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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One advantage of this approach is that there is no need for a VTT power supply. The standard defines a reference voltage VREF which is used at the receivers as well as a voltage VTT to which termination resistors are connected.
Compliant devices jexd8 meet the VSwing ac specification under actual use conditions. NOTE 4 AC test conditions may be measured under nominal voltage conditions as long as the supplier can demonstrate by analysis that the device will meet its timing specifications under all supported voltage conditions. The ac values are chosen to indicate the levels at which the receiver must meet its timing specifications.
If the driver maintains a resistance lower than the Maximum On Resistance, more than the mV will be presented to the receiver. This can be expressed by equation-1 or equation If the driver outputs are sized for this condition, then for all other Jdsd8 voltage applications, the resulting input signal will be larger than the minimum mV.
An example is shown in figure 8. 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.
Typically the value of VREF nesd8 expected to be 0. However a Class II buffer would dissipate more power due to its larger current drive and thus might require special cooling. All recipients of this errata are asked to replace page 7 with the corrected page included in this errata.
The standard is particularly intended to improve operation in situations where busses must be isolated from relatively large stubs. Note however, that all timing specifications are still set relative to the ac input level.
Stub Series Terminated Logic
O rgan iz atio ns m ay ob tain perm issio n to rep rod uce a lim ited n um b er o f co pies thro ugh enterin g in to a licen se agreem en t. The third clause specifies the minimum required output characteristics of, and ac test conditions for, compliant outputs targeted for various application environments. While driver characteristics are derived from 9bb 50?
Note however, that all timing specifications are still set relative to the differential jesx8 input level.
The system 9v can be sure that the device will switch jesf8 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.
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. VTT is specified as being equal to 0. F or info rm ationcon tact: 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. The tester may therefore supply signals with a 1. Days after publication of this standard in Mayit was brought to the attention of the sponsor that there were errors in Table 4.
The output specifications are jesdd8 into two classes, Class I and Class II, which are distinguished by drive requirements and application. Under these conditions VOH is 1.
However in order to provide a basis, the driver characteristics will be derived in terms of a typical 50? 9 V V Notes 2. See also figure 2. The driver specification now must guarantee that these values of VIN are obtained in the worst case conditions specified by this standard.
An jssd8 of ringing is illustrated in the dotted wave-form. This clause is added to set the conditions under which the driver ac specifications can be tested.
Memory Interfaces | Aragio
However, the drivers are connected directly onto the bus so there are no stubs present. External resistors provide this isolation and also reduce the on-chip power dissipation of the drivers.
The Standards, Publications, and Outlines that kesd8 generate are accepted throughout the world. Units V mV Notes 1 1 0. The test circuit is assumed to be similar to the circuit shown in figure 4.