CY7B9945V-2AXI(2011) データシートの表示（PDF） - Cypress Semiconductor

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CY7B9945V-2AXI
(Rev.:2011)

High Speed Multi-phase PLL Clock Buffer

Cypress Semiconductor 

PRELIMINARY

RoboClock®

CY7B9945V

Output Disable Description

The output of each output bank can be independently put into a

HOLD OFF or high impedance state. The combination of the

MODE and DIS[1:2] inputs determines the clock outputs’ state

for each bank. When the DIS[1:2] is LOW, the outputs of the

corresponding banks are enabled. When DIS[1:2] is HIGH, the

outputs for that bank are disabled to a high impedance (HI-Z) or

HOLD OFF state. Table 5 defines the disabled outputs functions.

The HOLD OFF state is a power saving feature. An output bank

is disabled to the HOLD OFF state in a maximum of six output

clock cycles from the time the disable input is HIGH. When

disabled to the HOLD OFF state, outputs are driven to a logic

LOW state on their falling edges. This makes certain that the

output clocks are stopped without a glitch. When a bank of

outputs is disabled to HI-Z state, the respective bank of outputs

go High-Z immediately.

Table 5. DIS[1:2] Functionality

MODE

HIGH/LOW

HIGH

LOW

MID

DIS[1:2]

LOW

HIGH

HIGH

X

1Q[0:3], 2Q[0:5]

ENABLED

HI-Z

HOLD-OFF

FACTORY TEST

Notes

1. FB connected to an output selected for “Zero” skew (i.e., FBF0 = MID or XF[1:0] = MID).

2. The level set on FS is determined by the “nominal” operating frequency (fNOM) of the VCO and Phase Generator. fNOM always appears on an output when the output

is operating in the undivided mode. The REF and FB are at fNOM when the output connected to FB is undivided.

3. BK1Q denotes following the skew setting of indicated Bank1 outputs.

4. These inputs are normally wired to VCC, GND, or left unconnected (actual threshold voltages vary as a percentage of VCC). Internal termination resistors hold the

unconnected inputs at VCC/2. If these inputs are switched, the function and timing of the outputs may glitch and the PLL may require an additional tLOCK time before

all data sheet limits are achieved.

5. This is for non-three level inputs.

Document Number: 38-07336 Rev. *J

Page 6 of 15

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