R820T Rafael Micro

| marzo 13, 2013

RTL-SDR Raphael Micro R820T software defined radio receiver.R820T Rafael Micro

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

R820T Block Diagram

Quick Reference Data

Typical figures

■ 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

Pin Allocation (note: E-Pad is GND)

R820T Pin Description

Pin Assignment

Summary List of Pin Assignment

Pin Number Symbol Description
24 RF_In RF Input
1 NC Not Connect
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
12 IF_N IF output
13 IF_P IF output
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.
16 GND Ground
0 GND Exposed pad

IF Frequency

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

AGC Control

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.

Crystal Specifications

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

Parameter Min Typical Max Units
Frequency Range   16   MHz
ESR     50 Q_
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

Parameter Min Typical Max Units
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.

R820T Crystal Parallel Capacitors and Share Crystal


Crystal X1=16MHz/ CL=16pF

Bypass capacitor C3=10nF

Crystal parallel capacitors C1=C2=27pF


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