DATA SHEET MOS INTEGRATED CIRCUIT PD43256B 256K-BIT CMOS STATIC RAM 32K-WORD BY 8-BIT Description The PD43256B is a high speed, low power, and 262,144 bits (32,768 words by 8 bits) CMOS static RAM. Battery backup is available. And A and B versions are wide voltage operations. The PD43256B is packed in 28-pin PLASTIC DIP, 28-pin PLASTIC SOP and 28-pin PLASTIC TSOP (I) (8 x 13.4 mm). Features * 32,768 words by 8 bits organization * Fast access time: 70, 85, 100, 120 ns (MAX.) * Low voltage operation (A version: VCC = 3.0 to 5.5 V, B version: VCC = 2.7 to 5.5 V) * Low VCC data retention: 2.0 V (MIN.) * /OE input for easy application Part number Access time Operating supply Operating ambient ns (MAX.) PD43256B-xxL 70, 85 voltage temperature At operating At standby At data retention V C mA (MAX.) A (MAX.) A (MAX.) Note1 4.5 to 5.5 0 to 70 45 50 3 15 2 PD43256B-xxLL PD43256B-Axx PD43256B-Bxx Note2 85, 100 Note2 , 120 100, 120 Note2 Supply current 3.0 to 5.5 2.7 to 5.5 Notes 1. TA 40 C, VCC = 3.0 V 2. Access time: 85 ns (MAX.) (VCC = 4.5 to 5.5 V) The information in this document is subject to change without notice. Before using this document, please confirm that this is the latest version. Not all products and/or types are available in every country. Please check with an NEC Electronics sales representative for availability and additional information. Document No. M10770EJFV0DS00 (15th edition) Date Published November 2008 Printed in Japan 1990, 1993, 1994 PD43256B Ordering Information Part number Package Access time Operating supply Operating ambient ns (MAX.) PD43256BCZ-70L 28-pin PLASTIC DIP 70 PD43256BCZ-85L (15.24 mm (600)) 85 PD43256BCZ-70LL 70 PD43256BCZ-85LL 85 PD43256BGU-70L 28-pin PLASTIC SOP 70 PD43256BGU-85L (11.43 mm (450)) 85 PD43256BGU-70LL 70 PD43256BGU-85LL 85 PD43256BGU-A85 85 PD43256BGU-A10 100 PD43256BGU-A12 120 PD43256BGU-B12 V C 4.5 to 5.5 0 to 70 L version LL version L version LL version A version 120 2.7 to 5.5 B version 4.5 to 5.5 LL version 4.5 to 5.5 L version 28-pin PLASTIC TSOP (I) 70 PD43256BGW-85LL-9JL (8x13.4) (Normal bent) 85 PD43256BGU-70L-A 28-pin PLASTIC SOP 70 PD43256BGU-85L-A (11.43 mm (450)) 85 PD43256BGU-70LL-A 70 PD43256BGU-85LL-A 85 PD43256BGU-A85-A 85 PD43256BGU-A10-A 100 PD43256BGU-A12-A 120 PD43256BGU-B10-A 100 PD43256BGU-B12-A 120 PD43256BGW-70LL-9JL-A 28-pin PLASTIC TSOP (I) 70 PD43256BGW-85LL-9JL-A (8x13.4) (Normal bent) 85 2 temperature 3.0 to 5.5 PD43256BGW-70LL-9JL Remark voltage Remark Products with -A at the end of the part number are lead-free products. Data Sheet M10770EJFV0DS LL version 3.0 to 5.5 A version 2.7 to 5.5 B version 4.5 to 5.5 LL version PD43256B Pin Configurations (Marking Side) /xxx indicates active low signal. 28-pin PLASTIC DIP (15.24 mm (600)) [ PD43256BCZ-xxL ] [ PD43256BCZ-xxLL ] 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 VCC : Power supply GND : Ground Remark Refer to Package Drawings for the 1-pin index mark. Data Sheet M10770EJFV0DS 3 PD43256B 28-pin PLASTIC SOP (11.43 mm (450)) [ PD43256BGU-xxL ] [ PD43256BGU-xxLL ] [ PD43256BGU-Axx ] [ PD43256BGU-Bxx ] [ PD43256BGU-xxL-A ] [ PD43256BGU-xxLL-A ] [ PD43256BGU-Axx-A ] [ PD43256BGU-Bxx-A ] 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 