CY14B256K_09 Datasheet, PDF (1/28 Pages) Cypress Semiconductor – 256 Kbit (32K x 8) nvSRAM with Real Time Clock

CY14B256K
256 Kbit (32K x 8) nvSRAM with Real Time Clock
Features
■ 25 ns, 35 ns, and 45 ns access times
■ Pin compatible with STK17T88
■ Data integrity of Cypress nvSRAM combined with full featured
Real Time Clock
❐ Low power, 350 nA RTC current
❐ Capacitor or battery backup for RTC
■ Watchdog timer
■ Clock alarm with programmable interrupts
■ 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 at 55°C
■ Single 3V operation with tolerance of +20%, -10%
■ Commercial and industrial temperature
■ 48-Pin SSOP (ROHS compliant)
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 is 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.
Logic Block Diagram
A₅
A₆
A₇
A₈
A₉
A ₁₁
A ₁₂
A ₁₃
A ₁₄
DQ ₀
DQ ₁
DQ ₂
DQ ₃
DQ ₄
DQ ₅
DQ ₆
DQ ₇
QuantumTrap
512 X 512
STORE
STATIC RAM
ARRAY
512 X 512
RECALL
COLUMN IO
COLUMN DEC
A₀ A₁ A₂ A₃ A₄ A₁₀
V_CC
V_CAP
POWER
CONTROL
STORE/
RECALL
CONTROL
V_RTCbat
V_RTCcap
HSB
SOFTWARE
DETECT
- A13 A₀
RTC
MUX
x₁
x₂
INT
- A14 A₀
OE
CE
WE
Cypress Semiconductor Corporation • 198 Champion Court
Document Number: 001-06431 Rev. *H
• San Jose, CA 95134-1709 • 408-943-2600
Revised February 24, 2009
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