Hitachi 42PMA225EZ, Service Manual

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Plasma TV Service Manual 11/01/2005
SDRAMs offer substantial advances in DRAM operating performance, including the ability to
synchronously burst data at a high data rate with automatic column-address generation, the ability to
interleave between internal banks in order to hide precharge time and the capability to randomly
change column addresses on each clock cycle during a burst access.
9.23.2. Features
• PC66-, PC100-, and PC133-compliant
• Fully synchronous; all signals registered on positive edge of system clock
• Internal pipelined operation; column address can be changed every clock cycle
• Internal banks for hiding row access/precharge
• Programmable burst lengths: 1, 2, 4, 8, or full page
• Auto Precharge, includes CONCURRENT AUTO PRECHARGE, and Auto Refresh Modes
• Self Refresh Modes: standard and low power
• 64ms, 4,096-cycle refresh
• LVTTL-compatible inputs and outputs
• 3.3V ±0.3V power supply
9.23.3. Pin Descriptions
PIN NUMBERS SYMBOL TYPE DESCRIPTION
38 CLK Input Clock: CLK is driven by the system clock. All SDRAM input
signals are sampled on the positive edge of CLK. CLK also
increments the internal burst counter and controls the output
registers.
37 CKE Input Clock Enable: CKE activates (HIGH) and deactivates (LOW)
the CLK signal. Deactivating the clock provides PRECHARGE
POWER-DOWN and SELF REFRESH operation (all banks
idle), ACTIVE POWER-DOWN (row active in any bank) or
CLOCK SUSPEND operation (burst/access in progress). CKE
is synchronous except after the device enters power-down and
self refresh modes, where CKE becomes asynchronous until