DATA SHEET MOS INTEGRATED CIRCUIT µPD43256B 256K-BIT CMOS STATIC RAM 32K-WORD BY 8-BIT Description The µPD43256B is a high speed, low power, and 262, 144 bits (32,768 words by 8 bits) CMOS static RAM. Battery backup is available (L, LL, A, and B versions). And A and B versions are wide voltage operations. The µPD43256B is packed in 28-pin plastic DIP, 28-pin plastic SOP and 28-pin plastic TSOP (I). Features • 32,768 words by 8 bits organization • Fast access time: 70, 85, 100, 120, 150 ns (MAX.) • Wide voltage range (A version: VCC = 3.0 to 5.5 V, B version: VCC = 2.7 to 5.5 V) • 2 V data retention • OE input for easy application Part number µPD43256B-L µPD43256B-LL µPD43256B-A µPD43256B-BNote 2 Access time ns (MAX.) Operating supply voltage V Operating temperature °C Standby supply current µA (MAX.) Data retention supply currentNote 1 µA (MAX.) 70, 85 4.5 to 5.5 0 to 70 50 3 15 2 70, 85 85, 100Note 2, 120Note 2 100, 120, 150 3.0 to 5.5 2.7 to 5.5 Notes 1. TA ≤ 40 ˚C, VCC = 3 V 2. Access time : 85 ns (MAX.) (VCC = 4.5 to 5.5 V) Version X and P This data sheet can be applied to the version X and P. Each version is identified with its lot number. Letter X in the fifth character position in a lot number signifies version X, letter P, version P. JAPAN D43256B Lot number The information in this document is subject to change without notice. Document No. M10770EJ9V0DS00 (9th edition) Date Published May 1997 N Printed in Japan The mark shows major revised points. © 1990, 1993, 1994 µPD43256B Ordering Information Part number µ PD43256BCZ-70L µ PD43256BCZ-85L Package 28-pin plastic DIP (600 mil) µ PD43256BCZ-70LL µ PD43256BGU-85L Operating temperature ˚C Remark 70 4.5 to 5.5 0 to 70 L Version 85 70 70 µ PD43256BGU-85LL 85 µ PD43256BGU-A85 85 µ PD43256BGU-A10 100 µ PD43256BGU-A12 120 µ PD43256BGU-B10 100 µ PD43256BGU-B12 120 µ PD43256BGW-85LL-9JL µ PD43256BGW-A85-9JL µ PD43256BGW-A10-9JL 70 85 100 µ PD43256BGW-B12-9JL 120 µ PD43256BGW-B15-9JL 150 µ PD43256BGW-A10-9KL A Version 2.7 to 5.5 B Version 4.5 to 5.5 LL Version 3.0 to 5.5 A Version 2.7 to 5.5 B Version 4.5 to 5.5 LL Version 3.0 to 5.5 A Version 2.7 to 5.5 B Version 100 µ PD43256BGW-B10-9JL µ PD43256BGW-A85-9KL 3.0 to 5.5 85 120 µ PD43256BGW-85LL-9KL LL Version 150 28-pin plastic TSOP (I) (8 × 13.4 mm) (Normal bent) µ PD43256BGW-A12-9JL µ PD43256BGW-70LL-9KL L Version 85 µ PD43256BGU-70LL µ PD43256BGW-70LL-9JL LL Version 85 28-pin plastic SOP (450 mil) µ PD43256BGU-B15 2 Operating supply voltage V 70 µ PD43256BCZ-85LL µ PD43256BGU-70L Access time ns (MAX.) 28-pin plastic TSOP (I) (8 × 13.4 mm) (Reverse bent) 70 85 85 100 µ PD43256BGW-A12-9KL 120 µ PD43256BGW-B10-9KL 100 µ PD43256BGW-B12-9KL 120 µ PD43256BGW-B15-9KL 150 µPD43256B Pin Configuration (Marking Side) 28-pin plastic DIP (600 mil) µ PD43256BCZ 28-pin plastic SOP (450 mil) µ PD43256BGU A14 1 28 VCC A12 2 27 WE A7 3 26 A13 A6 4 25 A8 A5 5 24 A9 A4 6 23 A11 A3 7 22 OE A2 8 21 A10 A1 9 20 CS A0 10 19 I/O8 I/O1 11 18 I/O7 I/O2 12 17 I/O6 I/O3 13 16 I/O5 GND 14 15 I/O4 A0 - A14 : Address inputs I/O1 - I/O8 : Data inputs/outputs CS : Chip Select WE : Write Enable OE : Output Enable V CC : Power supply GND : Ground 3 µPD43256B 28-pin plastic TSOP (I) (8 × 13.4 