CY23FS08-04 Datasheet, PDF (1/11 Pages) Cypress Semiconductor – FailSafe™ 1.8V Zero Delay Buffer

CY23FS08-04
FailSafe™ 1.8V Zero Delay Buffer
Features
■ Internal DCXO for continuous glitch free operation
■ Zero input-output propagation delay
■ Low output cycle-to-cycle jitter (<46 ps RMS)
■ Low output-output skew (<200 ps)
■ 3.84 MHz reference input
■ Supports industry standard input crystals
■ Up to 133 MHz (industrial) outputs
■ Phase-locked loop (PLL) bypass mode
■ Dual reference inputs
■ 28-pin SSOP
■ 1.8V output power supplies
■ 3.3V core power supply
■ Industrial temperature
Logic Block Diagram
Functional Description
The CY23FS08-04 is a FailSafe Zero Delay Buffer with two
reference clock inputs and eight phase aligned outputs. The
device provides an optimum solution for applications where
continuous operation is required in the event of a primary clock
failure.
Continuous, glitch free operation is achieved by using a DCXO
that serves as a redundant clock source in the event of a
reference clock failure by maintaining the last frequency and
phase information of the reference clock.
The unique feature of the CY23FS08-04 is that the DCXO is in
fact, the primary clocking source, that is synchronized (phase
aligned) to the external reference clock. When this external clock
is restored, the DCXO automatically resynchronizes to the
external clock.
The frequency of the crystal that is connected to the DCXO is
chosen as an integer factor of the frequency of the reference
clock. This factor is set by four select lines: S[4:1]. For more
information, see Table 2 on page 3. The CY23FS08-04 has three
split power supplies; one for core, another for Bank A outputs,
and the third for Bank B outputs. Each output power supply,
except VDDC is connected to 1.8V. VDDC is the power supply
pin for internal circuits and is connected to 3.3V.
REFSEL
XIN XOUT
DCXO
REF1
REF2
FBK
Failsafe^TM
Block
PLL
S[4:1]
Decoder
4
4
CLKA[1:4]
4
CLKB[1:4]
FAIL# /SAFE
Cypress Semiconductor Corporation • 198 Champion Court
Document Number: 001-17042 Rev. **
• San Jose, CA 95134-1709 • 408-943-2600
Revised September 20, 2007
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