DS1265Y/AB 8M Nonvolatile SRAM www.maxim-ic.com FEATURES PIN ASSIGNMENT 10 years minimum data retention in the absence of external power Data is automatically protected during power loss Unlimited write cycles Low-power CMOS operation Read and write access times as fast as 70 ns Lithium energy source is electrically disconnected to retain freshness until power is applied for the first time Full 10% VCC operating range (DS1265Y) Optional 5% VCC operating range (DS1265AB) Optional industrial temperature range of -40C to +85C, designated IND NC NC A18 A16 A14 A12 A7 A6 A5 A4 A3 36 35 34 33 32 31 30 29 28 27 26 25 VCC A19 NC A15 A17 WE A13 A8 A9 A11 OE A2 1 2 3 4 5 6 7 8 9 10 11 12 A1 13 24 CE A0 DQ0 14 23 15 DQ7 DQ6 DQ1 16 22 21 DQ2 17 20 DQ4 GND 18 19 DQ3 A10 DQ5 36-Pin ENCAPSULATED PACKAGE 740-mil EXTENDED PIN DESCRIPTION A0 - A19 DQ0 - DQ7 CE WE OE VCC GND NC - Address Inputs - Data In/Data Out - Chip Enable - Write Enable - Output Enable - Power (+5V) - Ground - No Connect DESCRIPTION The DS1265 8M Nonvolatile SRAMs are 8,388,608-bit, fully static nonvolatile SRAMs organized as 1,048,576 words by 8 bits. Each NV SRAM has a self-contained lithium energy source and control circuitry which constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent data corruption. There is no limit on the number of write cycles which can be executed and no additional support circuitry is required for microprocessor interfacing. 1 of 8 110602 DS1265Y/AB READ MODE The DS1265 devices execute a read cycle whenever WE (Write Enable) is inactive (high) and CE (Chip Enable) and OE (Output Enable) are active (low). The unique address specified by the 20 address inputs (A0 - A19) defines which of the 1,048,576 bytes of data is accessed. Valid data will be available to the eight data output drivers within tACC (Access Time) after the last address input signal is stable, providing that CE and OE (Output Enable) access times are also satisfied. If OE and CE access times are not satisfied, then data access must be measured from the later-occurring signal ( CE or OE ) and the limiting parameter is either tCO for CE or tOE for OE rather than tACC. WRITE MODE The DS1265 devices execute a write cycle whenever WE and CE signals are active (low) after address inputs are stable. The later-occurring falling edge of CE or WE will determine the start of the write cycle. The write cycle is terminated by the earlier rising edge of CE or WE . All address inputs must be kept valid throughout the write cycle. WE must return to the high state for a minimum recovery time (tWR) before another cycle can be initiated. The OE control signal should be kept inactive (high) during write cycles to avoid bus contention. However, if the output drivers are enabled ( CE and OE active) then WE will disable the outputs in tODW from its falling edge. DATA RETENTION MODE The DS1265AB provides full functional capability for VCC greater than 4.75 volts and write protects by 4.5 volts. The DS1265Y provides full functional capability for VCC greater than 4.5 volts and write protects by 4.25 volts. Data is maintained in the absence of VCC without any additional support circuitry. The nonvolatile static RAMs constantly monitor VCC. Should the supply voltage decay, the NV SRAMs automatically write protect themselves, all inputs become don't care, and all outputs become highimpedance. As VCC falls below approximately 3.0 volts, a power switching circuit connects the lithium energy source to RAM to retain data. During power-up, when VCC rises above approximately 3.0 volts, the power switching circuit connects external VCC to RAM and disconnects the lithium energy source. Normal RAM operation can resume after VCC exceeds 4.75 volts for the DS1265AB and 4.5 volts for the DS1265Y. FRESHNESS SEAL Each DS1265 device is shipped from Dallas Semiconductor with its lithium energy source disconnected, guaranteeing full energy capacity. When VCC is first applied at a level greater than VTP, the lithium energy source is enabled for battery backup operation. 