DS1254 Maxim, DS1254 Datasheet
DS1254
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DS1254 Summary of contents
Page 1
... It has a self-contained lithium energy source and control circuitry that constantly monitors V tolerance condition. When such a condition occurs, the DS1254 makes use of an attached DS3800 battery cap to maintain clock information and preserve stored data while protecting that data by disallowing all memory accesses. ...
Page 2
... The phantom clock operates in either 24-hour or 12-hour format with an AM/PM indicator. Because the DS1254 has a total of 168 balls and only 35 active signals, balls are wired together into groups, thus providing redundant connections for every signal. ...
Page 3
... OE RAM WRITE MODE The DS1254 is in the write mode whenever WE and CE are in their active (low) state after address inputs are stable. The later occurring falling edge will determine the start of the write cycle. The write cycle is terminated by the earlier rising edge WE. All address inputs must be kept valid throughout the write cycle. ...
Page 4
... Figure 2. Phantom Clock Protocol Definition NOTE: THE PATTERN RECOGNITION IN HEX IS C5, 3A, A3, 5C, C5, 3A, A3, 5C. THE ODDS OF THIS PATTERN BEING ACCIDENTALLY DUPLICATED AND CAUSING INADVERTENT ENTRY TO THE PHANTOM CLOCK IS LESS THAN THIS PATTERN IS SENT TO THE PHANTOM CLOCK LSB TO MSB DS1254 ...
Page 5
... Figure 3. Phantom Clock Register Definition DS1254 ...
Page 6
... Registers and 6 contain one or more bits that will always read logic 0. When writing these locations, either a logic 1 or logic 0 is acceptable. BATTERY MONITORING The DS1254 automatically monitors the battery in an attached DS3800 battery cap on a 24-hour time interval. Such monitoring begins within t after V REC After each 24-hour period has elapsed, the battery is connected to an internal 1M ...
Page 7
... See IPC/JEDEC J-STD-020 MIN TYP MAX UNITS 3.0 3.3 3 2.0 V 0.3 -0.3 0.6 V TYP MAX UNITS A +4.0 2.0 3 2.97 V TYP MAX UNITS DS1254 NOTES NOTES NOTES ...
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... MAX UNITS ns 150 150 MIN TYP MAX UNITS s 0 s 300 s 10 s 150 125 MIN TYP MAX UNITS 10 years DS1254 NOTES NOTES 3 NOTES 4 ...
Page 9
... Input Pulse Rise and Fall Times: 5ns Figure 4. Memory Read Cycle Timing (Note 9) ADDRESS CE OE DQ0–DQ7 C) SYMBOL MIN t BTC t BTPW BPU ACC COE t COE DATA VALID TYP MAX UNITS 24 hour 1 seconds 1 seconds 1 seconds OUTPUT DS1254 NOTES 3 ...
Page 10
... DQ0–DQ7 Figure 6. Memory Write Cycle Timing, Chip-Enable Controlled (Notes 10, 11, 12, and 13) ADDRESS CE WE DQ0–DQ7 ODW OEW DH1 DATA IN STABLE ODW COE t t DH2 DS DATA IN STABLE DS1254 t AH1 t AH2 ...
Page 11
... Figure 7. Read Cycle to Phantom Clock DQ0 Figure 8. Write Cycle to Phantom Clock DQ0 COE OD t COE OUTPUT DATA VALID DATA IN STABLE DS1254 AH2 t DH2 t DH1 ...
Page 12
... Figure 9. Power-Up/Power-Down Waveform Timing (Note 14 PF(max) V PF(min) V BAT Figure 10. Battery Warning Detection (Note BAT BATTERY TEST ACTIVE SLEWS WITH V CC SLEWS WITH BPU 2.6V t BTC t BTPW REC BPU DS1254 ...
Page 13
... 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. 14 power-down condition, the voltage on any pin cannot exceed the voltage measured from the latter going low to the DS1254 . ...
Page 14
... For the latest package outline information www.maxim-ic.com/packages.) PKG MIN MAX IN 1.570 1.580 A MM 39.88 40.13 IN 1.570 1.580 B MM 39.88 40.13 IN 0.033 0.043 C MM 0.84 1.09 IN 1.497 1.503 D MM 38.02 38.18 IN 0.047 0.053 E MM 1.19 1.35 IN 0.033 0.043 F MM 0.84 1.09 IN 0.047 0.053 G MM 1.19 1.35 IN 0.234 0.240 H MM 5.94 6.10 IN 0.160 0.200 I MM 4.00 5.10 IN 0.025 0.032 K MM 0.64 0. DS1254 ...
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... PACKAGE INFORMATION (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/packages.) DS1254 with Attached DS3800 Battery Cap PKG MIN A IN 1.656 MM 42. 1.656 MM 42. — MM — ...
Page 16
... Recommended Land Pattern (with Overlaid Package Outline) The DS1254 BGA is a subset of the industry-standard 40mm BGA format, with all balls on a 50-mil grid. Corner balls have been removed to provide space for the electrical and mechanical interface features that facilitate attachment of the DS3800 battery cap ...
Page 17
... AWMIN 12/09 Removed the DS1254YB ordering information and 5V operational characteristics. Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. ...