[ /Title (CD74 HC297 , CD74 HCT29 7) /Subject (HighSpeed CMOS Logic Digital PhaseLocked CD74HC297, CD74HCT297 Data sheet acquired from Harris Semiconductor SCHS177 High-Speed CMOS Logic Digital Phase-Locked-Loop November 1997 Features Description • Digital Design Avoids Analog Compensation Errors The Harris CD74HC297 and CD74HCT297 are high-speed silicon gate CMOS devices that are pin-compatible with low power Schottky TTL (LSTTL). • Easily Cascadable for Higher Order Loops • Useful Frequency Range - K-Clock . . . . . . . . . . . . . . . . . . . . . . . . . .DC to 55MHz (Typ) - I/D-Clock . . . . . . . . . . . . . . . . . . . . DC to 35MHz (Typ) These devices are designed to provide a simple, cost-effective solution to high-accuracy, digital, phase-locked-loop applications. They contain all the necessary circuits, with the exception of the divide-by-N counter, to build first-order phase-locked-loops. • Dynamically Variable Bandwidth • Very Narrow Bandwidth Attainable Both EXCLUSIVE-OR (XORPD) and edge-controlled phase detectors (ECPD) are provided for maximum flexibility. The input signals for the EXCLUSIVE-OR phase detector must have a 50% duty factor to obtain the maximum lock-range. • Power-On Reset • Output Capability - Standard . . . . . . . . . . . . . . . . . . . . XORPDOUT, ECPDOUT - Bus Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I/DOUT Proper partitioning of the loop function, with many of the building blocks external to the package, makes it easy for the designer to incorporate ripple cancellation (see Figure 2) or to cascade to higher order phase-locked-loops. • Fanout (Over Temperature Range) - Standard Outputs . . . . . . . . . . . . . . . . . . 10 LSTTL Loads - Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads The length of the up/down K-counter is digitally programmable according to the K-counter function table. With A, B, C and D all LOW, the K-counter is disabled. With A HIGH and B, C and D LOW, the K-counter is only three stages long, which widens the bandwidth or capture range and shortens the lock time of the loop. When A, B, C and D are all programmed HIGH, the K-counter becomes seventeen stages long, which narrows the bandwidth or capture range and lengthens the lock time. Real-time control of loop bandwidth by manipulating the A to D inputs can maximize the overall performance of the digital phase-locked-loop. • Balanced Propagation Delay and Transition Times • Significant Power Reduction Compared to LSTTL Logic ICs • CD74HC297 Types - Operation Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 to 6V - High Noise Immunity NIL = 30%, NIH = 30% of VCC at 5V • CD74HCT297 Types - Operation Voltage . . . . . . . . . . . . . . . . . . . . . . . . 4.5 to 5.5V - Direct LSTTL Input Logic Compatibility VIL = 0.8V (Max), VIH = 2V (Min) - CMOS Input Compatibility II ≤ 1µA at VOL, VOH The CD74HC297 and CD74HCT297 can perform the classic first order phase-locked-loop function without using analog components. The accuracy of the digital phase-locked-loop (DPLL) is not affected by VCC and temperature variations but depends solely on accuracies of the K-clock and loop propagation delays. Ordering Information PART NUMBER TEMP. RANGE (oC) PACKAGE PKG. NO. CD74HC297E -55 to 125 16 Ld PDIP E16.3 CD74HCT297E -55 to 