INTEGRATED CIRCUITS DATA SHEET For a complete data sheet, please also download: * The IC06 74HC/HCT/HCU/HCMOS Logic Family Specifications * The IC06 74HC/HCT/HCU/HCMOS Logic Package Information * The IC06 74HC/HCT/HCU/HCMOS Logic Package Outlines 74HC/HCT191 Presettable synchronous 4-bit binary up/down counter Product specification File under Integrated Circuits, IC06 December 1990 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter Overflow/underflow indications are provided by two types of outputs, the terminal count (TC) and ripple clock (RC). The TC output is normally LOW and goes HIGH when a circuit reaches zero in the count-down mode or reaches "15" in the count-up-mode. The TC output will remain HIGH until a state change occurs, either by counting or presetting, or until U/D is changed. Do not use the TC output as a clock signal because it is subject to decoding spikes. The TC signal is used internally to enable the RC output. When TC is HIGH and CE is LOW, the RC output follows the clock pulse (CP). This feature simplifies the design of multistage counters as shown in Figs 5 and 6. FEATURES * Synchronous reversible counting * Asynchronous parallel load * Count enable control for synchronous expansion * Single up/down control input * Output capability: standard * ICC category: MSI GENERAL DESCRIPTION The 74HC/HCT191 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A. In Fig.5, each RC output is used as the clock input to the next higher stage. It is only necessary to inhibit the first stage to prevent counting in all stages, since a HIGH on CE inhibits the RC output pulse as indicated in the function table. The timing skew between state changes in the first and last stages is represented by the cumulative delay of the clock as it ripples through the preceding stages. This can be a disadvantage of this configuration in some applications. The 74HC/HCT191 are asynchronously presettable 4-bit binary up/down counters. They contain four master/slave flip-flops with internal gating and steering logic to provide asynchronous preset and synchronous count-up and count-down operation. Asynchronous parallel load capability permits the counter to be preset to any desired number. Information present on the parallel data inputs (D0 to D3) is loaded into the counter and appears on the outputs when the parallel load (PL) input is LOW. As indicated in the function table, this operation overrides the counting function. Fig.6 shows a method of causing state changes to occur simultaneously in all stages. The RC outputs propagate the carry/borrow signals in ripple fashion and all clock inputs are driven in parallel. In this configuration the duration of the clock LOW state must be long enough to allow the negative-going edge of the carry/borrow signal to ripple through to the last stage before the clock goes HIGH. Since the RC output of any package goes HIGH shortly after its CP input goes HIGH there is no such restriction on the HIGH-state duration of the clock. Counting is inhibited by a HIGH level on the count enable (CE) input. When CE is LOW internal state changes are initiated synchronously by the LOW-to-HIGH transition of the clock input. The up/down (U/D) input signal determines the direction of counting as indicated in the function table. The CE input may go LOW when the clock is in either state, however, the LOW-to-HIGH CE transition must occur only when the clock is HIGH. Also, the U/D input should be changed only when either CE or CP is HIGH. December 1990 74HC/HCT191 In Fig.7, the configuration shown avoids ripple delays and their associated restrictions. Combining the TC signals from all the preceding stages forms the CE input for a given stage. An enable must be included in each carry gate in order to inhibit counting. The TC output of a given stage it not affected by its own CE signal therefore the simple inhibit scheme of Figs 5 and 6 does not apply. 