent current approximately 1 mA in the stand-by mode due to wake-up concept
· Wide power supply voltage range 3 to 13 V
· Sensitive IF-amplifier for 10.7 MHz operating frequency
· Logarithmic AM demodulator
· FM demodulator
· Monoflop exit to wake up a microcontroller
· High performance operational amplifier to realize a data recovering filter
· Inverting clamping comparator with amplitudedepending hysteresis for data regeneration

The U4313B is well-suited to implement UHF remote control or data transmission systems, based on a low current superheterodyne receiver concept. SAW-devices may be used in the transmitter as well as in the receiver local oscillator. The front end should be a discrete circuit application with low-current UHF transistors like S822T or S852T from TEMIC TELEFUNKEN microelectronic GmbH. The frequency of the local oscillator can be determined either by coaxial resonators or SAW-devices. Due to large SAW-resonator tolerance an IF-bandwidth - and in a FM-system additionally the discriminator amplitude characteristic (figure 28) - of 300 kHz or higher is proposed.As the circuit needs only 3.0 V supply voltage for operation, the front end may be a stacked design in order to achieve a total receiver current consumption of approximately 1 mA. Figure 29 shows a principle receiver concept diagram. The application notes ANT012,ANT013 and ANT015 contain more detailed information on complete RF links.

The U4313B is a monolithic integrated circuit in bipolar technology for low-current UHF remote control uperheterodyne
receivers in amplitude- or frequencymodulated mode. U4313B applications are keyless carlock-, alarm or telecontrol remote indication systems. Especially for automotive applications it supports a superhet design with less than 1 mA total current consumption, as required by the car manufacturers.