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| SN54/74LS256 DUAL 4-BIT ADDRESSABLE LATCH The SN54/74LS256 is a Dual 4-Bit Addressable Latch with common control inputs; these include two Address inputs (A0, A1), an active LOW Enable input (E) and an active LOW Clear input (CL). Each latch has a Data input (D) and four outputs (Q0 - Q3). When the Enable (E) is HIGH and the Clear input (CL) is LOW, all outputs (Q0 - Q3) are LOW. Dual 4-channel demultiplexing occurs when the (CL) and E are both LOW. When CL is HIGH and E is LOW, the selected output (Q0 - Q3), determined by the Address inputs, follows D. When the E goes HIGH, the contents of the latch are stored. When operating in the addressable latch mode (E = LOW, CL = HIGH), changing more than one bit of the Address (A0, A1) could impose a transient wrong address. Therefore, this should be done only while in the memory mode (E= CL = HIGH). DUAL 4-BIT ADDRESSABLE LATCH LOW POWER SCHOTTKY * * * * * * Serial-to-Parallel Capability Output From Each Storage Bit Available Random (Addressable) Data Entry Easily Expandable Active Low Common Clear Input Clamp Diodes Limit High Speed Termination Effects J SUFFIX CERAMIC CASE 620-09 16 1 16 1 N SUFFIX PLASTIC CASE 648-08 CONNECTION DIAGRAM DIP (TOP VIEW) VCC 16 CL 15 E 14 Db 13 Q3b 12 Q2b 11 Q1b 10 Q0b 9 NOTE: The Flatpak version has the same pinouts (Connection Diagram) as the Dual In-Line Package. 16 1 D SUFFIX SOIC CASE 751B-03 ORDERING INFORMATION SN54LSXXXJ SN74LSXXXN SN74LSXXXD Ceramic Plastic SOIC 1 A0 2 A1 3 Da 4 Q0a 5 Q1a 6 Q2a 7 Q3a 8 GND PIN NAMES LOADING (Note a) HIGH LOW 0.25 U.L. 0.25 U.L. 0.5 U.L. 0.25 U.L. 5 (2.5) U.L. 3 LOGIC SYMBOL 2 1 15 14 13 A0, A1 Da, Db E CL Q0a - Q3a, Q0b - Q3b Address Inputs Data Inputs Enable Input (Active LOW) Clear Input (Active LOW) Parallel Latch Outputs (Note b) 0.5 U.L. 0.5 U.L. 1.0 U.L. 0.5 U.L. 10 U.L. Da E A0 A1 NOTES: a) 1 TTL Unit Load (U.L.) = 40 A HIGH/1.6 mA LOW. b) The Output LOW drive factor is 2.5 U.L. for Military (54) and 5 U.L. for Commercial (74) Temperature Ranges. CL A0 A1 E Db CL Q0b Q1b Q2b Q3b Q0a Q1a Q2a Q3a 4 5 6 7 VCC = PIN 16 GND = PIN 8 9 10 11 12 FAST AND LS TTL DATA 5-421 SN54/74LS256 LOGIC DIAGRAM E 14 3 Da 1 A0 2 A1 CL 15 13 Db 4 5 6 7 9 10 11 12 Q0a VCC = PIN 16 GND = PIN 8 = PIN NUMBERS Q1a Q2a Q3a Q0b Q1b Q2b Q3b TRUTH TABLE CL L L L L L L L L L H H H H H H H H H E H L L L L L L L L H L L L L L L L L D X L H L H L H L H X L H L H L H L H A0 X L L H H L L H H X L L H H L L H H A1 X L L L L H H H H X L L L L H H H H Q0 L L H L L L L L L QN-1 L H QN-1 QN-1 QN-1 QN-1 QN-1 QN-1 Q1 L L L L H L L L L QN-1 QN-1 QN-1 L H QN-1 QN-1 QN-1 QN-1 Q2 L L L L L L H L L QN-1 QN-1 QN-1 QN-1 QN-1 L H QN-1 QN-1 Q3 L L L L L L L L H QN-1 QN-1 QN-1 QN-1 QN-1 QN-1 QN-1 L H MODE Clear Demultiplex Memory Addressable Latch H = HIGH Voltage Level L = LOW Voltage Level X = Immaterial MODE SELECTION E L H L H CL H H L L MODE Addressable Latch Memory Dual 4-Channel Demultiplexer Clear FAST AND LS TTL DATA 5-422 SN54/74LS256 GUARANTEED OPERATING