Output drive and fan-out limits
The output stage is rated for 400µA source and 8mA sink. That sink current is enough to drive a standard TTL load or a couple of LS inputs, but it will not directly drive an LED or a relay coil without a buffer. If the downstream load pulls more than 8mA low, the output voltage rises above the guaranteed VOL level and the logic-low margin disappears. Keep the fan-out to ten 74LS loads or fewer, and verify the input current of whatever comes next.
Lifecycle and compliance
The SN74LS153D carries an Active product status and is ROHS3 compliant. For new designs, this part is a straightforward choice if the 74LS logic family and 5V supply are already in the BOM.
