Cypress CY14B256L, AN20639 User Manual

Comparison between CY14B256L

Note

1. STK14C88-3 applications usually specify the use of 68 µF or 100 µF capacitors, which fall within the range of the CY14B256L device.

and STK14C88-3 nvSRAM

AN20639

Author: Shivendra Singh

Associated Project: No

Associated Part Family: CY14B256L and STK14C88-3

Associated Application Notes: None

Application Note Abstract

This application note compares the CY14B256L (0.25 μm) and the STK14C88-3 (0.8 μm) devices and presents the results.

Introduction

CY14B256L and STK14C88-3 are both 256K (32K x 8), 3V
nvSRAMs in two different technologies, 0.25 μm and 0.8 μm
respectively. These parts are functionally similar and can be
used in the same applications. However there are differences
in parameters, which should be considered when replacing
one part with the other.

The specifications in the data sheets of CY14B256L (0.25
μm) and STK14C88-3 (0.8 μm) are compared. Table 1 lists
the differences between these two devices. This comparison

Most applications use autostore and autorecall features of
nvSRAM. To simplify the comparison, all electrical parame­ters which may affect the application performance directly or
indirectly are considered. Designers must consider these dif­ferences, and if necessary do appropriate changes in their
design.

Only those specifications that differ between CY14B256L
(0.25 μm) and STK14C88-3 (0.8 μm) nvSRAM are listed in

Table 1. These specifications may cause functional issues

when replacing one part with the other.

is not intended to be comprehensive, because there are sub­tle differences that are not relevant in most applications.

Table 1. Comparison Table

Specification CY14B256L (35 nsec) STK14C88-3 (35 nsec)

Endurance 200,000 cycles 1,000,000 cycles
Retention 20 year 100 year

DC Electrical Characteristics

Vcc 2.7V min 3.6V max 3.0V min 3.6V max
Icc1 55 mA max 52 mA max
Icc3 10 mA max 9 mA max
Icc4 3 mA max 2 mA max
V

IH

[1]

Vcap
C

in

AC Switching Characteristics

t

OHA

t

LZCE

t

LZWE

2.0V min Vcc + 0.3V max 2.2V min Vcc + 0.5V max
17 µF min 120 µF max 68 µF min 220 µF max

7 pF max 5 pF max

3 ns min 5 ns min
3 ns min 5 ns min
3 ns min 5 ns min

November 11, 2008 Document No. 001-20639 Rev. *C 1

[+] Feedback

Table 1. Comparison Table (continued)

Notes

2. The power up recall specification is the most dra matic differ ence between the two devices. To accommodat e the much slower specification of the CY14B256L
device, system timing modifications may be required.

3. Store timing differences are not an issue because it occurs as a background operation when the system is powering down.

4. Even though there are small differences here they are unlikely to cause system level problems.

Specification CY14B256L (35 nsec) STK14C88-3 (35 nsec)

Auto Store/Power Up Recall

[3]

[4]

[2]

20 ms max 550 µs max

12.5 ms max 10 ms max

No minimum 2.65V max 2.7V min 2.95V max

t

HRECALL

t

STORE

V

SWITCH

Summary

In most applications you can directly substitute the CY14B256L for the STK14C88-3 nvSRAM.

AN20639

November 11, 2008 Document No. 001-20639 Rev. *C 2

[+] Feedback