# TMI3343B

**TMI** · DC-DC Converters · ESOP-8

TMI3343B from TMI, 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 | High-side gate driver bootstrap pin that supplies the high-side LDMOS gate driver; connect a 100nF capacitor between BS and SW. |
| 2 | IN | power_in | Power input pin, with recommended VIN range of 4.5V to 30V and input overvoltage protection typically at 32V. |
| 3 | SW | output | Switch pin connected to the external inductor; the high-side switch drives it toward IN and the low-side switch returns it to GND. |
| 4 | GND | power_in | Ground pin; the datasheet recommends returning FB, COMP and RT to this signal ground and joining it to power GND at a single point. |
| 5 | FB | input | Feedback pin regulated to the internal 0.8V reference, with a feedback threshold of 784mV to 816mV. |
| 6 | COMP | passive | External compensation pin for the peak current mode control loop. |
| 7 | EN | input | Drive to logic high to enable the IC and logic low to enter micro-power shutdown; do not leave floating, and keep the pull-up EN sink current below 1mA when pulled up to VIN through a resistor. |
| 8 | RT | passive | Connect an external resistor from RT to GND to set the switching frequency, which is adjustable from 50kHz to 1.5MHz. |
| 9 | GND | power_in | Exposed pad ground that should be connected to the power ground copper area with copper and vias for heat dissipation and noise immunity. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | TMI |
| 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 Supply Voltage, SW |  | -0.3 |  | 33 | V |  | 2 |
| BS to SW Voltage |  | -0.3 |  | 6 | V |  | 2 |
| All Other Pins (FB, EN, RT, COMP) Voltage |  | -0.3 |  | 6 | V |  | 2 |
| Storage Temperature Range |  | -50 |  | 150 | °C |  | 2 |
| Junction Temperature |  | -40 |  | 150 | °C |  | 2 |
| Voltage Range | VIN | 4.5 |  | 30 | V |  | 3 |
| Input Voltage Range | VIN | 4.5 |  | 30 | V |  | 4 |
| Feedback Threshold Voltage | VFBTH | 784 | 800 | 816 | mV | PWM operation | 4 |
| EN Rising Threshold |  | 1 | 1.15 | 1.3 | V |  | 4 |
| FB Pin input current | IFB | -50 |  | 50 | nA |  | 4 |
| Input Quiescent Current | IQ |  | 0.38 | 0.48 | mA | VFB=1V | 4 |
| Shutdown Current | ISD |  | 3 | 10 | μA | EN = 0V | 4 |
| Maximum Duty-cycle | DMAX |  |  | 91 | % |  | 4 |
| Under Voltage Lockout | VUVLO |  | 4.3 |  | V | VIN rising | 4 |
| UVLO Hysteresis | VUVLO_HY |  | 0.35 |  | V |  | 4 |
| Input OVP Voltage | VINOVP |  | 32 |  | V |  | 4 |
| Input Supply Current | IIN |  | 0.45 |  | mA | No load | 4 |
| EN Hysteresis |  |  | 100 |  | mV |  | 4 |
| EN sink current | IEN_Sink |  | 1 |  | mA |  | 4 |
| Soft start time | TSS |  | 1.4 |  | ms |  | 4 |
| High-side cycle-by-cycle current limit | ILIM_MAX |  | 4.2 |  | A |  | 4 |
| SW leakage | ISW_LEAK |  | 10 |  | μA |  | 4 |
| Switch On-Resistance (high side) | RDSON_H |  | 120 |  | mΩ |  | 4 |
| Switch On-Resistance (low side) | RDSON_L |  | 80 |  | mΩ |  | 4 |
| Switching Frequency | FSW |  | 1050 |  | kHz | RT=50kΩ | 4 |
| Switching Frequency | FSW |  | 345 |  | kHz | RT=150kΩ | 4 |
| Switching Frequency | FSW |  | 105 |  | kHz | RT=500kΩ | 4 |
| Minimum Turn-on Time | TON_MIN |  | 200 |  | ns |  | 4 |
| FB UV Threshold to Hiccup | VUV |  | 35 |  | % of VREF | VFB refers to VREF | 4 |
| Hiccup on Time |  |  | 2 |  | ms |  | 4 |
| Hiccup Time Before Restart |  |  | 64 |  | ms |  | 4 |
| Thermal Shutdown Threshold | TSDN |  | 160 |  | °C |  | 4 |
| Thermal Shutdown Hysteresis | TSDN_HY |  | 10 |  | °C |  | 4 |
| Junction-to-ambient thermal resistance | θJA |  | 60 |  | °C/W |  | 3 |

## CAD (KiCad official)

- Symbol: `TMI3343B`
- Footprint: `Package_SO:SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.41x3.3mm`
- 3D model: ESOP-8 (KiCad packages3D, STEP)
- 3D model files: `tmi3343b-etched.step` / `tmi3343b-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tmi3343b.step` / `tmi3343b.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [TMI datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8590456248668880896) (15 pp, sha256 `3b83b19504c02345`, retrieved 2026-10-19, 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/tmi3343b-datasheet.pdf)