VCC : Power supply GND : Ground Remark Refer to Package Drawings for the 1-pin index mark. 4 Data Sheet M10770EJFV0DS PD43256B 28-pin PLASTIC TSOP (I) (8x13.4) (Normal bent) [ PD43256BGW-xxLL-9JL ] [ PD43256BGW-Axx-9JL ] [ PD43256BGW-Bxx-9JL ] [ PD43256BGW-xxLL-9JL-A ] [ PD43256BGW-Axx-9JL-A ] [ PD43256BGW-Bxx-9JL-A ] 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 28 27 26 25 24 23 22 21 20 19 18 17 16 15 A0 - A14 : Address inputs /OE : Output Enable I/O1 - I/O8 : Data inputs / outputs VCC : Power supply /CS : Chip Select GND : /WE : Write Enable A10 /CS I/O8 I/O7 I/O6 I/O5 I/O4 GND I/O3 I/O2 I/O1 A0 A1 A2 Ground Remark Refer to Package Drawings for the 1-pin index mark. Data Sheet M10770EJFV0DS 5 PD43256B Block Diagram A0 Address buffer A14 Row decoder I/O1 Input data controller I/O8 Memory cell array 262,144 bits Sense amplifier / Switching circuit Column decoder Output data controller Address buffer /CS /OE /WE VCC GND Truth Table /CS /OE /WE Mode I/O Supply current H x x Not selected High impedance ISB L H H Output disable L x L Write DIN L L H Read DOUT ICCA Remark x : VIH or VIL 6 Data Sheet M10770EJFV0DS PD43256B Electrical Specifications Absolute Maximum Ratings Parameter Symbol Supply voltage Condition Rating VCC -0.5 -0.5 Note Note Unit to +7.0 V to VCC + 0.5 V Input / Output voltage VT Operating ambient temperature TA 0 to 70 C Storage temperature Tstg -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 Rating could cause permanent damage. The device is not meant to be operated under conditions outside the limits described in the operational section of this specification. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Recommended Operating Conditions Parameter Symbol Condition PD43256B-xxL PD43256B-Axx PD43256B-Bxx Unit PD43256B-xxLL MIN. MAX. MIN. MAX. MIN. MAX. Supply voltage VCC 4.5 5.5 3.0 5.5 2.7 5.5 V High level input voltage VIH 2.2 VCC+0.5 2.2 VCC+0.5 2.2 VCC+0.5 V +0.5 V 70 C Note Low level input voltage VIL -0.3 Operating ambient temperature TA 0 +0.8 -0.3 70 Note +0.5 0 70 -0.3 0 Note Note -3.0 V (MIN.) (Pulse width: 50 ns) Capacitance (TA = 25 C, f = 1 MHz) Parameter Symbol Test conditions MIN. TYP. MAX. Unit Input capacitance CIN VIN = 0 V 5 pF Input / Output capacitance CI/O VI/O = 0 V 8 pF Remarks 1. VIN : Input voltage VI/O : Input / Output voltage 2. These parameters are periodically sampled and not 100% tested. Data Sheet M10770EJFV0DS 7 PD43256B DC Characteristics (Recommended Operating Conditions Unless Otherwise Noted) (1/2) Parameter Symbol Test condition PD43256B-xxL MIN. TYP. PD43256B-xxLL MAX. MIN. TYP. Unit MAX. Input leakage current ILI VIN = 0 V to VCC -1.0 +1.0 -1.0 +1.0 A I/O leakage current ILO VI/O = 0 V to VCC, /OE = VIH or -1.0 +1.0 -1.0 +1.0 A mA /CS = VIH or /WE = VIL Operating supply current ICCA1 /CS = VIL, Minimum cycle time, II/O = 0 mA 45 45 ICCA2 /CS = VIL, II/O = 0 mA 10 10 ICCA3 /CS 0.2 V, Cycle = 1 MHz, 10 10 3 3 mA 15 A II/O = 0 mA, VIL 0.2 V, VIH VCC - 0.2 V Standby supply current High level output voltage Low level output voltage ISB /CS = VIH ISB1 /CS VCC - 0.2 V VOH1 IOH = -1.0 mA 2.4 2.4 VOH2 IOH = -0.1 mA VCC-0.5 VCC-0.5 VOL IOL = 2.1 mA 1.0 0.4 Remarks 1. VIN : Input voltage VI/O : Input / Output voltage 2. These DC characteristics are in common regardless of package types. 