125 16 Ld PDIP E16.3 Pinout CD74HC297, CD74HCT297 (PDIP) TOP VIEW NOTES: 1. When ordering, use the entire part number. Add the suffix 96 to obtain the variant in the tape and reel. 2. Wafer or die for this part number is available which meets all electrical specifications. Please contact your local sales office or Harris customer service for ordering information. B 1 16 VCC A 2 15 C ENCTR 3 14 D KCP 4 I/DCP 5 D/U 6 I/DOUT 7 GND 8 CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures. Copyright © Harris Corporation 1997 1 13 φA2 12 ECPDOUT 11 XORPDOUT 10 φB 9 φA 1 File Number 1852.1 CD74HC297, CD74HCT297 Functional Diagram The phase detector generates an error signal waveform that, at zero phase error, is a 50% duty factor square wave. At the limits of linear operation, the phase detector output will be either HIGH or LOW all of the time depending on the direction of the phase error (φIN - φOUT). Within these limits the phase detector output varies linearly with the input phase error according to the gain Kd, which is expressed in terms of phase detector output per cycle or phase error. The phase detector output can be defined to vary between ±1 according to the relation: D 4 KCP 6 D/U 3 C 14 15 B A 1 2 CARRY MODULO-K COUNTER 5 I/DCP 9 φA1 11 10 φB The output of the phase detector will be Kdφe, where the phase error φe = φIN - φOUT. I/DOUT I/D CKT ENCTR %HIGH - %LOW phase detector output = -------------------------------------------100 7 BORROW J 13 φA2 K F/F 12 Q XORPDOUT ECPDOUT FUNCTION TABLE EXCLUSIVE-OR PHASE DETECTOR EXCLUSIVE-OR phase detectors (XORPD) and edge-controlled phase detectors (ECPD) are commonly used digital types. The ECPD is more complex than the XORPD logic function but can be described generally as a circuit that changes states on one of the transitions of its inputs. The gain (Kd) for an XORPD is 4 because its output remains HIGH (XORPDOUT = 1) for a phase error of one quarter cycle. Similarly, Kd for the ECPD is 2 since its output remains HIGH for a phase error of one half cycle. The type of phase detector will determine the zero-phase-error point, i.e., the phase separation of the phase detector inputs for a φe defined to be zero. For the basic DPLL system of Figure 3, φe = 0 when the phase detector output is a square wave. φA1 φB XORPD OUT L L L L H H H L H H H L FUNCTION TABLE EDGE-CONTROLLED PHASE DETECTOR The XORPD inputs are one quarter cycle out-of-phase for zero phase error. For the ECPD, φe = 0 when the inputs are one half cycle out of phase. The phase detector output controls the up/down input to the K-counter. The counter is clocked by input frequency Mfc which is a multiple M of the loop center frequency fc. When the K-counter recycles up, it generates a carry pulse. Recycling while counting down generates a borrow pulse. If the carry and the borrow outputs are conceptually combined into one output that is positive for a carry and negative for a borrow, and if the K-counter is considered as a frequency divider with the ratio Mfc/K, the output of the K-counter will equal the input frequency multiplied by the division ratio. Thus the output from the K-counter is (KdφeMfc)/K. φA2 φB ECPD OUT H or L ↓ H ↓ H or L L H or L ↑ No Change ↑ H or L No Change H = Steady-State High Level, L = Steady-State