Memory PCB: The Ultimate FAQ Guide

In this guide, you will find all information you are looking for about memory PCB.

Whether you want to know the memory types, vital features, or mounting options, you will find all information right here.

Keep reading to learn more.

What Is A Memory PCB?

A memory PCB is an integrated circuit construction that employs a combination of transistors and capacitors in the storage of data.

memory PCB

Memory PCB

You find memory PCBs useful in storage of both volatile and non-volatile memory.

Volatile memory depends on sustained power to retain data which you lose once you cut power supply. Contrarily, with non-volatile memory you retain stored data even after loss of power.

Where Do You Use Memory PCBs?

You employ memory PCBs in electronic devices such as mobile phones and computers to store data such as programmes.

Memory PCBs allow you to store information useful in the operation or performance of the device.

Some common applications of the memory PCB are:

  • You find memory PCBs storing data in memory-based electronic devices such as mobile phones, communication equipment and computers.
  • Memory PCBs find use in smart cards such as credit cards and smart IDs such as electronic passports and modern licenses.

What Do You Consider When Buying A Memory PCB?

You need to consider the following when buying memory PCBs:

  • Application: Your area of use determines the memory PCB you buy.

While a DRAM PCB can boost the performance of your computer, a NAND Flash Memory PCB can increase your storage capacity.

  • Mean Time Before Failure: This is a metric that assesses the sturdiness of a memory PCB.

It defines the length of time you can employ a memory PCB before it reaches the end of its useful life.

  • Performance: The read/write speed of a memory chip can define its performance. This is the rate at which it can read and write data.
  • Storage: Memory PCBs allow you to supplement your existing storage capacity.

When selecting a memory PCB, you must first determine your requirement for extra storage.

  • Write/Erase Cycles: The number of times you can write and erase a memory PCB before eventual wear and failing defines its write/erase cycles.

Which Memory PCB Types Do We Have?

You’ll come across two major types of memory PCBs: volatile and non-volatile memory PCBs.

Volatile Memory PCBs lose data when you turn off power supply, whereas non-volatile memory PCBs can keep data even without power.

DRAM PCB

The dynamic RAM PCB employs memory cells to store volatile data.

A DRAM PCB memory cell consists of a single capacitor and transistor with the former storing a bit of data.

The data is in charge form and the transistor plays a switching role for converting electrical power to charge for the capacitor.

DRAM PCB

DRAM PCB

To activate the desired transistor, you send a charge through a specific column.

When writing data, the row lines influence the capacitor state while during the read process the sense-amplifier is responsible.

Charge levels lower than 50% describe a “0” value, whereas charge levels greater than 50% describe a “1.”

You find the following benefits in employing the DRAM PCB:

  • The design is simple as it only requires a single transistor.
  • You have a high memory density.
  • While executing a program, you can remove and refresh memory.
  • DRAM PCBs are inexpensive.
  • You have the capacity to store more data with a DRAM PCB.

EPROM PCB

The Erasable Programmable Read-Only Memory (EPROM) PCB stores non-volatile memory allowing reprogramming via erasing data using UV light.

You find EPROM PCBs useful in BIOS storage in computers facilitating the boot process.

Each cell in an EPROM PCB contains a transistors paring of a floating gate and a control gate transistor. The floating gate transistor serves as the storage site with a channel isolating it from the control gate.

EPROM PCB

EPROM PCB

Energized electrons enter the channel when you add a charge taking up a negative polarity and blocking the floating gate transistor.

A sensor controls the charge level with flow exceeding fifty percent identified as a “1” and less as a “0”.

EEPROM PCB

The EEPROM PCB refers to the Electrically Erasable Programmable Read-Only Memory which stores non-volatile memory that you can write and erase.

An EEPROM PCB consists of floating transistors with a transistor pairing of store and access transistors.

The store and access transistors are both field effect transistors.

EEPROM PCB

EEPROM PCB

The memory cell’s activity execution is by the access transistor, while data storage is by the storage transistor.

The floating gate of the storage transistor collects electrons, changing the cell’s properties.

You describe cell deletion when electrons get caught within the floating gate.

You can use an EEPROM PCB in various ways including:

  • Executing certain tasks in microcontrollers.
  • Save specific data in digital equipment such as temperature sensors in the case of limited power.
  • Saving setup parameters in electronic devices.
  • Storing personal information in smart cards.