8 50 Data Sheet M10770EJFV0DS 0.5 V 0.4 V PD43256B DC Characteristics (Recommended Operating Conditions Unless Otherwise Noted) (2/2) Parameter Symbol PD43256B-Axx Test condition MIN. TYP. PD43256B-Bxx MAX. MIN. TYP. Unit MAX. Input leakage current ILI VIN = 0 V to VCC -1.0 +1.0 -1.0 +1.0 A I/O leakage current ILO VI/O = 0 V to VCC, /OE = VIH or -1.0 +1.0 -1.0 +1.0 A mA /CS = VIH or /WE = VIL Operating supply current ICCA1 /CS = VIL, PD43256B-Axx 45 - Minimum cycle time, PD43256B-Bxx - 45 VCC 3.3 V - 20 10 10 - 5 /CS 0.2 V, Cycle = 1 MHz, II/O = 0 mA, 10 10 VIL 0.2 V, VIH VCC - 0.2 V - 5 3 3 - 2 II/O = 0 mA ICCA2 /CS = VIL, II/O = 0 mA VCC 3.3 V ICCA3 Standby supply current ISB VCC 3.3 V /CS = VIH VCC 3.3 V ISB1 /CS VCC - 0.2 V 0.5 VCC 3.3 V High level output voltage Low level output voltage VOH1 15 0.5 15 - 0.5 10 IOH = -1.0 mA, VCC 4.5 V 2.4 2.4 IOH = -0.5 mA, VCC < 4.5 V 2.4 2.4 VCC-0.1 VCC-0.1 A V VOH2 IOH = -0.02 mA VOL IOL = 2.1 mA, VCC 4.5 V 0.4 0.4 IOL = 1.0 mA, VCC < 4.5 V 0.4 0.4 IOL = 0.02 mA 0.1 0.1 VOL1 mA V Remarks 1. VIN : Input voltage VI/O : Input / Output voltage 2. These DC characteristics are in common regardless of package types. Data Sheet M10770EJFV0DS 9 PD43256B AC Characteristics (Recommended Operating Conditions Unless Otherwise Noted) AC Test Conditions [ PD43256B-70L, PD43256B-85L, PD43256B-70LL, PD43256B-85LL ] Input Waveform (Rise and Fall Time 5 ns) 2.2 V 1.5 V Test points 1.5 V 0.8 V Output Waveform Output Load AC characteristics should be measured with the following output load conditions. Figure 1 Figure 2 (tAA, tACS, tOE, tOH) (tCHZ, tCLZ, tOHZ, tOLZ, tWHZ, tOW ) +5 V +5 V 1.8 k I/O (Output) 1.8 k I/O (Output) 990 990 100 pF CL Remark CL includes capacitance of the probe and jig, and stray capacitance. [ PD43256B-A85, PD43256B-A10, PD43256B-A12, PD43256B-B10, PD43256B-B12 ] Input Waveform (Rise and Fall Time 5 ns) 2.2 V 1.5 V Test points 1.5 V 0.5 V Output Waveform Output Load AC characteristics should be measured with the following output load conditions. 10 tAA, tACS, tOE, tOH tCHZ, tCLZ, tOHZ, tOLZ, tWHZ, tOW 1TTL + 100 pF 1TTL + 5 pF Data Sheet M10770EJFV0DS 5 pF CL PD43256B Read Cycle (1/2) Parameter VCC 4.5 V Symbol PD43256B-70 Unit Condition PD43256B-85 PD43256B-A85/A10/A12 PD43256B-B10/B12 MIN. MAX. MIN. Read cycle time tRC Address access time tAA 70 85 ns /CS access time tACS 70 85 ns /OE access time tOE 35 40 ns Output hold from address change tOH 10 10 ns /CS to output in low impedance tCLZ 10 10 ns /OE to output in low impedance tOLZ 5 5 ns /CS to output in high impedance tCHZ 30 30 ns /OE to output in high impedance tOHZ 30 30 ns Note 70 MAX. 85 ns Note See the output load. Remark These AC characteristics are in common regardless of package types and L, LL versions. Read Cycle (2/2) Parameter VCC 3.0 V Symbol VCC 2.7 V Unit PD43256B PD43256B PD43256B PD43256B PD43256B -A85 -A10 -A12 -B10 -B12 MIN. MAX. 85 MIN. MAX. 100 MIN. MAX. 120 MIN. MAX. 100 MIN. Condition MAX. Read cycle time tRC 120 ns Address access tAA 85 100 120 100 120 ns /CS access time tACS 85 100 120 100 120 ns /OE access time tOE 50 60 60 60 60 ns Output hold from tOH 10 10 10 10 10 ns