Texas Instruments SN75494 Digit Driver Chip aka SN27423, SN27914


The SN75494 provides the same basic function as the SN75492 but with some key differences:

Operates from lower VCC voltages, as low as 3.2 V
The SN75494 provides access to the pre-driver collectors via the VCC pin to allow good saturation of the output transistors
An enable input is provided to allow display blanking

The SN75494 is preferred on designs running on 3 batteries and is typically found in early designs with additional segment drivers (TMS0120).

QUICK-LINK to Display Drivers.

Family Members and Applications

SR-10 and other early LED calculators

Technical Specifications

Item Min Typ Max Unit Comments
VCC 3.2 7.2 8.8 V  
VSS 6.5 7.2 8.8 V  
IL  250     mA VI=6.5 V, VO=3.5 V
IL     0.2 mA Output Leakage Current
VI-VD     10 V  


The SN75494 was manufactured in a 10 um metal gate Bipolar process (metal width = 0.4 mil / 10 um, metal spacing = 0.4 mil / 10 um).

The die size of the SN75494 is approximately tbd mils * tbd mils / tbd mm * tbd mm.


The SN75494 uses a standard 0.3 wide 16-pin DIP (Dual In-line Package with a 0.1 / 2.54 mm lead pitch).

Pin Configuration

Pin IO Function Pin IO Function
1 V VSS 16 V VCC
2 I Digit input 1 15 I Digit input 6
3 O Digit output 1 14 O Digit output 6
4 O Digit output 2 13 O Digit output 5
5 I Digit input 2 12 I Digit input 5
6 O Digit output 3 11 O Digit output 4
7 I Digit input 3 10 I Digit input 4
8 V VDD 9 I Enable drivers

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If you have additions to the above datasheet please email:

Joerg Woerner, February 02, 2001. No reprints without written permission.