In recent years, an organic semiconductor field effect transistor (organic semiconductor FET) that operates with low power consumption has been researched and developed, and, for example, radio frequency identification (RFID) is noticed as a target of application of the organic semiconductor field effect transistor. Here, the RFID is technology for reading and writing data of a RF tag in a non-contact manner using radio waves, and for the RFID (RF tag), an operating speed of approximately 20 to 100 kb/second is demanded by standards such as ISO 14443 and ISO 15693.
Incidentally, for example, a RF tag to which a silicon semiconductor is applied receives and divides a signal of 13.56 MHz sent from a reader (reader-and-writer) and regenerates (generates) a clock of a given frequency. For example, according to ISO 15693, a carrier of 13.56 MHz from a reader is subjected to 1/512 division to generate a clock of 26 KHz while, according to ISO 14443, a carrier of 13.56 MHz is subjected to 1/128 division to generate a clock of 106 KHz. Each of the clocks of 26 KHz and 106 KHz is used as a clock of a symbol rate.
However, in a RF tag to which an organic semiconductor is applied, the operating frequency of an oscillator is on the order of 100 KHz, and it is difficult to generate a clock of a symbol rate by dividing the carrier of 13.56 MHz from a reader.
Incidentally, various proposals have been made for a clock regeneration circuit (clock data recovery circuit (CDR circuit)) for regenerating a clock of a symbol rate from a received signal (data).
As described hereinabove, it is difficult, for example, for a RF tag to which an organic semiconductor is applied to generate a clock of a symbol rate by dividing a signal sent from a reader like a RF tag to which a silicon semiconductor is applied.
Further, in a clock regeneration circuit (CDR), a clock is generated usually based on a phase locked loop (PLL). In this case, a voltage controlled oscillator (VCO) is used. However, since the dispersion is great with an organic semiconductor, there is the possibility that a generated (regenerated) clock may not be locked to a desired frequency.
It is to be noted that a clock regeneration circuit, a semiconductor integrated circuit device, and a RF tag according to the embodiment discussed herein are not limited to those to which an organic semiconductor is applied but may be those to which various semiconductors including a silicon semiconductor and a compound semiconductor are applied.
The followings are reference documents.    [Document 1] Japanese Laid-open Patent Publication No. 2011-040803,    [Document 2] Japanese Laid-open Patent Publication No. 07-273646,    [Document 3] Japanese Laid-open Patent Publication No. 08-107351,    [Document 4] S. Masui et al., “A 13.56 MHz CMOS RF Identification Transponder Integrated Circuit With A Dedicated CPU,” ISSCC 9.1, February 1999,    [Document 5] K. Myny et al., “Bidirectional Communication in an HF Hybrid Organic/Solution-Processed Metal-Oxide RFID Tag,” ISSCC 18.3, February 2012, and    [Document 6] V. Fiore et al., “A 13.56 MHz RFID Tag with Active Envelope Detection in an Organic Complementary TFT Technology,” ISSCC Dig. Tech. Papers, pp. 492-494, February 2014.