RANGES Symbol VCC TA IOH IOL Supply Voltage Operating Ambient Temperature Range Output Current -- High Output Current -- Low Parameter 54 74 54 74 54, 74 54 74 Min 4.5 4.75 - 55 0 Typ 5.0 5.0 25 25 Max 5.5 5.25 125 70 - 0.4 4.0 8.0 Unit V C mA mA DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified) Limits Symbol VIH VIL VIK VOH Parameter Input HIGH Voltage 54 Input LOW Voltage 74 Input Clamp Diode Voltage Output HIGH Voltage 54, 74 54, 74 VOL Output LOW Voltage 74 Input HIGH Current Others E Input Others E Input IIL IOS ICC Input LOW Current Others E Input Short Circuit Current (Note 1) Power Supply Current - 20 0.35 0.5 20 40 0.1 0.2 - 0.4 - 0.8 - 100 30 V A 2.4 - 0.65 3.5 0.25 0.4 0.8 - 1.5 V V V Min 2.0 0.7 V Typ Max Unit V Test Conditions Guaranteed Input HIGH Voltage for All Inputs Guaranteed Input LOW Voltage for All Inputs VCC = MIN, IIN = - 18 mA VCC = MIN, IOH = MAX, VIN = VIH or VIL per Truth Table IOL = 4.0 mA IOL = 8.0 mA VCC = VCC MIN, VIN = VIL or VIH per Truth Table VCC = MAX, VIN = 2.7 V IIH mA VCC = MAX, VIN = 7.0 V mA mA mA VCC = MAX, VIN = 0.4 V VCC = MAX VCC = MAX Note 1: Not more than one output should be shorted at a time, nor for more than 1 second. AC CHARACTERISTICS (TA = 25C) Limits Symbol tPLH tPHL tPLH tPHL tPLH tPHL tPHL Parameter Turn-Off Delay, Enable to Output Turn-On Delay, Enable to Output Turn-Off Delay, Data to Output Turn-On Delay, Data to Output Turn-Off Delay, Address to Output Turn-On Delay, Address to Output Turn-On Delay, Clear to Output Min Typ 20 16 20 13 20 14 12 Max 27 24 30 20 30 24 23 Unit ns ns ns ns ns ns ns Figure 1 Figure 2 Figure 3 Figure 5 Test Conditions VCC = 5.0 V, CL = 15 pF FAST AND LS TTL DATA 5-423 SN54/74LS256 AC SET-UP REQUIREMENTS (TA = 25C) Limits Symbol ts ts th th tW Parameter Data Setup Time Address Setup Time Data Hold Time Address Hold Time Enable Pulse Width Min 20 0 0 15 15 Typ Max Unit ns Figures 4 & 6 ns ns ns ns Figure 4 Figure 6 Figure 1 VCC = 5.0 V Test Conditions AC WAVEFORMS D D tpw E tpw 1.3 V Q 1.3 V 1.3 V tPHL 1.3 V tPLH 1.3 V tPHL Q tPLH 1.3 V OTHER CONDITIONS: E = L, CL = H, A = STABLE OTHER CONDITIONS: CL = H, A = STABLE Figure 2. Turn-on and Turn-off Delays, Data to Output Figure 1. Turn-on and Turn-off Delays, Enable To Output and Enable Pulse Width A1 1.3 V 1.3 V D th(H) th(L) ts(L) 1.3 V A1 1.3 V 1.3 V E ts(H) tPHL Q1 1.3 V tPLH 1.3 V Q Q=D Q=D OTHER CONDITIONS: E = L, CL = L, D = H OTHER CONDITIONS: C = H, A = STABLE Figure 3. Turn-on and Turn-off Delays, Address to Output Figure 4. Setup and Hold Time, Data to Enable C 1.3 V A tPHL ts E 1.3 V STABLE ADDRESS th 1.3 V Q 1.3 V OTHER CONDITIONS: E = H OTHER CONDITIONS: CL = H Figure 5. Turn-on Delay, Clear to Output Figure 6. Setup Time, Address to Enable (See Notes 1 and 2) NOTES: 1. The Address to Enable Setup Time is the time before the HIGH-to-LOW Enable transition that the Address must be stable so that the correct latch is addressed and the other latches are not affected. 