2 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 QUICK REFERENCE DATA GND = 0 V; Tamb = 25 C; tr = tf = 6 ns TYPICAL SYMBOL PARAMETER CONDITIONS UNIT HC tPHL/ tPLH propagation delay CP to Qn fmax maximum clock frequency CI input capacitance CPD power dissipation capacitance per package CL = 15 pF; VCC = 5 V notes 1 and 2 Notes 1. CPD is used to determine the dynamic power dissipation (PD in W): PD = CPD x VCC2 x fi + (CL x VCC2 x fo) where: fi = input frequency in MHz fo = output frequency in MHz (CL x VCC2 x fo) = sum of outputs CL = output load capacitance in pF VCC = supply voltage in V 2. For HC the condition is VI = GND to VCC For HCT the condition is VI = GND to VCC -1.5 V ORDERING INFORMATION See "74HC/HCT/HCU/HCMOS Logic Package Information". December 1990 3 HCT 22 22 ns 36 36 MHz 3.5 3.5 pF 31 33 pF Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 PIN DESCRIPTION PIN NO. SYMBOL NAME AND FUNCTION 3, 2, 6, 7 Q0 to Q3 flip-flop outputs 4 CE count enable input (active LOW) 5 U/D up/down input 8 GND ground (0 V) 11 PL parallel load input (active LOW) 12 TC terminal count output 13 RC ripple clock output (active LOW) 14 CP clock input (LOW-to-HIGH, edge triggered) 15, 1, 10, 9 D0 to D3 data inputs 16 VCC positive supply voltage Fig.1 Pin configuration. December 1990 Fig.2 Logic symbol. 4 Fig.3 IEC logic symbol. Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 Fig.4 Functional diagram. FUNCTION TABLE INPUTS OUTPUTS OPERATING MODE PL U/D CE CP Dn Qn parallel load L L X X X X X X L H L H count up H L I X count up count down H H I X count down hold (do nothing) H X H X X no change TC AND RC FUNCTION TABLE INPUTS TERMINAL COUNT STATE OUTPUTS U/D CE CP Q0 Q1 Q2 Q3 TC RC H L L L H H H H L H H L X X H H H L L L H H H L L L H H H L L L H H H L L L L H H H L H H H X X Notes 1. H = HIGH voltage level L = LOW voltage level I = LOW voltage level one set-up time prior to the LOW-to-HIGH CP transition X = don't care = LOW-to-HIGH CP transition = one LOW level pulse = TC goes LOW on a LOW-to-HIGH CP transition December 1990 5 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 Fig.5 N-stage ripple counter using ripple clock. Fig.6 Synchronous n-stage counter using ripple carry/borrow. Fig.7 Synchronous n-stage counter with parallel gated carry/borrow. December 1990 6 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 Sequence Load (preset) to binary thirteen; count up to fourteen, fifteen, zero, one and two; inhibit; count down to one, zero, fifteen, fourteen and thirteen. Fig.8 Typical load, count and inhibit sequence. Fig.9 Logic diagram. December 1990 7 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 DC CHARACTERISTICS FOR 74HC For the DC characteristics see "74HC/HCT/HCU/HCMOS Logic Family Specifications". Output capability: standard ICC category: MSI AC CHARACTERISTICS FOR 74HC GND = 0 V; tr = tf = 6 ns; CL = 50 pF Tamb (C) TEST CONDITIONS 74HC SYMBOL PARAMETER +25 -40 to +85 min. typ. max. min. -40 to +125 max. min. max. UNIT V CC (V) WAVEFORMS tPHL/ tPLH propagation delay CP to Qn 72 26 21 220 44 37 275 55 47 330 66 56 ns 2.0 4.5 6.0 Fig.10 tPHL/ tPLH propagation delay CP to TC 83 30 24 255 51 43 320 64 54 395 77 65 ns 2.0 4.5 6.0 Fig.10 tPHL/ tPLH propagation delay CP to RC 47 17 14 150 30 26 190 38 33 225 45 38 ns 2.0 4.5 6.0 Fig.11 tPHL/ tPLH propagation delay CE to RC 33 12 10 130 26 22 165 33 28 195 39 33 ns 2.0 4.5 6.0 Fig.11 tPHL/ tPLH propagation delay Dn to Qn 61 22 18 220 44 37 275 55 47 330 66 56 ns 2.0 4.5 6.0 Fig.12 tPHL/ tPLH propagation delay