component
LTC3633AEUFD#TRPBF
Public Made by Adomby adom
Analog Devices DC-DC Converters, QFN-28-EP(4x5). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
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Symbol & Footprint
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README
markdownLTC3633AEUFD#TRPBF
Analog Devices · DC-DC Converters · QFN-28-EP(4x5)
LTC3633AEUFD#TRPBF from Analog Devices, in a QFN-28-EP(4x5). 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 | PGOOD1 | output | Channel 1 open-drain power good output is pulled to ground when VFB1 is outside ±8% (typ) of the 0.6V reference and becomes high impedance once VFB1 is within ±5% (typ). |
| 2 | PHMODE | input | Phase select input: tie to ground to switch both channels in phase or to INTVCC for 180° out of phase, and do not float this pin. |
| 3 | RUN1 | input | Channel 1 enable pin: above 1.22V enables the channel, below 1V places it in shutdown, and it must not be floated. |
| 4 | MODE/SYNC | input | Mode select and external sync input: tie to ground for forced continuous operation, float or tie to INTVCC for Burst Mode operation at light load, or drive with a clock to synchronize switching. |
| 5 | RT | passive | Oscillator frequency program pin: a resistor between 80k and 640k from this pin to SGND sets 500kHz to 4MHz, and tying it to INTVCC defaults the switching frequency to 2MHz. |
| 6 | RUN2 | input | Channel 2 enable pin: above 1.22V enables the channel, below 1V places it in shutdown, and it must not be floated. |
| 7 | SGND | power_in | Signal ground that should have a low-noise connection to reference ground, to which the feedback divider, compensation network and RT resistor must be connected. |
| 8 | PGOOD2 | output | Channel 2 open-drain power good output is pulled to ground when VFB2 is outside ±8% (typ) of the 0.6V reference and becomes high impedance once VFB2 is within ±5% (typ). |
| 9 | VFB2 | input | Channel 2 output feedback input that compares the feedback voltage to the internal 0.6V reference and is connected to a resistor divider to set the output voltage. |
| 10 | TRACKSS2 | input | Channel 2 tracking and soft-start input: forcing a voltage below 0.6V makes the error amplifier servo FB to this voltage, and an internal 1.4µA pull-up from INTVCC allows a soft-start capacitor to SGND. |
| 11 | ITH2 | passive | Channel 2 error amplifier output and loop compensation pin, which should be connected to INTVCC to use the default internal compensation. |
| 12 | VON2 | input | Channel 2 on-time voltage input that sets the on-time comparator trip point, with a VON sense range of 0.6V-6V for LTC3633A (1.5V-12V for LTC3633A-1) and a nominal impedance of 140kΩ. |
| 13 | SW2 | output | Channel 2 switch node connecting to the external inductor, swinging from a diode voltage drop below ground up to VIN. |
| 14 | SW2 | output | Channel 2 switch node connecting to the external inductor, swinging from a diode voltage drop below ground up to VIN. |
| 15 | VIN2 | power_in | Power supply input for the channel 2 on-chip power MOSFETs, which may operate from a supply different from VIN1. |
