DRAM-dat

• ESP32-HDK-dat

Dynamic Random Access Memory (DRAM) is a type of volatile memory that stores data in capacitors within integrated circuits.

Key Characteristics:

• Dynamic: Requires periodic refreshing (every few milliseconds) because capacitors leak charge over time
• Volatile: Data is lost when power is removed
• Random Access: Any memory location can be accessed directly in any order
• High Density: Can store more data per chip compared to SRAM
• Lower Cost: Cheaper per bit than SRAM due to simpler cell structure

How DRAM Works:

1. Storage Cell: Each bit is stored as charge in a tiny capacitor
2. Transistor Switch: Controls access to the capacitor
3. Refresh Cycle: Memory controller periodically reads and rewrites data to maintain charge
4. Row/Column Addressing: Uses multiplexed addressing to reduce pin count

Types of DRAM:

• SDRAM: Synchronous DRAM - synchronized with system clock
• DDR SDRAM: Double Data Rate - transfers data on both clock edges
• DDR2/DDR3/DDR4/DDR5: Successive generations with higher speeds and lower power
• LPDDR: Low Power DDR for mobile devices
• GDDR: Graphics DDR for video cards

Common Applications:

• System RAM in computers and smartphones
• Frame buffers in graphics cards
• Buffer memory in networking equipment
• Temporary storage in embedded systems

DRAM vs Other Memory Types:

Type	Speed	Cost	Density	Volatility	Refresh
DRAM	Medium	Low	High	Volatile	Required
SRAM	High	High	Low	Volatile	Not Required
Flash	Low	Medium	High	Non-volatile	Not Required
EEPROM	Very Low	High	Low	Non-volatile	Not Required