# MT2499A

**Aerosemi** · DC-DC Converters · ESOP-8

MT2499A from Aerosemi, in a ESOP-8. 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 | BS | passive | Bootstrap pin; a capacitor connected between SW and BS is required to form a floating supply across the high-side switch driver. |
| 2 | VIN | power_in | Power supply input, operating range 4.5V to 21V (absolute maximum -0.3V to 23V). |
| 3 | SW | power_out | Switching node output of the converter (absolute maximum -0.3V to VIN+0.5V). |
| 4 | GND | power_in | Ground. |
| 5 | FB | input | Adjustable version feedback input; connect to the center point of the external resistor divider (0.925V reference, absolute maximum -0.3V to 6V). |
| 6 | NC | unconnected | No connect. |
| 7 | EN | input | Drive to logic-high to enable the IC and to logic-low to disable it and enter micro-power shutdown mode (absolute maximum -0.3V to 23V). |
| 8 | NC | unconnected | No connect. |
| 9 | GND | power_in | Exposed pad (EPAD), connected to ground; connect to a large copper area for cooling. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Aerosemi |
| Package | ESOP-8 |
| Category | Power Management (PMIC) |
| Pins | 9 |

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Input Voltage Range |  | 4.5 |  | 21 | V |  | 3 |
| Supply Current in Operation |  |  | 0.4 | 0.6 | mA | VEN=2.0V, VFB=1.1V | 3 |
| Regulated Feedback Voltage |  | 0.9 | 0.925 | 0.95 | V | TA = 25°C, 4.5V≤VIN ≤21V | 3 |
| OVP |  |  | 22 |  | V |  | 3 |
| High-Side Switch Leakage Current |  |  | 0 | 10 | µA | VEN=0V, VSW=0V | 3 |
| Input Supply Voltage (absolute maximum) |  | -0.3 |  | 23 | V |  | 2 |
| EN Voltages (absolute maximum) |  | -0.3 |  | 23 | V |  | 2 |
| FB Voltages (absolute maximum) |  | -0.3 |  | 6 | V |  | 2 |
| Power Dissipation |  |  |  | 2 | W |  | 2 |
| Junction Temperature |  |  |  | 150 | °C | Note 2 | 2 |
| Operating Temperature Range |  | -40 |  | 85 | °C | Listed under Absolute Maximum Ratings | 2 |
| Storage Temperature Range |  | -65 |  | 150 | °C |  | 2 |
| ESD HBM (Human Body Model) |  |  |  | 2 | kV | Human Body Model | 2 |
| Supply Current in Shutdown |  |  | 1 |  | µA | VEN =0 or EN = GND | 3 |
| High-Side Switch On-Resistance |  |  | 75 |  | mΩ |  | 3 |
| Low-Side Switch On-Resistance |  |  | 55 |  | mΩ |  | 3 |
| Upper Switch Current Limit |  |  | 5.8 |  | A | Minimum Duty Cycle | 3 |
| Oscillation Frequency |  |  | 0.34 |  | MHz |  | 3 |
| Maximum Duty Cycle |  |  | 92 |  | % | VFB=0.6V | 3 |
| EN Shutdown Threshold Voltage |  |  | 1.25 |  | V | VEN Rising | 3 |
| EN Shutdown Threshold Voltage Hysteresis |  |  | 50 |  | mV |  | 3 |
| Input Under Voltage Lockout Threshold |  |  | 4.2 |  | V | VIN Rising | 3 |
| Input Under Voltage Lockout Threshold Hysteresis |  |  | 100 |  | mV |  | 3 |
| Minimum On-Time |  |  | 100 |  | nS |  | 3 |
| Soft-Start |  |  | 1 |  | mS |  | 3 |
| Thermal Shutdown |  |  | 175 |  | ℃ |  | 3 |
| Thermal Resistance θJC | θJC |  | 10 |  | °C/W |  | 2 |
| Thermal Resistance θJA | θJA |  | 50 |  | °C/W |  | 2 |

## CAD (KiCad official)

- Symbol: `MT2499A`
- Footprint: `Package_SO:SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.41x3.3mm`
- 3D model: ESOP-8 (KiCad packages3D, STEP)
- 3D model files: `mt2499a-etched.step` / `mt2499a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mt2499a.step` / `mt2499a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Aerosemi datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8589835277830291456) (10 pp, sha256 `4d03ffe332e40048`, retrieved 2026-10-09, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `claude-sonnet-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/mt2499a-datasheet.pdf)