| 16 | VIN2 | power_in | Power supply input for the channel 2 on-chip power MOSFETs, which may operate from a supply different from VIN1. |
| 17 | BOOST2 | power_out | Boosted floating driver supply for channel 2 whose bootstrap capacitor connects between this pin and SW2, with a normal swing from a diode drop below INTVCC up to VIN+INTVCC. |
| 18 | V2P5 | power_out | 2.5V regulator output capable of supplying 10mA that requires a minimum 1µF low-ESR ceramic bypass capacitor, or should be tied to INTVCC if unused. |
| 19 | INTVCC | power_out | Internal 3.3V regulator output that powers the internal drivers and control circuits and requires a minimum 1µF low-ESR ceramic decoupling capacitor to power ground. |
| 20 | BOOST1 | power_out | Boosted floating driver supply for channel 1 whose bootstrap capacitor connects between this pin and SW1, with a normal swing from a diode drop below INTVCC up to VIN+INTVCC. |
| 21 | VIN1 | power_in | Power supply input for the channel 1 on-chip power MOSFETs, which also powers the internal LDO for INTVCC. |
| 22 | VIN1 | power_in | Power supply input for the channel 1 on-chip power MOSFETs, which also powers the internal LDO for INTVCC. |
| 23 | SW1 | output | Channel 1 switch node connecting to the external inductor, swinging from a diode voltage drop below ground up to VIN. |
| 24 | SW1 | output | Channel 1 switch node connecting to the external inductor, swinging from a diode voltage drop below ground up to VIN. |
| 25 | VON1 | input | Channel 1 on-time voltage input that sets the on-time comparator trip point, with a VON sense range of 0.6V-6V for LTC3633A (1.5V-12V for LTC3633A-1) and a nominal impedance of 140kΩ. |
| 26 | ITH1 | passive | Channel 1 error amplifier output and loop compensation pin, which should be connected to INTVCC to use the default internal compensation. |
| 27 | TRACKSS1 | input | Channel 1 tracking and soft-start input: forcing a voltage below 0.6V makes the error amplifier servo FB to this voltage, and an internal 1.4µA pull-up from INTVCC allows a soft-start capacitor to SGND. |
| 28 | VFB1 | input | Channel 1 output feedback input that compares the feedback voltage to the internal 0.6V reference and is connected to a resistor divider to set the output voltage. |
| 29 | PGND | power_in | Exposed pad power ground that must be soldered to the PCB for low-impedance electrical contact to power ground and good thermal contact. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Analog Devices |
| Package | QFN-28-EP(4x5) |
| Category | Power Management (PMIC) |
| Pins | 29 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| VIN1 Supply Range | VIN1 | 3.6 | 20 | V | 3 | ||
| VIN2 Supply Range | VIN2 | 1.5 | 20 | V | 3.6V < VIN1 < 20V | 3 | |
| Output Voltage Range (LTC3633A) | 0.6 | 6 | V | VON = VOUT | 3 | ||
| VFB Feedback Reference Voltage | VFB | 0.594 | 0.6 | 0.606 | V | 3 | |
| Feedback Pin Input Current | IFB | -30 | 30 | nA | 3 | ||
| Oscillator Frequency | fOSC | 1.4 | 2 | 2.6 | MHz | VRT = INTVCC | 3 |
| Oscillator Frequency | fOSC | 1.7 | 2 | 2.3 | MHz | RT = 162k | 3 |
| Oscillator Frequency | fOSC | 3.4 | 4 | 4.6 | MHz | RT = 80.6k | 3 |
| Positive Valley Switch Current Limit | ILIM | 2.6 | 3.5 | 4.5 | A | 3 | |