tCLZ 10 10 10 10 10 ns tOLZ 5 5 5 5 5 ns Note time address change /CS to output in low impedance /OE to output in low impedance /CS to output in tCHZ 35 35 40 35 40 ns tOHZ 35 35 40 35 40 ns high impedance /OE to output in high impedance Note See the output load. Remark These AC characteristics are in common regardless of package types. Data Sheet M10770EJFV0DS 11 PD43256B Read Cycle Timing Chart tRC Address (Input) tAA tOH /CS (Input) tCHZ tACS tCLZ /OE (Input) tOHZ tOE tOLZ I/O (Output) Remark 12 High impedance In read cycle, /WE should be fixed to high level. Data Sheet M10770EJFV0DS Data out PD43256B Write Cycle (1/2) Parameter VCC 4.5 V Symbol PD43256B-70 Unit Condition PD43256B-85 PD43256B-A85/A10/A12 PD43256B-B10/B12 MIN. MAX. MIN. MAX. Write cycle time tWC 70 85 ns /CS to end of write tCW 50 70 ns Address valid to end of write tAW 50 70 ns Write pulse width tWP 55 60 ns Data valid to end of write tDW 30 35 ns Data hold time tDH 0 0 ns Address setup time tAS 0 0 ns Write recovery time tWR 0 0 ns /WE to output in high impedance tWHZ Output active from end of write tOW Note 30 30 10 ns 10 Note ns See the output load. Remark These AC characteristics are in common regardless of package types and L, LL versions. Write Cycle (2/2) Parameter VCC 3.0 V Symbol VCC 2.7 V Unit PD43256B PD43256B PD43256B PD43256B PD43256B -A85 -A10 -A12 -B10 -B12 MIN. MAX. MIN. MAX. MIN. MAX. MIN. MAX. MIN. Condition MAX. Write cycle time tWC 85 100 120 100 120 ns /CS to end of write tCW 70 70 90 70 90 ns Address valid to tAW 70 70 90 70 90 ns Write pulse width tWP 60 60 80 60 80 ns Data valid to end tDW 60 60 70 60 70 ns Data hold time tDH 0 0 0 0 0 ns Address setup tAS 0 0 0 0 0 ns Write recovery tWR 0 0 0 0 0 ns /WE to output in tWHZ end of write of write 30 35 40 35 40 ns Note high impedance Output active tOW 10 10 10 10 10 ns from end of write Note See the output load. Remark These AC characteristics are in common regardless of package types. Data Sheet M10770EJFV0DS 13 PD43256B 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 tDH Data in 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, therefore the input signals must not be applied to the output. 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. 14 Data Sheet M10770EJFV0DS PD43256B Write Cycle Timing Chart 2 (/CS Controlled) tWC Address (Input) tAS tCW /CS (Input) tAW tWP tWR /WE (Input) tDW tDH High impedance Data in I/O (Input) 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, therefore the input signals must not be applied to the output. Remark Write operation is done during the overlap time of a low level /CS and a low level /WE. Data Sheet M10770EJFV0DS 15 PD43256B Low VCC Data Retention Characteristics (TA = 0 to 70 C) Parameter Symbol PD43256B-xxL Test Condition PD43256B-xxLL Unit PD43256B-Axx PD43256B-Bxx MIN. Data retention supply voltage VCCDR /CS VCC - 0.2 V TYP. 2.0 VCC = 3.0 V, /CS VCC - 0.2 V 0.5 MAX. MIN. 5.5 2.0 20 Note1 TYP. MAX. 5.5 0.5 7 Note2 V A Data retention supply current ICCDR Chip deselection tCDR 0 0 ns tR 5 5 ms to data retention mode Operation recovery time Notes 1. 3 A (TA 40 C) 2. 