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| DM74LS161A * DM74LS163A Synchronous 4-Bit Binary Counters August 1986 Revised April 2000 DM74LS161A * DM74LS163A Synchronous 4-Bit Binary Counters General Description These synchronous, presettable counters feature an internal carry look-ahead for application in high-speed counting designs. The DM74LS161A and DM74LS163A are 4-bit binary counters. The carry output is decoded by means of a NOR gate, thus preventing spikes during the normal counting mode of operation. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when so instructed by the count-enable inputs and internal gating. This mode of operation eliminates the output counting spikes which are normally associated with asynchronous (ripple clock) counters. A buffered clock input triggers the four flip-flops on the rising (positive-going) edge of the clock input waveform. These counters are fully programmable; that is, the outputs may be preset to either level. As presetting is synchronous, setting up a low level at the load input disables the counter and causes the outputs to agree with the setup data after the next clock pulse, regardless of the levels of the enable input. The clear function for the DM74LS161A is asynchronous; and a low level at the clear input sets all four of the flip-flop outputs LOW, regardless of the levels of clock, load, or enable inputs. The clear function for the DM74LS163A is synchronous; and a low level at the clear inputs sets all four of the flip-flop outputs LOW after the next clock pulse, regardless of the levels of the enable inputs. This synchronous clear allows the count length to be modified easily, as decoding the maximum count desired can be accomplished with one external NAND gate. The gate output is connected to the clear input to synchronously clear the counter to all low outputs. The carry look-ahead circuitry provides for cascading counters for n-bit synchronous applications without additional gating. Instrumental in accomplishing this function are two count-enable inputs and a ripple carry output. Both count-enable inputs (P and T) must be HIGH to count, and input T is fed forward to enable the ripple carry output. The ripple carry output thus enabled will produce a highlevel output pulse with a duration approximately equal to the high-level portion of the QA output. This high-level overflow ripple carry pulse can be used to enable successive cascaded stages. HIGH-to-LOW level transitions at the enable P or T inputs may occur, regardless of the logic level of the clock. These counters feature a fully independent clock circuit. Changes made to control inputs (enable P or T or load) that will modify the operating mode have no effect until clocking occurs. The function of the counter (whether enabled, disabled, loading, or counting) will be dictated solely by the conditions meeting the stable set-up and hold times. Features s Synchronously programmable s Internal look-ahead for fast counting s Carry output for n-bit cascading s Synchronous counting s Load control line s Diode-clamped inputs s Typical propagation time, clock to Q output 14 ns s Typical clock frequency 32 MHz s Typical power dissipation 93 mW Ordering Code: Order Number DM74LS161AM DM74LS161AN DM74LS163AM DM74LS163AN Package Number M16A N16E M16A N16E Package Description 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Devices also available in Tape and Reel. Specify by appending the suffix letter "X" to the ordering code. (c) 2000 Fairchild Semiconductor Corporation DS006397 www.fairchildsemi.com DM74LS161A * DM74LS163A Connection Diagram Logic Diagram DM74LS163A The DM74LS161A is similar, however, the clear buffer is connected directly to the flip-flops. www.fairchildsemi.com 2 DM74LS161A * DM74LS163A Parameter Measurement Information Switching