Second half CMOS Quizzes

yay

T/F: Copper can directly contact silicon without any additional materials in modern processes

False

T/F:Diffusion runners are preferred for long wires because they have low resistance

False

T/F: In modern processes, the aspect ratio (AR = t/w) of wires is typically much less than 1

False

T/F: Using repeaters always reduces both delay and energy consumption

False

Which parameter defines wire pitch?

w + s

Total wire capacitance is composed of:

Top + Bottom + 2×Adjacent capacitance

Which is NOT a common method to reduce crosstalk?

Shield wires

Increase spacing

Decrease spacing

Ensure neighbors switch at different times

Decreasing Spacing

What is the key difference between volatile and non-volatile memory?

Volatile memory loses data without power

Which of the following is volatile memory?

DRAM

ROM
SRAM
SSD

DRAM and SRAM

Which memory type can’t be written to multiple times?

ROM

What does EEPROM use to store data?

Floating-gate transistors

Which of the following about SRAM is correct?

Memory unit layout size is small compared to other memories

There is a precharge before reading process

It needs constant refreshing

Data will be lost after reading operation

All of the above

(T/F) One bit SRAM has 4 transistors

False

(T/F) To read from an SRAM, both bitline and bitline bar need to be precharged before turning on wordline

True

(T/F) During the reading process, one of bitline and bitline bar will stay high and the other will go low

True

(T/F) To write to an SRAM, you only need to write the data in from bitline or bitline bar side

False

(T/F) SRAM is widely used for on-chip memory because it’s fast and also small in area

False

(T/F) SRAM can be scaled down easily into the most advanced technology node because it’s a ratioed circuit

False

To ensure SRAM write operation success

Access transistor needs to be larger than pull up transistor

To ensure read success of SRAM

Pull down transistor needs to be larger than access transistor

(T/F)More SRAM cells connected to bitline and bitline bar means shorter reading time

False

(T/F)For an 8 column, 32 row SRAM array, you need 32 precharge circuits

False

(T/F) SRAM row decoder is necessary, but column decoder/mux is optional depending whether one bit or one row data is accessed during reading process

True

(T/F) It’s always a good practice to keep the write driver transistors as small as possible due to power and area concerns

False

(T/F)Reading sensing amplifier is a differential amplifier and should be enabled and turned on when either read enable or write enable signal is asserted.

False

(T/F)Testing normally costs less compared to chip design and fabrication.

False

(T/F)Most chip failures after fabrication are due to logic bugs rather than electrical failures.

True

(T/F)The stuck-at fault model assumes nodes can be stuck at either logic 0 or logic 1.

True

(T/F)Good observability and controllability increase the number of test vectors required.

False

Which of the following is NOT part of the testing process discussed?

Manufacturing test

Logic verification

Compiler optimization

Silicon debug

Compiler Optimization

What is the main purpose of Shmoo plots?

Diagnose failures by varying voltage and frequency

Which of the following best describes observability?

Ability to measure internal nodes from output pins