mm) (Normal bent) µ PD43256BGW-9JL OE A11 A9 A8 A13 WE VCC A14 A12 A7 A6 A5 A4 A3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 A10 CS I/O8 I/O7 I/O6 I/O5 I/O4 GND I/O3 I/O2 I/O1 A0 A1 A2 28-pin plastic TSOP (I) (8 × 13.4 mm) (Reverse bent) µ PD43256BGW-9KL A10 CS I/O8 I/O7 I/O6 I/O5 I/O4 GND I/O3 I/O2 I/O1 A0 A1 A2 4 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 OE A11 A9 A8 A13 WE VCC A14 A12 A7 A6 A5 A4 A3 µPD43256B A0 | A14 I/O1 | I/O8 Row decoder Address buffer Block Diagram Memory cell array 262,144 bits Input data controller Sense/Switch Output data controller Column decoder Address buffer CS OE WE VCC GND Truth Table CS OE WE Mode I/O Supply current H × × Not selected High impedance I SB L H H Output disable L × L Write D IN L L H Read D OUT I CCA Remark ×: Don’t care 5 µPD43256B Electrical Characteristics Absolute Maximum Ratings Parameter Symbol Rating Unit Supply voltage V CC –0.5 Note to +7.0 V Input/Output voltage VT –0.5 Note to V CC + 0.5 V Operating ambient temperature TA 0 to 70 ˚C Storage temperature T stg –55 to +125 ˚C Note –3.0 V (MIN.) (Pulse width 50 ns) Caution Exposing the device to stress above those listed in absolute maximum ratings could cause permanent damage. The device is not meant to be operated under conditions outside the limits described in the operational sections of this characteristics. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Recommended Operating Conditions Parameter µ PD43256B-A µ PD43256B-B MIN. MAX. MIN. MAX. MIN. MAX. Unit Supply voltage V CC 4.5 5.5 3.0 5.5 2.7 5.5 V High level input voltage V IH 2.2 V CC + 0.5 2.2 V CC + 0.5 2.2 V CC + 0.5 V Low level input voltage V IL –0.3 Note +0.8 –0.3 Note +0.5 –0.3 Note +0.5 V Operating ambient temperature TA 0 70 0 70 0 70 ˚C Note 6 Symbol µ PD43256B-L µ PD43256B-LL –3.0 V (MIN.) (Pulse width 50 ns) µPD43256B DC Characteristics (Recommended operating conditions unless otherwise noted) (1/2) µ PD43256B-L Parameter Symbol Test conditions µ PD43256B-LL MIN. TYP. MAX. MIN. TYP. MAX. Unit Input leakage current I LI V IN = 0 V to VCC –1.0 +1.0 –1.0 +1.0 µA I/O leakage current I LO V I/O = 0 V to V CC OE = V IH or CS = V IH or WE = V IL –1.0 +1.0 –1.0 +1.0 µA mA Operating supply current Standby supply current High level output voltage Low level output voltage I CCA1 CS = V IL, Minimum cycle time, I I/O = 0 mA 45 45 I CCA2 CS = V IL, I I/O = 0 mA 10 10 I CCA3 CS ≤ 0.2 V, Cycle = 1 MHz, I I/O = 0 mA V IL ≤ 0.2 V, V IH ≥ V CC – 0.2 V 10 10 I SB CS = V IH 3 3 mA I SB1 CS ≥ V CC – 0.2 V 15 µA V OH1 I OH = –1.0 mA 2.4 2.4 V OH2 I OH = –0.1 mA V CC–0.5 V CC–0.5 V OL I OL = 2.1 mA 1.0 50 0.5 0.4 V 0.4 V Remarks 1. V IN: Input voltage 2. These DC Characteristics are in common regardless of package types. 