 |
công cụ tìm kiếm bảng dữ liệu linh kiện điện tử |
|
|
công cụ tìm kiếm bảng dữ liệu linh kiện điện tử |
|
ML13135LP bảng dữ liệu(PDF) 6 Page - LANSDALE Semiconductor Inc. |
|
||||||||||||||||||||||||||||||
ML13135LP bảng dữ liệu(HTML) 6 Page - LANSDALE Semiconductor Inc. |
|
|
6 / 11 page  www.lansdale.com Page 6 of 11 Issue 0 LANSDALE Semiconductor, Inc. ML13135 The ML13135 is a complete dual conversion receiver. This includes two local oscillators, two mixers, a limiting IF ampli- fier and detector, and an op amp. It will provide a voltage buffered RSSI with 70 dB of usable range, isolated tuning diode and buffered LO output for PLL operation, and a sepa- rate VCC pin for the first mixer and LO. Improvements have been made in the temperature performance of both the recov- ered audio and the RSSI. VCC Two separate VCC lines enable the first LO and mixer to continue running while the rest of the circuit is powered down. They also isolate the RF from the rest of the internal circuit. Local Oscillators The local oscillators are grounded collector Colpitts, which can be easily crystal–controlled or VCO controlled with the on–board varactor and external PLL. The first LO transistor is internally biased, but the emitter is pinned–out and IQ can be increased for high frequency or VCO operation. The collector is not pinned out, so for crystal operation, the LO is generally limited to 3rd overtone crystal frequencies; typically around 60 MHz. For higher frequency operation, the LO can be provided externally as shown in Figure 16. Buffer An amplifier on the 1st LO output converts the single–ended LO output to a differential signal to drive the mixer. Capacitive coupling between the LO and the amplifier minimizes the effects of the change in oscillator current on the mixer. Buffered LO output is pinned–out at Pin 3 for use with a PLL, with a typical output voltage of 320 mVpp at VCC= 4.0 V and with a 5.1 k resistor from Pin 3 to ground. As seen in Figure 14, the buffered LO output varies with the supply voltage and a smaller external resistor may be needed for low voltage oper- ation. The LO buffer operates up to 60 MHz, typically. Above 60 MHz, the output at Pin 3 rolls off at approximately 6.0 dB per octave. Since most PLLs require about 200 mVpp drive, an external amplifier may be required. Mixers The first and second mixer are of similar design. Both are double balanced to suppress the LO and input frequencies to give only the sum and difference frequencies out. This config- uration typically provides 40 to 60 dB of LO suppression. New design techniques provide improved mixer linearity and third order intercept without increased noise. The gain on the output of the 1st mixer starts to roll off at about 20 MHz, so this receiver could be used with a 21 MHz first IF. It is designed for use with a ceramic filter, with an output impedance of 330 Ω. A series resistor can be used to raise the impedance for use with a crystal filter, which typically has an input impedance of 4.0 kΩ. The second mixer input impedance is approximately 4.0 kΩ; it requires an external 360 Ω parallel resistor for use with a standard ceramic filter. Limiting IF Amplifier and Detector The limiter has approximately 110 dB of gain, which starts rolling off at 2.0 MHz. Although not designed for wideband operation, the bandwidth of the audio frequency amplifier has been widened to 50 kHz, which gives less phase shift and enables the receiver to run at higher data rates. However, care should be taken not to exceed the bandwidth allowed by local regulations. The ML13135 is designed for use with an LC quadrature detector, and does not have sufficient drive to be used with a ceramic discriminator. The discriminators and the external matching circuit will affect the distortion and recovered audio. RSSI/Op Amp The Received Signal Strength Indicator (RSSI) on the ML13135 has about 70 dB of range. The resistor needed to translate the RSSI current to a voltage output has been includ- ed on the internal circuit, which gives it a tighter tolerance. A temperature compensated reference current also improves the RSSI accuracy over temperature. On the ML13135, the op amp is not connected internally and can be used for the RSSI or as a data slicer (see Figure 17c). CIRCUIT DESCRIPTION Figure 14. Buffered LO Output Voltage versus Supply Voltage 600 500 400 300 200 100 VCC, SUPPLY VOLTAGE (Vdc) 2.5 3.0 3.5 4.0 4.5 5.0 5.5 RPin3 = 3.0 kΩ RPin3 = 5.1 kΩ |
Số phần tương tự - ML13135LP |
|
Mô tả tương tự - ML13135LP |
|
|
|
Link URL |
| Chính sách bảo mật |
| ALLDATASHEET.VN |
| Cho đến nay ALLDATASHEET có giúp ích cho doanh nghiệp của bạn hay không? [ DONATE ] |
Alldatasheet là | Quảng cáo | Liên lạc với chúng tôi | Chính sách bảo mật | Trao đổi link | Tìm kiếm theo nhà sản xuất All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
Vietnamese ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