FRAM PCB

The Ferroelectric Random Access Memory (FRAM) PCB combines the speed of DRAM PCB with a ROM’s non-volatility.

You find this possible via the use of a ferroelectric rather than dielectric capacitor alongside a MOS transistor.

An electric field causes the ferroelectric material to generate a two state reversible and polarizable crystal.

This causes the central atom to approach the direction of the field breaking an energy barrier and causing breakdown in charge.

FRAM PCB

FRAM PCB

The internal circuits consequently set the memory and removal of the electric field polarizes the atom. Thus, the circuit takes up non-volatile form keeping the memory state intact.

While FRAM PCBs are expensive with restricted capacities, you find the following advantages:

  • Faster write processes with the capability to do more write and erase cycles.
  • These memory PCBs are energy efficient allowing you an extended life span.
  • You have no data loss when you lose power.

NAND Flash Memory PCB

This memory PCB stores non-volatile memory finding use in data storage gadgets such as memory sticks and solid state drives (SSDs).

You can store large data amounts in NAND Flash Memory PCBs despite their tiny size with faster speeds.

Programming one cell involves a voltage application at the control gate resulting in an accumulation of electrons at the gate.

The floating gate traps the electrons and disconnecting power results in an additional charge to the memory cell.

NAND Flash Memory PCB

NAND Flash memory PCB

NOR Flash PCB

A NOR Flash IC stores non-volatile memory like the NAND Flash PCB with architectural and functional difference.

Its capability of random access makes the NOR Flash PCB favored in code execution.

The NOR Flash PCB is useful in the storage of small amounts of code finding use in BIOS chips.

Their quick read capabilities allows their use in embedded designs and mobile phones and digital TV boxes.

A NOR Flash PCB consists a memory cell consisting a resistor with a gate pairing of control gate and floating gate.

NOR Flash memory

NOR Flash memory

An oxide layer functions as an insulator and surrounds the floating gate.

You achieve higher speeds of reading with the NOR Flash PCB compared to the NAND Flash PCB. Additionally, rather than just blocks, the NOR Flash PCB can address bytes of memory allowing random access.

SRAM PCB

With a constant supply of power, a static RAM PCB can maintain its data without the need of DRAM PCB’s refreshes.

Finding use in computers as cache memory, they’re constitute digital-to-analogue converter on video cards and also storage of microprocessor registers.

A SRAM PCB cell constitutes six MOS transistors with four transistors making cross-coupled inverters for storage of a data bit.

SRAM PCB

SRAM PCB

The remaining transistor pair determines access to storage cells utilizing just a small amount of energy.

How Can You Differentiate Memory PCBs?

When identifying a memory PCB, you can employ the following methods:

  • Different memory PCBs have different packaging designs.
  • Some memory PCB constructions are unique to a certain type.
  • The PCB length and notch position will be useful in identification.
  • The pin count can help you figure out what type of memory PCB you’re dealing with.
  • Whether heat shields are present or not can also aid in memory PCB identification.
  • You can determine the sort of memory PCB you have by examining the serial number.

What Describes The Internal Organization Of A Memory PCB?

A memory PCB’s organization of memory cells defines its internal organization.

You find these cells in an array of rows and columns each capable of single data bit storage.

You find memory PCBs defined in words and bits such that one with 16 words and 8 bits, is 16×8.

The input and output lines of data for Sense/Write circuits join a single data line that is bidirectional.

Along with the data and address lines, there is a Chip Select (CS) line and two control lines.

In a system with numerous memory PCBs, the Chip Select line is useful in choosing a certain chip.

A word line connects memory cell rows while a bit line connects memory cell columns with an address decoder driving the former.

Through a Sense/Write circuit, the bit lines connect with the data input and output lines.

The Sense/Write circuit decodes the word line data stored during the Read process before transmitting as the data line output.

This circuit alternatively receives data during the Write process and stores it in the specific cells.

How Does A Memory PCB Store Data?

Data in a memory PCB is in charge form with the capacitor as the storage center while a transistor switches.

Memory PCBs employ memory cells which consists a capacitor and one or more transistors for data storage.

The transistor activates data by acting as an amplifier or switch, whereas the capacitor holds data in form of charge.

