ASNT8110A-PQB View full size
  • Wide frequency range from DC to 24GHz
  • Continuous division ratios from 1 to 256
  • 50% duty cycle of the output divided clock signal
  • Fully differential CML input and output interfaces
  • Adjustable Power Consumption
  • Division programming through 8-bit parallel interface or 3-wire SPI compatible with CMOS/LVTTL standards
  • Optional external reset function
  • Dynamic division ratio adjustment with a short set-up time (about 20ns after the pulse edge on any control input)
  • Single +2.8V or -2.8V power supply
  • Industrial temperature range
  • Standard 40-pin QFN package with a thermal pad

Function Operating Frequency Power, mW Package
Programmable Integer Divider w/ SPI DC-24 GHz 2030-3150 40-pin QFN


Fig. 1 Functional Block Diagram

ASNT8110A-PQB is a high-speed programmable integer clock divider with dynamic adjustment of the division ratio. An optional external active-high CMOS/LVTTL reset signal is also provided. The functional block diagram of the device is shown in Fig. 1.

The divider accepts an input clock signal chip/chin with a speed from DC to the maximum specified frequency and provides a clean 50% duty cycle output divided clock signal cop/con in any operational mode. The divider allows for dynamic adjustment of the division ratio from 1 to 256 with a step of 1 through either full-scale CMOS 8-bit parallel interface or 1.2VCMOS 3-wire SPI. The parallel or serial interface mode is selected with a full-scale CMOS control signal spion. In the parallel mode, a binary code on the control inputs c0-c7 defines the value of the ratio from 1 to 255, where c7 is the most significant bit (MSB). All “0”s (“low” state) define the division by 256. Following any change of any control signal, the divider switches to idle after (64...128) periods of the high-speed system clock plus an additional 1.6ns delay, and returns back to normal operation with the new division ratio after an additional delay equal to 192 periods of the high-speed system clock.

In the serial mode, the 1-byte division coefficient code is supplied through the 3-wire interface with MSB first as shown in Fig. 2. Input data 3wdin are sampled at rising edges of SPI clock 3wcin and internal division coefficient value will be updated at a rising edge of the 3wenin signal. The device automatically resets itself after the initial power-up and any change of the division control signals. When the optional external reset signal reset is set to “high”, the divider switches to idle (static “0” output) after a 0.7ns delay as shown in the timing diagram in Fig. 3. When reset returns to “low”, the divider switches back to normal operation after (64...128) periods of the high-speed system clock plus an additional 1.6ns of delay. The minimum allowed reset pulse must be longer than 64 periods of the high-speed system clock.


The part’s I/O’s support the CML logic interface with on chip 50Ω termination to vcc and may be used differentially, AC/DC coupled, single-ended, or in any combination. In the DC-coupling mode, the input signal’s common mode voltage should comply with the specifications shown in the electrical characteristics section within the part's datasheet. In the AC-couping mode, the input termination provides the required common mode voltage automatically. The differential DC signaling mode is recommended for optimal performance.

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