bq4017/bq4017Y 2048Kx8 Nonvolatile SRAM Features General Description ➤ Data retention in the absence of power The CMOS bq4017 is a nonvolatile 16,777,216-bit static RAM organized as 2,097,152 words by 8 bits. The integral control circuitry and lithium energy source provide reliable nonvolatility coupled with the unlimited write cycles of standard SRAM. ➤ Automatic write-protection during power-up/power-down cycles ➤ Conventional SRAM operation; unlimited write cycles ➤ 5-year minimum data retention in absence of power ➤ Battery internally isolated until power is applied Pin Connections NC A20 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 17 18 The control circuitry constantly monitors the single 5V supply for an out-of-tolerance condition. When VCC falls out of tolerance, the SRAM is unconditionally write-protected to prevent an inadvertent write operation. Pin Names 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 VCC A19 NC A15 A17 WE A13 A8 A9 A11 OE A10 CE DQ7 DQ6 DQ5 DQ4 DQ3 At this time the integral energy source is switched on to sustain the memory until after VCC returns valid. The bq4017 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 bq4017 has the same interface as industry-standard SRAMs and requires no external circuitry. Block Diagram A0–A20 Address inputs DQ0–DQ7 Data input/output CE Chip enable input OE Output enable input WE Write enable input VCC Supply voltage input VSS Ground NC No connect 36-Pin DIP Module PN401701.eps Selection Guide Part Number bq4017MC -70 Maximum Access Time (ns) Negative Supply Tolerance 70 -5% Part Number bq4017YMC -70 5/95 1 Maximum Access Time (ns) Negative Supply Tolerance 70 -10% bq4017/bq4017Y 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 bq4017 operates as a standard CMOS SRAM. During power-down and power-up cycles, the bq4017 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 bq4017 monitors for VPFD = 4.62V typical for use in systems with 5% supply tolerance. The bq4017Y monitors for VPFD = 4.37V typical for use in systems with 10% supply tolerance. The internal coin cells used by the bq4017 have an extremely long shelf life. The bq4017 provides data retention for more than 5 years in the absence of system power. 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. As shipped from Unitrode, the integral lithium cells 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. 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 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 TOPR Operating temperature 0 to +70 °C TSTG Storage temperature -40 to +70 °C TBIAS Temperature under bias -10 to +70 °C TSOLDER Soldering temperature +260 °C Note: Conditions VT ≤ VCC + 0.3 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. 2 bq4017/bq4017Y Recommended DC Operating Conditions (TA = 0 to 70°C) Symbol VCC Parameter Minimum Typical Maximum Unit 4.5 5.0 5.5 V bq4017Y 4.75 5.0 5.5 V bq4017 0 0 0 V Supply voltage VSS Supply voltage 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 = 0 to 70°C, VCCmin Symbol Notes Parameter ≤ VCC ≤ VCCmax) Minimum Typical Maximum Unit Conditions/Notes ILI Input leakage current - - ±4 µA VIN = VSS to VCC ILO Output leakage current - - ±4 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 IOL = 2.1 mA ISB1 Standby supply current - 7 17 mA CE = VIH ISB2 Standby supply current - 2.5 5 mA 0V ≤ VIN ≤ 0.2V, CE ≥ VCC - 0.2V, or VIN ≥ VCC - 0.2 Min. cycle, duty = 100%, CE = VIL ,II/O = 0mA, A19 < VIL or A19 > VIH, A20 < VIL or A20 > VIH ICC Operating supply current VPFD Power-fail-detect voltage VSO Note: Supply switch-over voltage - 75 115 mA 4.55 4.62 4.75 V bq4017 4.30 4.37 4.50 V bq4017Y - 3 - V Typical values indicate operation at TA = 25°C, VCC = 5V. 3 bq4017/bq4017Y Capacitance (TA = 25°C, F = 1MHz, VCC = 5.0V) Symbol Parameter Minimum Typical Maximum Unit Conditions CI/O Input/output capacitance - - 40 pF Output voltage = 0V CIN Input capacitance - - 40 pF Input voltage = 0V Note: These parameters are sampled and not 100% tested. 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 = 0 to 70°C, VCCmin ≤ VCC ≤ VCCmax) -70 Symbol Parameter Min. Max. Unit Conditions tRC Read cycle time 70 - ns tAA Address access time - 70 ns Output load A tACE Chip enable access time - 70 ns Output load A tOE Output enable to output valid - 35 ns Output load A tCLZ Chip enable to output in low Z 5 - ns Output load B tOLZ Output enable to output in low Z 5 - ns Output load B tCHZ Chip disable to output in high Z 0 25 ns Output load B tOHZ Output disable to output in high Z 0 25 ns Output load B tOH Output hold from address change 10 - ns Output load A 4 bq4017/bq4017Y 1,2 Read Cycle No. 1 (Address Access) Read Cycle No. 2 (CE Access) 1,3,4 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. 5 bq4017/bq4017Y Write Cycle (TA = 0 to 70°C, VCCmin ≤ VCC ≤ VCCmax) -70 Symbol Parameter Min. Max. Units Conditions/Notes tWC Write cycle time 70 - ns tCW Chip enable to end of write 65 - ns (1) tAW Address valid to end of write 65 - ns (1) tAS Address setup time 0 - ns Measured from address valid to beginning of write. (2) tWP Write pulse width 55 - ns Measured from beginning of write to end of write. (1) tWR1 Write recovery time (write cycle 1) 5 - ns Measured from WE going high to end of write cycle. (3) tWR2 Write recovery time (write cycle 2) 15 - ns Measured from CE going high to end of write cycle. (3) tDW Data valid to end of write 30 - ns Measured to first low-to-high transition of either CE or WE. tDH1 Data hold time (write cycle 1) 0 - ns Measured from WE going high to end of write cycle. (4) tDH2 Data hold time (write cycle 2) 10 - ns Measured from CE going high to end of write cycle. (4) tWZ Write enabled to output in high Z 0 25 ns I/O pins are in output state. (5) tOW Output active from end of write 5 - 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. 6 bq4017/bq4017Y 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. 7 bq4017/bq4017Y Power-Down/Power-Up Cycle (TA = 0 to 70°C) 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 t Chip enable recovery time 40 80 120 ms tDR Data-retention time in absence of VCC 5 - - years tWPT Write-protect time 40 100 150 µs CER Notes: Conditions Time during which SRAM is write-protected after VCC passes VFPD on power-up. TA = 25°C. (2) Delay after VCC slews down past VPFD before SRAM is write-protected. 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 8 bq4017/bq4017Y MC: 36-Pin C-Type Module 36-Pin MC (C-Type Module) Dimension Minimum A 0.365 A1 0.015 B 0.017 C 0.008 D 2.070 E 0.710 e 0.590 G 0.090 L 0.120 S 0.175 All dimensions are in inches. 9 Maximum 0.375 0.023 0.013 2.100 0.740 0.630 0.110 0.150 0.210 bq4017/bq4017Y Ordering Information bq4017 MC Temperature: blank = Commercial (0 to +70°C) Speed Options: 70 = 70 ns Package Option: MC = C-type module Supply Tolerance: no mark = 5% negative supply tolerance Y = 10% negative supply tolerance Device: bq4017 2048K x 8 NVSRAM 10 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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