CY7B923
CY7B933
safety functions), the FOTO input can be asserted. While it is
possible to insure that the output state of the PECL drivers is
LOW (i.e., light is off) by sending all 0’s in Bypass mode, it is
often inconvenient to insert this level of control into the data
transmission channel, and it is impossible in Encoded mode.
FOTO is provided to simplify and augment this control function
(typically found in laser-based transmission systems). FOTO
will force OUTA+ and OUTB+ to go LOW, OUTA– and OUTB–
to go HIGH, while allowing OUTC± to continue to function
normally (OUTC is typically used as a diagnostic feedback and
cannot be disabled). This separation of function allows various
system configurations without undue load on the control
function or data channel logic.
that multiplies the frequency of CKW by ten (10) to maintain
the proper bit clock frequency. The jitter characteristics
(including both PLL and logic components) are shown below:
• Deterministic Jitter (Dj) < 35 ps (peak-peak). Typically
measured while sending a continuous K28.5 (C5.0).
• Random Jitter (Rj) < 175 ps (peak-peak). Typically
measured while sending a continuous K28.7 (C7.0).
Transmitter Test Mode Description
The CY7B923 Transmitter offers two types of test mode
operation, BIST mode and Test mode. In a normal system
application, the Built-In Self-Test (BIST) mode can be used to
check the functionality of the Transmitter, the Receiver, and
the link connecting them. This mode is available with minimal
impact on user system logic, and can be used as part of the
normal system diagnostics. Typical connections and timing
are shown in Figure 6.
Transmitter Serial Data Characteristics
The CY7B923 HOTLink Transmitter serial output conforms to
the requirements of the Fibre Channel specification. The serial
data output is controlled by an internal Phase-Locked Loop
0.01 µF
4 9 22
7
VCC
Tx PECL Load
0.01 µF
Config
MODE
VCC
82
130
25
5
24
23
8
Fiber Optic
Tx
FOTO
BISTEN
ENN
Fiber
TX
A
B
27
26
Control
and
Status
OUTA+
OUTA–
TX+
TX–
ENA
RP
82
130
CY7B923
Transmitter
GND
Unused Output Left
Open or Wired to V
to Minimize Power Dissipation
28
1
0.01 µF
19
18
17
16
15
14
13
12
11
10
21
OUTB+
OUTB–
CC
SC/D (Da)
D0 (Db)
D1 (Dc)
D2 (Dd)
D3 (De)
D4 (Di)
D5 (Df)
D6 (Dg)
D7 (Dh)
SVS(Dj)
CKW
Tx PECL Load
270
3
2
Coax or
Twisted Pair
OUTC+
OUTC–
A
B
Data
270
270
270
0.01 µF
GND
6 20
649
RL/2
1500
Transmission
Line
Coax or
Twisted Pair
Termination
0.01 µF
C
RL/2
9 2124
VCC
26
25
MODE
REFCLK
D
E
Config
Optional
Signal Det.
4
23
3
5
BISTEN
SO
A/B
RF
RDY
Control
and
Status
CY7B933
Receiver
28
27
7
IB+
IB–
E
19
18
17
16
15
14
13
12
11
10
22
270
130
SC/D (Qa)
D0 (Qb)
D1 (Qc)
D2 (Qd)
D3 (Qe)
D4 (Qi)
D5 (Qf)
D6 (Qg)
D7 (Qh)
RVS(Qj)
CKR
0.01 µF
VCC
Fiber
82
82
Fiber Optic
Rx
SIG
RX+
RX–
2
1
C
D
RX
IA+
IA–
Data
130
GND
0.01 µF
GND
6 8 20
Fiber Optic
PECL Load
Figure 5. HOTLink Connection Diagram
Document #: 38-02017 Rev. *E
Page 10 of 33
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