CYPRESS CY7B923
HOTLINK Transmitter/Receiver

MANUFACTURER'S DEVICE DESCRIPTION

The CY7B923 HOTLink(TM) Transmitter and CY7B933 HOTLink Receiver are point-to-point communications building blocks that transfer data over high-speed serial links (fiber, coax, and twisted pair). Standard HOTLink data rates range from 160-330 Mbits/second. Higher speed HOTLink is also available for high speed applications (160-400 Mbits/second), as well as for those Low Cost Fiber applications HOTLink-155 (150-160 Mbits/second operations).

Eight bits of user data or protocol information are loaded into the HOTLink transmitter and are encoded. Serial data is shifted out of the three differential positive ECL (PECL) serial ports at the bit rate (which is 10 times the byte rate).

The HOTLink receiver accepts the serial bit stream at its differential line receiver inputs and, using a completely integrated PLL Clock Synchronizer, recovers the timing information necessary for data reconstruction. The bit stream is deserialized, decoded, and checked for transmission errors. Recovered bytes are presented in parallel to the receiving host along with a byte rate clock.

The 8B/10B encoder/decoder can be disabled in systems that already encode or scramble the transmitted data. I/O signals are available to create a seamless interface with both asynchronous FIFOs (i.e., CY7C42X) and clocked FIFOs (i.e., CY7C44X). A Built-In Self-Test pattern generator and checker allows testing of the transmitter, receiver, and the connecting link as a part of a system diagnostic check.

TRANSMITTER FEATURES

	Input	Output
Throughput	120-320 Mbps (8-bits mode)	150-400 MBaud
# bits	8 or 10	1 (single-ended and differential) + 2 redundant
Frequency	15-40 MHz
Signal levels	TTL and CMOS	600 mV p-p

Synchronous/sync with idles/asynchronous	synchronous
Input data needs coding	no
Error detection	yes
Power consumption	300 mW (1 output used)
Power supply voltage	+5 V
Package size	28-pin PLCC / 1.54 cm² / 12.4 x 12.4 x 4 mm
Technology	BiCMOS 0.8 u
Radiation hardness	unknown
Price

DESCRIPTION

INTERFACING

The CYPRESS HOTLink is a serialiser component that was originally made for use on Fibre Channel optical link cards. The component exists already since 1991. The original version was made for 266 Mbps FC applications, while now a 400 Mbps version exists as well. The lower speed versions of the chip are not only available in a PLCC28 pin package, but also in an 28-pin SOIC package and even in a military version. Both Industrial and Commercial versions of the chip exist.

The CY7B923 has three differential outputs. Some may be disabled to reduce power consumption and noise generation. The outputs may drive directly a cable, although the application notes recommend some form of common mode suppression on the transmitter side, where they prefer a transformer-based coupling. Transformer-based coupling may be difficult to use in LHC applications where a large magnetic field may exist. Running at 400 Mbps, cable lengths between 50 and 70 m should be feasible, while by passive equaliser circuits the double of this can be reached. Application notes exist that describe those issues in detail.

The CY7B923 can take 8-bit data and will perform 8B10B coding on the data which will give a correct DC balance. The 8B10B coding also introduces some form of error detection. Whenever no data is given to the chip, it will send synchronisation characters K28.5. On the receiving side those characters (except the last one) will be removed. The chip can be used as a simple serialiser, but in this case the byte synchronisation can be difficult to implement. The chip has a relaxed setup time of 5 ns with no hold time requirement. The HOTLink has a built-in self-test which can be started by asserting one pin.

RADIATION HARDNESS

No data available on the chip from Cypress.

TEMIC Semiconductor sells the TSS923(E)/933(E) chips, which are pin and package compatible to the HOTLink. Those chips are radiation tolerant, covered by the ESA MCRT capability approval domain. On the other hand it only allows a byte clock of 33 MHz maximum, which probably makes it unusable for LHC applications. On the other hand one may ask TEMIC what happens if the chip is used in a controlled environment (temperature and power supply). This radiation tolerant version has the following features:

byte clock 33 MHz maximum
latch up immune
total dose better than 35 Krads
SEU LET better than 55 MeV
Prices: 600 EUR (quantity 25), 265 EUR (quantity 1000)

OTHER

The serialiser needs very little external components to work. Many application notes are available for all different aspects and applications of the chip.