# 74LCX540FT

**TOSHIBA** · Buffers, Drivers, Receivers, Transceivers · TSSOP-20

74LCX540FT from TOSHIBA, in a TSSOP-20. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | OE1 | input | Active-low output enable 1; when OE1 or OE2 is high the outputs are high-impedance. |
| 2 | A1 | input | Data input 1; unused inputs must be tied to VCC or GND, tolerant to 5.5 V. |
| 3 | A2 | input | Data input 2; unused inputs must be tied to VCC or GND, tolerant to 5.5 V. |
| 4 | A3 | input | Data input 3; unused inputs must be tied to VCC or GND, tolerant to 5.5 V. |
| 5 | A4 | input | Data input 4; unused inputs must be tied to VCC or GND, tolerant to 5.5 V. |
| 6 | A5 | input | Data input 5; unused inputs must be tied to VCC or GND, tolerant to 5.5 V. |
| 7 | A6 | input | Data input 6; unused inputs must be tied to VCC or GND, tolerant to 5.5 V. |
| 8 | A7 | input | Data input 7; unused inputs must be tied to VCC or GND, tolerant to 5.5 V. |
| 9 | A8 | input | Data input 8; unused inputs must be tied to VCC or GND, tolerant to 5.5 V. |
| 10 | GND | power_in | Ground (0 V) supply pin. |
| 11 | Y8 | tri_state | Inverted 3-state output 8 of A8, high-impedance when OE1 or OE2 is high; 24 mA output at VCC 3.0 to 3.6 V. |
| 12 | Y7 | tri_state | Inverted 3-state output 7 of A7, high-impedance when OE1 or OE2 is high; 24 mA output at VCC 3.0 to 3.6 V. |
| 13 | Y6 | tri_state | Inverted 3-state output 6 of A6, high-impedance when OE1 or OE2 is high; 24 mA output at VCC 3.0 to 3.6 V. |
| 14 | Y5 | tri_state | Inverted 3-state output 5 of A5, high-impedance when OE1 or OE2 is high; 24 mA output at VCC 3.0 to 3.6 V. |
| 15 | Y4 | tri_state | Inverted 3-state output 4 of A4, high-impedance when OE1 or OE2 is high; 24 mA output at VCC 3.0 to 3.6 V. |
| 16 | Y3 | tri_state | Inverted 3-state output 3 of A3, high-impedance when OE1 or OE2 is high; 24 mA output at VCC 3.0 to 3.6 V. |
| 17 | Y2 | tri_state | Inverted 3-state output 2 of A2, high-impedance when OE1 or OE2 is high; 24 mA output at VCC 3.0 to 3.6 V. |
| 18 | Y1 | tri_state | Inverted 3-state output 1 of A1, high-impedance when OE1 or OE2 is high; 24 mA output at VCC 3.0 to 3.6 V. |
| 19 | OE2 | input | Active-low output enable 2; when OE1 or OE2 is high the outputs are high-impedance. |
| 20 | VCC | power_in | Positive supply, 1.65 to 3.6 V operating range (absolute maximum -0.5 to 6.5 V). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | TOSHIBA |
| Package | TSSOP-20 |
| Category | Logic |
| Pins | 20 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| High-level input voltage | VIH | 1.7 |  |  | V | VCC = 2.3 to 2.7 V | 4 |
| High-level input voltage | VIH | 2 |  |  | V | VCC = 2.7 to 3.6 V | 4 |
| Low-level input voltage | VIL |  |  | 0.7 | V | VCC = 2.3 to 2.7 V | 4 |
| Low-level input voltage | VIL |  |  | 0.8 | V | VCC = 2.7 to 3.6 V | 4 |
| High-level output voltage | VOH | 1.05 |  |  | V | IOH = -4 mA, VCC = 1.65 V | 4 |
| High-level output voltage | VOH | 1.7 |  |  | V | IOH = -8 mA, VCC = 2.3 V | 4 |
| High-level output voltage | VOH | 2.2 |  |  | V | IOH = -12 mA, VCC = 2.7 V | 4 |
| High-level output voltage | VOH | 2.4 |  |  | V | IOH = -18 mA, VCC = 3.0 V | 4 |
| Low-level output voltage | VOL |  |  | 0.2 | V | IOL = 100 µA, VCC = 1.65 to 3.6 V | 4 |
| Low-level output voltage | VOL |  |  | 0.45 | V | IOL = 4 mA, VCC = 1.65 V | 4 |
| Low-level output voltage | VOL |  |  | 0.7 | V | IOL = 8 mA, VCC = 2.3 V | 4 |
