View ML688T_4122582.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

ML688T
Dual J-K Flip-Flop
Legacy Device: Motorola MC688T
The negative-edge-clocked dual J-K flip-flop operates on the master-slave principle. His device provides both SET and RESET inputs on both flip-flops in the package. Each flip-flop may be set or reset by applying a low level to that particular input when the clock is low. The J and K inputs are inhibited when the clock is low and enabled when the clock is high. The logical state of the J and K inputs MUST NOT be allowed to change when the clock is in the high state.
Page 1 of 3
www.lansdale.com
Issue 0
ML688T
LANSDALE Semiconductor, Inc.
Page 2 of 3
www.lansdale.com
Issue 0
ML688T
LANSDALE Semiconductor, Inc.
OPERATING NOTES
1. If any of the input of ML688 is not used, it should be returned through a 2k resistor to VCC. This is particularly true of the SET and RESET inputs, as these are most susceptible to noise. A single resistor may be used for up to 300 unused inputs. 2. The truth table shown for ML688 is completely valid only when the J & K inputs remain unchanged throughout the entire period when the clock input is high. This is a masterslave device, with the master receiving its instructions while the clock input is high. A study of the logic diagram will reveal that the J & K inputs are such that the flip-flop should reverse states at the negative clock transition, it will reverse state on the negative clock transition regardless of any subsequent change of J or K. The master-slave principle as used in this device leads to the aforementioned restriction which may not be desir able in some instances. However, it can be shown that an MHTL system is inherently more susceptible to negativegoing nose than positive-going due to the difference in impedance levels.The design of the ML688 is such that negative-going noise appearing on the J or K inputs must last throughout the entire duration of the clock pulse to have any effect. The net result can well be a system with greater than expected noise immunity if care is used in other areas of the system. 3. The SET and RESET inputs control the output states when activated while the clock is low. A logic zero on these inputs has no immediate effect on the outputs if the clock input is high, but it can change the state of the master section. As an example, consider SET & RESET high, all other inputs and Q output low. If a clock pulse is received under these conditions, the output will not change. However, if SET is momentarily activated with a logic zero while clock is high, the flip-flop will reverse states on the trailing edge of the clock. This provides a means of syn chronous data entry into the devices without using J & K inputs. This feature is quite useful in certain types of shift registers and counters made with the ML688. 4. As with other saturated logic devices, input rise and fall times should be minimized for best operation. The most critical input in this respect is CLOCK, which should have a transition time of less than 0.5 sec in either direction (measured from 6.5 to 8.5 volts). Failure to observe this restriction may result in triggering on positive clock transition or multiple triggering on negative clock transition.
Lansdale Semiconductor reserves the right to make changes without further notice to any products herein to improve reliability, function or design. Lansdale does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others. "Typical" parameters which may be provided in Lansdale data sheets and/or specifications can vary in different applications, and actual performance may vary over time. All operating parameters, including "Typicals" must be validated for each customer application by the customer's technical experts. Lansdale Semiconductor is a registered trademark of Lansdale Semiconductor, Inc.
Page 3 of 3
www.lansdale.com
Issue 0

▲Up To Search▲

Price & Availability of ML688T

	To Download ML688T Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .