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U4285BM Dataheets PDF



Part Number U4285BM
Manufacturers TEMIC Semiconductors
Logo TEMIC Semiconductors
Description AM / FM - PLL
Datasheet U4285BM DatasheetU4285BM Datasheet (PDF)

U4285BM AM / FM - PLL Description The U4285BM is an integrated circuit in BICMOS technology for frequency synthesizers. It performs all the functions of a PLL radio tuning system and is controlled by an I2C bus. The device is designed for all frequency synthesizer applications in radio receivers, as well as RDS ( Radio Data System ) applications. Features D Reference oscillator up to 15 MHz D Two programmable 16 bit dividers adjustable from 2 to 65535 D 4 programmable switching outputs (open d.

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U4285BM AM / FM - PLL Description The U4285BM is an integrated circuit in BICMOS technology for frequency synthesizers. It performs all the functions of a PLL radio tuning system and is controlled by an I2C bus. The device is designed for all frequency synthesizer applications in radio receivers, as well as RDS ( Radio Data System ) applications. Features D Reference oscillator up to 15 MHz D Two programmable 16 bit dividers adjustable from 2 to 65535 D 4 programmable switching outputs (open drain up to 15 V) D Fine tuning steps: AM FM y 1 kHz y 2 kHz D Few external component required due to integrated loop-push-pull stage for AM/FM D High signal/ noise ratio Ordering Information Extended Type Number U4285BM-AFS U4285BM-AFSG3 Package SSO20 plastic SSO20 plastic Remarks Taping according to IEC-286-3 Block Diagram SWO1 SWO2 SWO3 SWO4 5 6 7 8 OSCIN 18 Oscillator OSCOUT 19 SCL 2 I2C bus interface Phase detector Current sources 15 16 17 12 13 N-divider 1 VDD Figure 1. 20 GND1 PDAMO VA C PDFMO PDFM R-divider Switching outputs 14 PDAM SDA 3 AS FMOSC 4 9 AMOSC 11 AM/FM switch 10 GND2 95 10120 TELEFUNKEN Semiconductors Rev. A3, 14-May-97 1 (10) U4285BM Pin Description VDD SCL 1 2 3 4 5 20 19 18 17 16 GND1 OSCOUT OSCIN C VA PDAMO PDAM PDFM PDFMO AMOSC Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Symbol VDD SCL SDA AS SWO 1 SWO 2 SWO3 SWO4 FMOSC GND 2 AMOSC PDFMO PDFM PDAM PDAMO VA C OSCIN OSCOUT GND1 Function Supply voltage I2C bus clock I2C bus data Address selection Switching output 1 Switching output 2 Switching output 3 Switching output 4 FM oscillator input Ground 2 (analog) AM oscillator input FM analogue output FM current output AM current output AM analogue output Analogue supply voltage Capacitor Oscillator input Oscillator output Ground 1 (digital) SDA AS SWO 1 SWO 2 SWO3 SWO4 FMOSC GND 2 U4285BM 6 7 8 9 10 15 14 13 12 11 95 10121 Functional Description The U4285BM is controlled via the 2-wire I2C bus. For programming there are one module address byte, two subaddress bytes and five data bytes. The module address contains a programmable address bit A 1 which with address select input AS (Pin 4) makes it possible to operate two U4285BM in one system. If bit A 1 is identical with the status of the address select input AS, the chip is selected . The subaddress determines which one of the data bytes is transmitted first. If subaddress of R-divider is transmitted, the sequence of the next data bytes is DB 0 (Status), DB 1 and DB 2. If subaddress of N-divider is transmitted, the sequence of the next data bytes is DB 3 and DB 4. The bit organisation of the module address, subaddress and 5 data bytes are shown in figure 2. Each transmission on the I2C bus begins with the “START”- condition and has to be ended by the “STOP”condition (see figure 3). The integrated circuit U4285BM has two separate inputs for AM and FM oscillator. Pre-amplified AM and FM signals are fed to the 16 bit N-divider via AM/FM switch. AM/FM switch is con.


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