SN74LS248

The SN54/74LS247 thru SN54/74LS249 are BCD-to-Seven-Segment Decoder/Drivers.

The LS247 and LS248 are functionally and electrically identical to the LS47 and LS48 with the same pinout configuration. The LS249 is a 16-pin version of the 14-pin LS49 and includes full functional capability for lamp test and ripple blanking which was not available in the LS49.
The composition of all characters, except the 6 and 9 are identical between the LS247, 248, 249 and the LS47, 48 and 49. The LS47 thru 49 compose the and without tails, the LS247 thru 249 compose the and with the tails. The LS247 has active-low outputs for direct drive of indicators. The LS248 and 249 have active-high outputs for driving lamp buffers.

All types SN54/74LS247 thru SN54/74LS249 feature a lamp test input and have full ripple-blanking input/output controls. On all types an automatic leading and/or trailing-edge zero-blanking control (RBI and RBO) is incorporated and an overriding blanking input (BI) is contained which may be used to control the lamp intensity by pulsing or to inhibit the output's lamp test may be performed at any time when the BI/RBO node is at high level. Segment identification and resultant displays are shown below. Display pattern for BCD input counts above 9 are unique symbols to authenticate input conditions.