# LM25118Q1MH

**Texas Instruments** · DC-DC Controllers · HTSSOP-20-EP

LM25118Q1MH from Texas Instruments, in a HTSSOP-20-EP. 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 | VIN | power_in | Input supply voltage pin for the regulator (recommended VIN range 3 V to 42 V). |
| 2 | UVLO | input | Below 1.23 V the regulator stays in standby (VCC running, switching disabled); a fixed 5 µA source out of this pin lets an external divider set the undervoltage threshold. |
| 3 | RT | input | A single resistor from this pin to AGND sets the internal oscillator frequency, recommended range 50 kHz to 500 kHz. |
| 4 | EN | input | Below 0.5 V the regulator enters a low-power state drawing less than 10 µA from VIN; EN must be raised above 3 V for normal operation. |
| 5 | RAMP | input | An external capacitor to AGND sets the ramp slope used for emulated current mode control. |
| 6 | AGND | power_in | Analog ground. |
| 7 | SS | input | An external capacitor and an internal 10 µA source set the rise time of the error amp reference; SS is held low when VCC is below 3.7 V, UVLO is below 1.23 V, EN is below 0.5 V, or thermal shutdown is active. |
| 8 | FB | input | Feedback signal from the regulated output, connected to the inverting input of the internal error amplifier. |
| 9 | COMP | output | Output of the internal error amplifier; the loop compensation network connects between COMP and FB. |
| 10 | VOUT | input | Output voltage monitor for emulated current mode control; connect directly to the regulated output. |
| 11 | SYNC | input | Sync input for synchronizing the switching regulator to an external clock. |
| 12 | CS | input | Current sense input; connect to the diode side of the current sense resistor. |
| 13 | CSG | input | Current sense ground input; connect to the ground side of the current sense resistor. |
| 14 | PGND | power_in | Power ground. |
| 15 | LO | output | Boost MOSFET gate drive output; connect to the gate of the external boost MOSFET. |
| 16 | VCC | power_out | Output of the bias regulator; decouple locally to PGND with a low ESR/ESL capacitor placed as close to the controller as possible. |
| 17 | VCCX | power_in | Optional externally supplied bias input; if above 3.9 V the internal VCC regulator is disabled and VCC is tied to VCCX, and if unused it must be connected to AGND. |
| 18 | HB | input | High-side gate driver bootstrap supply; the bootstrap capacitor between HB and HS should be placed as close to the controller as possible. |
| 19 | HO | output | Buck MOSFET gate drive output; connect to the high-side buck MOSFET gate through a short, low-inductance path. |
| 20 | HS | input | Buck MOSFET source pin; connect to the source of the high-side buck MOSFET and the bootstrap capacitor. |
| 21 | EP | passive | Exposed pad (from the footprint; not named in the datasheet pin table). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | HTSSOP-20-EP |
| Category | Power Supply Chip |
| Pins | 21 |

## CAD (KiCad official)

- Symbol: `LM25118Q1MH`
- Footprint: `Package_SO:TSSOP-20-1EP_4.4x6.5mm_P0.65mm_EP2.15x3.35mm`
- 3D model: HTSSOP-20-EP, generated from the KiCad footprint (body from the F.Fab outline, terminals on the pads, 1.2 mm nominal TSSOP height). Neither the vendor nor KiCad ships a 3D model for this package, so the dimensions are nominal, not the manufacturer's CAD (STEP)
- 3D model files: `lm25118q1mh-etched.step` / `lm25118q1mh-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm25118q1mh.step` / `lm25118q1mh.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/cn/lit/gpn/lm25118-q1) (41 pp, sha256 `39d708876b7ff442`, retrieved 2026-10-11, tier: lcsc)
- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- **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/lm25118q1mh-datasheet.pdf)