Time Waveforms The input pulses are supplied by generators having the following characteristics: PRR 1 MHz, duty cycle 50%, ZOUT 50, tR 10 ns, tF 10 ns. Vary PRR to measure fMAX. Outputs QD and carry are tested at tN+16 where tN is the bit time when all outputs are LOW. VREF = 1.5V. Switching Time Waveforms The input pulses are supplied by generators having the following characteristics: PRR 1 MHz, duty cycle 50%, ZOUT 50, tR 6 ns, tF 6 ns. Vary PRR to measure fMAX. Enable P and enable T setup times are measured at tN+0. VREF = 1.3V. 3 www.fairchildsemi.com DM74LS161A * DM74LS163A Timing Diagram LS161A, LS163A Synchronous Binary Counters Typical Clear, Preset, Count and Inhibit Sequences Sequence: (1) Clear outputs to zero (2) Preset to binary twelve (3) Count to thirteen, fourteen, fifteen, zero, one, and two (4) Inhibit www.fairchildsemi.com 4 DM74LS161A * DM74LS163A Absolute Maximum Ratings(Note 1) Supply Voltage Input Voltage Operating Free Air Temperature Range Storage Temperature Range 7V 7V 0C to +70C -65C to +150C Note 1: The "Absolute Maximum Ratings" are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The "Recommended Operating Conditions" table will define the conditions for actual device operation. DM74LS161A Recommended Operating Conditions Symbol VCC VIH VIL IOH IOL fCLK tW Supply Voltage HIGH Level Input Voltage LOW Level Input Voltage HIGH Level Output Current LOW Level Output Current Clock Frequency (Note 2) Clock Frequency (Note 3) Pulse Width (Note 2) Pulse Width (Note 3) tSU Setup Time (Note 2) Setup Time (Note 3) tH Hold Time (Note 2) Hold Time (Note 3) tREL TA Clock Clear Clock Clear Data Enable P Load Data Enable P Load Data Others Data Others 0 0 20 20 25 25 20 25 25 20 30 30 0 0 5 5 20 25 0 70 -3 -3 ns ns ns ns C ns 8 17 15 ns 6 9 Parameter Min 4.75 2 0.8 -0.4 8 25 20 Nom 5 Max 5.25 Units V V V mA mA MHz MHz ns ns Clear Release Time (Note 2) Clear Release Time (Note 3) Free Air Operating Temperature Note 2: CL = 15 pF, RL = 2 k, TA = 25C and VCC = 5.5V. Note 3: CL = 50 pF, RL = 2 k, TA = 25C and VCC = 5.5V. 5 www.fairchildsemi.com DM74LS161A * DM74LS163A DM74LS161A Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol VI VOH VOL Parameter Input Clamp Voltage HIGH Level Output Voltage LOW Level Output Voltage II Input Current @ Max Input Voltage Conditions VCC = Min, II = -18 mA VCC = Min, IOH = Max VIL = Max, VIH = Min VCC = Min, IOL = Max VIL = Max, VIH = Min IOL = 4 mA, VCC = Min VCC = Max VI = 7V Enable T Clock Load Others IIH HIGH Level Input Current VCC = Max VI = 2.7V Enable T Clock Load Others IIL LOW Level Input Current VCC = Max VI = 0.4V Enable T Clock Load Others IOS ICCH ICCL Short Circuit Output Current VCC = Max (Note 5) -20 18 19 Supply Current with Outputs HIGH VCC = Max (Note 6) Supply Current with Outputs LOW VCC = Max (Note 7) 2.7 3.4 0.35 0.25 0.5 0.4 0.2 0.2 0.2 0.1 40 40 40 20 -0.8 -0.8 -0.8 -0.4 -100 31 32 mA mA mA mA A mA Min Typ (Note 4) Max -1.5 Units V V V Note 4: All typicals are at VCC = 5V, TA = 25C. Note 5: Not more than one output should be shorted at a time, and the duration should not exceed one second. Note 6: ICCH is measured with the load HIGH, then again with the load LOW, with all other inputs HIGH and all outputs OPEN. Note 7: ICCL is measured with the clock input HIGH, then again with the clock input LOW, with all other inputs LOW and all outputs OPEN. DM74LS161A Switching Characteristics at VCC = 5V and TA = 25C From (Input) Symbol Parameter To (Output) CL = 15 pF Min fMAX tPLH tPHL tPLH tPHL tPLH tPHL tPLH tPHL tPHL Maximum Clock Frequency Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time HIGH-to-LOW Level Output Clock to Ripple Carry Clock to Ripple Carry Clock to Any Q (Load HIGH) Clock to Any Q (Load HIGH) Clock to Any Q (Load LOW) Clock to Any Q (Load LOW) Enable T to Ripple Carry