CY14B256K Datasheet, PDF (1/23 Pages) Cypress Semiconductor – 256-Kbit (32K x 8) nvSRAM with Real-Time-Clock

PRELIMINARY
CY14B256K
256-Kbit (32K x 8) nvSRAM with Real-Time-Clock
Features
• Data integrity of Cypress nvSRAM combined with full
featured real time clock
— Low power, 300 nA Max, RTC current
— Capacitor or battery backup for RTC
• Watchdog timer
• Clock alarm with programmable interrupts
• 25 ns, 35 ns, and 45 ns access times
• “Hands-off” automatic STORE on power down with only a
small capacitor
• STORE to QuantumTrap™ initiated by software, device pin,
or on power down
• RECALL to SRAM initiated by software or on power up
• Infinite READ, WRITE, and RECALL cycles
• High reliability
— Endurance to 200K cycles
— Data retention: 20 years @ 55°C
• 10 mA typical I_CC at 200 ns cycle time
• Single 3V operation with tolerance of +15%, -10%
• Commercial and industrial temperature
• SSOP Package (ROHS compliant)
Logic Block Diagram
Functional Description
The Cypress CY14B256K combines a 256 Kbit nonvolatile
static RAM with a full featured real-time-clock in a monolithic
integrated circuit. The embedded nonvolatile elements
incorporate QuantumTrap technology producing the world’s
most reliable nonvolatile memory. The SRAM can be read and
written an infinite number of times, while independent,
nonvolatile data resides in the nonvolatile elements.
The real-time-clock function provides an accurate clock with
leap year tracking and a programmable, high accuracy
oscillator. The alarm function is programmable for one time
alarms or periodic seconds, minutes, hours, or days. There is
also a programmable watchdog timer for process control.
QuantumTrap
V_CC
V_CAP
512 X 512
POWER
V_RTCbat
A₅
STORE
CONTROL
V_RTCcap
A₆
A₇
A₈
A₉
STATIC RAM
ARRAY
RECALL
STORE/
RECALL
CONTROL
HSB
A ₁₁
512 X 512
A ₁₂
A ₁₃
A ₁₄
SOFTWARE
DETECT
- A13 A₀
DQ ₀
DQ ₁
DQ ₂
DQ ₃
DQ ₄
DQ ₅
DQ ₆
DQ ₇
COLUMN IO
COLUMN DEC
A₀ A₁ A₂ A₃ A₄ A₁₀
RTC
MUX
x₁
x₂
INT
- A14 A₀
OE
CE
WE
Cypress Semiconductor Corporation • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600
Document Number: 001-06431 Rev. *E
Revised January 29, 2007
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