SSTL_3, V, defined in EIA/JESD ; SSTL_2, V, defined in EIA/ JESDB used in DDR among other things. SSTL_18, V, defined in. STUB SERIES TERMINATED. LOGIC FOR VOLTS (SSTL_2). EIA/JESD SEPTEMBER ELECTRONIC INDUSTRIES ALLIANCE. JEDEC Solid State . SSTL (JESD, JESDB, JESD). • HSTL (JESD). LVTTL and LVCMOS were developed as a direct result of technology scaling. With each reduction in.
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Busses may be terminated by resistors to an external termination voltage.
If the driver maintains a resistance lower than the Maximum On Resistance, more than the mV will be presented to the receiver. Units V V Notes 2. This is illustrated in figure 2. The tester may therefore supply signals with a 1. The specifications are quite different from traditional specifications, where minimum values for VOH and maximum values for VOL are set that apply to the entire supply range.
The output specifications are divided into two classes, Class I and Class II, which are distinguished by drive requirements and application. VTT is specified as jeed8 equal to 0.
An example of this may be address drivers on a memory board.
Memory Interfaces | Aragio
See also figure 2. Vx ac indicates the voltage at which differential input signals must be crossing. In some standards nesd8 ratio equals 0. The ac values are chosen to indicate the levels at which the receiver must meet its timing specifications. NOTE 2 A 1. Typically the value of VREF is expected to be 0. In that case, the jese8 may decide to eliminate the series resistors entirely. However in order to provide a basis, the driver characteristics will be derived in terms of a typical 50?
This clause is added to set the conditions under which the driver ac specifications can be tested. An example of this is shown in figure 6. However, the drivers are connected directly onto the bus so there are no stubs present. No claims to be in conformance with this standard may be 99b unless all requirements stated in the standard are met. An example is shown in figure 7. The second clause defines jesc8 minimum dc and ac input parametric requirements and ac test conditions for inputs on compliant devices.
This can be expressed by equation-1 or equation The relationship of the different levels is shown in figure 1.
The system designer will be able to vary impedance levels, termination resistors and supply voltage and be able to calculate the effect on system voltage margins.
In this example a Class II type buffer might be preferred since it comes closer, in conjunction with the series resistor, to match the characteristic impedance of the transmission line.
One advantage of this approach is that there is no need for a VTT power supply. External resistors provide this isolation and also reduce the on-chip power dissipation of the drivers.
The information included in JEDEC standards and publications represents a sound approach to product specification and application, principally from the solid state device manufacturer viewpoint. Almost representatives, appointed by some JEDEC member companies work together in 50 JEDEC committees to meet the needs of every segment of the industry, manufacturers and consumers alike. This is accomplished precisely because drivers and receivers are specified independently of each other.
The b9 values are chosen such that the final logic state is unambiguously defined, jess8 is once the receiver input has crossed this value, the receiver will change to and maintain the new logic state. The standard is particularly intended to improve operation in situations where busses must be isolated from relatively large stubs. While driver characteristics are derived from a 50? The first clause defines pertinent supply voltage requirements common to all compliant ICs.
Stub Series Terminated Logic
An example of ringing is illustrated in the dotted wave-form. If the driver outputs are sized for this condition, then for all other VDDQ voltage applications, the resulting input signal will be larger than the minimum mV. JEDEC standards and publications are adopted without regard to whether or not their adoption may involve patents or articles, materials, or processes.
The driver specification now must guarantee that these values of VIN are obtained in the worst case conditions specified by this standard. Class I or Note however, that all timing specifications are still set relative to the ac input level. The system designer can be sure that the device will switch state a certain amount of time after the input has crossed ac threshold and not switch back as long as the input stays beyond the dc threshold.
Days after publication of this standard in Mayit was brought to the attention of the sponsor that there were errors in Table 4.