2 A (TA 40 C), 1 A (TA 25 C) Data Retention Timing Chart tCDR Data retention mode VCC 4.5 V Note /CS VIH (MIN.) VCCDR (MIN.) /CS VCC - 0.2 V VIL (MAX.) GND Note A version : 3.0 V, B version : 2.7 V Remark 16 The other pins (Address, /OE, /WE, I/O) can be in high impedance state. Data Sheet M10770EJFV0DS tR PD43256B Package Drawings 28-PIN PLASTIC DIP (15.24 mm (600)) 28 15 1 14 A J K I L F D C N B R M M H G NOTES 1. Each lead centerline is located within 0.25 mm of its true position (T.P.) at maximum material condition. 2. Item "K" to center of leads when formed parallel. ITEM MILLIMETERS A 38.10 MAX. B 2.54 MAX. C 2.54 (T.P.) D 0.500.10 F 1.2 MIN. G 3.60.3 H 0.51 MIN. I 4.31 MAX. J 5.72 MAX. K L 15.24 (T.P.) 13.2 M 0.25 +0.10 -0.05 N 0.25 R 0 - 15 P28C-100-600A1-2 Data Sheet M10770EJFV0DS 17 PD43256B 28-PIN PLASTIC SOP (11.43 mm (450)) 28 15 detail of lead end P 1 14 A F H G I J S C D M N M L S B K E NOTE Each lead centerline is located within 0.12 mm of its true position (T.P.) at maximum material condition. ITEM MILLIMETERS A 18.0 +0.6 -0.05 B 1.27 MAX. C 1.27 (T.P.) D 0.42 +0.08 -0.07 E 0.20.1 F 2.95 MAX. G 2.550.1 H 11.80.3 I 8.40.1 J 1.70.2 K 0.220.05 L M 0.70.2 0.12 N 0.10 P 3 +7 -3 P28GU-50-450A-4 18 Data Sheet M10770EJFV0DS PD43256B 28-PIN PLASTIC TSOP(I) (8x13.4) 1 28 detail of lead end S R 14 Q 15 P A J I G S L B C H N S D M M K NOTES 1. Each lead centerline is located within 0.08 mm of its true position (T.P.) at maximum material condition. 2. "A" excludes mold flash. (Includes mold flash : 8.4mm MAX.) ITEM A MILLIMETERS 8.00.1 B C 0.6 MAX. 0.55 (T.P.) D 0.22 +0.08 -0.07 G H 1.0 12.40.2 I 11.80.1 J 0.80.2 K 0.145 +0.025 -0.015 L 0.50.1 M 0.08 N 0.10 P 13.40.2 Q 0.10.05 R S 3 +7 -3 1.2 MAX. P28GW-55-9JL-2 Data Sheet M10770EJFV0DS 19 PD43256B Recommended Soldering Conditions Please consult with our sales offices for soldering conditions of the PD43256B. Types of Surface Mount Device PD43256BGU-xxL : 28-pin PLASTIC SOP (11.43 mm (450)) PD43256BGU-xxLL : 28-pin PLASTIC SOP (11.43 mm (450)) PD43256BGU-Axx : 28-pin PLASTIC SOP (11.43 mm (450)) PD43256BGU-Bxx : 28-pin PLASTIC SOP (11.43 mm (450)) PD43256BGW-xxLL-9JL : 28-pin PLASTIC TSOP (I) (8x13.4) (Normal bent) PD43256BGU-xxL-A : 28-pin PLASTIC SOP (11.43 mm (450)) PD43256BGU-xxLL-A : 28-pin PLASTIC SOP (11.43 mm (450)) PD43256BGU-Axx-A : 28-pin PLASTIC SOP (11.43 mm (450)) PD43256BGU-Bxx-A : 28-pin PLASTIC SOP (11.43 mm (450)) PD43256BGW-xxLL-9JL-A : 28-pin PLASTIC TSOP (I) (8x13.4) (Normal bent) Types of Through Hole Mount Device PD43256BCZ-xxL : 28-pin PLASTIC DIP (15.24 mm (600)) PD43256BCZ-xxLL : 28-pin PLASTIC DIP (15.24 mm (600)) Soldering process Wave soldering (only to leads) Soldering conditions 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. 20 Data Sheet M10770EJFV0DS PD43256B Revision History Edition/ Date 15th edition/ Page Type of This Previous edition edition through through Description revision Modification Ordering Information revised. Nov. 2008 Data Sheet M10770EJFV0DS 21 PD43256B [ MEMO ] 22 Data Sheet M10770EJFV0DS PD43256B NOTES FOR CMOS DEVICES 1 VOLTAGE APPLICATION WAVEFORM AT INPUT PIN Waveform distortion due to input noise or a reflected wave may cause malfunction. If the input of the CMOS device stays in the area between VIL (MAX) and VIH (MIN) due to noise, etc., the device may malfunction. Take care to prevent chattering noise from entering the device when the input level is fixed, and also in the transition period when the input level passes through the area between VIL (MAX) and VIH (MIN). 