# TMI3256B

**TMI** · DC-DC Converters · DFN-6-EP(2x2)

TMI3256B from TMI, in a DFN-6-EP(2x2). 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 | IN | power_in | Power supply pin; input voltage range is 4.5V to 18V per the recommended operating conditions. |
| 2 | LX | output | Switching pin; absolute maximum LX voltage is -0.3V to 20V, with -4.5V to 22V allowed for transients under 10ns. |
| 3 | GND | power_in | Ground pin. |
| 4 | BS | passive | Bootstrap pin; a capacitor connected between LX and BS is required to form a floating supply across the high-side switch driver. |
| 5 | EN | input | Drive to logic-high to enable the IC and to logic-low to disable it into micro-power shutdown; EN rising threshold is 0.95V to 1.25V and it must not be left floating. |
| 6 | FB | input | Output voltage feedback input connected to the center point of the external resistor divider; regulated feedback voltage is 0.788V to 0.812V. |
| 7 | GND | power_in | Ground and exposed pad; it must be connected to GND. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | TMI |
| Package | DFN-6-EP(2x2) |
| Category | Power Management (PMIC) |
| Pins | 7 |

## 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, EN |  | -0.3 |  | 20 | V |  | 2 |
| LX Voltages |  | -0.3 |  | 20 | V |  | 2 |
| LX Voltages (<10ns transient) |  | -4.5 |  | 22 | V | <10ns transient | 2 |
| FB Voltage |  | -0.3 |  | 6 | V |  | 2 |
| BS Voltage |  | -0.3 |  | 23 | V |  | 2 |
| Storage Temperature Range |  | -65 |  | 150 | °C |  | 2 |
| Junction Temperature |  |  |  | 160 | °C |  | 2 |
| Power Dissipation |  |  |  | 1500 | mW |  | 2 |
| Lead Temperature (Soldering, 10s) |  |  |  | 260 | °C | Soldering, 10s | 2 |
| Voltage Range IN | IN | 4.5 |  | 18 | V |  | 3 |
| TJ Operating Junction Temperature | TJ | -40 |  | 125 | °C |  | 3 |
| Input Voltage Range |  | 4.5 |  | 18 | V |  | 4 |
| OVP Threshold |  | 18 | 19 | 20 | V |  | 4 |
| Quiescent Current |  |  | 340 | 600 | μA | VEN=2V, VFB=VREF x 105% | 4 |
| Shutdown Current |  |  | 5 | 15 | μA | VIN=12V, EN=0V | 4 |
| Regulated Feedback Voltage | VREF | 0.788 | 0.8 | 0.812 | V | TA=25°C | 4 |
| High-Side Switch Leakage Current |  |  | 1 | 10 | μA | VEN=0V, VLX=0V | 4 |
| On Time |  | 132 | 166 | 200 | ns | VIN=12V, VOUT=1.2V, IOUT=1A | 4 |
| Oscillation Frequency |  | 450 | 600 | 750 | kHz |  | 4 |
| Minimum On-Time |  | 70 | 80 | 100 | ns |  | 4 |
| Soft Start Time |  | 0.6 | 1.2 | 1.8 | ms |  | 4 |
| EN Rising Threshold |  | 0.95 | 1.1 | 1.25 | V |  | 4 |
| OVP Hysteresis |  |  | 0.45 |  | V |  | 4 |
| UVLO Rising Threshold |  |  | 4.2 |  | V |  | 4 |
| UVLO Hysteresis |  |  | 0.5 |  | V |  | 4 |
| High-Side Switch On-Resistance |  |  | 30 |  | mΩ |  | 4 |
| Low-Side Switch On-Resistance |  |  | 16 |  | mΩ |  | 4 |
| High-side Switch Peak Current Limit |  |  | 9 |  | A |  | 4 |
| Low-side Switch Valley Current Limit |  |  | 7 |  | A |  | 4 |
| Maximum Duty Cycle |  |  | 84 |  | % |  | 4 |
| Hiccup on Time |  |  | 1.5 |  | ms |  | 4 |
| Hiccup Time Before Restart |  |  | 15 |  | ms |  | 4 |
| EN Hysteresis |  |  | 140 |  | mV |  | 4 |
| Thermal Shutdown Threshold |  |  | 165 |  | °C |  | 4 |
| Thermal Shutdown Hysteresis |  |  | 30 |  | °C |  | 4 |
| Junction-to-ambient thermal resistance | θJA |  | 25 |  | °C/W | JESD51-7, 4-layer PCB | 3 |
| Junction-to-case(top) thermal resistance | θJC |  | 5 |  | °C/W |  | 3 |

## CAD (KiCad official)

- Symbol: `TMI3256B`
- Footprint: `Package_DFN_QFN:DFN-6-1EP_2x2mm_P0.65mm_EP1x1.6mm`
- 3D model: DFN-6-EP(2x2) (KiCad packages3D, STEP)
- 3D model files: `tmi3256b-etched.step` / `tmi3256b-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tmi3256b.step` / `tmi3256b.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [TMI datasheet](docs/tmi3256b-datasheet.pdf) (13 pp, sha256 `30814d9fc50e2041`, retrieved 2026-10-28, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `off` (skipped (clean text read)), 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/tmi3256b-datasheet.pdf)