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. 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.
An example is shown in figure 8. The second clause defines the minimum dc and ac input parametric jesdd8 and ac test conditions for inputs on compliant devices.
Stub Series Terminated Logic
Compliant devices must meet the VSwing ac specification under actual use conditions. VTT is specified as being equal 9 0. However, the drivers are connected directly onto the bus so there are no stubs present. All recipients of this errata are asked to replace page 7 with the corrected page jdsd8 in this errata.
The standard is jess8 intended to improve operation in situations where busses must be isolated from relatively large stubs. This is accomplished precisely because drivers and receivers are specified independently b9 each other. An example of this may be address drivers on a memory board. 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.
NOTE 2 A 1. In some standards this ratio equals 0. Vx ac indicates the voltage at which differential input signals must be crossing. No claims to be in conformance with this standard may be made unless all requirements stated in the standard are met.
However a Class II buffer would dissipate more power due to its larger current drive and thus might require special cooling. Class I or However in order to provide a basis, the driver characteristics will be derived in terms of a typical 50?
An example of ringing is illustrated in the dotted wave-form. One advantage of this approach is that there is no need for a VTT power supply. Units V V Jesr8 2. See also figure 2.
Memory Interfaces | Aragio
The relationship of the different levels is shown in figure 1. JEDEC is the leading developer of standards for the solid-state industry, they have published over documents to date.
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. Under these conditions VOH is 1. Viso Parameter Input clock signal offset voltage Viso variation Min. JEDEC standards and publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for use by those other than JEDEC members, whether the standard is to be used either domestically or internationally.
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. 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. The third clause specifies the minimum required output characteristics of, and ac test conditions for, compliant outputs targeted for various application environments.
In that case, the designer may decide to eliminate the series resistors entirely. The driver specification now must guarantee that these values of VIN are obtained in the worst case conditions specified by this standard. F or info rm ationcon tact: Making this distinction is important for the design of high gain, differential, receivers that are required. The ac values are chosen to indicate the levels at which the receiver must meet its timing specifications.
Units V mV Notes 1 1 0. 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. While driver characteristics are derived from a 50?
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.
An example is shown in figure 7. By downloading this file the individual agrees not to charge for or resell the resulting material. Note however, that all timing specifications are still set relative to the differential ac input level.
Typically the value of VREF is expected to be 0. 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. 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.
Clearly it is not the intention to show all possible variations in this standard. External resistors provide jeed8 isolation and also reduce the on-chip power dissipation of the drivers.
The tester may therefore supply signals with a 1. The jwsd8 circuit is assumed to be similar to the circuit shown in figure 5. 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.