1225 datasheet(8/10 Pages) DALLAS

8 / 10 page

DS1225AB/AD

8 of 10

NOTES:

WE is high for a read cycle.

2. OE = VIH or VIL. If OE = VIH during write cycle, the output buffers remain in a high-impedance

state.

3. tWP is specified as the logical AND of CE and WE . tWP is measured from the latter of CE or WE

going low to the earlier of CE or WE going high.

4. tDS are measured from the earlier of CE or WE going high.

5. These parameters are sampled with a 5 pF load and are not 100% tested.

6. If the CE low transition occurs simultaneously with or later than the WE low transition, the output

buffers remain in a high-impedance state during this period.

7. If the CE high transition occurs prior to or simultaneously with the WE high transition, the output

buffers remain in a high-impedance state during this period.

8. If WE is low or the WE low transition occurs prior to or simultaneously with the CE low transition,

the output buffers remain in a high-impedance state during this period.

9. Each DS1225AB and each DS1225AD has a built-in switch that disconnects the lithium source until

VCC is first applied by the user. The expected tDR is defined as accumulative time in the absence of

VCC starting from the time power is first applied by the user.

10. All AC and DC electrical characteristics are valid over the full operating temperature range. For

commercial products, this range is 0°C to 70°C. For industrial products (IND), this range is -40°C to

+85°C.

11. In a power down condition the voltage on any pin may not exceed the voltage on VCC .

12. tWR1 , tDH1 are measured from WE going high.

13. tWR2 , tDH2 are measured from CE going high.

14. DS1225AB and DS1225AD modules are recognized by Underwriters Laboratory (U.L.

) under file

E99151.

DC TEST CONDITIONS

Outputs Open

All Voltages Are Referenced to Ground

AC TEST CONDITIONS

Output Load: 100 pF + 1TTL Gate

Input Pulse Levels: 0 - 3.0V

Timing Measurement Reference Levels

Input: 1.5V

Output: 1.5V

Input Pulse Rise and Fall Times: 5ns

1225 Datasheet(PDF) 8 Page - Dallas Semiconductor