| Switch Leakage Current | ISW(LKG) | -1 | 0.01 | 1 | µA | VIN = 20V, VRUN = 0V | 3 |
| VIN Overvoltage Lockout Threshold (VIN Rising) | VVIN-OV | 20.3 | 22.5 | V | VIN Rising | 3 | |
| VIN Overvoltage Lockout Threshold (VIN Falling) | VVIN-OV | 21.5 | 22.5 | V | VIN Falling | 3 | |
| INTVCC Voltage | INTVCC | 3.1 | 3.3 | 3.5 | V | 3.6V < VIN < 20V, 0mA Load | 3 |
| RUN Threshold Rising | RUN | 1.18 | 1.22 | 1.26 | V | Rising | 3 |
| RUN Threshold Falling | RUN | 0.98 | 1.01 | 1.04 | V | Falling | 3 |
| RUN Leakage Current | IRUN | -3 | 0 | 3 | µA | VIN = 20V | 3 |
| V2P5 Voltage | V2P5 | 2.46 | 2.5 | 2.54 | V | ILOAD = 0mA to 10mA | 3 |
| PGOOD Good-to-Bad Threshold | 8 | 10 | % | VFB Rising | 3 | ||
| PGOOD Good-to-Bad Threshold | -10 | -8 | % | VFB Falling | 3 | ||
| PGOOD Bad-to-Good Threshold | -5 | -3 | % | VFB Rising | 3 | ||
| PGOOD Bad-to-Good Threshold | 3 | 5 | % | VFB Falling | 3 | ||
| Power Good Filter Time | tPGOOD | 20 | 40 | µs | 3 | ||
| Internal Soft-Start Time | tSS | 400 | 700 | µs | 10% to 90% Rise Time | 3 | |
| VFB During Tracking | VFB | 0.28 | 0.3 | 0.315 | V | TRACKSS = 0.3V | 3 |
| PHMODE Threshold Voltage VIH | VPHMODE | 1 | V | VIH | 4 | ||
| PHMODE Threshold Voltage VIL | VPHMODE | 0.3 | V | VIL | 4 | ||
| MODE/SYNC Threshold Voltage VIH | VMODE/SYNC | 1 | V | MODE VIH | 4 | ||
| MODE/SYNC Threshold Voltage VIL | VMODE/SYNC | 0.4 | V | MODE VIL | 4 | ||
| MODE/SYNC Input Current | IMODE | 1.5 | µA | MODE = 0V | 4 | ||
| MODE/SYNC Input Current | IMODE | -1.5 | µA | MODE = INTVCC | 4 | ||
| Absolute Maximum VIN1, VIN2 | VIN1, VIN2 | -0.3 | 20 | V | 2 | ||
| Absolute Maximum PGOOD1, PGOOD2, VON1, VON2 | PGOOD1, PGOOD2, VON1, VON2 | -0.3 | 18 | V | 2 | ||
| Absolute Maximum BOOST1, BOOST2 | BOOST1, BOOST2 | -0.3 | 23 | V | 2 | ||
| Absolute Maximum BOOST1-SW1, BOOST2-SW2 | BOOST1-SW1, BOOST2-SW2 | -0.3 | 3.6 | V | 2 | ||
| Absolute Maximum V2P5, INTVCC, TRACKSS1, TRACKSS2 | V2P5, INTVCC, TRACKSS1, TRACKSS2 | -0.3 | 3.6 | V | 2 | ||
| Absolute Maximum ITH1, ITH2, RT, MODE/SYNC (upper limit printed as INTVCC + 0.3V) | ITH1, ITH2, RT, MODE/SYNC | -0.3 | V | Max = INTVCC + 0.3V | 2 | ||
| Absolute Maximum VFB1, VFB2, PHMODE (upper limit printed as INTVCC + 0.3V) | VFB1, VFB2, PHMODE | -0.3 | V | Max = INTVCC + 0.3V | 2 | ||
| Absolute Maximum RUN1, RUN2 (upper limit printed as VIN + 0.3V) | RUN1, RUN2 | -0.3 | V | Max = VIN + 0.3V | 2 | ||
| Operating Junction Temperature Range | TJ | -40 | 125 | °C | Notes 2, 3 | 2 | |
| Storage Temperature Range | TSTG | -65 | 150 | °C | 2 | ||
| Junction-to-Ambient Thermal Resistance (QFN) | θJA | 43 | °C/W | 28-lead 4mm x 5mm QFN (UFD), exposed pad soldered to PCB | 2 |
CAD (KiCad official)
- Symbol:
LTC3633AEUFD#TRPBF - Footprint:
Package_DFN_QFN:QFN-28-1EP_4x5mm_P0.5mm_EP2.65x3.65mm - 3D model: QFN-28-EP(4x5) (KiCad packages3D, STEP)
- 3D model files:
ltc3633aeufd-trpbf-etched.step/ltc3633aeufd-trpbf-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);ltc3633aeufd-trpbf.step/ltc3633aeufd-trpbf.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Analog Devices datasheet (30 pp, sha256
6b61ad8d472eb56e, 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).