Cypress STK14C88-5 Data Protection, Noise Considerations, Hardware Protect, Preventing Store

Page 5

STK14C88-5

Data Protection

Figure 5. Current Versus Cycle Time (READ)

The STK14C88-5 protects data from corruption during low voltage conditions by inhibiting all externally initiated STORE and WRITE operations. The low voltage condition is detected when VCC is less than VSWITCH. If the STK14C88-5 is in a WRITE mode (both CE and WE are low) at power up after a RECALL or after a STORE, the WRITE is inhibited until a negative transition on CE or WE is detected. This protects against inadvertent writes during power up or brown out condi- tions.

Noise Considerations

The STK14C88-5 is a high speed memory. It must have a high frequency bypass capacitor of approximately 0.1 µF connected between VCC and VSS, using leads and traces that are as short as possible. As with all high speed CMOS ICs, careful routing of power, ground, and signals reduce circuit noise.

Hardware Protect

The STK14C88-5 offers hardware protection against inadvertent STORE operation and SRAM WRITEs during low voltage condi- tions. When VCAP<VSWITCH, all externally initiated STORE operations and SRAM WRITEs are inhibited. AutoStore can be completely disabled by tying VCC to ground and applying + 5V to VCAP. This is the AutoStore Inhibit mode; in this mode, STOREs are only initiated by explicit request using either the software sequence or the HSB pin.

Low Average Active Power

CMOS technology provides the STK14C88-5 the benefit of drawing significantly less current when it is cycled at times longer than 50 ns. Figure 5 and Figure 6 shows the relationship between ICC and READ or WRITE cycle time. Worst case current consumption is shown for both CMOS and TTL input levels (commercial temperature range, VCC = 5.5V, 100% duty cycle on chip enable). Only standby current is drawn when the chip is disabled. The overall average current drawn by the STK14C88-5 depends on the following items:

■The duty cycle of chip enable

■The overall cycle rate for accesses

■The ratio of READs to WRITEs

■CMOS versus TTL input levels

■The operating temperature

■The VCC level

■IO loading

Figure 6. Current Versus Cycle Time (WRITE)

Preventing Store

The STORE function is disabled by holding HSB high with a driver capable of sourcing 30 mA at a VOH of at least 2.2V, because it has to overpower the internal pull down device. This device drives HSB LOW for 20 μs at the onset of a STORE. When the STK14C88-5 is connected for AutoStore operation (system VCC connected to VCC and a 68 μF capacitor on VCAP) and VCC crosses VSWITCH on the way down, the STK14C88-5 attempts to pull HSB LOW. If HSB does not actually get below VIL, the part stops trying to pull HSB LOW and abort the STORE attempt.

Document Number: 001-51038 Rev. **

Page 5 of 17

[+] Feedback

Page 4 Page 6
Image 5
Page 4 Page 6
Contents Functional Description FeaturesCypress Semiconductor Corporation 198 Champion Court San Jose, CA Document Number 001-51038 Rev Revised March 02Pin Definitions Pin ConfigurationsDevice Operation AutoStore Inhibit modeSram Read Sram WriteHardware Store HSB Operation Hardware Recall Power UpSoftware Store Software RecallData Protection Low Average Active PowerNoise Considerations Hardware ProtectBest Practices Hardware Mode SelectionA13-A0 Mode Power Maximum Ratings DC Electrical CharacteristicsOperating Range Data Retention and EnduranceAC Test Conditions CapacitanceThermal Resistance Parameter Description 35 ns 45 ns Unit Cypress Alt Min Max AC Switching CharacteristicsSwitching Waveforms Switching Parameter Alt Description STK14C88-5 Unit Min Max AutoStore or Power Up RecallParameter Alt Description 35 ns 45 ns Unit Min Max Software Controlled STORE/RECALL CycleHardware Store High to Inhibit Off 700 Hardware Store CycleHardware Store Pulse Width Hardware Store Low to Store Busy 300Ordering Information Part Numbering Nomenclature STK14C88 5 C 35 MPin 300-Mil Side Braze DIL Package DiagramPad 450-Mil LCC Document History Sales, Solutions, and Legal InformationNew data sheet

STK14C88-5 specifications

The Cypress STK14C88-5 is a high-performance, non-volatile static random-access memory (SRAM) solution that caters to a wide range of applications. This device seamlessly combines the benefits of SRAM technology with non-volatile memory, making it a compelling option for embedded systems requiring fast access speeds alongside persistent data storage.

One of the key features of the STK14C88-5 is its memory density. This chip comes with an 88 Kbit storage capacity, which is ample for various applications, including configuration storage and data logging in industrial systems, telecommunications, and consumer electronics. The memory is organized in a way that supports both byte-wise and word-wise access, ensuring flexibility to accommodate different data structures.

Speed is another attractive characteristic of the STK14C88-5. It operates at access speeds of up to 55 nanoseconds, providing quick read and write capabilities. This rapid performance is crucial for time-sensitive applications, enabling the device to handle real-time data processing effectively. The SRAM also supports a wide operating voltage range from 2.7V to 5.5V, making it versatile for different power supply configurations.

The device utilizes advanced technology to enhance reliability and endurance. The STK14C88-5 features built-in EEPROM technology, which allows it to retain data even when power is lost. This non-volatility is ideal for critical applications where data integrity is paramount.

In terms of interface, the STK14C88-5 provides a simple parallel interface, ensuring compatibility with various microcontrollers and processors. It also has control signals that support straightforward data read and write operations, allowing designers to integrate it easily into their existing architectures.

Moreover, the Cypress STK14C88-5 incorporates low-power consumption features, making it suitable for battery-operated devices. Its efficient power management ensures minimal energy usage without compromising performance, which is crucial in today’s energy-conscious environment.

Overall, the Cypress STK14C88-5 stands out with its combination of non-volatile storage, high-speed access, flexibility of operation, and power efficiency. These features make it an ideal choice for applications that demand reliable memory solutions with fast data processing capabilities, solidifying its position as a valuable component in the semiconductor industry.
Top Page Image Contents