Low Level, ↑ = LOW to HIGH φ Transition, ↓ = HIGH to LOW φ Transition K-COUNTER FUNCTION TABLE (DIGITAL CONTROL) The carry and borrow pulses go to the increment/decrement (I/D) circuit which, in the absence of any carry or borrow pulses has an output that is one half of the input clock (I/DCP). The input clock is just a multiple, 2N, of the loop center frequency. In response to a carry of borrow pulse, the I/D circuit will either add or delete a pulse at I/DOUT. Thus the output of the I/D circuit will be Nfc + (KdφeMfc)/2K. The output of the N-counter (or the output of the phaselocked-loop) is thus: fo = fc + (KdφeMfc)/2KN. If this result is compared to the equation for a first-order analog phase-locked-loop, the digital equivalent of the gain of the VCO is just Mfc/2KN or fc/K for M = 2N. Thus, the simple first-order phase-locked-loop with an adjustable K-counter is the equivalent of an analog phase-lockedloop with a programmable VCO gain. 2 A MODULO (K) L L Inhibited L H 23 L H L 24 L L H H 25 L H L L 26 L H L H 27 L H H L 28 L H H H 29 H L L L 210 H L L H 211 H L H L 212 H L H H 213 H H L L 214 H H L H 215 H H H L 216 H H H H 217 D C B L L L L L CD74HC297, CD74HCT297 Absolute Maximum Ratings Thermal Information DC Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 7V DC Input Diode Current, IIK For VI < -0.5V or VI > VCC + 0.5V . . . . . . . . . . . . . . . . . . . . . .±20mA DC Output Diode Current, IOK For VO < -0.5V or VO > VCC + 0.5V . . . . . . . . . . . . . . . . . . . .±20mA DC Drain Current, per Output, IO For -0.5V < VO < VCC + 0.5V. . . . . . . . . . . . . . . . . . . . . . . . . .±25mA DC Output Source or Sink Current per Output Pin, IO For VO > -0.5V or VO < VCC + 0.5V . . . . . . . . . . . . . . . . . . . .±25mA DC VCC or Ground Current, ICC . . . . . . . . . . . . . . . . . . . . . . . . .±50mA Thermal Resistance (Typical, Note 2) θJA (oC/W) PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . 150oC Maximum Storage Temperature Range . . . . . . . . . .-65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300oC Operating Conditions Temperature Range, TA . . . . . . . . . . . . . . . . . . . . . . -55oC to 125oC Supply Voltage Range, VCC HC Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2V to 6V HCT Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.5V to 5.5V DC Input or Output Voltage, VI, VO . . . . . . . . . . . . . . . . . 0V to VCC Input Rise and Fall Time 2V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000ns (Max) 4.5V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500ns (Max) 6V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400ns (Max) CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. NOTE: 3. θJA is measured with the component mounted on an evaluation PC board in free air. DC Electrical Specifications TEST CONDITIONS PARAMETER SYMBOL VI (V) High Level Input Voltage VIH - Low Level Input Voltage VIL 25oC IO (mA) VCC (V) -40oC TO 85oC -55oC TO 125oC MIN TYP MAX MIN MAX MIN MAX UNITS 2 1.5 - - 1.5 - 1.5 - V 4.5 3.15 - - 3.15 - 3.15 - V 6 4.2 - - 4.2 - 4.2 - V 2 - - 0.5 - 0.5 - 0.5 V 4.5 - - 1.35 - 1.35 - 1.35 V 6 - - 1.8 - 1.8 - 1.8 V -0.02 2 1.9 - - 1.9 - 1.9 - V -0.02 4.5 4.4 - - 4.4 - 4.4 - V -0.02 6 5.9 - - 5.9 - 5.9 - V -6 (Note 4) 4.5 3.98 - - 3.84 - 3.7 - V -7.8 (Note 