bq4015/Y 512Kx8 Nonvolatile SRAM Features ➤ Data retention for at least 10 years without power - Snap-on power-source for lithium battery backup is unconditionally write-protected to prevent an inadvertent write operation. - Replaceable power-source (part number: bq40MS) At this time the integral energy source is switched on to sustain the memory until after V CC returns valid. ➤ Automatic write-protection during power-up/power-down cycles ➤ Conventional SRAM operation, including unlimited write cycles ➤ Internal isolation of battery before power application ➤ Industry standard 32-pin DIP pinout ➤ 34-pin LIFETIME LITHIUM™ module - Module completely surface-mounted General Description The CMOS bq4015/Y is a nonvolatile 4,194,304-bit static RAM organized as 524,288 words by 8 bits. The integral control circuitry and lithium energy source provide reliable nonvolatility coupled with the unlimited write cycles of standard SRAM. The control circuitry constantly monitors the single 5V supply for an out-of-tolerance condition. When VCC falls out of tolerance, the SRAM Pin Connections The bq4015/Y uses extremely low standby current CMOS SRAMs, coupled with small lithium coin cells to provide nonvolatility without long write-cycle times and the write-cycle limitations associated with EEPROM. The bq4015/Y requires no external circuitry and is compatible with the industry-standard 4Mb SRAM pinout. Pin Names A0–A18 A18 A16 A14 A12 A7 A6 A5 A4 A3 A2 A1 A0 DQ0 DQ1 DQ2 VSS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 Address inputs DQ0–DQ7 Data input/output VCC A15 A17 WE A13 A8 A9 A11 OE A10 CE DQ7 DQ6 DQ5 DQ4 DQ3 NC A15 A16 NC VCC WE OE CE DQ7 DQ6 DQ5 DQ4 DQ3 DQ2 DQ1 DQ0 VSS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 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 LIFETIME LITHIUM Module PN4015Yncm.eps CE Chip enable input OE Output enable input WE Write enable input NC No connect VCC Supply voltage input VSS Ground 32-Pin DIP Module PN401501.eps Selection Guide Maximum Access Time (ns) Negative Supply Tolerance bq4015x -70 70 -5% bq4015x -85 85 -5% Part Number Maximum Access Time (ns) Negative Supply Tolerance bq4015Yx -70 70 -10% bq4015Yx -85 85 -10% Part Number Note: x = MA for PDIP or MS for LIFETIME LITHIUM module. 5/99 E 1 bq4015/Y As VCC falls past VPFD and approaches 3V, the control circuitry switches to the internal lithium backup supply, which provides data retention until valid VCC is applied. Functional Description When power is valid, the bq4015/Y operates as a standard CMOS SRAM. During power-down and power-up cycles, the bq4015/Y acts as a nonvolatile memory, automatically protecting and preserving the memory contents. When VCC returns to a level above the internal backup cell voltage, the supply is switched back to VCC. After VCC ramps above the VPFD threshold, write-protection continues for a time tCER (120ms maximum) to allow for processor stabilization. Normal memory operation may resume after this time. Power-down/power-up control circuitry constantly monitors the VCC supply for a power-fail-detect threshold VPFD. The bq4015 monitors for VPFD = 4.62V typical for use in systems with 5% supply tolerance. The bq4015Y monitors for VPFD = 4.37V typical for use in systems with 10% supply tolerance. The internal coin cells used by the bq4015/Y have an extremely long shelf life and provide data retention for more than 10 years in the absence of system power. As shipped from Unitrode, the integral lithium cells of the MT-type module are electrically isolated from the memory. (Self-discharge in this condition is approximately 0.5% per year.) Following the first application of VCC, this isolation is broken, and the lithium backup provides data retention on subsequent power-downs. The LIFETIME LITHIUM package option is shipped as two parts. When VCC falls below the VPFD threshold, the SRAM automatically write-protects the data. All outputs become high impedance, and all inputs are treated as “don’t care.” If a valid access is in process at the time of power-fail detection, the memory cycle continues to completion. If the memory cycle fails to terminate within time tWPT, write-protection takes place. Block Diagram OE WE Power CE A0–A18 1024K x 8 SRAM Block DQ0–DQ7 CECON Power-Fail Control VCC Lithium Cell BD4015.eps 2 bq4015/Y Truth Table Mode CE WE OE I/O Operation Power Not selected H X X High Z Standby Output disable L H H High Z Active Read L H L DOUT Active Write