Technical Summary: K4E661612C 4Mx16 EDO Mode DRAM

Overview

The K4E661612C is a high-performance 4Mx16 Extended Data Out (EDO) Mode Dynamic Random Access Memory (DRAM) component manufactured using Samsung's advanced CMOS process technology. This device belongs to a family of 3.3V DRAMs that offer high bandwidth, low power consumption, and enhanced reliability for memory-intensive applications. The component is available in two variants with different refresh cycle configurations (8K and 4K refresh), and features multiple refresh modes including self-refresh capability in the L-version.

With its 16-bit wide data bus and EDO mode operation, the K4E661612C provides improved performance over conventional DRAMs by allowing data to remain valid on the output after CAS# deassertion, enabling faster memory access cycles. The device complies with JEDEC standard pinouts and is offered in space-efficient TSOP(II) packages.

Key Features

• 4Mx16 organization (67,108,864 bits total capacity)
• Extended Data Out (EDO) Mode operation for improved performance
• 3.3V ±0.3V power supply (LVTTL compatible)
• Multiple refresh modes:
  • CAS-before-RAS refresh capability
  • RAS-only refresh capability
  • Hidden refresh capability
  • Self-refresh capability (L-version only)
• 2 CAS Byte/Word Read/Write operation
• Fast parallel test mode capability
• Early Write or output enable controlled write
• JEDEC standard 44-pin TSOP(II) package

Functional Description

Memory Architecture

The K4E661612C organizes its 67,108,864 bits into 4,194,304 words of 16 bits each. The memory array is divided into upper and lower banks, each with independent data paths consisting of input buffers, output buffers, and sense amplifiers. The device incorporates a 4K refresh scheme (8K in the -TC variant) with dedicated refresh control circuitry including a refresh timer, refresh counter, and VBB generator.

Data Path Operation

The device features separate data paths for upper (DQ8-DQ15) and lower (DQ0-DQ7) bytes, each with dedicated input and output buffers. This architecture enables byte-wide operations when needed while supporting full 16-bit word access. The EDO mode functionality is implemented through careful timing of the output buffers relative to the CAS# control signal.

Refresh Modes

The K4E661612C supports several refresh methodologies to accommodate different system requirements:

• CAS-before-RAS Refresh: The traditional DRAM refresh method where CAS# is asserted before RAS# to initiate refresh cycles
• RAS-only Refresh: Allows refresh cycles to be initiated by RAS# alone
• Hidden Refresh: Enables refresh operations to occur during active memory accesses
• Self Refresh (L-version): Autonomous refresh capability for low-power applications

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (Vcc): -0.5V to +4.6V
• Input Voltage (Vin): -0.5V to Vcc+0.5V
• Output Voltage (Vout): -0.5V to Vcc+0.5V
• Operating Temperature: 0°C to +70°C
• Storage Temperature: -55°C to +125°C

Recommended Operating Conditions

• Supply Voltage (Vcc): 3.3V ±0.3V
• Operating Temperature: 0°C to +70°C
• Input High Voltage (Vih): 2.0V min
• Input Low Voltage (Vil): 0.8V max

DC Characteristics

• Input Leakage Current: ±1.0μA max
• Output Leakage Current: ±1.0μA max
• Operating Current: 120mA max (active), 30mA max (standby)
• Self Refresh Current (L-version): 100μA max

AC Characteristics

• RAS# Access Time: 60ns max
• CAS# Access Time: 15ns max
• CAS# Precharge Time: 20ns min
• Write Pulse Width: 15ns min
• Refresh Cycle Time: 64ms (4096 cycles) or 128ms (8192 cycles)

Package Information

The K4E661612C is available in a 44-pin Plastic Thin Small Outline Package (TSOP) Type II configuration. Key package characteristics include:

• Package Dimensions: 10.16mm x 18.41mm x 1.2mm (typical)
• Lead Pitch: 0.8mm
• Lead Count: 44 (22 per side)
• Package Weight: 0.22g (typical)
• Moisture Sensitivity Level (MSL): 3 (168 hours floor life)

Pin Configuration

The device follows JEDEC standard pin assignments for 4Mx16 DRAMs. Notable pin functions include:

• DQ0-DQ15: Data input/output lines
• A0-A10: Address inputs
• RAS#: Row Address Strobe
• UCAS#, LCAS#: Upper and Lower Column Address Strobes
• W#: Write Enable
• OE#: Output Enable
• Vcc, Vss: Power and ground

Applications

The K4E661612C is suitable for a wide range of applications requiring moderate density DRAM with improved performance characteristics:

• Mid-range computer systems and workstations
• Embedded systems with memory expansion requirements
• Graphics subsystems and display buffers
• Networking equipment (routers, switches)
• Industrial control systems
• Test and measurement equipment
• Legacy system upgrades and repairs

Design Considerations

Power Supply Decoupling

Proper decoupling is essential for reliable operation. A 0.1μF ceramic capacitor should be placed as close as possible to each Vcc pin, with additional bulk capacitance (10-100μF) distributed across the power plane.

Signal Integrity

Due to the high-speed nature of EDO operations, careful attention should be paid to signal routing:

• Maintain controlled impedance for address and control lines
• Minimize trace lengths to data lines
• Implement proper termination for longer traces

Thermal Management

While the TSOP package has relatively good thermal characteristics, systems operating at high ambient temperatures should ensure adequate airflow over the memory components, especially in high-density configurations.

Conclusion

The K4E661612C 4Mx16 EDO DRAM provides a cost-effective memory solution for systems requiring moderate density with enhanced performance characteristics. Its multiple refresh modes, including the self-refresh capability of the L-version, make it suitable for both performance-oriented and power-sensitive applications. The device's JEDEC-standard pinout and package allow for easy design-in and second-source options, while Samsung's advanced CMOS process ensures reliable operation and low power consumption.