You can charge or discharge a capacitor, with the binary values 0 and 1 denoting the respective state.

Rows of memory cells connect to a bit line and a memory address referred to as a word line.

You can determine the data storage location using the address.

The word line is an electrical route that allows memory cell rows activation during a read or write procedure.

Electrical signals enable data access via indication of the memory cell location and employing row or column address strobes.

The transistor will conduct if a charge is present in a specific cell’s capacitor transferring it to the associated bit line.

Consequently, a small voltage increase results interpreted as “1” in binary language.

What Is The Difference Between The Address And Data Bus In Memory PCBs?

An address bus is a conduit for info to the memory from the processor which obtains required data by depositing its address.

Data transfer in the address bus is only in one direction with it determining the memory locations count.

A data bus provides a conduit for data transfer between the PCB’s memory cells and the processor.

Data bus Guide

Data bus guide

Data transmission in a data bus is in two directions allowing transmission and reception if data.

What Are Some Of The Features Of A Memory PCB?

Memory PCBs have several features that distinguish them as follows:

  • Access Methods: This defines how you access data in a memory PCB.

Data access can take a random (no order), serial (sequential), or semi-random approach.

  • Capacity: You define the capacity of a memory PCB in words as bytes, where a single byte is equivalent to 8 bits.
  • Location: You can employ a memory PCB in one of three locations: CPU cache, internal memory or external memory.
  • Organization: Memory PCBs can be erasable or non-erasable, the former allowing deletion of data and subsequent reprogramming.

Upon programming, non-erasable memory PCBs are permanent.

  • Performance: Memory cycle time, transfer rate and access time are the major parameters defining a memory PCB’s performance.

Access time constitutes that taken for a RAM PCB to execute a read/write function.

For non-random memory PCBs, it is the time to align the read/write head in the proper location. Memory cycle time is the sum of that spent gaining access and period before the second access begins.

The speed at which you can transfer data on a memory chip is the transfer rate.

  • Unit of Transfer: The transfer unit is the maximum bit count you can write or read in a memory PCB.

The primary memory limit is in words, whereas secondary memory is much greater in blocks.

  • Volatility: When you turn off power, the memory PCB’s capacity to hold or maintain data refers to its volatility.

Without power, volatile memory PCBs cannot store data. Contrarily, non-volatile memory PCBs keep data even without power.

What Are Some Of The Limitations Of Memory PCBs?

There are some drawbacks you experience when employing memory PCBs. They include the following:

  • Although you can erase and write some memory PCBs, you can perform a limited number of write-erase cycles.
  • Memory PCBs like the EPROM PCB require a significant amount of power.
  • Memory PCBs such as the Flash Memory PCB have a restriction on how long they can keep data.
  • Memory PCBs with volatile memory such as DRAM PCBs lose data on turning off power.
  • NVRAM PCBs employ large blocks for writing making them harder to address.
  • Some memory PCBs lack a write-protection mechanism.
  • While some memory PCBs are inexpensive, others such as the NOR Flash PCB are not.

How Do You Make A Memory PCB?

Because of their sophisticated circuitry, memory PCBs need clean conditions of manufacture to avoid damage by microscopic contaminations.

You achieve this by constantly filtering and moving air into the rooms, as well as the wearing specific garments.

In making memory chips, silicon ingots are sliced into minute wafers followed by application of a glass and nitride layer.

You form glass by oxygen exposure of the wafer at high temperatures exceeding 800 degrees Celsius for roughly an hour.

After creating, testing, and simulation, you lay out the circuitry on the wafer.

You employ photo-masks to highlight the electronic components individualities and in the desired layer pattern.

You use wet acid or dry plasma glass to remove the exposed nitride layer allowing placement of memory PCBs on the wafer.

After applying an insulating glass layer, you define the contact points for the circuit before etching the entire wafer.

You add a passivation layer over the wafer for contaminant protection during assembly before proceeding to testing.

You then cut out dies before encapsulating them, heating them, and packaging them.

What Is The Difference Between A Microprocessor And Memory PCB?

You find both are integrated circuits with entirely different functionality.

A microprocessor combines the central processing unit capabilities of a computer via an ALU, control unit, and a register array.

The arithmetic logic unit (ALU) allows the microprocessor to conduct logical and arithmetic functions.

Microprocessor

Microprocessor

The control unit controls the flow of data whereas the register array has letter identifiable registers.