7 µPD43256B DC Characteristics (Recommended operating conditions unless otherwise noted) (2/2) µ PD43256B-A Parameter Symbol Test conditions µ PD43256B-B MIN. TYP. MAX. MIN. TYP. MAX. Unit Input leakage current I LI V IN = 0 V to VCC –1.0 +1.0 –1.0 +1.0 µA I/O leakage current I LO V I/O = 0 V to V CC CS = V IH or WE = V IL or OE = V IH –1.0 +1.0 –1.0 +1.0 µA mA Operating supply current I CCA1 I CCA2 CS = V IL, µ PD43256B-A85 Minimum cycle time, µ PD43256B-A10 I I/O = 0 mA µ PD43256B-A12 45 — µ PD43256B-B10 µ PD43256B-B12 µ PD43256B-B15 — 45 V CC ≤ 3.3 V — 20 10 10 — 5 10 10 — 5 3 3 — 2 CS = V IL, I I/O = 0 mA V CC ≤ 3.3 V I CCA3 CS ≤ 0.2 V, Cycle = 1 MHz, I I/O = 0 mA, V IL ≤ 0.2 V, V IH ≥ V CC – 0.2 V Standby supply current I SB V CC ≤ 3.3 V CS = V IH V CC ≤ 3.3 V I SB1 CS ≥ V CC – 0.2 V 0.5 V CC ≤ 3.3 V High level output voltage V OH1 V OH2 V OL V OL1 0.5 15 — 0.5 10 I OH = –1.0 mA, VCC ≥ 4.5 V 2.4 2.4 I OH = –0.5 mA, V CC < 4.5 V 2.4 2.4 I OH = –0.1 mA — — VCC –0.1 VCC –0.1 I OH = –0.02 mA Low level output voltage 15 mA µA V I OL = 2.1 mA, V CC ≥ 4.5 V 0.4 0.4 I OL = 1.0 mA, V CC < 4.5 V 0.4 0.4 I OL = 0.02 mA 0.1 0.1 V Remarks 1. V IN: Input voltage 2. These DC characteristics are in common regardless of package types. Capacitance (T A = 25 ˚C, f = 1 MHz) Parameter Symbol Test conditions MIN. MAX. Unit Input capacitance CIN V IN = 0 V 5 pF Input/Output capacitance CI/O V I/O = 0 V 8 pF Remarks 1. V IN: Input voltage 2. These parameters are periodically sampled and not 100 % tested. 8 TYP. µPD43256B AC Characteristics (Recommended operating conditions unless otherwise noted) AC Test Conditions Input waveform (Rise/fall time ≤ 5 ns) Input pulse levels 0.8 V to 2.2 V: µ PD43256B-L, 43256B-LL 0.5 V to 2.2 V: µ PD43256B-A, 43256B-B 1.5 V Test points 1.5 V 1.5 V Test points 1.5 V Output waveform Output load µ PD43256B-A, 43256B-B : 1TTL + 100 pF µ PD43256B-L, 43256B-LL: AC characteristics with notes should be measured with the output load shown in Figure 1 and Figure 2. Figure 1 Figure 2 (For t AA, tACS , t OE, t OH) (For t CHZ, t CLZ , t OHZ, t OLZ , t WHZ, t OW ) +5 V +5 V 1.8 kΩ I/O (Output) 1.8 kΩ I/O (Output) 990 Ω Remark 100 pF CL 990 Ω 5 pF CL C L includes capacitances of the probe and jig, and stray capacitances. 9 µPD43256B Read Cycle (1/2) V CC ≥ 4.5 V Parameter µ PD43256B-85 µ PD43256B-A85/A10/A12 µ PD43256B-B10/B12/B15 µ PD43256B-70 Symbol MIN. MAX. MIN. 70 Unit Condition MAX. Read cycle time t RC 85 ns Address access time t AA 70 85 ns CS access time t ACS 70 85 ns OE access time t OE 35 40 ns Output hold from address change t OH 10 10 ns CS to output in low impedance t CLZ 10 10 ns OE to output in low impedance t OLZ 5 5 ns CS to output in high impedance t CHZ 30 30 ns OE to output in high impedance t OHZ 30 30 ns Note 1 Note 2 Notes 1. See the output load shown in Figure 1 except for µ PD43256B-A, 43256B-B. 2. See the output load shown in Figure 2 except for µ PD43256B-A, 43256B-B. Remark These AC characteristics are in common regardless of package types and L, LL versions. Read Cycle (2/2) V CC ≥ 3.0 V Parameter V CC ≥ 2.7 V Symbol µ PD43256B-A85 µ PD43256B-A10 µ PD43256B-A12 µ PD43256B-B10 µ PD43256B-B12 µ PD43256B-B15 Unit Condition MIN. MAX. MIN. MAX. MIN. MAX. MIN. MAX. MIN. MAX. MIN. MAX. Read cycle time t RC 85 100 120 100 120 150 ns Address access time t AA 85 100 120 100 120 150 ns Note CS access time t ACS 85 100 120 100 120 150 ns OE access time t OE 50 60 60 60 60 Output hold from address change tOH 10 10 10 10 10 10 ns CS to output in low impedance tCLZ 10 10 10 10 10 10 ns OE to output in low impedance tOLZ 5 5 5 5 5 5 ns CS to output in high impedance tCHZ 35 35 40 35 40 50 ns OE to output in high impedance tOHZ 35 35 40 35 40 50 ns 70 ns Note Loading condition is 1TTL + 100 pF. Remark These AC characteristics are in common regardless of package types and L, LL versions. 