| Low-level output voltage | VOL |  |  | 0.4 | V | IOL = 12 mA, VCC = 2.7 V | 4 |
| Low-level output voltage | VOL |  |  | 0.55 | V | IOL = 24 mA, VCC = 3.0 V | 4 |
| Input leakage current | IIN | -5 |  | 5 | µA | VIN = 0 to 5.5 V, VCC = 1.65 to 3.6 V | 4 |
| Power-OFF leakage current | IOFF |  |  | 10 | µA | VIN/VOUT = 5.5 V, VCC = 0 V | 4 |
| Quiescent supply current | ICC |  |  | 10 | µA | VIN = VCC or GND, VCC = 1.65 to 3.6 V | 4 |
| Quiescent supply current | ΔICC |  |  | 500 | µA | VIH = VCC - 0.6 V (per input), VCC = 2.7 to 3.6 V | 4 |
| Propagation delay time | tPLH,tPHL |  |  | 25 | ns | VCC = 1.8 ± 0.15 V | 5 |
| Propagation delay time | tPLH,tPHL |  |  | 8.5 | ns | VCC = 2.5 ± 0.2 V | 5 |
| Propagation delay time | tPLH,tPHL |  |  | 7.5 | ns | VCC = 2.7 V | 5 |
| Propagation delay time | tPLH,tPHL |  |  | 6.5 | ns | VCC = 3.3 ± 0.3 V | 5 |
| 3-state output enable time | tPZL,tPZH |  |  | 34 | ns | VCC = 1.8 ± 0.15 V | 5 |
| 3-state output enable time | tPZL,tPZH |  |  | 17 | ns | VCC = 2.5 ± 0.2 V | 5 |
| 3-state output enable time | tPZL,tPZH |  |  | 9.5 | ns | VCC = 2.7 V | 5 |
| 3-state output enable time | tPZL,tPZH |  |  | 8.5 | ns | VCC = 3.3 ± 0.3 V | 5 |
| 3-state output disable time | tPLZ,tPHZ |  |  | 32 | ns | VCC = 1.8 ± 0.15 V | 5 |
| 3-state output disable time | tPLZ,tPHZ |  |  | 16 | ns | VCC = 2.5 ± 0.2 V | 5 |
| 3-state output disable time | tPLZ,tPHZ |  |  | 8.5 | ns | VCC = 2.7 V | 5 |
| 3-state output disable time | tPLZ,tPHZ |  |  | 7.5 | ns | VCC = 3.3 ± 0.3 V | 5 |
| Output skew | tosLH,tosHL |  |  | 1 | ns | VCC = 3.3 ± 0.3 V | 5 |
| Supply voltage | VCC | -0.5 |  | 6.5 | V |  | 3 |
| Input voltage | VIN | -0.5 |  | 6.5 | V |  | 3 |
| Output voltage | VOUT | -0.5 |  | 6.5 | V | Output in OFF state (Note 1) | 3 |
| Input diode current | IIK | -50 |  |  | mA |  | 3 |
| Output diode current | IOK | -50 |  | 50 | mA |  | 3 |
| Output current | IOUT | -50 |  | 50 | mA |  | 3 |
| Power dissipation | PD |  |  | 180 | mW |  | 3 |
| VCC/ground current | ICC/IGND | -100 |  | 100 | mA |  | 3 |
| Storage temperature | Tstg | -65 |  | 150 | °C |  | 3 |
| Supply voltage | VCC | 1.65 |  | 3.6 | V | Data retention only per note 1 of the operating range table | 4 |
| Output current (high) | IOH | -24 |  | 24 | mA | VCC = 3.0 to 3.6 V | 4 |
| Output current (low) | IOL | -12 |  | 12 | mA | VCC = 2.7 to 3.0 V | 4 |
| Operating temperature | Topr | -40 |  | 85 | °C |  | 4 |
| Input rise and fall times | dt/dv | 0 |  | 10 | ns/V | VIN = 0.8 to 2.0 V, VCC = 3.0 V | 4 |
| Quiet output maximum dynamic VOL | VOLP |  | 0.8 |  | V | VIH = 3.3 V, VIL = 0 V, VCC = 3.3 V, Ta = 25 °C | 5 |
| Quiet output minimum dynamic VOL | /VOLV/ |  | 0.8 |  | V | VIH = 3.3 V, VIL = 0 V, VCC = 3.3 V, Ta = 25 °C | 5 |
| Input capacitance | CIN |  | 7 |  | pF | fIN = 10 MHz, VCC = 3.3 V | 5 |
| Output capacitance | COUT |  | 8 |  | pF | VCC = 3.3 V | 5 |
| Power dissipation capacitance | CPD |  | 40 |  | pF | VCC = 3.3 V | 5 |

## CAD (KiCad official)

- Symbol: `74LCX540FT`
- Footprint: `Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm`
- 3D model: TSSOP-20 (KiCad packages3D, STEP)
- 3D model files: `74lcx540ft-etched.step` / `74lcx540ft-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `74lcx540ft.step` / `74lcx540ft.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [TOSHIBA datasheet](docs/74lcx540ft-datasheet.pdf) (9 pp, sha256 `24d960886deaf868`, retrieved 2026-10-18, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/74lcx540ft-datasheet.pdf)