DIV46E15-97SDC003_Datasheet PDF

 人参与 | 时间:2021-06-20 03:46:09

Bei Step&Image handelt es sich um ein hochauflösendes Inspektionsverfahren. Dabei werden kurze Pulse ultravioletten Lichts eingesetzt. Die zweidimensionale Brennpunktebene führt zu Belichtungsfeldern, deren Abmessungen der Fläche der einzelnen Dies auf dem Wafer entsprechen. Damit erreicht das System einen hohen Durchsatz sowohl unter Verwendung von Hellfeld- als auch von Dunkelfeld-Techniken. Die UV-Lichtquelle ermöglicht eine hohe optische Auflösung, die eine schnelle Aufnahme großer zweidimensionaler Bilder mit kleinen Pixeln erlaubt.

Executes events in a reactive phase” of the current simulation time, appropriately synchronized to hardware simulation events.

Can use a special $exit” system task that will wait to exit simulation until after all concurrent program blocks have completed execution (unlike $finish,” which exits simulation immediately).

DIV46E15-97SDC003_Datasheet PDF

Clocking domains. SystemVerilog adds a special clocking block, using the keywords clocking” and endclocking.” The clocking block identifies a clocking domain,” containing a clock signal and the timing and synchronization requirements of the blocks in which the clock is used. A testbench may contain one or more clocking domains, each containing its own clock plus an arbitrary number of signals. Clocking domains allow the testbench to be defined using a cycle-based methodology, rather than the traditional event-based methodology of defining specific transition times for each test signal.

A clocking domain can define detailed skew information for the relationship between a clock and one or more signals. Input skews specify the amount of time before a clock edge that signals should be sampled by a testbench. Output skews specify how many time units after a clock edge that signals should be driven. Note that input” and output” are relative to the testbench that is, an output of the design under test is an input to the testbench. For example:

DIV46E15-97SDC003_Datasheet PDF

In regular Verilog, which does not have clocking domains, the initial” procedure in the preceding example would have race conditions with the design under test if the design is using the same positive edge of the clock to store values in registers. By using SystemVerilog clocking domain skews, the testbench can reference a clock edge to sample a value or drive stimulus. The appropriate skew will automatically be applied, thus avoiding race conditions with the design. Clocking domains greatly simplify defining a testbench that does not have race conditions with the design being tested.

Direct Programming Interface (DPI). SystemVerilog provides a means for SystemVerilog code to directly call functions written C, C++ or SystemC, without having to use the complex Verilog Programming Language Interface (PLI). Values can be passed directly to the foreign language function, and values can be received from the function. The foreign language function can also call Verilog tasks and functions, which gives the foreign language functions access to simulation events and simulation time. The SystemVerilog DPI provides a bridge between high-level system design using C, C++ or SystemC and lower-level RTL and gate-level hardware design.

DIV46E15-97SDC003_Datasheet PDF

Is SystemVerilog ready for use? Savvy engineers will have no doubt seen many SystemVerilog features in this article that will help them in their design and verification work. This, then, raises two important questions: Is this new SystemVerilog standard really ready for software companies to implement, and how soon will software tools supporting SystemVerilog be available?”

The answer to Is the SystemVerilog standard ready?” is a resounding YES! The many experts from EDA companies and the Verilog user community that participated in the development of SystemVerilog have voted that the standard is ready to be released. Their recommendation, along with the SystemVerilog 3.1 Language Reference Manual, has been sent to the Accellera board of directors for final approval. The Board will be voting in late May 2003 on ratifying SystemVerilog 3.1. A subset of SystemVerilog which focused primarily on enhanced hardware modeling constructs was approved by the Accellera board in June of 2002, and released to EDA vendors as SystemVerilog 3.0.

As mentioned, power-down sequencing with Auto-Track is subject to the same constraint as power up. That is a valid input voltage must be available to all modules under the control of the Track control, throughout the power-down sequence. This constraint makes it necessary for the power system to conduct a coordinated power shutdown for all circumstances. This is irrespective of whether a shutdown is initiated by a human operator, or the result of a line voltage failure. In the case of the latter, there must be sufficient hold-up charge in the power system, to allow time for a power-down sequence to be completed prior to any drop in the input voltage to the circuit. The nanopower supervisor (U3) will only turn off U1 (via the Inhibit pin) after the input voltage has already begun to decay. Therefore, it cannot be used to initiate power-down. This requires the use of a separate transistor. Q1 in Figure5, is in parallel with U3 and can turn off U1 prior to any drop in the input voltage. When U1 (PT5801) is turned off, its output is tri-stated. This means it will neither source nor sink current from the load. This allows the output voltage to fall only as fast as the load discharges the output capacitors. Once the output voltage from U1 decays below U2's set-point voltage, it pulls down U2's output via its Track pin.

Figure 7 shows the output waveforms to the circuit of Figure 5 during power down. To ensure Auto-Track can follow the output of another module, the voltage being followed must not change faster than Auto-Track's slew rate capability. This is 10 V/ms. During power down, a decay rate faster than this will result in a delay before the lower voltage outputs begin to follow the higher voltage. This could produce an excessive voltage differential. The decay rate limitation correlates to a minimum of 100 uF of capacitance per ampere of load current at the output of U1. Also, in addition to having the highest output voltage, the module selected for U1 should be carefully chosen to ensure that it does not sink current when turned off via its on/off Inhibit control.

顶: 111踩: 61