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6-BIT UNIVERSAL UP/DOWN COUNTER
SY10E136 SY100E136
FEATURES
s s s s s s s 550MHz count frequency Extended 100E VEE range of -4.2V to -5.5V Look-ahead-carry input and output Fully synchronous up and down counting Asynchronous Master Reset Internal 75K input pull-down resistors Available in 28-pin PLCC package
DESCRIPTION
The SY10/100E136 are 6-bit synchronous, presettable, cascadable universal counters. These devices generate a look-ahead-carry output and accept a look-ahead-carry input. These two features allow for the cascading of multiple E136s for wider bit width counters that operate at very nearly the same frequency as the stand-alone counter. The CLOUT output will pulse LOW for one clock cycle one count before the E136 reaches terminal count. The COUT output will pulse LOW for one clock cycle when the counter reaches terminal count. For more information on utilizing the look-ahead-carry features of the device, please refer to the applications section of this data sheet. The differential COUT output facilitates the E136's use in programmable divider and self-stopping counter applications. Unlike the H136 and other similar universal counter designs, the E136 carry-out and look-ahead-carry-out signals are registered on chip. This design alleviates the glitch problem seen on many counters where the carryout signals are merely gated. Because of this architecture, there are some minor functional differences between the E136 and H136 counters. The user, regardless of familiarity with the H136, should read this data sheet carefully. Note specifically (see block diagram) the operation of the carry-out outputs and the look-aheadcarry-in input when utilizing the Master Reset. When left open, all of the input pins will be pulled LOW via an input pulldown resistor. The Master Reset is an asynchronous signal which, when asserted, will force the Q outputs LOW. The Q outputs need not be terminated for the E136 to function properly. In fact, if these outputs will not be used in a system, it is recommended that they be left open to save power and minimize noise. This practice will minimize switching noise which can reduce the maximum count frequency of the device, or significantly reduce margins against other noise in the system.
PIN CONFIGURATION
VCCO VCCO
25 24 23 22 21
Q5
20 19 18 17
Q4
D3
D4
D5
D2 S2 S1 VEE CLK CIN CLIN
26 27 28 1 2 3 4 5 6 7 8 9 10 11
Q3 Q2 VCC VCCO COUT COUT CLOUT
PLCC TOP VIEW J28-1
16 15 14 13 12
D1
VCCO
MR
Q0
D0
PIN NAMES
Pin D0-D5 Q0-Q5 S1, S2 MR CLK COUT, COUT CLOUT CIN CLIN VCCO Function Preset Data Inputs Differential Data Outputs Mode Control Pins Master Reset Clock Input Carry Out Output (Active LOW) Look-Ahead-Carry Output Carry-In Input (Active LOW) Look-Ahead-Carry Input VCC to Output
VCCO
Q1
Rev.: C
Amendment: /1
1
Issue Date: February, 1998
Micrel
SY10E136 SY100E136
LOGIC DIAGRAM BLOCK DIAGRAM (1)
COUT COUT CLOUT DQ S
QM0
DQ SQ
QM1
QM0
Q5
DQ RQ
D5 Q2 - Q5 BITS 2 - 4 D2 - D4
Q1
DQ RQ
D1 Q0
DQ RQ
D0
S1 S2
DQ S
E136 Universal Up/Down Counter Logic Diagram NOTE: 1. This diagram is provided for understanding of logic operation only. It should not be used for propagation delays as many gate functions are achieved internally without incurring a full gate delay.
CLIN
2
MR CLK
CIN
Micrel
SY10E136 SY100E136
LOGIC TABLE(1) TRUTH DIAGRAM
S1 L L L H H H X S2 L H H L L H X CIN X L H L H X X MR L L L L L L H CLK Z Z Z Z Z Z X Function Preset Parallel Data Inputs Increment (Count Up) Hold Count Decrement (Count Down) Hold Count Hold Count Reset (Qn = LOW; COUT = HIGH)
NOTE: 1. Expanded truth table included on following pages.