PL to Qn 61 22 18 220 44 37 275 55 47 330 66 56 ns 2.0 4.5 6.0 Fig.13 tPHL/ tPLH propagation delay U/D to TC 44 16 13 190 38 32 240 48 41 285 57 48 ns 2.0 4.5 6.0 Fig.14 tPHL/ tPLH propagation delay U/D to RC 50 18 14 210 42 36 265 53 45 315 63 54 ns 2.0 4.5 6.0 Fig.14 tTHL/ tTLH output transition time 19 7 6 75 15 13 95 19 16 110 22 19 ns 2.0 4.5 6.0 Fig.15 tW clock pulse width HIGH or LOW 125 25 21 28 10 8 155 31 26 195 39 33 ns 2.0 4.5 6.0 Fig.10 tW parallel load pulse width LOW 100 20 17 22 8 6 125 25 21 150 30 26 ns 2.0 4.5 6.0 Fig.15 December 1990 8 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 Tamb (C) TEST CONDITIONS 74HC SYMBOL PARAMETER +25 min. typ. max. -40 to +85 min. -40 to +125 max. min. UNIT V CC (V) WAVEFORMS max. trem removal time PL to CP 35 7 6 8 3 2 45 9 8 55 11 9 ns 2.0 4.5 6.0 Fig.15 tsu set-up time U/D to CP 205 41 35 50 18 14 255 51 43 310 62 53 ns 2.0 4.5 6.0 Fig.17 tsu set-up time Dn to PL 100 20 17 19 7 6 125 25 21 150 30 26 ns 2.0 4.5 6.0 Fig.16 tsu set-up time CE to CP 140 28 24 44 16 13 175 35 30 210 42 36 ns 2.0 4.5 6.0 Fig.17 th hold time U/D to CP 0 0 0 -39 -14 -11 0 0 0 0 0 0 ns 2.0 4.5 6.0 Fig.17 th hold time Dn to PL 0 0 0 -11 -4 -3 0 0 0 0 0 0 ns 2.0 4.5 6.0 Fig.16 th hold time CE to CP 0 0 0 -28 -10 -8 0 0 0 0 0 0 ns 2.0 4.5 6.0 Fig.17 fmax maximum clock pulse frequency 4.0 20 24 11 33 39 3.2 16 19 2.6 13 15 MHz 2.0 4.5 6.0 Fig.10 December 1990 9 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 DC CHARACTERISTICS FOR 74HCT For the DC characteristics see "74HC/HCT/HCU/HCMOS Logic Family Specifications". Output capability: standard ICC category: MSI Note to HCT types The value of additional quiescent supply current (ICC) for a unit load of 1 is given in the family specifications. To determine ICC per input, multiply this value by the unit load coefficient shown in the table below. INPUT UNIT LOAD COEFFICIENT Dn CP U/D CE, PL 0.5 0.65 1.15 1.5 December 1990 10 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 AC CHARACTERISTICS FOR 74HCT GND = 0 V; tr = tf = 6 ns; CL = 50 pF Tamb (C) TEST CONDITIONS 74HC SYMBOL PARAMETER +25 -40 to +85 min. typ. max. min. -40 to +125 max. min. max. UNIT V CC (V) WAVEFORMS tPHL/ tPLH propagation delay CP to Qn 26 48 60 72 ns 4.5 Fig.10 tPHL/ tPLH propagation delay CP to TC 32 51 64 77 ns 4.5 Fig.10 tPHL/ tPLH propagation delay CP to RC 19 35 44 53 ns 4.5 Fig.11 tPHL/ tPLH propagation delay CE to RC 19 33 41 50 ns 4.5 Fig.11 tPHL/ tPLH propagation delay Dn to Qn 22 44 55 66 ns 4.5 Fig.12 tPHL/ tPLH propagation delay PL to Qn 27 46 58 69 ns 4.5 Fig.13 tPHL/ tPLH propagation delay U/D to TC 23 45 56 68 ns 4.5 Fig.14 tPHL/ tPLH propagation delay U/D to RC 24 45 56 68 ns 4.5 Fig.14 tTHL/ tTLH output transition time 7 15 19 22 ns 4.5 Fig.15 tW clock pulse width HIGH or LOW 16 9 20 24 ns 4.5 Fig.10 tW parallel load pulse width LOW 22 11 28 33 ns 4.5 Fig.15 trem removal time PL to CP 7 1 9 11 ns 4.5 Fig.15 tsu set-up time U/D to CP 41 20 51 62 ns 4.5 Fig.17 tsu set-up time Dn to PL 20 9 25 30 ns 4.5 Fig.16 tsu set-up time CE to CP 30 18 38 45 ns 4.5 Fig.17 th hold time U/D to CP 0 -18 0 0 ns 4.5 Fig.17 th hold time Dn to PL 0 -5 0 0 ns 4.5 Fig.16 th hold time CE to CP 0 -10 0 0 ns 4.5 Fig.17 fmax maximum clock pulse frequency 20 33 16 13 MHz 4.5 Fig.10 December 1990 11 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 AC WAVEFORMS (1) HC : VM = 50%; VI = GND to VCC. HCT : VM = 1.3 V; VI = GND to 3 V. Fig.10 Waveforms showing the clock (CP) to output (Qn) propagation delays, the clock pulse width and the maximum clock pulse frequency. (1) HC : VM = 50%; VI = GND to VCC. HCT : VM = 1.3 V; VI = GND to 3 V. Fig.11 Waveforms showing the clock and count enable inputs (CP, CE) to ripple clock