2 HANDLING OF UNUSED INPUT PINS Unconnected CMOS device inputs can be cause of malfunction. If an input pin is unconnected, it is possible that an internal input level may be generated due to noise, etc., causing malfunction. CMOS devices behave differently than Bipolar or NMOS devices. Input levels of CMOS devices must be fixed high or low by using pull-up or pull-down circuitry. Each unused pin should be connected to VDD or GND via a resistor if there is a possibility that it will be an output pin. All handling related to unused pins must be judged separately for each device and according to related specifications governing the device. 3 PRECAUTION AGAINST ESD A 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 when it has occurred. Environmental control must be adequate. When it is dry, a humidifier should be used. It is recommended to avoid using insulators that easily build up 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 benches and floors should be grounded. The operator should be grounded using a wrist strap. Semiconductor devices must not be touched with bare hands. Similar precautions need to be taken for PW boards with mounted semiconductor devices. 4 STATUS BEFORE INITIALIZATION Power-on does not necessarily define the initial status of a MOS device. Immediately after the power source is turned ON, devices with reset functions have not yet been initialized. Hence, power-on does not guarantee output pin levels, I/O settings or contents of registers. A device is not initialized until the reset signal is received. A reset operation must be executed immediately after power-on for devices with reset functions. 5 POWER ON/OFF SEQUENCE In the case of a device that uses different power supplies for the internal operation and external interface, as a rule, switch on the external power supply after switching on the internal power supply. When switching the power supply off, as a rule, switch off the external power supply and then the internal power supply. Use of the reverse power on/off sequences may result in the application of an overvoltage to the internal elements of the device, causing malfunction and degradation of internal elements due to the passage of an abnormal current. The correct power on/off sequence must be judged separately for each device and according to related specifications governing the device. 6 INPUT OF SIGNAL DURING POWER OFF STATE Do not input signals or an I/O pull-up power supply while the device is not powered. The current injection that results from input of such a signal or I/O pull-up power supply may cause malfunction and the abnormal current that passes in the device at this time may cause degradation of internal elements. Input of signals during the power off state must be judged separately for each device and according to related specifications governing the device. Data Sheet M10770EJFV0DS 23 PD43256B * The information in this document is current as of November, 2008. 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