4) 6 5.48 - - 5.34 - 5.2 - V 0.02 2 - - 0.1 - 0.1 - 0.1 V 0.02 4.5 - - 0.1 - 0.1 - 0.1 V 0.02 6 - - 0.1 - 0.1 - 0.1 V 4 (Note 4) 4.5 - - 0.26 - 0.33 - 0.4 V 5.2 (Note 4) 6 - - 0.26 - 0.33 - 0.4 V HC TYPES High Level Output Voltage CMOS Loads VOH - VIH or VIL High Level Output Voltage TTL Loads Low Level Output Voltage CMOS Loads Low Level Output Voltage TTL Loads VOL VIH or VIL - - 3 CD74HC297, CD74HCT297 DC Electrical Specifications (Continued) TEST CONDITIONS SYMBOL VI (V) II VCC or GND - ICC VCC or GND High Level Input Voltage VIH Low Level Input Voltage High Level Output Voltage CMOS Loads PARAMETER Input Leakage Current Quiescent Device Current 25oC IO (mA) VCC (V) -40oC TO 85oC -55oC TO 125oC MIN TYP MAX MIN MAX MIN MAX UNITS 6 - - ±0.1 - ±1 - ±1 µA 0 6 - - 8 - 80 - 160 µA - - 4.5 to 5.5 2 - - 2 - 2 - V VIL - - 4.5 to 5.5 - - 0.8 - 0.8 - 0.8 V VOH VIH or VIL -0.02 4.5 4.4 - - 4.4 - 4.4 - V -4 4.5 3.98 - - 3.84 - 3.7 - V 0.02 4.5 - - 0.1 - 0.1 - 0.1 V 4 4.5 - - 0.26 - 0.33 - 0.4 V HCT TYPES High Level Output Voltage TTL Loads Low Level Output Voltage CMOS Loads VOL VIH or VIL Low Level Output Voltage TTL Loads Input Leakage Current Quiescent Device Current Additional Quiescent Device Current Per Input Pin: 1 Unit Load (Note 3) II VCC to GND 0 5.5 - - ±0.1 - ±1 - ±1 µA ICC VCC or GND 0 5.5 - - 8 - 80 - 160 µA ∆ICC VCC -2.1 - 4.5 to 5.5 - 100 360 - 450 - 490 µA NOTE: 4. For dual-supply systems theoretical worst case (VI = 2.4V, VCC = 5.5V) specification is 1.8mA. 5. XORPD, ECPD HCT Input Loading Table INPUT UNIT LOADS ENCTR, D/U 0.3 A, B, C, D, KCP, φA2 0.6 I/DCP, φA1, φB 1.5 NOTE: Unit Load is ∆ICC limit specified in DC Electrical Specifications table, e.g., 360µA max at 25oC. 4 CD74HC297, CD74HCT297 Prerequisite For Switching Function 25oC PARAMETER -40oC TO 85oC -55oC TO 125oC SYMBOL VCC (V) MIN MAX MIN MAX MIN MAX UNITS Maximum Clock Frequency KCP fMAX 2 6 - 5 - 4 - MHz 4.5 30 - 24 - 20 - MHz 6 35 - 28 - 24 - MHz Maximum Clock Frequency I/DCP fMAX 2 4 - 3 - 2 - MHz 4.5 20 - 16 - 13 - MHz 6 24 - 19 - 15 - MHz 2 80 - 100 - 120 - ns 4.5 16 - 20 - 24 - ns 6 14 - 17 - 20 - ns 2 125 - 155 - 190 - ns 4.5 25 - 31 - 38 - ns 6 21 - 26 - 32 - ns 2 100 - 125 - 150 - ns 4.5 20 - 25 - 30 - ns 6 17 - 21 - 26 - ns 2 0 - 0 - 0 - ns 4.5 0 - 0 - 0 - ns 6 0 - 0 - 0 - ns HC TYPES Clock Pulse Width KCP tw Clock Pulse Width I/DCP tW Set-up Time D/U, ENCTR to KCP tSU Hold Time D/U, ENCTR to KCP tH HCT TYPES Maximum Clock Frequency KCP fMAX 4.5 30 - 24 - 20 - MHz Maximum Clock Frequency I/DCP fMAX 4.5 20 - 16 - 13 - MHz Clock Pulse Width KCP tw 4.5 16 - 20 - 24 - ns Clock Pulse Width I/DCP tw 4.5 25 - 31 - 38 - ns Set-up Time D/U, ENCTR to KCP tSU 4.5 20 - 25 - 30 - ns Hold Time D/U, ENCTR to KCP tH 4.5 0 - 0 - 0 - ns Switching Specifications PARAMETER Input tr, tf = 6ns SYMBOL TEST CONDITIONS tPLH, tPHL CL = 50pF 25oC -40oC TO 85oC -55oC TO 125oC VCC (V) TYP MAX MAX MAX UNITS 2 - 175 220 265 ns 4.5 - 35 44 53 ns 6 - 30 34 43 ns HC TYPES Propagation Delay, I/DCP to I/DOUT 5 CD74HC297, CD74HCT297 Switching Specifications PARAMETER Propagation Delay, φA1, φB to XORPDOUT Propagation Delay, φB, φA2 to ECPDOUT Output Transition Time XORPDOUT ECPDOUT Output Transition Time I/DOUT Input Capacitance Input tr, tf = 6ns (Continued) SYMBOL TEST CONDITIONS tPLH, tPHL