output (RC) propagation delays. (1) HC : VM = 50%; VI = GND to VCC. HCT : VM = 1.3 V; VI = GND to 3 V. Fig.12 Waveforms showing the input (Dn) to output (Qn) propagation delays. December 1990 12 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 (1) HC : VM = 50%; VI = GND to VCC. HCT : VM = 1.3 V; VI = GND to 3 V. Fig.13 Waveforms showing the input (PL) to output (Qn) propagation delays. (1) HC : VM = 50%; VI = GND to VCC. HCT : VM = 1.3 V; VI = GND to 3 V. Fig.14 Waveforms showing the up/down count input (U/D) to terminal count and ripple clock output (TC, RC) propagation delays. (1) HC : VM = 50%; VI = GND to VCC. HCT : VM = 1.3 V; VI = GND to 3 V. Fig.15 Waveforms showing the parallel load input (PL) pulse width, removal time to clock (CP) and the output (Qn) transition times. December 1990 13 Philips Semiconductors Product specification Presettable synchronous 4-bit binary up/down counter 74HC/HCT191 The shaded areas indicate when the input is permitted to change for predictable output performance. (1) HC : VM = 50%; VI = GND to VCC. HCT : VM = 1.3 V; VI = GND to 3 V. Fig.16 Waveforms showing the set-up and hold times from the parallel load input (PL) to the data input (Dn). The shaded areas indicate when the input is permitted to change for predictable output performance. (1) HC : VM = 50%; VI = GND to VCC. HCT : VM = 1.3 V; VI = GND to 3 V. Fig.17 Waveforms showing the set-up and hold times from the count enable and up/down inputs (CE, U/D) to the clock (CP). PACKAGE OUTLINES See "74HC/HCT/HCU/HCMOS Logic Package Outlines". December 1990 14 Philips Semiconductors - PIP - 74HC/HCT191; Presettable synchronous 4-bit binary up/down counter Submit Query Philips Semiconductors Home ProductBuy MySemiconductors ContactProduct Information catalogonline Products MultiMarket Semiconductors * Product Selector Catalog by * Function Catalog by * System * Cross-reference * Packages End of Life * information Distributors Go * Here! * Models * SoC solutions * 74HC/HCT191; Presettable synchronous 4-bit binary up/down counter Information as of 2003-04-22 My.Semiconductors.COM. Your personal service from Use right mouse button to Philips Semiconductors. download datasheet Please register now ! Download datasheet Stay informed General description Features Block diagram Products & packages Buy online Applications Support & tools Parametrics Similar products Datasheet Email/translate General description top The 74HC/HCT191 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A. The 74HC/HCT191 are asynchronously presettable 4-bit binary up/down counters. They contain four master/slave flip-flops with internal gating and steering logic to provide asynchronous preset and synchronous count-up and count-down operation. Asynchronous parallel load capability permits the counter to be preset to any desired number. Information present on the parallel data inputs (D0 to D3) is loaded into the counter and appears on the outputs when the parallel load (PL) input is LOW. As indicated in the function table, this operation overrides the counting function. Counting is inhibited by a HIGH level on the count enable (CE) input. When CE is LOW internal state changes are initiated synchronously by the LOW-to-HIGH transition of the clock input. The up/down (U/D) input signal determines the direction of counting as indicated in the function table. The CE input may go LOW when the clock is in either state, however, the LOW-to-HIGH CE transition must occur only when the clock is HIGH. Also, the U/D input should be changed only when either CE or CP is HIGH. Overflow/underflow indications are provided by two types of outputs, the terminal count (TC) and ripple clock (RC). The TC output is normally LOW and