The uniqueness of microprocessors is with regard to their clock speed bit count capacity per instruction. Contrarily, memory PCBs store data and process codes either temporarily or permanent depending on the memory PCB type.

How Do You Read Data From A Memory PCB?

The following procedure can help you read data from a memory PCB with the following three system buses involved:

  • You select the memory address of the location.
  • Set to high the control bus’s read/write wire to execute a read operation.
  • Set to high the control wire of the valid address.
  • On the matching memory, the valid indicator of the address and the value of address bus activate the chip select wire.
  • The data bus receives the contents of the appropriate location of memory.
  • Reading the value from the data bus is possible via a microprocessor register.
  • Finally, make the read/write, address valid, and chip select wire all low.

Can You Erase Data From A Memory PCB?

Yes, you can.

The erase cycles of a memory PCB is dependent on type. You can wipe data in EPROM, EEPROM and Flash Memory PCBs several times.

However, withstanding indefinite write-erase cycles is impossible eventually hampering their ability to store data.

Memory PCBs such as the PROM PCB are not erasable and writing data on them is permanent.

What Determines The Speed Of A Memory PCB?

You find the main determinants of a memory PCB’s speed are the rate of data transfer and access time.

The access time defines the duration between a processor’s request for data and its receipt of same data usually in nanoseconds.

The bit count you can achieve during transfer of data for a second refers to its data rate.

How Can You Tell Your Memory PCB Is Faulty?

When your memory PCB is faulty it ceases to perform as expected. You can determine chip degradation as follows:

  • A blue screen especially during startup can indicate a faulty memory PCB.
  • Failure to launch a program can suggest memory PCB fault.
  • Some damage in memory PCBs will present itself in the form of unprompted computer reboots.
  • Where you have broken points of contact in a memory PCB.
  • Whether there signs of physical interference such as bending or puncturing.

What Industries Employ Memory PCBs?

Several industries employ memory PCBs including the following:

  • DRAM PCBs find use in the computer industry as the primary computer memory.
  • Financial institutions employ memory PCBs in customer bank cards to store personal information and grant access.
  • Memory PCBs are also present in consumer electronic devices such as washing machines, digital TV boxes, and televisions.
  • NVRAM PCBs find use in medical equipment and in aircraft for critical data storage.
  • ROM PCBs are prevalent in electronic instruments in the music industry.
  • The prevalence of flash memory PCBs in personal electronic gadgets like mobile phones and media players is ubiquitous.
  • You find EEPROM PCBs in the motor vehicle industry applied in safety systems such as brake systems and air bags.

How Can You Test A Memory PCB?

Performing a memory PCB test is essential for several reasons such as highlighting chip failure, wiring issues, and faulty installation.

The following three consecutive procedures can help evaluate a memory PCB:

Test of the Data Bus

You start by checking the data bus wiring establishing the accuracy of reception by the chip.

You can determine this through undertaking many write procedures and checking the storage bit by bit.

The test is successful when independent setting of data bits as 0s and 1s is possible.

Independent bit testing is by the “walking 1’s test” carried out by inputting a data value and retrieving its value.

Test of the Address Bus

You perform this test only after a successful data bus test since a faulty data bus automatically suggests a faulty address bus.

In your test, you isolate the addresses for each bit independent pin adjustment to 0 or 1.

Testing an address bus test has issues with overlapping locations requiring a double check after a write process.

This involves writing an initial data value for every power of two to an address and then writing new values.

Device Test

After confirming the correct operation of the data and address bus, you perform a device test.

To test the memory PCB, you must determine whether each bit can contain a 0 or a 1.

A comprehensive test involves writing and corroborating every memory location twice.

You must invert the value you chose for the preceding test during the second test.

What Packages Can You Employ For A Memory PCB?

Memory PCBs come in a variety of packaging technologies as follows:

DIP

The Dual Inline Pin Package features an oblong design with pins running along its two lengths.

Earlier DRAM PCBs employed this package using Page Mode and Fast Page Mode but are now outdated.

SIPP

The Single Inline Pin Package modifies the DIP package permitting more memory density.

The SIPP organizes the leads to a single side that is parallel to the plane of the PCB.

You have two SIMM forms: the 30-pin and 72-pin with different modes available.

