DATA SHEET MOS INTEGRATED CIRCUIT μPD43256B-X 256K-BIT CMOS STATIC RAM 32K-WORD BY 8-BIT EXTENDED TEMPERATURE OPERATION Description The μPD43256B-X is a high speed, low power, and 262,144 bits (32,768 words by 8 bits) CMOS static RAM. The μPD43256B-X is an extended-operating-temperature version of the μPD43256B (X version : TA = –25 to +85°C). And A and B versions are low voltage operations. Battery backup is available. The μPD43256B-X is packed in 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, 150 ns (MAX.) • Operating ambient temperature: TA = –25 to +85 °C • 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.) μPD43256B-xxX 70, 85 μPD43256B-AxxX μPD43256B-BxxX voltage 85 Note2 Note2 , 100, 120 100, 120 Note2 Note2 , 150 Note2 temperature Supply current At operating At standby At data retention μA (MAX.) Note1 2 V °C mA (MAX.) μA (MAX.) 4.5 to 5.5 −25 to +85 45 50 3.0 to 5.5 2.7 to 5.5 40 Notes 1. TA ≤ 40 °C, VCC = 3.0 V 2. 100 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. M11012EJ6V0DS00 (6th edition) Date Published June 2006 NS CP (K) Printed in Japan 1995 μPD43256B-X Ordering Information Part number Package Access time Operating supply Operating ambient ns (MAX.) μPD43256BGW-70X-9JL 28-pin PLASTIC TSOP(I) 70 μPD43256BGW-85X-9JL (8x13.4) (Normal bent) 85 μPD43256BGW-A85X-9JL 85 μPD43256BGW-A10X-9JL 100 μPD43256BGW-A12X-9JL 120 μPD43256BGW-B10X-9JL 100 μPD43256BGW-B12X-9JL 120 μPD43256BGW-B15X-9JL 150 μPD43256BGW-70X-9KL 28-pin PLASTIC TSOP(I) 70 μPD43256BGW-85X-9KL (8x13.4) (Reverse bent) 85 μPD43256BGW-A85X-9KL 85 μPD43256BGW-A10X-9KL 100 μPD43256BGW-A12X-9KL 120 μPD43256BGW-B10X-9KL 100 μPD43256BGW-B12X-9KL 120 μPD43256BGW-B15X-9KL 150 μPD43256BGW-70X-9JL-A 28-pin PLASTIC TSOP(I) 70 μPD43256BGW-85X-9JL-A (8x13.4) (Normal bent) 85 μPD43256BGW-A85X-9JL-A 85 μPD43256BGW-A10X-9JL-A 100 μPD43256BGW-A12X-9JL-A 120 μPD43256BGW-B10X-9JL-A 100 μPD43256BGW-B12X-9JL-A 120 μPD43256BGW-B15X-9JL-A 150 μPD43256BGW-70X-9KL-A 28-pin PLASTIC TSOP(I) 70 μPD43256BGW-85X-9KL-A (8x13.4) (Reverse bent) 85 μPD43256BGW-A85X-9KL-A 85 μPD43256BGW-A10X-9KL-A 100 μPD43256BGW-A12X-9KL-A 120 μPD43256BGW-B10X-9KL-A 100 μPD43256BGW-B12X-9KL-A 120 μPD43256BGW-B15X-9KL-A 150 Remark 2 Products with -A at the end of the part number are lead-free products. Data Sheet M11012EJ6V0DS voltage temperature V °C 4.5 to 5.5 –25 to +85 Remark 3.0 to 5.5 A version 2.7 to 5.5 B version 4.5 to 5.5 3.0 to 5.5 A version 2.7 to 5.5 B version 4.5 to 5.5 3.0 to 5.5 A version 2.7 to 5.5 B version 4.5 to 5.5 3.0 to 5.5 A version 2.7 to 5.5 B version μPD43256B-X Pin Configurations (Marking Side) /xxx indicates active low signal. 28-pin PLASTIC TSOP(I) (8x13.4) (Normal bent) [μPD43256BGW-xxX-9JL] [μPD43256BGW-AxxX-9JL] [μPD43256BGW-BxxX-9JL] [μPD43256BGW-xxX-9JL-A] [μPD43256BGW-AxxX-9JL-A] [μPD43256BGW-BxxX-9JL-A] /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) (8x13.4) (Reverse bent) [μPD43256BGW-xxX-9KL] [μPD43256BGW-AxxX-9KL] [μPD43256BGW-BxxX-9KL] [μPD43256BGW-xxX-9KL-A] [μPD43256BGW-AxxX-9KL-A] [μPD43256BGW-BxxX-9KL-A] A10 /CS I/O8 I/O7 I/O6 I/O5 I/O4 GND I/O3 I/O2 I/O1 A0 A1 A2 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 : Ground /WE : Write Enable 