10 µPD43256B Read Cycle Timing Chart tRC Address (Input) tOH tAA tACS CS (Input) tCLZ tCHZ OE (Input) tOE tOHZ tOLZ I/O (Output) Remark High impedance Data out High impedance In read cycle, WE should be fixed to high level. 11 µPD43256B Write Cycle (1/2) V CC ≥ 4.5 V Parameter µ PD43256B-85 µ PD43256B-A85/A10/A12 µ PD43256B-B10/B12/B15 µ PD43256B-70 Symbol MIN. MAX. MIN. Unit Condition MAX. Write cycle time t WC 70 85 ns CS to end of write t CW 50 70 ns Address valid to end of write t AW 50 70 ns Write pulse width t WP 55 60 ns Data valid to end of write t DW 30 35 ns Data hold time t DH 0 0 ns Address setup time t AS 0 0 ns Write recovery time t WR 0 0 ns WE to output in high impedance t WHZ Output active from end of write t OW 30 30 10 ns 10 Note ns Note See the output load shown in Figure 2 except for µ PD43256B-A, 43256B-B. Remark These AC characteristics are in common regardless of package types and L, LL versions. Write Cycle (2/2) V CC ≥ 3.0 V Parameter V CC ≥ 2.7 V Symbol µ PD43256B-A85 µ PD43256B-A10 µ PD43256B-A12 µ PD43256B-B10 µ PD43256B-B12 µ PD43256B-B15 Unit Condition MIN. MAX. MIN. MAX. MIN. MAX. MIN. MAX. MIN. MAX. MIN. MAX. Write cycle time t WC 85 100 120 100 120 150 ns CS to end of write t CW 70 70 90 70 90 100 ns Address valid to end of write t AW 70 70 90 70 90 100 ns Write pulse width t WP 60 60 80 60 80 90 ns Data valid to end of write t DW 60 60 70 60 70 80 ns Data hold time t DH 0 0 0 0 0 0 ns Address setup time t AS 0 0 0 0 0 0 ns Write recovery time t WR 0 0 0 0 0 0 ns WE to output in high impedance tWHZ Output active from end of write t OW 30 10 35 10 40 10 35 10 40 10 50 10 ns Note ns Note Loading condition is 1TTL + 100 pF. Remark These AC characteristics are in common regardless of package types and L, LL versions. 12 µPD43256B Write Cycle Timing Chart 1 (WE Controlled) tWC Address (Input) tCW CS (Input) tAW tAS tWP tWR WE (Input) tOW tWHZ I/O (Input/Output) Indefinite data out tDW High impedance Data in tDH High impedance Indefinite data out Cautions 1. CS or WE should be fixed to high level during address transition. 2. When I/O pins are in the output state, do not apply to the I/O pins signals that are opposite in phase with output signals. Remarks 1. Write operation is done during the overlap time of a low level CS and a low level WE. 2. When WE is at low level, the I/O pins are always high impedance. When WE is at high level, read operation is executed. Therefore OE should be at high level to make the I/O pins high impedance. 3. If CS changes to low level at the same time or after the change of WE to low level, the I/O pins will remain high impedance state. 13 µPD43256B Write Cycle Timing Chart 2 (CS Controlled) tWC Address (Input) tAS tCW CS (Input) tAW tWP tWR WE (Input) tDW High impedance I/O (Input) tDH Data In High impedance Cautions 1. CS or WE should be fixed to high level during address transition. 