VESTEL MB37, Service Manual

Page: 31 / 111

9 HY5DV281622DT-5 DDR SDRAM 128M
9.1 General Description
The Hynix HY5DV281622 is a 134,217,728-bit CMOS Double Data Rate(DDR)
Synchronous DRAM, ideally suited for the point-to-point applications which requires high
bandwidth. The Hynix 8Mx16 DDR SDRAMs offer fully synchronous operations
referenced to both rising and falling edges of the clock. While all addresses and control
inputs are latched on the rising edges of the CK (falling edges of the /CK), Data,Data
strobes and Write data masks inputs are sampled on both rising and falling edges of it.
The data paths are internally pipelined and 2-bit prefetched to achieve very high
bandwidth. All input and output voltage levels are compatible with SSTL_2.
9.2 Features

3.3V for VDD and 2.5V for VDDQ power supply

All inputs and outputs are compatible with SSTL_2 interface

JEDEC standard 400mil 66pin TSOP-II with 0.65mm pin pitch

Fully differential clock inputs (CK, /CK) operation

Double data rate interface

Source synchronous - data transaction aligned to bidirectional data strobe (DQS)

x16 device has 2 bytewide data strobes (LDQS, UDQS) per each x8 I/O

Data outputs on DQS edges when read (edged DQ) Data inputs on DQS centers
when write (centered DQ)

Data(DQ) and Write masks(DM) latched on the both rising and falling edges of the
data strobe

All addresses and control inputs except Data, Data strobes and Data masks
latched on the rising edges of the clock

Write mask byte controls by LDM and UDM

Programmable /CAS latency 3 / 4 supported

Programmable Burst Length 2 / 4 / 8 with both sequential and interleave mode

Internal 4 bank operations with single pulsed /RAS

tRAS Lock-Out function supported

Auto refresh and self refresh supported

4096 refresh cycles / 32ms

Full, Half and Matched Impedance(Weak) strength driver option controlled by
EMRS