# LM43603AQPWPTQ1

**Texas Instruments** · DC-DC Converters · HTSSOP-16-EP

LM43603AQPWPTQ1 from Texas Instruments, in a HTSSOP-16-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 | SW | power_out | Switching output of the regulator, internally connected to both power MOSFETs; connect to the power inductor. |
| 2 | SW | power_out | Switching output of the regulator, internally connected to both power MOSFETs; connect to the power inductor. |
| 3 | CBOOT | passive | Bootstrap capacitor connection for the high-side driver; connect a high-quality 470-nF capacitor from CBOOT to SW. |
| 4 | VCC | power_out | Internal bias supply output for bypassing to AGND; do not connect external loading to this pin and never short it to ground during operation. |
| 5 | BIAS | power_in | Optional internal LDO supply input, recommended tied to VOUT for 3.3 V ≤ VOUT ≤ 28 V; BIAS pin voltage should never exceed VIN, and the pin must be tied to ground when unused and not left floating. |
| 6 | SYNC | input | Clock input to synchronize switching action to an external clock; use proper high-speed termination, connect to ground if not used, and do not float. |
| 7 | RT | passive | Resistor connection from this pin to AGND programs the switching frequency; leave floating for the 500 kHz default. |
| 8 | PGOOD | output | Open-drain power-good flag output; use a 10-kΩ to 100-kΩ pullup to a logic rail or DC voltage no higher than 12 V. |
| 9 | FB | input | Feedback sense input connected to the midpoint of the feedback divider to set VOUT; do not short this pin to ground during operation. |
| 10 | AGND | power_in | Analog ground pin serving as the ground reference for internal references and logic; connect to system ground. |
| 11 | SS/TRK | passive | Soft-start control pin: leave floating for internal soft-start slew rate, connect a capacitor to extend soft-start time, or connect an external voltage ramp for tracking. |
| 12 | EN | input | Enable input to the internal LDO and regulator, high = ON and low = OFF; connect to VIN, a resistor divider, or an external voltage or logic source and do not float. |
| 13 | VIN | power_in | Supply input to the internal LDO and high-side power FET; bypass with CIN and keep the path from VIN to CIN and PGND as short as possible. |
| 14 | VIN | power_in | Supply input to the internal LDO and high-side power FET; bypass with CIN and keep the path from VIN to CIN and PGND as short as possible. |
| 15 | PGND | power_in | Power ground pin connected internally to the low-side power FET; connect to system ground, PAD, AGND and the CIN and COUT grounds. |
| 16 | PGND | power_in | Power ground pin connected internally to the low-side power FET; connect to system ground, PAD, AGND and the CIN and COUT grounds. |
| 17 | EP | passive | Exposed pad (from the footprint; not named in the datasheet pin table). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | HTSSOP-16-EP |
| Category | Power Supply Chip |
| Pins | 17 |

## CAD (KiCad official)

- Symbol: `LM43603AQPWPTQ1`
- Footprint: `Package_SO:TSSOP-16-1EP_4.4x5mm_P0.65mm`
- 3D model: HTSSOP-16-EP (KiCad packages3D, STEP)
- 3D model files: `lm43603aqpwptq1-etched.step` / `lm43603aqpwptq1-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm43603aqpwptq1.step` / `lm43603aqpwptq1.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/lm43603-q1) (50 pp, sha256 `a594b61b24d8e622`, retrieved 2026-10-08, 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/lm43603aqpwptq1-datasheet.pdf)