2. When I/O pins are in the output state, do not apply to the I/O pins signals that are opposite in phase with output signals. Remark Write operation is done during the overlap time of a low level CS and a low level WE. 14 µPD43256B Low V CC Data Retention Characteristics L Version ( µ PD43256B-L: T A = 0 to 70 ˚C) Parameter Symbol Test conditions MIN. TYP. MAX. Unit 5.5 V 20 Note µA Data retention supply voltage V CCDR CS ≥ V CC – 0.2 V Data retention supply current I CCDR V CC = 3.0 V, CS ≥ V CC – 0.2 V Chip deselection to data retention mode t CDR 0 ns Operation recovery time tR 5 ms 2.0 0.5 Note 3 µ A (T A ≤ 40 ˚C) LL Version ( µ PD43256B-LL: T A = 0 to 70 ˚C) A Version ( µ PD43256B-A: T A = 0 to 70 ˚C) B Version ( µ PD43256B-B: T A = 0 to 70 ˚C) Parameter Symbol Test conditions MIN. TYP. Data retention supply voltage V CCDR CS ≥ V CC – 0.2 V Data retention supply current I CCDR V CC = 3.0 V, CS ≥ V CC – 0.2 V Chip deselection to data retention mode t CDR 0 ns Operation recovery time tR 5 ms 2.0 0.5 MAX. Unit 5.5 V 7 Note µA Note 2 µ A (T A ≤ 40 ˚C), 1 µ A (T A ≤ 25 ˚C) 15 µPD43256B Data Retention Timing Chart tCDR Data retention mode tR 5.0 V Note 4.5 V VCC CS VIH (MIN.) VCCDR CS ≥ VCC – 0.2 V VIL (MAX.) GND Note A Version: 3.0 V, B Version: 2.7 V Remark The other pins (address, OE, WE, I/Os) can be in high impedance state. 16 µPD43256B Package Drawings 28 PIN PLASTIC DIP (600 mil) 15 28 14 1 A K H G J I L F D N M C M B R NOTES 1) Each lead centerline is located within 0.25 mm (0.01 inch) of its true position (T.P.) at maximum material condition. 2) Item "K" to center of leads when formed parallel. ITEM MILLIMETERS INCHES A 38.10 MAX. 1.500 MAX. B 2.54 MAX. 0.100 MAX. C 2.54 (T.P.) D 0.50±0.10 0.100 (T.P.) +0.004 0.020 –0.005 F 1.2 MIN. 0.047 MIN. G 3.6±0.3 0.142±0.012 H 0.51 MIN. 0.020 MIN. I 4.31 MAX. 0.170 MAX. J 5.72 MAX. 0.226 MAX. K L 15.24 (T.P.) 13.2 0.600 (T.P.) 0.520 M 0.25 +0.10 –0.05 N 0.25 R 0 ~ 15 ° 0.010 +0.004 –0.003 0.01 0 ~ 15° P28C-100-600A1-1 17 µPD43256B 28 PIN PLASTIC SOP (450 mil) 28 15 P detail of lead end 1 14 A G H I E K F J N C D M B L M NOTE Each lead centerline is located within 0.12 mm (0.005 inch) of its true position (T.P.) at maximum material condition. ITEM MILLIMETERS INCHES A 19.05 MAX. 0.750 MAX. B 1.27 MAX. 0.050 MAX. C 1.27 (T.P.) 0.050 (T.P.) D 0.40±0.10 0.016 +0.004 –0.005 E 0.2±0.1 0.008±0.004 F 3.0 MAX. 0.119 MAX. G 2.55±0.1 0.100 +0.005 –0.004 H 11.8±0.3 0.465 +0.012 –0.013 I 8.4±0.1 0.331 +0.004 –0.005 J 1.7±0.2 0.067±0.008 K 0.20 +0.07 –0.03 0.008 +0.003 –0.002 L 0.7±0.2 0.028 +0.008 –0.009 M 0.12 0.005 N 0.10 P 5°±5° 0.004 5°±5° P28GU-50-450A-1 18 µPD43256B 28PIN PLASTIC TSOP ( I ) (8×13.4) 1 28 detail of lead end S R 14 Q 15 P J I A G H L B C N D M M K NOTE (1) Each lead centerline is located within 0.08 mm (0.003 inch) of its true position (T.P.) at maximum material condition. (2) "A" excludes mold flash. (Includes mold flash : 8.4mm MAX. <0.331 inch MAX.>) ITEM MILLIMETERS A 8.0±0.1 INCHES 0.315±0.004 B C 0.6 MAX. 0.55 (T.P.) 0.024 MAX. 0.022 (T.P.) D 0.22 +0.08 –0.07 0.009±0.003 G H 1.0 12.4±0.2 0.039 0.488±0.008 I 11.8±0.1 0.465 +0.004 –0.005 J 0.8±0.2 0.031 +0.009 –0.008 K 0.145 +0.025 –0.015 0.006±0.001 L 0.5±0.1 0.020 +0.004 –0.005 M 0.08 0.003 N 0.10 0.004 P 13.4±0.2 0.528 +0.008 –0.009 Q 0.1±0.05 0.004±0.002 R 3 ° +7° –3° S 1.2 MAX. 3° +7° –3° 0.048 MAX. P28GW-55-9JL-1 19 µPD43256B 28PIN PLASTIC TSOP ( I ) (8×13.4) 1 28 detail of lead end Q R S 14 15 K M D N M H L C I J A B G P NOTE (1) Each lead centerline is located within 0.08 mm (0.003 inch) of its true position (T.P.) at maximum material condition. (2) "A" excludes mold flash. (Includes mold flash : 8.4mm MAX. <0.331 inch MAX.