goes HIGH when a circuit reaches zero in the count-down mode or reaches '15' in the count-up-mode. The TC output will remain HIGH until a state change occurs, either by counting or presetting, or until U/D is changed. Do not use the TC output as a clock signal because it is subject to decoding spikes. The TC signal is used internally to enable the RC output. When TC is HIGH and CE is LOW, the RC output follows the clock pulse (CP). This feature simplifies the design of multistage counters as shown in Figs 5 and 6. In Fig.5, each RC output is used as the clock input to the next higher stage. It is only necessary to inhibit the first stage to prevent counting in all stages, since a HIGH on CE inhibits the RC output pulse as indicated in the function table. The timing skew between state changes in the first and last stages is represented by the cumulative delay of the clock as it ripples through the preceding stages. This can be a disadvantage of this configuration in some applications. file:///G|/imaging/BITTING/CPL/20030424/04232003_9/PHGL/_HTML04232003/74HC191N.html (1 of 4) [Apr-29-2003 12:34:20 PM] Philips Semiconductors - PIP - 74HC/HCT191; Presettable synchronous 4-bit binary up/down counter Fig.6 shows a method of causing state changes to occur simultaneously in all stages. The RC outputs propagate the carry/borrow signals in ripple fashion and all clock inputs are driven in parallel. In this configuration the duration of the clock LOW state must be long enough to allow the negative-going edge of the carry/borrow signal to ripple through to the last stage before the clock goes HIGH. Since the RC output of any package goes HIGH shortly after its CP input goes HIGH there is no such restriction on the HIGH-state duration of the clock. In Fig.7, the configuration shown avoids ripple delays and their associated restrictions. Combining the TC signals from all the preceding stages forms the CE input for a given stage. An enable must be included in each carry gate in order to inhibit counting. The TC output of a given stage it not affected by its own CE signal therefore the simple inhibit scheme of Figs 5 and 6 does not apply. Features top Synchronous reversible counting Asynchronous parallel load Count enable control for synchronous expansion Single up/down control input Output capability: standard ICC category: MSI Datasheet top Type number Title Publication release date 74HC/HCT191 Presettable 12/1/1990 synchronous 4-bit binary up/down counter Datasheet status Page count File size (kB) Datasheet Product specification 14 102 Download Download PDF File Additional datasheet info To complete the device datasheet with package and family information, also download the following PDF files. The "Logic Package Information" document is required to determine in which package(s) this device is available. Document 1 Download HCT_FAMILY_SPECIFICATIONS PDF 2 Download File HCT_PACKAGE_INFO PDF 3 Download File HCT_PACKAGE_OUTLINES PDF File Description HC/T Family Specifications, The IC06 74HC/HCT/HCMOS Logic Family Specifications HC/T Package Info, The IC06 74HC/HCT/HCMOS Logic Package Information HC/T Package Outlines, The IC06 74HC/HCT/HCMOS Logic Package Outlines file:///G|/imaging/BITTING/CPL/20030424/04232003_9/PHGL/_HTML04232003/74HC191N.html (2 of 4) [Apr-29-2003 12:34:20 PM] Philips Semiconductors - PIP - 74HC/HCT191; Presettable synchronous 4-bit binary up/down counter Parametrics top Type number Package Description Propagation Voltage No. Power Logic Output Delay(ns) of Dissipation Switching Drive Pins Considerations Levels Capability Presettable Synchronous 4-Bit Binary 15 Up/Down Counter 5 Volts 16 + Low Power or Battery Applications CMOS Low Presettable Synchronous SOT338-1 