LOGIC DIAGRAM EXPANDED TRUTH TABLE(1)
Function Preset Down S1 L H H H H L L L L L L L H H H H H H H H H H H L L L L L L L L L L L L X S2 L L L L L L H H H H H H H H L L L L L L L L H L H H H H H H H H H H H X MR L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L H CIN CLIN CLK X L L L L X L L L L L L X X L H L H H H L L L X L L H L H H L L L L L X X L L L L X L L L L L L X X L L L L L H H L L X L L L L L H L L L L L X Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z X D5 L X X X X H X X X X X X X X X X X X X X X X X H X X X X X X X X X X X X D4 L X X X X H X X X X X X X X X X X X X X X X X H X X X X X X X X X X X X D3 L X X X X H X X X X X X X X X X X X X X X X X H X X X X X X X X X X X X D2 L X X X X H X X X X X X X X X X X X X X X X X H X X X X X X X X X X X X D1 H X X X X L X X X X X X X X X X X X X X X X X L X X X X X X X X X X X X D0 H X X X X L X X X X X X X X X X X X X X X X X L X X X X X X X X X X X X Q5 L L L L H H H H H L L L L L L L L L L L L L L H H H H H H H H L L L L L Q4 L L L L H H H H H L L L L L L L L L L L L L L H H H H H H H H L L L L L Q3 L L L L H H H H H L L L L L L L L L L L L L L H H H H H H H H L L L L L Q2 L L L L H H H H H L L L L L L L L L L L L L L H H H H H H H H L L L L L Q1 H H L L H L L H H L L H H H L L L L L L L L L L L H H H H H H L L H H L Q0 COUT CLOUT H L H L H L H L H L H L L L H H L L L L L L L L H L L H H H H L H L H L H H H L H H H H L H H H H H H H L H H H L L L H H H H L H H L H H H H H H H L H H H H L H H H H H H L H H H H H H H H H H L H H H H H H H H H H
Preset Up
Hold Down Hold Down Hold
Hold Hold Preset Up Hold Up Hold Hold Up
Reset
NOTE: 1. Z = LOW-to-HIGH transition
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Micrel
SY10E136 SY100E136
DC ELECTRICAL CHARACTERISTICS LOGIC DIAGRAM
VEE = VEE (Min.) to VEE (Max.); VCC = VCCO = GND
TA = 0C Symbol IIH IEE Parameter Input HIGH Current Power Supply Current 10E 100E -- -- 125 125 150 150 -- -- 125 125 150 150 -- -- 125 140 150 170 -- -- 150 TA = +25C -- -- 150 TA = +85C Max. 150 Unit A mA Condition -- -- -- --
Min. Typ. Max. Min. Typ.
Max. Min. Typ.
AC ELECTRICAL LOGIC DIAGRAM CHARACTERISTICS
VEE = VEE (Min.) to VEE (Max.); VCC = VCCO = GND
TA = 0C Symbol fCOUNT tPLH tPHL Parameter Maximum Count Frequency Propagation Delay to Output CLK to Q MR to Q CLK to COUT CLK to CLOUT Set-up Time S1, S2 D CLIN CIN Hold Time S1, S2 D CLIN CIN Reset Recovery Time Minimum Pulse Width CLK, MR Rise/Fall Times 20% to 80% COUT Other Min. 550 850 850 800 825 1500 800 150 800 150 150 300 150 1000 700 Typ. 650 1150 1150 1150 1150 650 400 0 400 -200 -250 0 -250 700 400 Max. -- 1450 1450 1300 1400 -- -- -- -- -- -- -- -- -- -- TA = +25C Min. 550 850 850 800 825 1500 800 150 800 150 150 300 150 1000 700 Typ. 650 1150 1150 1150 1150 650 400 0 400 -200 -250 0 -250 700 400 Max. -- 1450 1450 1300 1400 -- -- -- -- -- -- -- -- -- -- TA = +85C Min. 550 850 850 800 825 1500 800 150 800 150 150 300 150 1000 700 Typ. 650 1150 1150 1150 1150 650 400 0 400 -200 -250 0 -250 700 400 Max. -- 1450 1450 1300 1400 ps -- -- -- -- ps -- -- -- -- -- -- ps ps ps 275 300 -- -- 600 700 275 300 -- -- 600 700 275 300 -- -- 600 700 -- -- -- -- -- Unit MHz ps Condition -- --
tS
tH
tRR tPW tr tf
PRODUCT ORDERING CODE
Ordering Code SY10E136JC SY10E136JCTR SY100E136JC SY100E136JCTR Package Type J28-1 J28-1 J28-1 J28-1 Operating Range Commercial Commercial Commercial Commercial
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Micrel
SY10E136 SY100E136
APPLICATIONS INFORMATION LOGIC DIAGRAM
Overview The SY10E/100E136 are 6-bit synchronous, presettable, cascadable universal counters. Using the S1 and S2 control pins, the user can select between preset, count up, count down and hold count. The Master Reset pin will reset the internal counter and set the COUT, CLOUT and CLIN flipflops. Unlike previous 136-type counters, the carry-out outputs will go to a high state during the preset operation. In addition, since the carry-out outputs are registered, they will not go low if terminal count is loaded into the register. The look-ahead-carry-out output functions similarly. Note from the schematic the use of the master information from the least significant bits for control of the two carry-out functions. This architecture not only reduces the carry-out delay, but is essential to incorporate the registered carryout functions. In addition to being faster, the resulting carryout signals are stable and glitch free because