>) ITEM MILLIMETERS A 8.0±0.1 INCHES 0.315±0.004 B C 0.6 MAX. 0.55 (T.P.) 0.024 MAX. 0.022 (T.P.) D 0.22 +0.08 –0.07 0.009±0.003 G H 1.0 12.4±0.2 0.039 0.488±0.008 I 11.8±0.1 0.465 +0.004 –0.005 J 0.8±0.2 0.031 +0.009 –0.008 K 0.145 +0.025 –0.015 0.006±0.001 L 0.5±0.1 0.020 +0.004 –0.005 M 0.08 0.003 N 0.10 0.004 P 13.4±0.2 0.528 +0.008 –0.009 Q 0.1±0.05 0.004±0.002 R 3 ° +7° –3° S 1.2 MAX. 3° +7° –3° 0.048 MAX. P28GW-55-9KL-1 20 µPD43256B Recommended Soldering Conditions The following conditions (See table below) must be met when soldering µ PD43256B. For more details, refer to our document “SEMICONDUCTOR DEVICE MOUNTING TECHNOLOGY MANUAL” (C10535E). Please consult with our sales offices in case other soldering process is used, or in case soldering is done under different conditions. Types of Surface Mount Device µ PD43256BGU: 28-pin plastic SOP (450 mil) µ PD43256BGW-9JL: 28-pin plastic TSOP (I) (8 × 13.4 mm) (Normal bent) µ PD43256BGW-9KL: 28-pin plastic TSOP (I) (8 × 13.4 mm) (Reverse bent) Please consult with our sales offices. Type of Through Hole Mount Device µ PD43256BCZ: 28-pin plastic DIP (600 mil) Soldering process Soldering conditions Wave soldering (only to leads) Solder temperature: 260 ˚C or below, Flow time: 10 seconds or below Partial heating method Terminal temperature: 300 ˚C or below, Time: 3 seconds or below (Per one lead) Caution Do not jet molten solder on the surface of package. 21 µPD43256B [MEMO] 22 µPD43256B NOTES FOR CMOS DEVICES 1 PRECAUTION AGAINST ESD FOR SEMICONDUCTORS Note: Strong electric field, when exposed to a MOS device, can cause destruction of the gate oxide and ultimately degrade the device operation. Steps must be taken to stop generation of static electricity as much as possible, and quickly dissipate it once, when it has occurred. Environmental control must be adequate. When it is dry, humidifier should be used. It is recommended to avoid using insulators that easily build static electricity. Semiconductor devices must be stored and transported in an anti-static container, static shielding bag or conductive material. All test and measurement tools including work bench and floor should be grounded. The operator should be grounded using wrist strap. Semiconductor devices must not be touched with bare hands. Similar precautions need to be taken for PW boards with semiconductor devices on it. 2 HANDLING OF UNUSED INPUT PINS FOR CMOS Note: No connection for CMOS device inputs can be cause of malfunction. If no connection is provided to the input pins, it is possible that an internal input level may be generated due to noise, etc., hence causing malfunction. CMOS device behave differently than Bipolar or NMOS devices. Input levels of CMOS devices must be fixed high or low by using a pull-up or pull-down circuitry. Each unused pin should be connected to VDD or GND with a resistor, if it is considered to have a possibility of being an output pin. All handling related to the unused pins must be judged device by device and related specifications governing the devices. 