TIL306

• Ripple-blanking input and output for blanking leading or trailing zeroes
• Floating-decimal-point logic capability
• Overriding blanking for suppressing entire display or pulse modulation of LED brightness
• Dual count-enable inputs for parallel lookahead and serial ripple logic to build high-speed fully synchronous, multidigit counter systems with no external logic, minimizing total propagation delay from the clock to the last latch output
• Provision for ripple-count cascading between packages
• Positive-edge-triggered synchronous BCD counter
• Parallel BCD data outputs available to drive logic processors or remote slaved displays simultaneously with data being displayed
• Latch strobe input allows counter to operate while a previous data point is displayed
• Reset-to-zero capability with clear input.

These internally-driven seven-segment light-emitting-diode (LED) displays TIL306 contain a BCD counter, a four-bit latch, and a decoder/LED driver in a single 16-pin package. A description of the functions of the inputs and outputs of these devices are in the terminal function table.

The TTL MSI circuits TIL306 contain the equivalent of 86 gates on a single chip. Logic inputs and outputs are completely TTL/DTL compatible. The buffered inputs are implemented with relatively large resistors in series with the bases of the input transistors to lower drive-current requirements to one-half of that required for a standard Series 54/74 TTL input. The serial-carry input, actually two internal loads, is rated as one standard series 54/74 load.

The TIL306 logic outputs, except RBO, are active pullup, and the latch outputs QA, QB, QC, and QD are each capable of driving three standard Series 54/74 loads at a low logic level or six loads at a high logic level while the maximum-count output is capable of driving five Series 54/74 loads at a low logic level or ten loads at a high logic level. The RBO node with passive pull-up serves as a ripple-blanking output with the capability to drive three Series 54/74 loads.

The TIL306 LED driver outputs are designed specifically to maintain a relatively constant on-level current of approximately 7 mA through each LED segment and decimal point. All inputs are diode clamped to minimize transmission-line effects, thereby simplifying system design. Maximum clock frequency is typically 18 MHz and power dissipation is typically 600 mW with all segments on.