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參數(shù)資料
| 型號： | LNBEH21 |
| 廠商： | 意法半導體 |
| 英文描述： | LNB SUPPLY AND CONTROL IC WITH STEP-UP CONVERTER AND IC INTERFACE |
| 中文描述： | LNB電源與控制集成電路升壓轉換器及IC的接口 |
| 文件頁數(shù)： | 9/22頁 |
| 文件大?。?/td> | 588K |
| 代理商： | LNBEH21 |
LNBEH21
9/22
VOM bit and TEN/VSEL pin functions with OM=1 (13/18V Control Word mode).
- When OM=1, the TEN/VSEL controls the 13/18V output voltage level. The usage of the TEN/VSEL
pin in combination with the VOM bit allows the 13/18V Control Word Communication (see block diagram
on page 1). The TEN/VSEL is a TTL control logic pin.
- in 13/18V Control Word Communication mode, the VOM bit does not control the LNB output voltage but
only forces the DC/DC Converter output voltage (V
UP
) in a steady state (V
UP
=21.7V typ. if LLC=0 and
V
UP
=22.7V typ. if LLC=1). When OM=VOM=1, the LNB output voltage is controlled only by the TEN/VSEL
pin.
COMMUNICATION MODE IMPLEMENTATION
DiSEqC
TM
2.0 and 1.x mode, OM=0
When OM=0, the LNBEH21 is suitable both for DiSEqC 2.0 and for unidirectional DiSEqC 1.x
applications.
The bi-directional DiSEqC 2.0 protocol implementation is allowed by an easy PWK modulation/
demodulation of the 22KHz carrier. The PWK data are exchanged between the LNBEH21 and the main
μP, using logic levels that are compatible with both 3.3 and 5V microcontrollers. This data exchange is
made through two dedicated pins, TEN/VSEL (when OM=0) and DSQOUT, in order to maintain the timing
relationships between the PWK data and the PWK modulation as accurate as possible. These two pins
should be directly connected to two I/O pins of the μP, thus leaving to the resident firmware the task of
encoding and decoding the PWK data in accordance to the DiSEqC protocol. The fully bi-directional
DiSEqC
TM
2.0 interfacing is completed by the built-in 22KHz tone detector. Its input pin (DETIN) must be
AC coupled to the DiSEqC TM bus and the extracted PWK data are available on the DSQOUT pin biased
with a pull-up resistor to a fixed voltage (see Fig. 7 and 8).
Full compliance of the system to the specification is not implied by the bare use of the LNBEH21; the
system designer should also take in consideration that, to comply to the bi-directional DiSEqC TM 2.0 bus
hardware requirements, an output R-L filter is needed. In order to help the system designer to avoid any
distortion during the 22KHz tone transmission, due to the output R-L impedance, the LNBEH21 is
provided with two output pins: the V
O
TX, to be used during the 22KHz tone transmission; and the V
O
RX,
to be used when the tone is received (see DiSEqC 2.0 typical application circuit). This allows the 22KHz
tone to pass without any losses due to the R-L filter.
During the 22KHz transmission, activated by TEN/VSEL pin, the V
O
TX pin must be preventively activated
by the TTX I
2
C bit, so that, both the power supply and the 22KHz tone, are provided by mean of V
O
TX
output. As soon as the tone transmission is expired, the V
O
TX must can set to OFF by setting the TTX I
2
C
bit to zero, and the power supply is provided to the LNB by the V
O
RX pin through the R-L filter.
Unidirectional DiSEqC 1.x and non-DiSEqC systems normally don't need the output R-L termination, and
the V
O
TX pin can be directly connected to the LNB supply port of the Tuner (see DiSeqC 1.x typical
application circuit). There is also no need of Tone Decoding, thus DETIN and DSQOUT pins can be left
connected to ground; both the 22KHz tone and the power supply, are provided by the V
O
TX by setting
always TTX=1.
When In DiSEqC mode, the Output Voltage level (13.1V,14.1V,19.5V,20.5V) is selected only by the VOM
and LLC I
2
C bits combinations (refer to DiSEqC section in the Complete Truth Table on page 10 for
detailed logic combination and corresponding function description).
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相關代理商/技術參數(shù) |
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| LNBEH21PD | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:LNB SUPPLY AND CONTROL IC WITH STEP-UP CONVERTER AND IC INTERFACE |
| LNBEH21PD-TR | 功能描述:其他電源管理 LNB Supply/Control RoHS:否 制造商:Texas Instruments 輸出電壓范圍: 輸出電流:4 mA 輸入電壓范圍:3 V to 3.6 V 輸入電流: 功率耗散: 工作溫度范圍:- 40 C to + 110 C 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-48 封裝:Reel |
| LNBEH221PD-R | 制造商:STMicroelectronics 功能描述:LNBEH221PD-R - Tape and Reel |
| LNBH2 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:LNB SUPPLY AND CONTROL IC WITH STEP-UP CONVERTER AND I2C INTERFACE |
| LNBH21 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:LNB SUPPLY AND CONTROL IC WITH STEP-UP CONVERTER AND I2C INTERFACE |
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