DIMM

With the Dual Inline Memory Module both memory PCB sides have connectors with different sizes available depending on pin count.

Available pin counts vary from 100 to 232 with some spotting different notches to prevent interchanging.

What Specifications Do You Identify Memory PCBs With?

When choosing memory PCBs, you must take into account its efficiency and speed. These parameters can guide you:

  • Access Time: The time between a processor’s data request and delivery measured in nanoseconds.
  • Bandwidth: Maximum data amount a memory PCB can handle in a given amount of time given in bits per second (bps).
  • Cycle Time: The duration it takes to perform a single read/write process and retuning the PCB for the next cycle.
  • Data Rate: Number of bits you can transfer in a memory PCB in a second measured in hertz (Hz).

Which PCB Materials Are Best For Memory PCBs?

You find different materials employed for memory PCBs. Some common materials are:

i. Metals: The conducting layer of a memory PCB is typically metallic utilizing copper, aluminum, or iron.

Copper finds common because of its superior electrical conductivity and low cost due to its wide availability.

ii. PTFE: Commonly known as Teflon, polytetrafluoroethylene (PTFE) is a durable, lightweight, and malleable substance.

You find PTFE useful in delicate applications since it exhibits less response to temperature changes while being resistance to flame.

iii. FR-4: FR-4 is a woven fiberglass composite reinforced with an epoxy resin binder that is flame-resistant.

FR-4 is the most common material used in making memory PCB laminates.

iv. Polyimide: Polyimide is a great option for flexible memory PCBs and also rigid board types. Although polyimide is expensive, it has great thermal properties such as stability at temperatures as high as 260°C.

Which Surface Finish Can You Apply On Memory PCB?

Choosing a surface finish for your memory PCB is an important step in the design process.

A good PCB surface finish protects the conductive pattern from deterioration while enhancing solderability.

When selecting a surface finish for your memory PCB, you consider several factors like: material, durability, cost, components, and environmental impact.

Common surface finishes you can employ for your memory PCB include:

  • HASL: Hot Air Solder Leveling is the least expensive surface finish with a relatively good surface finish.
  • Immersion Silver and Immersion Tin: Offers you better solderability and shelf life than HASL.
  • ENIG: Electroless Nickel Immersion Gold Finish is one of the most expensive but with excellent surface finish quality and shelf life.
  • OSP: Organic Solderability Preservatives employ environmental friendly material in its synthesis.

How Do You Mount Components On Memory PCB?

Lately, there has been an increase in demand for memory PCBs with higher functionality, reduced size, and improved performance.

Through-hole mounting and surface mounting are the two basic ways for attaching components to a memory.

Through-Hole Mounting

With through-hole mounting, you insert component leads into a memory PCB via drilled holes.

THM offers you durability and reliability where you require strong connections since you fasten the leads through the board.

Surface Mount Technology

SMT involves mounting components directly onto the memory PCB’s surface.

SMT is more popular today reducing assembly costs and improving overall memory PCB quality and performance.

SMT and through-hole mounting vary in the following ways:

  • You don’t need to drill holes for component attachment with SMT.
  • Since SMT components are substantially smaller, you achieve higher densities.
  • You can place SMT components on both board sides.

While both mounting technologies have their own advantages, you can extract both benefits by applying both technologies to your memory PCB.

Consequently, you can achieve memory PCBs that are smaller and more efficient, with greater density and durable connections.

Which Quality Standards Should Memory PCBs Comply With?

Quality standards in the memory PCB industry are necessary to ensure the memory chips are effective in their functionality.

You find these standards specific to the memory PCB type.

Some of the applied standards are as follows:

  • BS EN 61964: Defines the pin configuration of memory PCBs.
  • MIL-M-38510/201: Guides PROM PCBs of 512-bit capacity.
  • DESC-DWG-5962-00536: 8-bit capacity SRAM PCBs follow this standard.
  • MIL-M-38510/224: This standard is specific to EPROM PCB erasable via UV.
  • DESC-DWG-5962-01516: Regulates PROM PCBs of 8-bit capacity.
  • MIL-M-38510/240: DRAM PCBs adhere to this industry quality standard.
  • SMD 5962-08208: Which is an industry standard for FIFO PCBs.
  • MIL-M-38510/227: EEPROM PCBs with 384 bit capacity conform to this standard.

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