STK14D88 STK14C88-3 MA0013 14D88 14C88-3

STK14D88 & STK14C88-3 Products in Your System Simtek has launched a new family of 0.25 micron nvSRAM products that bring new

Designing To Support Both STK14D88 STK14D88 & STK14C88-3 STK14C88-3 Products in Your System Simtek has launched a new family of 0.25 micron nvSRAM products that bring new benefits to your design: · · · · · nvSRAM densities of 256Kb and 1Mb Wider power supply range (+2.7V to +3.6V) Faster 25 ns speed grade New smaller footprint 48-pin SSOP Package Small VCAP requirement to reduces board space Some customers may wish to consider designing systems that support both our earlier 0.8 micron 256Kb products and our new 0.25 micron products in the same design and footprint: · · · You already have an existing STK14C88-3 STK14C88-3 design and may wish to provide the option to upgrade to the STK14D88 STK14D88 in the future You want to support both products to assure continuous supply as your demand ramps. You want the lowest production price now but option to move to newer technology later. The STK14C88-3 STK14C88-3 product in the 32-pin SOIC package is still our highest volume production product and carries a lower sales price. You may wish to support both products in your design so that you can move to the STK14D88 STK14D88 when its price drops in the future. Design Considerations to Support Both Products The 32-pin SOIC version of the STK14D88 STK14D88 is pin and function compatible with the STK14C88-3 STK14C88-3 with some exceptions noted in the product comparison chart below. To support both products in your design, you must limit your design options: · · · · · · Specify a 32-pin SOIC package (NF-package) and either 35 or 45 ns speed grade Limit Power Supply Range to +3V to +3.6V Specify a VCAP value of 68-120 uF with 6.3 V min specification Specify RECALL time on power-up of 20 ms Specify a STORE time on power-down of 12.5 ms (commercial) or 15 ms (industrial) Specify Software Recall Time at 40 uS October 2006 1 of 3 MA0013 MA0013 1.0 Designing To Support Both STK14D88 STK14D88 & STK14C88-3 STK14C88-3 Products in Your System · · · Do not use software or hardware AutoStore disable features Use 0.1 uF decoupling capacitor on both VCC & VCAP Make sure power supply ramp on power up is longer than 150 uS If these rules are followed, your design can support both STK14D88 STK14D88 and STK14C88-3 STK14C88-3. Product Comparison Table Specification 14D88 14D88 14C88-3 14C88-3 Comment Access Times 25, 35 and 45ns 35, 45 ns 25 ns Speed Grade Storage Capacitor Size 17-120uf,6.3v min 68-220uf, 4v min Storage Capacitor Voltage Internal Pump creates 5V on Storage Capacitor 20 ms Max 12.5ms max (comm.) 15 ms max (industrial) No pump, voltage limited to VCC. Smaller Capacitor Size Reduces Cost & Area Higher Capacitor Voltage Reduces Capacitor Size Longer Recall Time Recall Time 50us max 10us max AutoStore disable/enable New soft sequence control Only support via HSB AutoStore Disable via HSB AutoStore Disable via supply wiring Feature removed. Electrical/Timing No Changes Hold HSB high with high current driver Power the device via the VCAP -pin and ground the VCCX pin. No Changes 0.1 uF Decoupling Capacitor Location Technology Connect to VCC Connect to VCAP 0.25um 0.8um Smaller Die Power up ramp rate 150 us min Unspecified Packaging/Pin out Same Same Most power supplies are slower than this. Compatible with 32pin SOIC pkg. Power up Time Store Time October 2006 Not Supported, Use Soft Sequence 0.55 ms Max 10ms max 2 of 3 This feature makes the 14D88 14D88 easier to use. Easier support via soft sequence. Rarely used by customers. Except as noted in this document. MA0013 MA0013 1.0 Designing To Support Both STK14D88 STK14D88 & STK14C88-3 STK14C88-3 Products in Your System Document Revision History Revision Date Comments 0.0 April 2005 Initial Release 1.0 October 2006 Add Details on Designing For Both 14D88 14D88 and 14C88-3 14C88-3 In Common Design October 2006 3 of 3 MA0013 MA0013 1.0