CL = 50pF tPHL, tPHL tTLH tTLH CI CL = 50pF CL = 50pF CL = 50pF - 25oC -40oC TO 85oC -55oC TO 125oC VCC (V) TYP MAX MAX MAX UNITS 2 - 150 190 225 ns 4.5 - 30 38 45 ns 6 - 26 33 38 ns 2 - 200 250 300 ns 4.5 - 40 50 60 ns 6 - 34 43 51 ns 2 - 75 95 110 ns 4.5 - 15 19 22 ns 6 - 13 16 19 ns 2 - 60 75 90 ns 4.5 - 12 15 18 ns 6 - 10 13 15 ns - - 10 10 10 pF HCT TYPES Propagation Delay, I/DCP to I/DOUT tPLH, tPHL CL = 50pF 4.5 - 35 44 53 ns Propagation Delay, φA1, φB to XORPDOUT tPLH, tPHL CL = 50pF 4.5 - 30 38 45 ns Propagation Delay, φB, φA2 to ECPDOUT tPHL, tPHL CL = 50pF 4.5 - 40 50 60 ns Output Transition Time XORPDOUT tTLH CL = 50pF 4.5 - 15 19 22 ns Output Transition Time ECPDOUT tTLH CL = 50pF 4.5 - 12 15 18 ns - - 10 10 10 pF Input Capacitance CI - 6 CD74HC297, CD74HCT297 Logic Diagram MODULO-K COUNTER 2 1 A B 1 2 4 8 15 C D 14 CONTROL CIRCUIT 14 13 12 11 10 0 9 8 7 6 5 4 3 2 1 TO MODE CONTROLS 12-2 (11 STAGES NOT SHOWN) KCP 4 6 D/U RD D CP FF Q T RD FF Q T FF R Q T FF Q R D D T FF14 R D DQ T FF13 Q M R D DQ T FF1 M M RD T Q FF T Q FF 3 ENCTR D M T CP FF Q D FF R Q D T M FF14 Q T FF1 M Q T FF13 DR D DR Q D DR RD D POWER ON RESET 1=1 1 BORROW CARRY INCREMENT/DECREMENT CIRCUIT 5 I/DCP 7 I/DOUT D D Q CP FF Q Q CP FF Q D D Q CP FF CP FF Q Q CP FF J K D Q CP FF Q φA1 D Q CP FF Q D Q D Q CP FF CP FF Q 9 EXCLUSIVE-OR PHASE DETECTOR 11 XORPDOUT 10 φB EDGE-CONTROLLED PHASE DETECTOR φA2 13 SD Q FF Q RD 12 SD Q FF Q RD ECPDOUT 7 CD74HC297, CD74HCT297 CARRY KCP MfC D/U DIVIDE-BY-K COUNTER ENCTR BORROW XORPDOUT φA1 φB fOUT φOUT I/D CIRCUIT ECPDOUT φA2 fIN φIN J I/DCP 2NfC J ECPD K FF I/DOUT DIVIDE-BY-N COUNTER FIGURE 1. DPLL USING BOTH PHASE DETECTORS IN A RIPPLE-CANCELLATION SCHEME CARRY KCP MfC D/U DIVIDE-BY-K COUNTER BORROW XORPDOUT φA 1 φB fOUT φIN I/D CIRCUIT I/DCP I/DOUT fOUT DIVIDE-BY-N COUNTER φOUT FIGURE 2. DPLL USING EXCLUSIVE-OR PHASE DETECTION CARRY PULSE (INTERNAL SIGNAL) BORROW PULSE (INTERNAL SIGNAL) I/DCP INPUT I/DOUT OUTPUT FIGURE 3. TIMING DIAGRAM: I/DOUT IN-LOCK CONDITION 8 2NfC CD74HC297, CD74HCT297 øB INPUT øA2 INPUT ECPDOUT OUTPUT FIGURE 4. TIMING DIAGRAM: EDGE CONTROLLED PHASE COMPARATOR WAVEFORMS øB INPUT øA1 INPUT XORPDOUT OUTPUT FIGURE 5. TIMING DIAGRAM: EXCLUSIVE OR PHASE DETECTOR WAVEFORMS I/fMAX tW I/DCP VS tPHL tPLH VS I/DOUT tTLH tTHL FIGURE 6. WAVEFORMS SHOWING THE CLOCK (I/DCP) TO OUTPUT (I/DOUT) PROPAGATION DELAYS, CLOCK PULSE WIDTH, OUTPUT TRANSITION TIMES AND MAXIMUM CLOCK PULSE FREQUENCY VS øB INPUT VS øA1 INPUT tTLH XORPDOUT VS OUTPUT tPLH tPLH tPLH tTHL tPHL FIGURE 7. WAVEFORMS SHOWING THE PHASE INPUT (øB, øA1) TO OUTPUT (XORPDOUT) PROPAGATION DELAYS AND OUTPUT TRANSITION TIMES 9 CD74HC297, CD74HCT297 øB INPUT VS øA2 INPUT VS ECPDOUT OUTPUT tPHL VS tPLH tTLH tTHL FIGURE 8. WAVEFORMS SHOWING THE PHASE INPUT (øB, øA2) TO OUTPUT (ECPDOUT) PROPAGATION DELAYS AND OUTPUT TRANSITION TIMES tH D/U, ENCTR INPUT tH VS tSU tSU VS KCP INPUT tW 1/fMAX NOTE: The shaded areas indicate when the input is permitted to change for predictable output performance. FIGURE 9. WAVEFORMS SHOWING THE CLOCK (KCP) PULSE WIDTH AND MAXIMUM CLOCK PULSE FREQUENCY, AND THE INPUT (D/U, ENCTR) TO CLOCK (KCP) SETUP AND HOLD TIMES 10 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. 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