# BD9E303EFJ-LBE2

**ROHM** · DC-DC Converters · HTSOP-8-EP

BD9E303EFJ-LBE2 from ROHM, in a HTSOP-8-EP. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | BOOT | passive | Bootstrap capacitor terminal for the high-side MOSFET gate driver. Connect a 0.1 µF bootstrap capacitor between BOOT and SW; the voltage on this capacitor is the gate drive voltage of the high-side MOSFET. Absolute max VBOOT: -0.3 to +45 V referenced to GND (ΔVBOOT: -0.3 to +7 V). |
| 2 | VIN | power_in | Power supply input for the switching regulator and internal control circuit. Operating range 7.0 V to 36 V (abs max 40 V). A 10 µF and 0.1 µF ceramic input capacitor combination is recommended. |
| 3 | EN | input | Enable input. Low level (≤0.8 V) forces the device into shutdown; high level (≥2.5 V) enables the device. Must be terminated (do not leave floating). Absolute max 40 V; typical IEN = 4.2 µA at VEN = 3 V. |
| 4 | AGND | power_in | Analog ground for the internal control circuitry. Should be connected to the system ground plane (star-connected to PGND at the exposed pad). |
| 5 | FB | input | Inverting input of the gm error amplifier and feedback sense node. Reference voltage VFB = 1.000 V typ (0.990-1.010 V at TJ=25°C). Set the output voltage via an external resistor divider from VOUT to FB. Abs max -0.3 to +7 V. |
| 6 | COMP | output | Error amplifier output and PWM comparator input. Connect external RC phase-compensation components (typical 15 kΩ + 6800 pF to AGND). Abs max -0.3 to +7 V. |
| 7 | PGND | power_in | Power ground for the switching output stage (return for the low-side MOSFET). Must be tied to AGND at the exposed pad through a low-impedance path. |
| 8 | SW | power_out | Switch node - source of the high-side MOSFET and drain of the low-side MOSFET. Connect the 0.1 µF bootstrap capacitor between SW and BOOT, and the external inductor (e.g. 10 µH) from SW to VOUT. Abs max -0.5 V to VIN+0.3 V. |
| 9 | E-Pad | power_in | Exposed thermal pad on the package bottom. Connect to the internal PCB ground plane using multiple thermal vias for heat dissipation; electrically tied to ground. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | ROHM |
| Package | HTSOP-8-EP |
| Category | PMIC |
| Pins | 9 |

## Ordering variants

Same part, different packaging or reel option.

- `BD9E303EFJ-LBE2`

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Supply Current in Operating | IOPR |  | 2.2 | 3 | mA | VFB = 1.1V, No switching | 5 |
| Supply Current in Standby | ISTBY |  | 0 | 10 | µA | VEN = 0V | 5 |
| Reference Voltage (TJ = 25°C) | VFB | 0.99 | 1 | 1.01 | V | TJ = 25°C | 5 |
| Reference Voltage (TJ = -40 to +150°C) | VFB | 0.965 | 1 | 1.035 | V | TJ = -40 to +150°C | 5 |
| FB Input Current | IFB | -1 | 0 | 1 | µA | VFB = 1.1V | 5 |
| Switching frequency | FOSC | 255 | 300 | 345 | kHz |  | 5 |
| Maximum Duty ratio | Maxduty | 90 | 95 | 99 | % |  | 5 |
| UVLO detection voltage | VUVLO | 4.7 | 5 | 5.3 | V | VIN falling | 5 |
| UVLO hysteresis voltage | VUVLOHYS | 1.2 | 1.4 | 1.6 | V |  | 5 |
| EN high-level input voltage | VENH | 2.5 |  |  | V |  | 5 |
| EN low-level input voltage | VENL | 0 |  | 0.8 | V |  | 5 |
| EN Input current | IEN | 2.1 | 4.2 | 8.4 | µA | VEN = 3V | 5 |
| Soft Start time | TSS | 1.25 | 2.5 | 5 | msec | EN rising to FB=0.85V | 5 |
| Supply Voltage (recommended) | VIN | 7 |  | 36 | V |  | 5 |
| Output Current (recommended) | IOUT | 0 |  | 3 | A |  | 5 |
| Output Voltage Range (recommended) | VRANGE | 1 |  |  | V | Note 2: output pulse width not 200nsec (Typ) or less | 5 |
| Supply Voltage | VIN | -0.3 |  | 40 | V |  | 5 |
| EN Input Voltage | VEN | -0.3 |  | 40 | V |  | 5 |
| Voltage from GND to BOOT | VBOOT | -0.3 |  | 45 | V |  | 5 |
| Voltage from SW to BOOT | ΔVBOOT | -0.3 |  | 7 | V |  | 5 |
| FB Input Voltage | VFB | -0.3 |  | 7 | V |  | 5 |
| COMP Input Voltage | VCOMP | -0.3 |  | 7 | V |  | 5 |
| SW Input Voltage | VSW | -0.5 |  |  | V |  | 5 |
| Allowable Power Dissipation | Pd |  |  | 2.76 | W | Note 1: derate 22mW/°C for operating Ta ≥ 25°C | 5 |
| Operating Junction Temperature Range | Tj | -40 |  | 150 | C |  | 5 |
| Storage Temperature Range | Tstg | -55 |  | 150 | C |  | 5 |
| Thermal resistance, junction to ambient | θJA |  | 45.2 |  | °C / W | ROHM standard JEDEC board, 4-layer PCB (74.2 mm x 74.2 mm copper area on 2nd/3rd layer and reverse side) | 23 |

## CAD (KiCad official)

- Symbol: `BD9E303EFJ-LBE2`
- Footprint: `Package_SO:HTSOP-8-1EP_3.9x4.9mm_P1.27mm_EP2.4x3.2mm`
- 3D model: HTSOP-8-EP (KiCad packages3D, STEP)
- 3D model files: `bd9e303efj-lbe2-etched.step` / `bd9e303efj-lbe2-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bd9e303efj-lbe2.step` / `bd9e303efj-lbe2.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [ROHM datasheet](docs/bd9e303efj-lbe2-datasheet.pdf) (31 pp, sha256 `559a764e9a5064b1`, retrieved 2026-08-17, tier: lcsc)
- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/bd9e303efj-lbe2-datasheet.pdf)