High Performance Low Power Advanced Digital TV Silicon Tuner
R820T Rafael Micro. In heritage from Rafael Micro’s state-of-the-art architecture, the R820T digital silicon tuner achieves the lowest power consumption and the smallest font factor. R820T offers unmatchable RF performance for all digital broadcast television standards including DVB-T, ATSC, DMB-T, ISDB-T,. With innovative AccuTuneTM and TrueRFTM mechanisms, R820T provides superior performance in sensitivity, linearity, adjacent channel immunity, and image rejection. The chip embeds a smart power detector to optimize different input power scenarios as well as the spurious free dynamic range.
The R820T is a highly integrated silicon tuner that builds in low noise amplifier (LNA), mixer, fractional PLL, VGA, voltage regulator and tracking filter, eliminating the need for external SAW filters, LNA, balun, and LDO. Thanks the LNA architecture, R820T offers the lowest cost and high performance solution for digital TV application. On-chip LDO, high performance LNA, and small package enable R820T the perfect solution for both cost and font factor sensitive applications.
With proprietary GreenRF techniques, R820T achieves both high performance and the lowest power consumption which perfectly compliant with the worldwide trend. The R820T comes in a small and thin QFN RoHs compliant package.
- Support all digital TV standards: DVB-T, ATSC, DTMB and ISDB-T.
- Lowest BOM cost WITHOUT external SAW filters, LNA, balun, LDO, and adjustable parts.
- Low cost Single-In Digital TV Application
- Compliant with EN 300 744, Nordig 2.2, D-BOOK 7.0, ARIB B21, ABNT 15604, ATSC A74 and GB20600-2006
- Compliant with EN-55020, EN55013 and FCC
- Ultra low power consumption < 178mA
- Single power supply 3.3V
- 2-wired I2C interface
- 24-pin 4×4 QFN lead-free package
- Terrestrial Digital TV
- Desktop/Laptop PCTV, Mini-card, and USB peripherals
- Set Top Box
- Portable Media Player
- Automobile TV
Simplified R820T Block Diagram
Quick Reference Data
■ Frequency range: 42 to 1002 MHz
■ Noise figure : 3.5 dB @ RF_IN
■ Phase noise: -98 dBc/Hz @ 10 kHz
■ Current consumption: <178 mA @ 3.3V power supply
■ Max input power: +10 dBm
■ Image rejection: 65 dBc
Pin Allocation (note: E-Pad is GND)
Summary List of Pin Assignment
|2,11,18,23||VCC||Tuner 3.3V voltage input|
|3||LT||Loop through output|
|4,5||Detx||Power detector decoupling capacitor|
|6||SCL||I2C bus, clock input|
|7||SDA||I2C bus, data input/ output|
|8||Xtal_I||Crystal oscillator Input|
|9||Xtal_O||Crystal oscillator Output|
|10||CLK_Out||Clock output for sharing Crystal oscillator|
|14||IF_AGC||IF automatic gain control input|
|15||CP||PLL charge pump|
|17||VDD_PLL||PLL 2V supply output decoupling|
|19,20,21,22||TFxx||Tracking filter, the detail as Figure 2-1: Pin Allocation.|
R820T receives RF signal and feed through internal low-noise amplifier, power detector, band-pass filter, and image rejection filter. The mixer down-converts the RF signal to a low-IF frequency, which depends on channel bandwidth in different applications. The standard IF filters are implemented for 6/7/8 MHz channel bandwidths.
IF Frequency Table
|TV Standard||Channel BW||Center Frequency|
|1||ATSC ( Digital)||BW = 6MHz||Fcenter= 4.063MHz|
|2||DVB-T ( Digital)||BW = 6MHz||Fcenter= 3.57MHz|
|3||DVB-T ( Digital)||BW = 7MHz||Fcenter= 4.07MHz|
|4||DVB-T ( Digital)||BW = 7MHz||Fcenter= 4.57MHz|
|5||DVB-T ( Digital)||BW = 8MHz||Fcenter= 4.57MHz|
|7||ISDB-T ( Digital)||BW = 6MHz||Fcenter = 4.063MHz|
|8||DTMB ( Digital)||BW = 8MHz||Fcenter = 4.57MHz|
The R820T has built-in RFAGC to achieve the optimal SNR while minimizing distortion. When RF input power increases, the internal power detector is activated to attenuate internal LNA gain in an optimal level. On another hand, when RF input power decreases, internal power detector will increase internal LNA gain to achieve good picture quality.
The IFVGA control is available for the demodulator to control the gain of output VGA. R820T provides a wide range of IFVGA gain from +1dB to +48dB. Demodulator AGC output voltage range from 0.6V to 2.5V.
The default crystal frequency for R820T is 16 MHz. The R820T is well accompanied with traditional DIP package crystal. To reduce component count and font factor, a low profile SMD package crystal is recommended. Please contact Rafael Micro application engineering for other crystal frequencies (12, 20, 20.48, 24, 27, 28.8, 32 MHz) applications.
Table Crystal Specifications
|Frequency accuracy||± 30||± 50||ppm|
|Load Capacitor (CL)||16||pF|
|Input level to XTAL_P pin when using external clock||120||3300||mVp-p|
Clock Output Swing
The R820T clock output swing is programmable through I2C interface. The IC provides a clock output signal in triangle waveform with output voltage typical at 2.0Vp-p. The output voltage specification assumes an off-chip load impedance of 16pF/ 10MQ.
Table Clock Output Specifications
|Clock Output Swing (16pF // 10MQ)||2.0||Vp-p|
Crystal Parallel Capacitors and Share Crystal
Crystal parallel capacitors are recommended when a default crystal frequency of 16 MHz is implemented. Please contact Rafael Micro application engineering for crystal parallel capacitors using other crystal frequencies. For cost sensitive project, the R820T can share crystal with backend demodulators or baseband ICs to reduce component count. The recommended reference design for crystal loading capacitors and share crystal is shown as below.
Crystal X1=16MHz/ CL=16pF
Bypass capacitor C3=10nF
Crystal parallel capacitors C1=C2=27pF
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