Enable T to Ripple Carry Clear to Any Q 25 25 30 22 27 24 27 14 15 28 Max RL = 2 k CL = 50 pF Min 20 30 38 27 38 30 38 27 27 45 Max MHz ns ns ns ns ns ns ns ns ns Units www.fairchildsemi.com 6 DM74LS161A * DM74LS163A DM74LS163A Recommended Operating Conditions Symbol VCC VIH VIL IOH IOL fCLK tW Supply Voltage HIGH Level Input Voltage LOW Level Input Voltage HIGH Level Output Current LOW Level Output Current Clock Frequency (Note 8) Clock Frequency (Note 9) Pulse Width (Note 8) Pulse Width (Note 9) tSU Setup Time (Note 8) Setup Time (Note 9) tH Hold Time (Note 8) Hold Time (Note 9) tREL TA Clear Release Time (Note 8) Clear Release Time (Note 9) Free Air Operating Temperature Note 8: CL = 15 pF, RL = 2 k, TA = 25C and VCC = 5V. Note 9: CL = 50 pF, RL = 2 k, TA = 25C and VCC = 5V. Parameter Min 4.75 2 Nom 5 Max 5.25 0.8 -0.4 8 Units V V V mA mA MHz MHz ns ns 0 0 Clock Clear Clock Clear Data Enable P Load Data Enable P Load Data Others Data Others 20 20 25 25 20 25 25 20 30 30 0 0 5 5 20 25 0 -3 -3 8 17 15 6 9 25 20 ns ns ns ns ns ns 70 C DM74LS163A Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol VI VOH VOL Parameter Input Clamp Voltage HIGH Level Output Voltage LOW Level Output Voltage II Input Current @ Max Input Voltage Conditions VCC = Min, II = -18 mA VCC = Min, IOH = Max VIL = Max, VIH = Min VCC = Min, IOL = Max VIL = Max, VIH = Min IOL = 4 mA, VCC = Min VCC = Max VI = 7V Enable T Clock, Clear Load Others IIH HIGH Level Input Current VCC = Max VI = 2.7V Enable T Load Clock, Clear Others IIL LOW Level Input Current VCC = Max VI = 0.4V Enable T Clock, Clear Load Others IOS ICCH ICCL Short Circuit Output Current VCC = Max (Note 11) -20 18 18 Supply Current with Outputs HIGH VCC = Max (Note 12) Supply Current with Outputs LOW VCC = Max (Note 13) 2.7 3.4 0.35 0.25 0.5 0.4 0.2 0.2 0.2 0.1 40 40 40 20 -0.8 -0.8 -0.8 -0.4 -100 31 32 mA mA mA mA A mA Min Typ (Note 10) Max -1.5 Units V V V Note 10: All typicals are at VCC = 5V, TA = 25C. Note 11: Not more than one output should be shorted at a time, and the duration should not exceed one second. Note 12: ICCH is measured with the load HIGH, then again with the load LOW, with all other inputs HIGH and all outputs OPEN. Note 13: ICCL is measured with the clock input HIGH, then again with the clock input LOW, with all other inputs LOW and all outputs OPEN. 7 www.fairchildsemi.com DM74LS161A * DM74LS163A DM74LS163A Switching Characteristics at VCC = 5V and TA = 25C From (Input) Symbol fMAX tPLH tPHL tPLH tPHL tPLH tPHL tPLH tPHL tPHL Parameter Maximum Clock Frequency Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time LOW-to-HIGH Level Output Propagation Delay Time HIGH-to-LOW Level Output Propagation Delay Time HIGH-to-LOW Level Output Clock to Ripple Carry Clock to Ripple Carry Clock to Any Q (Load HIGH) Clock to Any Q (Load HIGH) Clock to Any Q (Load LOW) Clock to Any Q (Load LOW) Enable T to Ripple Carry Enable T to Ripple Carry Clear to Any Q (Note 14) To (Output) CL = 15 pF Min 25 25 30 22 27 24 27 14 15 28 Max RL = 2 k CL = 50 pF Min 20 30 38 27 38 30 38 27 27 45 Max MHz ns ns ns ns ns ns ns ns ns Units Note 14: The propagation delay clear to output is measured from the clock input transition. www.fairchildsemi.com 8 DM74LS161A * DM74LS163A Physical Dimensions inches (millimeters) unless otherwise noted 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow Package Number M16A 9 www.fairchildsemi.com DM74LS161A * DM74LS163A Synchronous 4-Bit Binary Counters Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Package Number N16E Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications. LIFE SUPPORT POLICY FAIRCHILD'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. www.fairchildsemi.com 10 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com |
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