IDT72T51546 Integrated Device Technology, IDT72T51546 Datasheet - Page 31

• Manufacturer Part Number: IDT72T51546
• Description: 2.5v Multi-queue Flow-control Devices 32 Queues 36 Bit Wide Configuration 1,179,648 Bits And 2,359,296 Bits
• Manufacturer: Integrated Device Technology

Q
NOTES:
1. REN is LOW. OE is LOW.
2. t
3. Qslowest is the data output with the slowest access time, t
4. Time, t
ECHO READ CLOCK (ERCLK)
selectable via IOSEL. The ERCLK is a free-running clock output, it will always
follow the RCLK input regardless of REN and RADEN.
delay provides the user with a more effective read clock source when reading
data from the Qn outputs. This is especially helpful at high speeds when
variables within the device may cause changes in the data access times. These
variations in access time maybe caused by ambient temperature, supply
voltage, device characteristics. The ERCLK output also compensates for any
trace length delays between the Qn data outputs and receiving devices inputs.
effect on the ERCLK output produced by the Queue device, therefore the
ERCLK output level transitions should always be at the same position in time
relative to the data outputs. Note, that ERCLK is guaranteed by design to be
IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES
(32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits
SLOWEST
ERCLK
ERCLK
RCLK
The Echo Read Clock output is provided in both HSTL and LVTTL mode,
The ERCLK output follows the RCLK input with an associated delay. This
Any variations effecting the data access time will also have a corresponding
Figure 3. Echo Read Clock and Data Output Relationship
(3)
> t
D
is greater than zero, guaranteed by design.
A
, guaranteed by design.
t
A
t
ERCLK
t
D
t
ERCLK
A
.
5998 drw08
31
slower than the slowest Qn, data output. Refer to Figure 3, Echo Read Clock
and Data Output Relationship and Figure 27, Echo RCLK & Echo REN
Operation for timing information.
ECHO READ ENABLE (EREN)
selectable via IOSEL.
output and provides the reading device with a more effective scheme for reading
data from the Qn output port at high speeds. The EREN output is controlled by
internal logic that behaves as follows: The EREN output is active LOW for the
RCLK cycle that a new word is read out of the Queue. That is, a rising edge
of RCLK will cause EREN to go active (LOW) if REN is active and the Queue
is NOT empty.
The Echo Read Enable output is provided in both HSTL and LVTTL mode,
The EREN output is provided to be used in conjunction with the ERCLK
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES