参数资料
型号: GS8662DT10BGD-400IT
厂商: GSI TECHNOLOGY
元件分类: SRAM
英文描述: 8M X 9 QDR SRAM, 0.45 ns, PBGA165
封装: 13 X 15 MM, 1 MM PITCH, ROHS COMPLIANT, FPBGA-165
文件页数: 28/29页
文件大小: 963K
代理商: GS8662DT10BGD-400IT
Resulting Write Operation
Byte 1
D0–D8
Byte 2
D9–D17
Byte 1
D0–D8
Byte 2
D9–D17
Byte 1
D0–D8
Byte 2
D9–D17
Byte 1
D0–D8
Byte 2
D9–D17
Written
Unchanged
Written
Unchanged
Written
Beat 1
Beat 2
Beat 3
Beat 4
GS8662DT07/10/19/37BD-450/400/350/333/300
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
Rev: 1.00 5/2011
8/29
2011, GSI Technology
FLXDrive-II Output Driver Impedance Control
HSTL I/O SigmaQuad-II+ SRAMs are supplied with programmable impedance output drivers. The ZQ pin must be connected to
VSS via an external resistor, RQ, to allow the SRAM to monitor and adjust its output driver impedance. The value of RQ must be
5X the value of the desired RAM output impedance. The allowable range of RQ to guarantee impedance matching continuously is
between 175
Ω and 350Ω. Periodic readjustment of the output driver impedance is necessary as the impedance is affected by drifts
in supply voltage and temperature. The SRAM’s output impedance circuitry compensates for drifts in supply voltage and
temperature. A clock cycle counter periodically triggers an impedance evaluation, resets and counts again. Each impedance
evaluation may move the output driver impedance level one step at a time towards the optimum level. The output driver is
implemented with discrete binary weighted impedance steps.
Input Termination Impedance Control
These SigmaQuad-II+ SRAMs are supplied with programmable input termination on Data (D), Byte Write (BW), and Clock (K,K)
input receivers. The input termination is always enabled, and the impedance is programmed via the same RQ resistor (connected
between the ZQ pin and VSS) used to program output driver impedance, in conjuction with the ODT pin (6R). When the ODT pin
is tied Low, input termination is "strong" (i.e., low impedance), and is nominally equal to RQ*0.3 Thevenin-equivalent when RQ is
between 175 and 350. When the ODT pin is tied High (or left floating—the pin has a small pull-up resistor), input termination
is "weak" (i.e., high impedance), and is nominally equal to RQ*0.6 Thevenin-equivalent when RQ is between 175 and 250.
Periodic readjustment of the termination impedance occurs to compensate for drifts in supply voltage and temperature, in the same
manner as for driver impedance (see above).
Note:
D, BW, K, K inputs should always be driven High or Low; they should never be tri-stated (i.e., in a High-Z state). If the inputs are
tri-stated, the input termination will pull the signal to VDDQ/2 (i.e., to the switch point of the diff-amp receiver), which could cause
the receiver to enter a meta-stable state, resulting in the receiver consuming more power than it normally would. This could result
in the device’s operating currents being higher.
相关PDF资料
PDF描述
GS8662Q18BD-357 4M X 18 STANDARD SRAM, 0.45 ns, PBGA165
GS8662Q18BGD-357IT 4M X 18 STANDARD SRAM, 0.45 ns, PBGA165
GS8662Q18GE-167IT 4M X 18 STANDARD SRAM, 0.5 ns, PBGA165
GS8662R09BD-350 8M X 9 STANDARD SRAM, 0.45 ns, PBGA165
GS8662R09BGD-400I 8M X 9 STANDARD SRAM, 0.45 ns, PBGA165
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