DS1250W 3.3V 4096k Nonvolatile SRAM www.dalsemi.com FEATURES PIN ASSIGNMENT 10 years minimum data retention in the absence of external power Data is automatically protected during power loss Replaces 512k x 8 volatile static RAM, EEPROM or Flash memory Unlimited write cycles Low-power CMOS Read and write access times as fast as 150 ns Lithium energy source is electrically disconnected to retain freshness until power is applied for the first time Optional industrial temperature range of -40°C to +85°C, designated IND JEDEC standard 32-pin DIP package New PowerCap Module (PCM) package - Directly surface-mountable module - Replaceable snap-on PowerCap provides lithium backup battery - Standardized pinout for all nonvolatile SRAM products - Detachment feature on PCM allows easy removal using a regular screwdriver A18 A16 A14 A12 A7 A6 A5 A4 A3 A2 A1 32 31 30 29 28 27 26 25 24 23 22 21 VCC A15 A17 WE A13 A8 A9 A11 OE A10 CE A0 1 2 3 4 5 6 7 8 9 10 11 12 DQ0 13 20 DQ6 DQ1 DQ2 14 19 15 DQ5 DQ4 GND 16 18 17 DQ7 DQ3 32-Pin ENCAPSULATED PACKAGE 740-mil EXTENDED NC A15 A16 NC VCC WE OE CE DQ7 DQ6 DQ5 DQ4 DQ3 DQ2 DQ1 DQ0 GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 GND VBAT 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 A18 A17 A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 34-PIN POWERCAP MODULE (PCM) (USES DS9034PC POWERCAP) PIN DESCRIPTION A0 - A18 DQ0 - DQ7 CE WE OE VCC GND NC 1 of 11 - Address Inputs - Data In/Data Out - Chip Enable - Write Enable - Output Enable - Power (+3.3V) - Ground - No Connect 111999 DS1250W DESCRIPTION The DS1250W 3.3V 4096k Nonvolatile SRAM is a 4,194,304-bit, fully static, nonvolatile SRAM organized as 524,288 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. DIP-package DS1250W devices can be used in place of existing 512k x 8 static RAMs directly conforming to the popular bytewide 32-pin DIP standard. DS1250W devices in the PowerCap Module package are directly surface mountable and are normally paired with a DS9034PC PowerCap to form a complete Nonvolatile SRAM module. There is no limit on the number of write cycles that can be executed and no additional support circuitry is required for microprocessor interfacing. READ MODE The DS1250W executes 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 19 address inputs (A0 - A18) defines which of the 524,288 bytes of data is to be 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 address access. WRITE MODE The DS1250W executes a write cycle whenever the 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 DS1250W provides full functional capability for VCC greater than 3.0 volts and write protects by 2.8 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 high-impedance. As VCC falls below approximately 2.5 volts, a power switching circuit connects the lithium energy source to RAM to retain data. During power-up, when VCC rises above approximately 2.5 volts, the power switching circuit connects external VCC to RAM and disconnects the lithium energy source. Normal RAM operation can resume after VCC exceeds 3.0 volts. FRESHNESS SEAL Each DS1250W 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 3.0 volts, the lithium energy source is enabled for battery back-up operation. PACKAGES The DS1250W is available in two packages: 32-pin DIP and 34-pin PowerCap Module (PCM). The 32pin DIP integrates a lithium battery, an SRAM memory and a nonvolatile control function into a single package with a JEDEC-standard 600-mil DIP pinout. The 34-pin PowerCap Module integrates SRAM 2 of 11 DS1250W memory and nonvolatile control into a module base along with contacts for connection to the lithium battery in the DS9034PC PowerCap. The PowerCap Module package design allows a DS1250W PCM device to be surface mounted without subjecting its lithium backup battery to destructive hightemperature reflow soldering. After a DS1250W module base is reflow soldered, a DS9034PC PowerCap is snapped on top of the base to form a complete Nonvolatile SRAM module. The DS9034PC is keyed to prevent improper attachment. DS1250W module bases and DS9034PC PowerCaps are ordered separately and shipped in separate containers. See the DS9034PC data sheet for further information. ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature * -0.3V to +4.6V 0°C to 70°C, -40°C to +85°C for IND parts -40°C to +70°C, -40°C to +85°C for IND parts 260°C 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 Power Supply Voltage SYMBOL VCC MIN 3.0 Logic 1 VIH Logic 0 VIL DC ELECTRICAL CHARACTERISTICS PARAMETER (tA: See Note 10) TYP 3.3 MAX 3.6 UNITS V 2.2 VCC V 0.0 +0.4 V (tA: See Note 10) (VCC=3.3V ±=0.3V) SYMBOL MIN MAX UNITS Input Leakage Current IIL -1.0 +1.0 V I/O Leakage Current CE ≥ VIH ≤ VCC IIO -1.0 +1.0 µA Output Current @ 2.2V IOH -1.0 mA Output Current @ 0.4V IOL 2.0 mA TYP Standby Current CE =2.2V ICCS1 50 250 µA Standby Current CE =VCC-0.2V ICCS2 30 150 µA Operating Current ICCO1 85 mA Write Protection Voltage VTP 3.0 V 2.8 2.9 CAPACITANCE PARAMETER NOTES NOTES (tA=25°C) SYMBOL MIN TYP MAX UNITS Input Capacitance CIN 5 10 pF Input/Output Capacitance CI/O 5 10 pF 3 of 11 NOTES DS1250W AC ELECTRICAL CHARACTERISTICS (tA: See Note 10) (VCC=3.3V ±=0.3V) DS1250W-150 PARAMETER Read Cycle Time Access Time SYMBOL tRC MIN MAX 150 TYPE UNITS ns tACC 150 ns NOTES OE to Output Valid tOE 70 ns CE to Output Valid tCO 150 ns OE or CE to Output Active tCOE Output High Z from Deselection tOD Output Hold from Address Change tOH 5 ns Write Cycle Time tWC 150 ns Write Pulse Width tWP 100 ns Address Setup Time tAW 0 ns Write Recovery Time tWR1 tWR2 5 20 ns ns 12 13 Output High Z from WE tODW ns 5 Output Active from WE tOEW 5 ns 5 Data Setup Time tDS 60 ns 4 Data Hold Time tDH1 tDH2 0 20 ns ns 12 13 READ CYCLE SEE NOTE 1 4 of 11 5 35 35 ns 5 ns 5 3 DS1250W WRITE CYCLE 1 SEE NOTES 2, 3, 4, 6, 7, 8, AND 12 5 of 11 DS1250W WRITE CYCLE 2 SEE NOTES 2, 3, 4, 6, 7, 8, AND 12 POWER-DOWN/POWER-UP CONDITION 6 of 11 DS1250W POWER-DOWN/POWER-UP TIMING PARAMETER (tA: See Note 10) SYMBOL tPD MIN VCC slew from VTP to 0V tF 150 µs VCC slew from 0V to VTP tR 150 µs VCC Valid to CE and WE Inactive tPU 2 ms VCC Valid to End of Write Protection tREC 125 ms VCC Fail Detect to CE and WE Inactive TYP MAX 1.5 UNITS µs NOTES 11 (tA=25°C) PARAMETER Expected Data Retention Time SYMBOL MIN tDR 10 TYP MAX UNITS NOTES years 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 and WE . tWP is measured from the latter of CE or WE going low to the earlier of CE or WE going high. 4. tDH, 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 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. 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 DS1250W 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 and tDH1 are measured from WE going high. 13. tWR2 and tDH2 are measured from CE going high. 7 of 11 DS1250W DC TEST CONDITIONS AC TEST CONDITIONS Outputs Open Cycle = 200 ns for operating current All voltages are referenced to ground 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: 5 ns ORDERING INFORMATION DS1250 W P - SSS - III Operating Temperature Range blank: 0° to 70° IND: -40° to +85°C Access Speed 150: 150 ns Package Type blank: 28-pin 600 mil DIP P: 34-pin PowerCap Module DS1250W NONVOLATILE SRAM, 32-PIN 740 MIL EXTENDED DIP MODULE PKG 8 of 11 32-PIN DIM MIN MAX A IN. MM 1.680 42.67 1.700 43.18 B IN. MM 0.720 18.29 0.740 18.80 C IN. MM 0.355 9.02 0.375 9.52 D IN. MM 0.080 2.03 0.110 2.79 E IN. MM 0.015 0.38 0.025 0.63 F IN. MM 0.120 3.05 0.160 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 0.021 0.53 DS1250W DS1250W NONVOLATILE SRAM, 34-PIN POWERCAP MODULE 9 of 11 INCHES PKG DIM MIN NOM MAX A 0.920 0.925 0.930 B 0.980 0.985 0.990 C - - 0.080 D 0.052 0.055 0.058 E 0.048 0.050 0.052 F 0.015 0.020 0.025 G 0.020 0.025 0.030 DS1250W DS1250W NONVOLATILE SRAM, 34-PIN POWERCAP MODULE WITH POWERCAP INCHES PKG DIM MIN NOM MAX A 0.920 0.925 0.930 B 0.955 0.960 0.965 C 0.240 0.245 0.250 D 0.052 0.055 0.058 E 0.048 0.050 0.052 F 0.015 0.020 0.025 G 0.020 0.025 0.030 ASSEMBLY AND USE Reflow soldering Dallas Semiconductor recommends that PowerCap Module bases experience one pass through solder reflow oriented label-side up (live-bug). Hand soldering and touch-up Do not touch soldering iron to leads for more than 3 seconds. To solder, apply flux to the pad, heat the lead frame pad and apply solder. To remove part, apply flux, heat pad until solder reflows, and use a solder wick. LPM replacement in a socket To replace a Low Profile Module in a 68-pin PLCC socket, attach a DS9034PC PowerCap to a module base then insert the complete module into the socket one row of leads at a time, pushing only on the corners of the cap. Never apply force to the center of the device. To remove from a socket, use a PLCC extraction tool and ensure that it does not hit or damage any of the module IC components. Do not use any other tool for extraction. 10 of 11 DS1250W RECOMMENDED POWERCAP MODULE LAND PATTERN PKG DIM INCHES MIN NOM MAX A - 1.050 - B - 0.826 - C - 0.050 - D - 0.030 - E - 0.112 - RECOMMENDED POWERCAP MODULE SOLDER STENCIL 11 of 11 INCHES PKG DIM MIN NOM MAX A - 1.050 - B - 0.890 - C - 0.050 - D - 0.030 - E - 0.080 -