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MICRF001
QwikRadio Receiver/Data Demodulator Advance Information General Description
The MICRF001 is a single chip OOK (ON-OFF Keyed) Receiver IC for remote wireless applications, employing Micrel’s latest QwikRadiotm technology. This device is a true “antenna-in, dataout” monolithic device. All RF and IF tuning is accomplished automatically within the IC, which eliminates manual tuning, and reduces production costs. Receiver functions are completely integrated. The result is a highly reliable yet extremely low cost solution for high volume wireless applications. Because the MICRF001 is a true single-chip radio receiver, it is extremely easy to apply, minimizing design and production costs, and improving time to market. The MICRF001 uses a novel architecture that allows the receiver to demodulate signals over a wide RF band, which eliminates the need for manual tuning. This also significantly relaxes the frequency accuracy and stability requirements of the Transmitter, allowing the MICRF001 to be compatible with both SAW-based and LC-based transmitters. The receiver sensitivity and selectivity are sufficient to provide low bit error rates for decode ranges over 100 meters, equaling the performance of other more expensive solutions. All tuning and alignment are accomplished on-chip by a lowcost ceramic resonator or with an externally supplied clock reference. Initial tolerance requirements on the ceramic resonator or external clock is a modest ±0.5%. The MICRF001 performance is insensitive to data modulation duty cycle. The MICRF001 may be used with such coding schemes as Manchester or 33/66% PWM. All post-detection (demodulator) data filtering is provided on the MICRF001, so no external filters need to be designed. Any one of four filter bandwidths may be selected externally by the user. Bandwidths range from 0.6kHz to 4.8kHz in binary steps
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Features
• • • • • • • • •
Complete UHF receiver on a monolithic chip Frequency range 300 to 440 MHz Typical range over 100 meters with monopole antenna Data rates to 4.8kbps Automatic tuning, no manual adjustment No Filters or Inductors required Very low RF re-radiation at the antenna Direct CMOS logic interface to standard decoder and microprocessor ICs Extremely low external part count
Applications
• • • •
Keyless Entry Security Systems Remote Fan/Light Control Garage Door Openers
Typical Operating Circuit
387 MHz, 1200 BAUD OOK RECEIVER
Micrel Inc. • 1849 Fortune Drive San Jose, Ca 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
MICRF001
QwikRadio tm
Micrel
Ordering Information Part Number MICRF001BN MICRF001BM Pin Configuration (DIP and SOIC) Temperature Range -40°C to +85°C -40°C to +85°C Package 14-Pin DIP 14-Pin SOIC
Figure 1
Pin Description
Pin Number
1 2/3
Pin Name
SEL0 VSSRF
Pin Function
Programs desired Demodulator Filter Bandwidth. This pin in internally pulled-up to VDD. See Table 1. This pin is the ground return for the RF section of the IC. The bypass capacitor connected from VDDRF to VSSRF should have the shortest possible lead length. For best performance, connect VSSRF to VSSBB at the power supply only (i.e., keep VSSBB currents from flowing through VSSRF return path). This is the receive RF input, internally ac-coupled. Connect this pin to the receive antenna. Input impedance is high (FET gate) with approximately 2pF of shunt (parasitic) capacitance. For applications located in high ambient noise environments, a fixed value band-pass network may be connected between the ANT pin and VSSRF to provide additional receive selectivity and input overload protection. (See “Application Note 22, MICRF001 Theory of Operation”.) This pin is the positive supply input for the RF section of the IC. VDDBB and VDDRF should be connected directly at the IC pins. Connect a low ESL, low ESR decoupling capacitor from this pin to VSSRF, as short as possible. This pin is the positive supply input for the baseband section of the IC. VDDBB and VDDRF should be connected directly at the IC pins. This capacitor extracts the (DC) average value from the demodulated waveform, which becomes the reference for the internal data slicing comparator. Treat this as a low-pass RC filter with source impedance described in Table 1 . (See “Application Note 22, MICRF001 Theory of Operation”, section 6.4). A standard ± 20% X7R ceramic capacitor is generally sufficient. Output data pin. CMOS level compatible. This is the ground return for the baseband section of the IC. The bypass and output capacitors connected to VSSBB should have the shortest possible lead lengths. For best performance, connect VSSRF to VSSBB at the power supply only (i.e., keep VSSBB currents from flowing through VSSRF return path). Integrating capacitor for on-chip receive AGC. The Decay/Attack time-constant (TC) ratio is nominally set as 10:1. CAGC = 10(Attack Time Constant) µF. A standard ± 20% X7R ceramic capacitor is generally sufficient. Programs desired Demodula.