these functions are registered. Cascading Multiple E136 Devices Many applications require counters significantly larger than the 6 bits available with the E136. For these applications, several E136 devices can be cascaded to increase the bit width of the counter to meet the needs of the application. In the past, cascading several 136-type universal counters necessarily impacted the maximum count frequency of the resulting counter chain. This performance impact was the result of the terminal count signal of the lower order counters having to ripple through the entire counter chain. As a result, past counters of this type were not widely used in large bit counter applications. An alternative counter architecture similar to the E016 binary counter was implemented to alleviate the need to ripple propagate the terminal count signal. Unfortunately, these types of counters require external gating for cascading designs of more than two devices. In addition to requiring additional components, these external gates limit the cascaded count frequency to a value less than the free running count frequency of a single counter. Although there is a performance impact with this type of architecture, it is minor compared to the impact of the ripple propagate designs. As a result, the E016-type counters have been used extensively in applications requiring very high speed, wide bit width synchronous counters. Several improvements have been incorporated to past universal counter designs in the E136 universal counter. These enhancements make the E136 the unparalleled leader in its class. With the addition of look-ahead-carry features on the terminal count signal, very large counter chains can be designed which function at very nearly the same clock frequency as a single free running device. More importantly, these counter chains require no external gating. Figure 1 below illustrates the interconnect scheme for using the lookahead-carry features of the E136 counter.
Q0 - Q5 CLOCK
Q0 - Q5
Q0 - Q5
Q0 - Q5
CLK LSB
CLK
CLK
CLK MSB
"LO" "LO"
CIN CLIN
COUT CLOUT
"LO"
CIN CLIN
COUT CLOUT
CIN CLIN
COUT CLOUT
CIN CLIN
COUT CLOUT
D0 - D5 111101 CLK CLOUT 111110
D0 - D5 111111
D0 - D5 000000
D0 - D5 000001
COUT
Figure 1. 24-bit Cascaded E136 Counter
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Micrel
SY10E136 SY100E136
CIN CLIN CLK D Q
ACTIVE LOW
Figure 2. Look-Ahead-Carry Input Structure
Note from the waveforms that the look-ahead-carry output (CLOUT) pulses low one clock pulse before the counter reaches terminal count. Also note that both CLOUT and the carry-out pin (COUT) of the device pulse low for only one clock period. The input structure for look-ahead-carry-in (CLIN) and carry-in (CIN) is pictured in Figure 2. The CLIN input is registered and then OR'ed with the CIN input. From the truth table one can see that both the CIN and the CLIN inputs must be in a LOW state for the E136 to be enabled to count (either count up or count down). The CLIN inputs are driven by the CLOUT output of the lower order E136 and, therefore, are only asserted for a single clock period. Since the CLIN input is registered, it must be asserted one clock period prior to the CIN input. If the counter previous to a given counter is at terminal count, its COUT output, and thus the CIN input of the given counter will be in the "LOW" state. This signals the given counter that it will need to count one upon the next terminal count of the least significant counter (LSC). The CLOUT output of the LSC will pulse low one clock period before it reaches terminal count. This CLOUT signal will be clocked into the CLIN input of the higher order counters on the following positive clock transition. Since both CIN and CLIN are in the LOW state, the next clock pulse will cause the least significant counter to roll over and all higher order counters, if signaled by the CIN inputs, to count by one. During the clock pulse in which the higher order counter is counting by one, the CLIN is clocking in the high signal presented by the CLOUT of the LSC. The CINs in the higher order counter will ripple through the chain to update the