2 of 8 DS1265Y/AB ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature * -0.3V to +7.0V 0C to 70C; -40C to +85C for IND parts -40C to +70C; -40C to +85C for IND parts 260C for 10 seconds This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. RECOMMENDED DC OPERATING CONDITIONS PARAMETER (tA: See Note 10) SYMBOL MIN TYP MAX UNITS DS1265AB Power Supply Voltage VCC 4.75 5.0 5.25 V DS1265Y Power Supply Voltage VCC 4.5 5.0 5.5 V Logic 1 Input Voltage VIH 2.2 VCC V Logic 0 Input Voltage VIL 0 +0.8 V DC ELECTRICAL CHARACTERISTICS PARAMETER (VCC=5V 5% for DS1265AB) (tA: See Note 10) (VCC=5V 10% for DS1265Y) SYMBOL MIN MAX UNITS Input Leakage Current IIL -2.0 +2.0 mA I/O Leakage Current IIO -2.0 +2.0 mA Output Current @ 2.4V IOH -1.0 mA Output Current @ 0.4V IOL 2.0 mA TYP Standby Current CE =2.2V ICCS1 1.0 1.5 mA Standby Current CE =VCC-0.5V ICCS2 100 200 mA Operating Current ICCO1 85 mA Write Protection Voltage (DS1265AB) VTP 4.50 4.62 4.75 V Write Protection Voltage (DS1265Y) VTP 4.25 4.37 4.5 V CAPACITANCE PARAMETER Input Capacitance Output Capacitance NOTES NOTES (tA=25C) SYMBOL CIN CI/O 3 of 8 MIN TYP 10 MAX 20 UNITS pF 10 20 pF NOTES DS1265Y/AB AC ELECTRICAL CHARACTERISTICS PARAMETER Read Cycle Time Access Time (VCC=5V 5% for DS1265AB) (tA: See Note 10) (VCC=5V 10% for DS1265Y) SYMBOL tRC DS1265AB-70 DS1265Y-70 DS1265AB-100 DS1265Y-100 MIN 70 MIN 100 MAX MAX UNITS ns tACC 70 100 ns NOTES OE to Output Valid tOE 35 50 ns CE to Output Valid tCO 70 100 ns OE or CE to Output Active tCOE Output High Z from Deselection tOD Output Hold from Address Change tOH 5 5 ns Write Cycle Time tWC 70 100 ns Write Pulse Width tWP 55 75 ns Address Setup Time tAW 0 0 ns Write Recovery Time tWR1 tWR2 5 15 5 15 ns ns 12 13 Output High Z from WE tODW ns 5 Output Active from WE tOEW 5 5 ns 5 Data Setup Time tDS 30 40 ns 4 Data Hold Time tDH1 tDH2 0 10 0 10 ns ns 12 13 5 5 25 35 25 TIMING DIAGRAM: READ CYCLE SEE NOTE 1 4 of 8 35 ns 5 ns 5 3 DS1265Y/AB TIMING DIAGRAM: WRITE CYCLE 1 TIMING DIAGRAM: WRITE CYCLE 2 SEE NOTES 2, 3, 4, 6, 7, 8 AND 13 5 of 8 DS1265Y/AB POWER-DOWN/POWER-UP CONDITION SEE NOTE 11 POWER-DOWN/POWER-UP TIMING PARAMETER SYMBOL (tA: See Note 10) MIN TYP MAX 1.5 UNITS VCC Fail Detect to CE and WE Inactive tPD VCC slew from VTP to 0V tF 150 ms VCC slew from 0V to VTP tR 150 ms VCC Valid to CE and WE Inactive tPU 2 ms VCC Valid to End of Write Protection tREC 125 ms ms NOTES 11 (tA=25C) PARAMETER Expected Data Retention Time SYMBOL tDR MIN 10 TYP MAX UNITS years NOTES 9 WARNING: Under no circumstance are negative undershoots, of any amplitude, allowed when device is in battery backup mode. NOTES: 1. 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 or WE . tWP is measured from the latter of CE or WE going low to the earlier of CE or WE going high. 4. tDS is 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 latter 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 high-impedance state during this period. 6 of 8 DS1265Y/AB 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 DS1265 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 0C to 70C. For industrial products (IND), this range is -40C to +85C. 11. In a power-down condition the voltage on any pin may not exceed the voltage on VCC. 12. tWR1 and tDH1 are measured from WE going high. 13. tWR2 and tDH2 are measured from CE going high. 14. DS1265 modules are recognized by Underwriters Laboratory (U.L.O) under file E99151. DC TEST CONDITIONS AC TEST CONDITIONS Outputs Open Cycle = 200ns for operating current All voltages are referenced to ground Output Load: 100 pF + 1TTL Gate Input Pulse Levels: 0V to 3.0V Timing Measurement Reference Levels Input: 1.5V Output: 1.5V Input pulse Rise and Fall Times: 5 ns ORDERING INFORMATION DS1265 TTP - SSS - III Operating Temperature Range blank: 0 to 70 IND: -40 to +85C Access Speed 70: 70 ns 100: 100 ns Package Type blank: 36-pin 600-mil DIP VCC Tolerance AB: 5% Y: 10% 7 of 8 DS1265Y/AB DS1265Y/AB NONVOLATILE SRAM 36-PIN 740-MIL EXTENDED MODULE, LONG PKG 8 of 8 36-PIN DIM MIN MAX A IN. MM 2.080 52.83 2.100 53.34 B IN. MM 0.720 18.29 0.740 18.80 C IN. MM 0.355 9.02 0.405 10.29 D IN. MM 0.180 4.57 0.210 5.33 E IN. MM 0.015 0.38 0.025 0.63 F IN. MM 0.120 3.05 0.150 4.06 G IN. MM 0.090 2.29 0.110 2.79 H IN. MM 0.590 14.99 0.630 16.00 J IN. MM 0.008 0.20 0.012 0.30 K IN. MM 0.015 0.38 0.025 0.58