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 Remark Refer to Package Drawings for the 1-pin index mark. Data Sheet M11012EJ6V0DS 3 μPD43256B-X 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 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 ISB L H H Output disable L × L Write DIN L L H Read DOUT ICCA Remark × : VIH or VIL 4 Data Sheet M11012EJ6V0DS μPD43256B-X 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 –25 to +85 °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 μPD43256B-xxX Symbol Condition μPD43256B-AxxX μPD43256B-BxxX MIN. MAX. MIN. MAX. MIN. MAX. Unit Supply voltage VCC 4.5 5.5 3.0 5.5 2.7 5.5 V High level input voltage VIH 2.4 VCC+0.5 2.4 VCC+0.5 2.4 VCC+0.5 V +0.4 V +85 °C MAX. Unit Low level input voltage VIL Operating ambient temperature TA –0.3 Note –25 +0.6 –0.3 +85 Note +0.4 –25 +85 –0.3 Note –25 Note –3.0 V (MIN.) (Pulse width: 50 ns) Capacitance (TA = 25°C, f = 1 MHz) Parameter Symbol Test conditions MIN. TYP. 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 M11012EJ6V0DS 5 μPD43256B-X DC Characteristics (Recommended Operating Conditions Unless Otherwise Noted) (1/2) Parameter Symbol Test condition μPD43256B-xxX MIN. TYP. Unit MAX. Input leakage current ILI VIN = 0 V to VCC –1.0 +1.0 μA I/O leakage current ILO VI/O = 0 V to VCC, /OE = VIH or –1.0 +1.0 μA mA /CS = VIH or /WE = VIL Operating supply current ICCA1 /CS = VIL, Minimum cycle time, II/O = 0 mA 45 ICCA2 /CS = VIL, II/O = 0 mA 15 ICCA3 /CS ≤ 0.2 V, Cycle = 1 MHz, 15 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 VOH2 IOH = –0.1 mA VCC–0.5 VOL IOL = 2.1 mA 1.0 Remarks 1. VIN : Input voltage VI/O : Input / Output voltage 2. These DC characteristics are in common regardless of package types. 6 Data Sheet M11012EJ6V0DS 3 mA 50 μA V 0.4 V μPD43256B-X DC Characteristics (Recommended Operating Conditions Unless Otherwise Noted) (2/2) Parameter Symbol μPD43256B-AxxX Test condition MIN. TYP. μPD43256B-BxxX MAX. MIN. TYP. Unit MAX. Input leakage current ILI VIN = 0 V to VCC –1.0 +1.0 –1.0 +1.0 μA I/O leakage current ILO VI/O = 0 V to VCC, /OE = VIH or –1.0 +1.0 –1.0 +1.0 μA mA /CS = VIH or /WE = VIL Operating supply current ICCA1 ICCA2 /CS = VIL, μPD43256B-A85X 45 – Minimum cycle time, μPD43256B-A10X 40 – II/O = 0 mA μPD43256B-A12X 40 – μPD43256B-B10X – 40 μPD43256B-B12X – 40 μPD43256B-B15X – 40 VCC ≤ 3.3 V – 25 15 15 – 10 /CS ≤ 0.2 V, Cycle = 1 MHz, II/O = 0 mA, 15 15 VIL ≤ 0.2 V, VIH ≥ VCC – 0.2 V – 10 3 3 – 2 /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 1.0 VCC ≤ 3.3 V High level output voltage VOH1 VOH2 Low level output voltage VOL VOL1 50 1.0 – μA 25 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– VCC– 0.1 0.1 IOH = –0.02 mA 50 mA V 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 V Remarks 1. VIN : Input voltage VI/O : Input / Output voltage 2. These DC characteristics are in common regardless of package types. Data Sheet M11012EJ6V0DS 7 μPD43256B-X AC Characteristics (Recommended Operating Conditions Unless Otherwise Noted) AC Test Conditions [μPD43256B-70X, μPD43256B-85X] Input Waveform (Rise and Fall Time ≤ 5 ns) 2.4 V 1.5 V Test points 1.5 V 1.5 V Test points 1.5 V 0.6 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 kΩ 1.8 kΩ I/O (Output) I/O (Output) 990 Ω 990 Ω 100 pF CL 5 pF CL Remark CL includes capacitance of the probe and jig, and stray capacitance. [μPD43256B-A85X, μPD43256B-A10X, μPD43256B-A12X, μPD43256B-B10X, μPD43256B-B12X, μPD43256B-B15X] Input Waveform (Rise and Fall Time ≤ 5 ns) 2.4 V 1.5 V Test points 1.5 V 1.5 V Test points 1.5 V 0.4 V Output Waveform Output Load AC characteristics should be measured with the following output load conditions. 