2. The shaded areas indicate when the inputs are permitted to change for predictable output performance. FAST AND LS TTL DATA 5-424 -A- Case 751B-03 D Suffix 16-Pin Plastic SO-16 NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. 3. CONTROLLING DIMENSION: MILLIMETER. DIMENSION A AND B DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER SIDE. 5. 751B 01 IS OBSOLETE, NEW STANDARD 751B 03. 16 9 -B1 8 P 8 PL 0.25 (0.010) M B M R X 45 G -TD 16 PL 0.25 (0.010) M C SEATING PLANE K T B S M F J A S DIM A B C D F G J K M P R MILLIMETERS MIN MAX 9.80 3.80 1.35 0.35 0.40 10.00 4.00 1.75 0.49 1.25 INCHES MIN MAX 0.386 0.150 0.054 0.014 0.016 0.393 0.157 0.068 0.019 0.049 1.27 BSC 0.19 0.10 0 5.80 0.25 0.25 0.25 7 6.20 0.50 0.050 BSC 0.008 0.004 0 0.229 0.010 0.009 0.009 7 0.244 0.019 Case 648-08 N Suffix 16-Pin Plastic -A16 9 NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. 3. CONTROLLING DIMENSION: INCH. DIMENSION L" TO CENTER OF LEADS WHEN FORMED PARALLEL. 4. DIMENSION B" DOES NOT INCLUDE MOLD FLASH. 5. 6. ROUNDED CORNERS OPTIONAL. 648 01 THRU 07 OBSOLETE, NEW STANDARD 648 08. B 1 8 F S C -TK SEATING PLANE L H G D 16 PL 0.25 (0.010) M J M T A M DIM A B C D F G H J K L M S MILLIMETERS MIN MAX 18.80 6.35 3.69 0.39 1.02 19.55 6.85 4.44 0.53 1.77 INCHES MIN MAX 0.740 0.250 0.145 0.015 0.040 0.770 0.270 0.175 0.021 0.070 2.54 BSC 1.27 BSC 0.21 2.80 7.50 0 0.51 0.38 3.30 7.74 10 1.01 0.100 BSC 0.050 BSC 0.008 0.110 0.295 0 0.020 0.015 0.130 0.305 10 0.040 -A16 9 Case 620-09 J Suffix 16-Pin Ceramic Dual In-Line NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. -B1 8 3. DIMENSION L TO CENTER OF LEAD WHEN FORMED PARALLEL. 4. DIM F MAY NARROW TO 0.76 (0.030) WHERE THE LEAD ENTERS THE CERAMIC BODY. C L 5. 620 01 THRU 08 OBSOLETE, NEW STANDARD 620 09. -TSEATING PLANE K E F D 16 PL 0.25 (0.010) M N G T A S M J 16 PL 0.25 (0.010) M T B S DIM A B C D E F G J K L M N MILLIMETERS MIN MAX 19.05 6.10 19.55 7.36 4.19 0.39 0.53 INCHES MIN MAX 0.750 0.240 0.770 0.290 0.165 0.015 0.021 1.27 BSC 1.40 1.77 0.050 BSC 0.055 0.070 2.54 BSC 0.23 0.27 5.08 7.62 BSC 0 0.39 15 0.88 0.100 BSC 0.009 0.011 0.200 0.300 BSC 0 0.015 15 0.035 FAST AND LS TTL DATA 5-425 Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. "Typical" parameters can and do vary in different applications. All operating parameters, including "Typicals" must be validated for each customer application by customer's technical experts. Motorola does not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and hold Motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer. Literature Distribution Centers: USA: Motorola Literature Distribution; P.O. Box 20912; Phoenix, Arizona 85036. EUROPE: Motorola Ltd.; European Literature Centre; 88 Tanners Drive, Blakelands, Milton Keynes, MK14 5BP, England. JAPAN: Nippon Motorola Ltd.; 4-32-1, Nishi-Gotanda, Shinagawa-ku, Tokyo 141, Japan. ASIA PACIFIC: Motorola Semiconductors H.K. Ltd.; Silicon Harbour Center, No. 2 Dai King Street, Tai Po Industrial Estate, Tai Po, N.T., Hong Kong. FAST AND LS TTL DATA 5-426 |
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