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MP9942GJ-Z
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Monolithic Power Systems DC-DC Converters, TSOT-23-8. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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Contents
README
markdownMP9942GJ-Z
Monolithic Power Systems · DC-DC Converters · TSOT-23-8
MP9942GJ-Z from Monolithic Power Systems, in a TSOT-23-8. 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 | PG | output | Open-drain power-good output that goes high when VOUT exceeds 90% of nominal and is pulled low at 84%; it sinks at most 0.3V at 4mA and needs an external pull-up (e.g. 100kΩ) to VCC or another voltage. |
| 2 | IN | power_in | Supply input for the 4V to 36V continuous operating range; decouple with a ceramic input capacitor placed as close to IN and GND as possible and connect with a wide PCB trace. |
| 3 | SW | output | Switch output node that drives the inductor; absolute maximum rating is -0.3V to 41V, and it should be connected with a wide PCB trace. |
| 4 | GND | power_in | System ground and reference for the regulated output; connect to a large copper ground plane with vias near the pin. |
| 5 | BST | passive | Bootstrap pin that, with a capacitor from SW, forms the floating high-side driver supply; a 20Ω series resistor is recommended, and VBS must not exceed VSW+6V. |
| 6 | EN/SYNC | input | Enable input (high enables, low shuts down; floating shuts down via internal 500kΩ pull-down) that also accepts an external clock from 200kHz to 2.2MHz; it is Zener-clamped at 6.5V and must be limited to 6V or less if driven directly without a pull-up resistor. |
| 7 | VCC | power_out | Internal 5V bias regulator output (4.6V to 5.2V at ICC=0mA) that must be decoupled with 0.1µF to 0.22µF and not exceed 0.22µF. |
| 8 | FB | input | Feedback input connected to the output resistor divider tap, referenced to 0.792V, and it causes frequency fold-back when below 660mV to prevent current-limit runaway during a short. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Monolithic Power Systems |
| Package | TSOT-23-8 |
| Category | Power Management (PMIC) |
| Pins | 8 |
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 (Shutdown) | ISHDN | 8 | μA | VEN = 0V | 4 | ||
| Supply Current (Quiescent) | IQ | 0.5 | 0.7 | mA | VEN = 2V, VFB = 1V | 4 | |
| HS Switch-ON Resistance | RON_HS | 90 | 155 | mΩ | VBST-SW=5V | 4 | |
| LS Switch-ON Resistance | RON_LS | 55 | 105 | mΩ | VCC =5V | 4 | |
| Switch Leakage | ILKG_SW | 1 | μA | VEN = 0V, VSW =12V | 4 | ||
| Current Limit | ILIMIT | 3 | 4.2 | 5.5 | A | Under 40% Duty Cycle | 4 |
| Oscillator Frequency | fSW | 320 | 410 | 500 | kHz | VFB=750mV | 4 |
| Fold-Back Frequency | fFB | 70 | 100 | 130 | kHz | VFB<400mV | 4 |
| Maximum Duty Cycle | DMAX | 92 | 95 | % | VFB=750mV, 410kHz | 4 | |
| Minimum ON Time | tON_MIN | 70 | ns | 4 | |||
| Sync Frequency Range | fSYNC | 0.2 | 2.4 | MHz | 4 | ||
| Feedback Voltage | VFB | 780 | 792 | 804 | mV | 4 | |
| Feedback Current | IFB | 10 | 100 | nA | VFB=820mV | 4 | |
| EN Rising Threshold | VEN_RISING | 1.15 | 1.4 | 1.65 | V | 4 | |
| EN Falling Threshold | VEN_FALLING | 1.05 | 1.25 | 1.45 | V | 4 | |
| EN Input Current | IEN | 4 | 6 | μA | VEN=2V | 4 | |
| EN Input Current | IEN | 0 | 0.2 | μA | VEN=0 | 4 | |
| VIN Under-Voltage Lockout Threshold-Rising | INUVRISING | 3.3 | 3.5 | 3.7 | V | 4 | |
| VIN Under-Voltage Lockout Threshold-Falling | INUVFALLING | 3.1 | 3.3 | 3.5 | V | 4 | |
| VCC Regulator | VCC | 4.6 | 4.9 | 5.2 | V | ICC=0mA | 4 |
| VCC Load Regulation | 1.5 | 4 | % | ICC=5mA | 4 | ||
| Soft-Start Period | tSS | 0.55 | 1.45 | 2.45 | ms | VOUT from 10% to 90% | 4 |
| Thermal Shutdown | TSD | 150 | 170 | °C | 4 | ||
| PG Rising Threshold | PGVth_RISING | 86.5 | 90 | 93.5 | % | as percentage of VFB | 4 |
| PG Falling Threshold | PGVth FALLING | 80.5 | 84 | 87.5 | % | as percentage of VFB | 4 |
| PG Rising Delay | PGTd_RISING | 40 | 90 | 160 | μs | 5 | |
| PG Falling Delay | PGTd_FALLING | 30 | 55 | 95 | μs | 5 | |
| PG Sink Current Capability | VPG Sink | 0.1 | 0.3 | V | 4mA | 5 | |
| PG Leakage Current | ILKG_PG | 10 | 100 | nA | 5 | ||
| Input voltage | VIN | -0.3 | 40 | V | 3 | ||
| Switch voltage | VSW | -0.3 | 41 | V | 3 | ||
| All other pins | -0.3 | 6 | V | 3 | |||
| Continuous Power Dissipation | 1.25 | W | TSOT23-8, TA = +25°C | 3 | |||
| Junction Temperature | 150 | °C | 3 | ||||
| Lead Temperature | 260 | °C | 3 | ||||
| Storage Temperature | -65 | 150 | °C | 3 | |||
| Continuous Supply Voltage | VIN | 4 | 36 | V | 3 | ||
| Output Voltage (upper limit VIN*DMAX) | VOUT | 0.8 | V | 3 | |||
| Operating Junction Temperature | TJ | -40 | 125 | °C | 3 | ||
| Thermal Resistance Junction-to-Ambient | θJA | 100 | °C/W | Measured on JESD51-7, 4-layer PCB | 3 | ||
| Thermal Resistance Junction-to-Case | θJC | 55 | °C/W | Measured on JESD51-7, 4-layer PCB | 3 | ||
| VIN Under-Voltage Lockout Threshold-Hysteresis | INUVHYS | 200 | mV | 4 | |||
| EN Threshold Hysteresis | VEN_HYS | 150 | mV | 4 | |||
| Thermal Hysteresis | TSD_HYS | 30 | °C | 4 | |||
| PG Threshold Hysteresis | PGVth_HYS | 6 | % | as percentage of VFB | 5 |
Materials and finish
As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).
| Part | Material | Colour / plating | Datasheet says | Page |
|---|---|---|---|---|
| contacts | copper | 4 GND System Ground. This pin is the reference ground of the regulated output voltage, and PCB layout requires special care. For best results, connect to GND with copper traces and vias. | 6 |
CAD (KiCad official)
- Symbol:
MP9942GJ-Z - Footprint:
Package_TO_SOT_SMD:TSOT-23-8 - 3D model: TSOT-23-8 (KiCad packages3D, STEP)
- 3D model files:
mp9942gj-z-etched.step/mp9942gj-z-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);mp9942gj-z.step/mp9942gj-z.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Monolithic Power Systems datasheet (21 pp, sha256
05378bc62b8ab9d7, retrieved 2026-10-18, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-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).