8 tAA, tACS, tOE, tOH tCHZ, tCLZ, tOHZ, tOLZ, tWHZ, tOW 1TTL + 50 pF 1TTL + 5 pF Data Sheet M11012EJ6V0DS μPD43256B-X Read Cycle (1/2) Parameter VCC ≥ 4.5 V Symbol μPD43256B-70X μPD43256B-85X MIN. MIN. Unit μPD43256B-AxxX Condition μPD43256B-BxxX MAX. MIN. 85 MAX. Read cycle time tRC Address access time tAA 70 85 100 ns /CS access time tACS 70 85 100 ns /OE access time tOE 35 40 50 ns Output hold from address change tOH 10 10 10 ns /CS to output in low impedance tCLZ 10 10 10 ns /OE to output in low impedance tOLZ 5 5 5 ns /CS to output in high impedance tCHZ 30 30 35 ns /OE to output in high impedance tOHZ 30 30 35 ns Note 70 MAX. 100 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 Con- μPD43256B- μPD43256B- μPD43256B- μPD43256B- μPD43256B- μPD43256BA85X MIN. MAX. 85 A10X MIN. MAX. 100 A12X MIN. MAX. 120 B10X MIN. MAX. 100 B12X MIN. MAX. 120 dition B15X MIN. MAX. Read cycle time tRC 150 ns Address access tAA 85 100 120 100 120 150 ns /CS access time tACS 85 100 120 100 120 150 ns /OE access time tOE 50 60 60 60 60 70 ns Output hold from tOH 10 10 10 10 10 10 ns tCLZ 10 10 10 10 10 10 ns tOLZ 5 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 50 ns tOHZ 35 35 40 35 40 50 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 M11012EJ6V0DS 9 μPD43256B-X Read Cycle Timing Chart tRC Address (Input) tAA tOH /CS (Input) tCHZ tACS tCLZ /OE (Input) tOHZ tOE tOLZ I/O (Output) Remark 10 High impedance In read cycle, /WE should be fixed to high level. Data Sheet M11012EJ6V0DS Data out μPD43256B-X Write Cycle (1/2) Parameter VCC ≥ 4.5 V Symbol μPD43256B-70X μPD43256B-85X Unit Con- μPD43256B-AxxX dition μPD43256B-BxxX MIN. MAX. MIN. MAX. MIN. MAX. Write cycle time tWC 70 85 100 ns /CS to end of write tCW 60 70 80 ns Address valid to end of write tAW 60 70 80 ns Write pulse width tWP 55 60 70 ns Data valid to end of write tDW 30 35 40 ns Data hold time tDH 5 5 5 ns Address setup time tAS 0 0 0 ns Write recovery time tWR 0 0 0 ns /WE to output in high impedance tWHZ Output active from end of write tOW Note 30 30 5 35 5 ns 5 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 Con- μPD43256B- μPD43256B- μPD43256B- μPD43256B- μPD43256B- μPD43256BA85X MIN. MAX. A10X MIN. MAX. A12X MIN. MAX. B10X MIN. MAX. B12X MIN. MAX. dition B15X MIN. MAX. Write cycle time tWC 85 100 120 100 120 150 ns /CS to end of write tCW 70 70 90 70 90 100 ns Address valid to tAW 70 70 90 70 90 100 ns Write pulse width tWP 60 60 80 60 80 90 ns Data valid to end tDW 60 60 70 60 70 80 ns Data hold time tDH 5 5 5 5 5 5 ns Address setup time tAS 0 0 0 0 0 0 ns Write recovery time tWR 0 0 0 0 0 0 ns /WE to output in tWHZ end of write of write 35 35 40 35 40 40 ns Note high impedance Output active tOW 5 5 5 5 5 5 ns from end of write Note See the output load. Remark These AC characteristics are in common regardless of package types. Data Sheet M11012EJ6V0DS 11 μPD43256B-X 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, 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. 