L L X DIN Active Absolute Maximum Ratings Symbol Parameter Value Unit Conditions VCC DC voltage applied on VCC relative to VSS -0.3 to 7.0 V VT DC voltage applied on any pin excluding VCC relative to VSS -0.3 to 7.0 V VT ≤ VCC + 0.3 TOPR Operating temperature TSTG Storage temperature TBIAS Temperature under bias TSOLDER Soldering temperature Note: 0 to +70 °C Commercial -40 to +85 °C Industrial “N” -40 to +70 °C Commercial -40 to +85 °C Industrial “N” -10 to +70 °C Commercial -40 to +85 °C Industrial “N” +260 °C For 10 seconds Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional operation should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Exposure to conditions beyond the operational limits for extended periods of time may affect device reliability. 3 bq4015/Y Recommended DC Operating Conditions (TA = TOPR) Symbol VCC Parameter Minimum Typical Maximum Unit 4.5 5.0 5.5 V bq4015Y 4.75 5.0 5.5 V bq4015 Supply voltage VSS Supply voltage 0 0 0 V VIL Input low voltage -0.3 - 0.8 V VIH Input high voltage 2.2 - VCC + 0.3 V Note: Typical values indicate operation at TA = 25°C. DC Electrical Characteristics (TA = TOPR, VCCmin Symbol Notes Parameter ≤ VCC ≤ VCCmax) Minimum Typical Maximum Unit Conditions/Notes ILI Input leakage current - - ±1 µA VIN = VSS to VCC ILO Output leakage current - - ±1 µA CE = VIH or OE = VIH or WE = VIL VOH Output high voltage 2.4 - - V IOH = -1.0 mA VOL Output low voltage - - 0.4 V ISB1 Standby supply current - 3 5 mA CE = VIH ISB2 Standby supply current - 0.1 1 mA CE ≥ VCC - 0.2V, 0V ≤ VIN ≤ 0.2V, or VIN ≥ VCC - 0.2 Min. cycle, duty = 100%, CE = VIL, II/O = 0mA, A17 < VIL or A17 > VIH, A18 < VIL or A18 > VIH ICC Operating supply current VPFD Power-fail-detect voltage VSO Supply switch-over voltage Note: IOL = 2.1 mA - - 90 mA 4.55 4.62 4.75 V bq4015 4.30 4.37 4.50 V bq4015Y - 3 - V Typical values indicate operation at TA = 25°C, VCC = 5V. Capacitance (TA = 25°C, F = 1MHz, VCC = 5.0V) Symbol CI/O CIN Note: Parameter Input/output capacitance Input capacitance Minimum - Typical - These parameters are sampled and not 100% tested. 4 Maximum 8 10 Unit pF pF Conditions Output voltage = 0V Input voltage = 0V bq4015/Y AC Test Conditions Parameter Test Conditions Input pulse levels 0V to 3.0V Input rise and fall times 5 ns Input and output timing reference levels 1.5 V (unless otherwise specified) Output load (including scope and jig) See Figures 1 and 2 Figure 1. Output Load A Read Cycle Figure 2. Output Load B (TA = TOPR, VCCmin ≤ VCC ≤ VCCmax) -70 Symbol Parameter -85/-85N -120/-120N Min. Max. Min. Max. Min. Max. Unit 70 - 85 - 120 - ns Conditions tRC Read cycle time tAA Address access time - 70 - 85 - 120 ns Output load A tACE Chip enable access time - 70 - 85 - 120 ns Output load A tOE Output enable to output valid - 35 - 45 - 60 ns Output load A tCLZ Chip enable to output in low Z 5 - 5 - 5 - ns Output load B tOLZ Output enable to output in low Z 5 - 0 - 0 - ns Output load B tCHZ Chip disable to output in high Z 0 25 0 35 0 45 ns Output load B tOHZ Output disable to output in high Z 0 25 0 25 0 35 ns Output load B tOH Output hold from address change 10 - 10 - 10 - ns Output load A 5 bq4015/Y Read Cycle No. 1 (Address Access) 1, 2 Read Cycle No. 2 (CE Access) 1, 2, 3 Read Cycle No. 3 (OE Access) 1,5 Notes: 1. WE is held high for a read cycle. 2. Device is continuously selected: CE = OE = VIL. 3. Address is valid prior to or coincident with CE transition low. 4. OE = VIL. 5. Device is continuously selected: CE = VIL. 6 bq4015/Y Write Cycle (TA = TOPR, VCCmin ≤ VCC ≤ VCCmax) -70 Symbol Parameter -85/-85N Min. Max. Min. -120/-120N Max. Min. Max. Units Conditions/Notes tWC Write cycle time 70 - 85 - 120 - ns tCW Chip enable to end of write 65 - 75 - 100 - ns (1) tAW Address valid to end of write 65 - 75 - 100 - ns (1) tAS Address setup time 0 - 0 - 0 - ns Measured from address valid to beginning of write. (2) tWP Write pulse width 55 - 65 - 85 - ns Measured from beginning of write to end of write. (1) tWR1 Write recovery time (write cycle 1) 5 - 5 - 5 - ns Measured from WE going high to end of write cycle. (3) tWR2 Write recovery time (write cycle 2) 15 - 15 - 15 - ns Measured from CE going high to end of write cycle. (3) tDW Data valid to end of write 30 - 35 - 45 - ns Measured to first lowto-high transition of either CE or WE. tDH1 Data hold time (write cycle 1) 0 - 0 - 0 - ns Measured from WE going high to end of write cycle. (4) tDH2 Data hold time (write cycle 2) 10 - 10 - 10 - ns Measured from CE going high to end of write cycle. (4) tWZ Write enabled to output in high Z 0 25 0 30 0 40 ns I/O pins are in output state. (5) tOW Output active from end of write 5 - 0 - 0 - ns I/O pins are in output state. (5) Notes: 1. A write ends at the earlier transition of CE going high and WE going high. 2. A write occurs during the overlap of a low CE and a low WE. A write begins at the later transition of CE going low and WE going low. 3. Either tWR1 or tWR2 must be met. 4. Either tDH1 or tDH2 must be met. 5. If CE goes low simultaneously with WE going low or after WE going low, the outputs remain in high-impedance state. 