count status for the next occurrence of terminal count on the LSC. This ripple propagation will not affect the count frequency as it has 26-1 or 63 clock pulses to ripple through without affecting the count operation of the chain. The only limiting factor which could reduce the count frequency of the chain as compared to a free running single device will be the set-up time of the CLIN input. This limit will consist of the CLK to CLOUT delay of the E136, plus the CLIN set-up time, plus any path length differences between the CLOUT output and the clock. Programmable Divider Using external feedback of the COUT pin, the E136 can be configured as a programmable divider. Figure 3 illustrates the configuration for a 6-bit count-down programmable divider. If for some reason a count-up divider is preferred, the COUT signal is simply fed back to S2 rather than S1. Examination of the truth table for the E136 shows that when both S1 and S2 are LOW, the counter will parallel load on the next positive transition of the clock. If the S2 input is low and the S1 input is high, the counter will be in the count-down mode and will count towards an all zero state upon successive clock pulses. Knowing this and the operation of the COUT output, it becomes a trivial matter to build programmable dividers. For a programmable divider, one must to load a predesignated number into the counter and count to terminal count. Upon terminal count, the counter should automatically reload the divide number. With the architecture shown in Figure 3, when the counter reaches terminal count, the COUT output, and thus the S1 input, will go LOW. This, combined with the low on S2 will cause the counter to load the inputs present on D0-D5. Upon loading the divide value into the counter, COUT will go HIGH as the counter is no longer at terminal count, thereby placing the counter back into the count mode.
Divide Ratio 2 3 4 5 * * 36 37 38 * * 62 63 64 Preset Data Inputs D3 D2 L L L L * * L L L * * H H H L L L H * * L H H * * H H H
D5 L L L L * * H H H * * H H H
D4 L L L L * * L L L * * H H H
D1 L H H L * * H L L * * L H H
D0 H L H L * * H L H * * H L H
Q0 - Q5
S0 CLOCK CLK S1
"LO"
COUT COUT
D0 - D5
Figure 3. 6-bit Programmable Divider
Table 1. Preset Inputs Versus Divide Ratio
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LOAD CLOCK 100100 100011 000011 000010 000001 000000
SY10E136 SY100E136
LOAD
S1
COUT
DIVIDE BY 37
Figure 4. Programmable Divider Waveforms
The exercise of building a programmable divider then becomes simply determining what value to load into the counter to accomplish the desired division. Since the load operation requires a clock pulse, to divide by N, N-1 must be loaded into the counter. A single E136 device is capable of divide ratios of 2 to 64, inclusive. Table 1 outlines the load values for the various divide ratios. Figure 4 presents the waveforms resulting from a divide by 37 operation. Note that the availability of the COUT complimentary output (COUT) allows the user to choose the polarity of the divide by output. For single device programmable counters, the E016 counter is probably a better choice than the E136. The E016 has an internal feedback to control the reloading of the counter. This not only simplifies board design, but also will result in a faster maximum count frequency. For programmable dividers of larger than 8 bits, the
benefits of the E016 diminishes and, in fact, for very wide dividers, the E136 will provide the capability of a faster count frequency. Figure 5 shows the architecture of a 24bit programmable divider implemented using E136 counters. Note the need for one external gate to control the loading of the entire counter chain. An ideal device for the external gating of this architecture would be the 4-input OR function in the 8-lead SOIC ECLinPS LiteTM family. However, the final decision as to what device to use for external gating requires a balancing of performance needs, cost and available board space. Note that because of the need for external gating, the maximum count frequency of a given sized programmable divider will be less than that of a single cascaded counter.
Q0 - Q5
Q0 - Q5
Q0 - Q5
Q0 - Q5
CLOCK
CLK LSB
S1
CLK
S1
CLK
S1
CLK MSB
S1
"LO" "LO" "LO" CIN CLIN COUT CLOUT CIN CLIN COUT CLOUT CIN CLIN COUT CLOUT CIN CLIN COUT CLOUT
D0 - D5
D0 - D5
D0 - D5
D0 - D5
Figure 5. 24-bit Programmable Divider Architecture
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Micrel
SY10E136 SY100E136
28 LEAD PLCC (J28-1)
Rev. 03
MICREL-SYNERGY
TEL
3250 SCOTT BOULEVARD SANTA CLARA CA 95054 USA
FAX
+ 1 (408) 980-9191
+ 1 (408) 914-7878
WEB
http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. (c) 2000 Micrel Incorporated
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