12 Data Sheet M11012EJ6V0DS μPD43256B-X 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, 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. Data Sheet M11012EJ6V0DS 13 μPD43256B-X Low VCC Data Retention Characteristics (TA = −25 to +85 °C) Parameter Symbol Test Condition MIN. TYP. MAX. Unit 5.5 V Data retention supply voltage VCCDR /CS ≥ VCC − 0.2 V Data retention supply current ICCDR VCC = 3.0 V, /CS ≥ VCC − 0.2 V Chip deselection to data retention mode tCDR 0 ns tR 5 ms Operation recovery time 2.0 0.5 Note 2 μA (TA ≤ 40 °C), 7 μA (TA ≤ 70 °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 14 The other pins (Address, /OE, /WE, I/O) can be in high impedance state. Data Sheet M11012EJ6V0DS tR 20 Note μA μPD43256B-X Package Drawings 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 8.0±0.1 B C 0.6 MAX. 0.55 (T.P.) D 0.22 +0.08 −0.07 G H 1.0 12.4±0.2 I 11.8±0.1 J 0.8±0.2 K 0.145 +0.025 −0.015 L 0.5±0.1 M 0.08 N 0.10 P 13.4±0.2 Q 0.1±0.05 R S 3° +7° −3° 1.2 MAX. P28GW-55-9JL-2 Data Sheet M11012EJ6V0DS 15 μPD43256B-X 28-PIN PLASTIC TSOP(I) (8x13.4) 1 28 detail of lead end Q R 14 15 S K N H D S L M M C B S G I J A P NOTE 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 8.0±0.1 B C 0.6 MAX. 0.55 (T.P.) D 0.22 +0.08 −0.07 G H 1.0 12.4±0.2 I 11.8±0.1 J 0.8±0.2 K 0.145 +0.025 −0.015 L M 0.5±0.1 0.08 N 0.10 P 13.4±0.2 Q 0.1±0.05 R 3° +7° −3° S 1.2 MAX. P28GW-55-9KL-2 16 Data Sheet M11012EJ6V0DS μPD43256B-X Recommended Soldering Conditions Please consult with our sales offices for soldering conditions of the μPD43256B-X. Types of Surface Mount Device μPD43256BGW-xxX-9JL : 28-pin PLASTIC TSOP(I) (8x13.4) (Normal bent) μPD43256BGW-xxX-9KL : 28-pin PLASTIC TSOP(I) (8x13.4) (Reverse bent) μPD43256BGW-AxxX-9JL : 28-pin PLASTIC TSOP(I) (8x13.4) (Normal bent) μPD43256BGW-AxxX-9KL : 28-pin PLASTIC TSOP(I) (8x13.4) (Reverse bent) μPD43256BGW-BxxX-9JL : 28-pin PLASTIC TSOP(I) (8x13.4) (Normal bent) μPD43256BGW-BxxX-9KL : 28-pin PLASTIC TSOP(I) (8x13.4) (Reverse bent) μPD43256BGW-xxX-9JL-A : 28-pin PLASTIC TSOP(I) (8x13.4) (Normal bent) μPD43256BGW-xxX-9KL-A : 28-pin PLASTIC TSOP(I) (8x13.4) (Reverse bent) μPD43256BGW-AxxX-9JL-A : 28-pin PLASTIC TSOP(I) (8x13.4) (Normal bent) μPD43256BGW-AxxX-9KL-A : 28-pin PLASTIC TSOP(I) (8x13.4) (Reverse bent) μPD43256BGW-BxxX-9JL-A : 28-pin PLASTIC TSOP(I) (8x13.4) (Normal bent) μPD43256BGW-BxxX-9KL-A : 28-pin PLASTIC TSOP(I) (8x13.4) (Reverse bent) Data Sheet M11012EJ6V0DS 17 μPD43256B-X Revision History Edition/ Date 6th edition/ Page Type of This Previous edition edition p.1 p.1 Location (Previous edition → This edition) revision Deletion − Jun. 2006 18 Description Data Sheet M11012EJ6V0DS Description of Version X has been deleted. μPD43256B-X 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 M11012EJ6V0DS 19 μPD43256B-X • The information in this document is current as of June, 2006. 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