7 bq4015/Y Write Cycle No. 1 (WE-Controlled) 1,2,3 Write Cycle No. 2 (CE-Controlled) 1,2,3,4,5 Notes: 1. CE or WE must be high during address transition. 2. Because I/O may be active (OE low) during this period, data input signals of opposite polarity to the outputs must not be applied. 3. If OE is high, the I/O pins remain in a state of high impedance. 4. Either tWR1 or tWR2 must be met. 5. Either tDH1 or tDH2 must be met. 8 bq4015/Y Power-Down/Power-Up Cycle (TA = TOPR) Symbol Parameter Minimum Typical Maximum Unit tPF VCC slew, 4.75 to 4.25 V 300 - - µs tFS VCC slew, 4.25 to VSO 10 - - µs tPU VCC slew, VSO to VPFD (max.) 0 - - µs Conditions t Chip enable recovery time 40 80 120 ms Time during which SRAM is write-protected after VCC passes VPFD on power-up. tDR Data-retention time in absence of VCC 10 - - years TA = 25°C. (2) 150 µs CER tWPT Notes: Write-protect time 40 100 Delay after VCC slews down past VPFD before SRAM is writeprotected. 1. Typical values indicate operation at TA = 25°C, VCC = 5V. 2. Batteries are disconnected from circuit until after VCC is applied for the first time. tDR is the accumulated time in absence of power beginning when power is first applied to the device. Caution: Negative undershoots below the absolute maximum rating of -0.3V in battery-backup mode may affect data integrity. Power-Down/Power-Up Timing 9 bq4015/Y MA: 32-Pin A-Type Module 32-Pin MA (A-Type Module) Dimension Minimum A 0.365 A1 0.015 B 0.017 C 0.008 D 1.670 E 0.710 e 0.590 G 0.090 L 0.120 S 0.075 All dimensions are in inches. Maximum 0.375 0.023 0.013 1.700 0.740 0.630 0.110 0.150 0.110 MS: 34-Pin Leaded Chip carrier for LIFETIME LITHIUM Module 34-Pin LCR LIFETIME LITHIUM Module Dimension Minimum A 0.920 B 0.980 C D 0.052 E 0.045 F 0.015 G 0.020 H J 0.053 All dimensions are in inches. 10 Maximum 0.930 0.995 0.080 0.060 0.055 0.025 0.030 0.090 0.073 1 Centerline of lead within ±0.005 of true position. 2 Leads coplanar within ±0.004 at seating plane. 3 Components and location may vary. bq4015/Y MS: LIFETIME LITHIUM Module Housing LIFETIME LITHIUM Module Housing Dimension Minimum A 0.845 B 0.955 C 0.210 D 0.065 E 0.065 All dimensions are in inches. 1 Maximum 0.855 0.965 0.220 0.075 0.075 Edges coplanar within ±0.025. MS: LIFETIME LITHIUM Module with LCR attached LIFETIME LITHIUM Module Dimension Minimum A 0.955 B 0.980 C 0.240 D 0.052 E 0.045 F 0.015 All dimensions are in inches. 11 Maximum 0.965 0.995 0.250 0.060 0.055 0.025 1 Leads coplanar within ±0.004 at seating plane. 2 Components and location may vary. bq4015/Y Data Sheet Revision History Change No. Page No. 1 3 2 1, 2, 3, 4, 7, 8, 10 3 2, 10 4 1, 3, 10 5 1, 10 Notes: Description Nature of Change ICC test conditions Clarification bq4015MA part Addition Added industrial temperature range Addition Removed MB package selection Deletion Added MS package Addition Change 1 = Sept. 1992 B changes from Sept. 1990 A. Change 2 = Nov. 1993 C changes from Sept. 1992 B. Change 3 = June 1995 C changes from Nov. 1993 C. Change 4 = Nov. 1997 D changes from June 1995 C. Change 5 = May 1999 E changes from Nov. 1997 D. Ordering Information bq4015 xx Temperature: blank = Commercial (0 to +70°C) N = Industrial (-40 to +85°C)1 Speed Options: 70 = 70 ns 85 = 85 ns 120 = 120 ns Package Option: MA = A-type Module MS = LIFETIME LITHIUM LCR34 (preliminary package option)2 Supply Tolerance: no mark = 5% negative supply tolerance Y = 10% negative supply tolerance Device: bq4013 128K x 8 NVSRAM Notes: 1. Only 10% supply (“Y-MA”) version is available in industrial temperature range; contact factory for speed grade availability. 2. The LIFETIME LITHIUM module is ordered seperately under part number bq40MS. 12 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. 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