74HC191DB 4-Bit Binary 15 (SSOP16) Up/Down Counter 5 Volts 16 + Low Power or Battery Applications CMOS Low Presettable Synchronous 4-Bit Binary 15 Up/Down Counter 5 Volts 16 + Low Power or Battery Applications CMOS Low Presettable Synchronous SOT403-1 74HC191PW 4-Bit Binary 15 (TSSOP16) Up/Down Counter 5 Volts 16 + Low Power or Battery Applications CMOS Low SOT109 (SO16) Presettable Synchronous 4-Bit Binary 15 Up/Down Counter; TTL Enabled 5 Volts 16 + Low Power or Battery Applications TTL Low SOT38-1 (DIP16) Presettable Synchronous 4-Bit Binary 15 Up/Down Counter; TTL Enabled 5 Volts 16 + Low Power or Battery Applications TTL Low 74HC191D 74HC191N 74HCT191D 74HCT191N SOT109 (SO16) SOT38-1 (DIP16) Products, packages, availability and ordering top Type number North Ordering code Marking/Packing Package Device status Buy online Discretes American (12NC) Download packing info type number PDF File Standard Marking SOT109 74HC191D 74HC191D 9337 146 00652 * Bulk Pack, Full production order this (SO16) CECC product Standard Marking online SOT109 74HC191D9337 146 00653 * Reel Pack, Full production order this (SO16) T SMD, 13", CECC product Standard Marking SOT338-1 74HC191DB 74HC191DB 9351 886 00112 Full production online order this (SSOP16) * Bulk Pack product file:///G|/imaging/BITTING/CPL/20030424/04232003_9/PHGL/_HTML04232003/74HC191N.html (3 of 4) [Apr-29-2003 12:34:20 PM] - - Philips Semiconductors - PIP - 74HC/HCT191; Presettable synchronous 4-bit binary up/down counter online Standard Marking SOT338-1 74HC191DB9351 886 00118 * Reel Pack, Full production order this (SSOP16) T SMD, 13" product Standard Marking online SOT38-1 74HC191N 74HC191N 9336 694 60652 * Bulk Pack, Full production order this (DIP16) CECC product SOT403-1 online Standard Marking 74HC191PW 74HC191PW 9351 883 70112 (TSSOP16) Full production order this * Bulk Pack product Standard Marking SOT403-1 online 74HC191PW9351 883 70118 * Reel Pack, (TSSOP16) Full production order this T SMD, 13" product Standard Marking online SOT109 74HCT191D 74HCT191D 9337 150 80652 * Bulk Pack, Full production order this (SO16) CECC product Standard Marking online SOT109 74HCT191D9337 150 80653 * Reel Pack, Full production order this (SO16) T SMD, 13", CECC product Standard Marking online SOT38-1 74HCT191N 74HCT191N 9336 700 90652 * Bulk Pack, Full production order this (DIP16) CECC product online - - - - - - - Similar products top 74HC/HCT191 links to the similar products page containing an overview of products that are similar in Products function similar or related to the type number(s) as listed on this page. The similar products page includes products from the same catalog tree(s), relevant selection guides and products from the same functional category. to 74HC/HCT191 Support & tools top HC/T Family Specifications, The IC06 74HC/HCT/HCMOS Logic Family Specifications(date 01-Mar-98) Download Download PDF HC/T User Guide(date 01-Nov-97) File PDF File Email/translate this product information top Email this product information. Translate this product information page from English to: French Translate The English language is the official language used at the semiconductors.philips.com website and webpages. All translations on this website are created through the use of Google Language Tools and are provided for convenience purposes only. No rights can be derived from any translation on this website. About this Web Site | Copyright (c) 2003 Koninklijke Philips N.V. All rights reserved. | Privacy Policy | | Koninklijke Philips N.V. | Access to and use of this Web Site is subject to the following Terms of Use. | file:///G|/imaging/BITTING/CPL/20030424/04232003_9/PHGL/_HTML04232003/74HC191N.html (4 of 4) [Apr-29-2003 12:34:20 PM]