These bus buffers feature three-state outputs that, when enabled, have the low impedance characteristics of a TTL output with additional drive capability at high logic levels to permit driving heavily loaded bus lines without external pullup resistors. When disabled, both output transistors are turned off, presenting a high-impedance state to the bus so the output will act neither as a significant load nor as a driver. The 125 and LS125A devices outputs are disabled when G is high. The 126 and LS126A devices outputs are disabled when G is low.
The SN54125, SN54126, SN74125, SN74126, and SN54LS126A are obsolete and are no longer supplied.
| Technology family | LS |
| Supply voltage (min) (V) | 4.75 |
| Supply voltage (max) (V) | 5.25 |
| Number of channels | 4 |
| IOL (max) (mA) | 24 |
| Supply current (max) (µA) | 22000 |
| IOH (max) (mA) | -2.6 |
| Input type | Bipolar |
| Output type | 3-State |
| Features | High speed (tpd 10-50ns), Input clamp diode |
| Rating | Catalog |
| Operating temperature range (°C) | 0 to 70 |
| PDIP (N) | 14 | 181.42 mm² 19.3 x 9.4 |
| SOIC (D) | 14 | 51.9 mm² 8.65 x 6 |
| SOP (NS) | 14 | 79.56 mm² 10.2 x 7.8 |
| SSOP (DB) | 14 | 48.36 mm² 6.2 x 7.8 |