3 STATUS BEFORE INITIALIZATION OF MOS DEVICES Note: Power-on does not necessarily define initial status of MOS device. Production process of MOS does not define the initial operation status of the device. Immediately after the power source is turned ON, the devices with reset function have not yet been initialized. Hence, power-on does not guarantee out-pin levels, I/O settings or contents of registers. Device is not initialized until the reset signal is received. Reset operation must be executed immediately after power-on for devices having reset function. 23 µPD43256B [MEMO] No part of this document may be copied or reproduced in any form or by any means without the prior written consent of NEC Corporation. NEC Corporation assumes no responsibility for any errors which may appear in this document. NEC Corporation does not assume any liability for infringement of patents, copyrights or other intellectual property rights of third parties by or arising from use of a device described herein or any other liability arising from use of such device. No license, either express, implied or otherwise, is granted under any patents, copyrights or other intellectual property rights of NEC Corporation or others. While NEC Corporation has been making continuous effort to enhance the reliability of its semiconductor devices, the possibility of defects cannot be eliminated entirely. To minimize risks of damage or injury to persons or property arising from a defect in an NEC semiconductor device, customers must incorporate sufficient safety measures in its design, such as redundancy, fire-containment, and anti-failure features. NEC devices are classified into the following three quality grades: "Standard", "Special", and "Specific". The Specific quality grade applies only to devices developed based on a customer designated "quality assurance program" for a specific application. The recommended applications of a device depend on its quality grade, as indicated below. Customers must check the quality grade of each device before using it in a particular application. Standard: Computers, office equipment, communications equipment, test and measurement equipment, audio and visual equipment, home electronic appliances, machine tools, personal electronic equipment and industrial robots Special: Transportation equipment (automobiles, trains, ships, etc.), traffic control systems, anti-disaster systems, anti-crime systems, safety equipment and medical equipment (not specifically designed for life support) Specific: Aircrafts, aerospace equipment, submersible repeaters, nuclear reactor control systems, life support systems or medical equipment for life support, etc. The quality grade of NEC devices is "Standard" unless otherwise specified in NEC's Data Sheets or Data Books. If customers intend to use NEC devices for applications other than those specified for Standard quality grade, they should contact an NEC sales representative in advance. Anti-radioactive design is not implemented in this product. M4 96.5 2