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LTC3891EUDC#TRPBF
Public Made by Adomby adom
Analog Devices DC-DC Controllers, QFN-20-EP(3x4). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
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LTC3891EUDC#TRPBF
Analog Devices · DC-DC Controllers · QFN-20-EP(3x4)
LTC3891EUDC#TRPBF from Analog Devices, in a QFN-20-EP(3x4). 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 | PLLIN/MODE | input | External synchronization input to the phase detector and forced continuous mode input, with grounding selecting Burst Mode operation and tying to INTVCC forcing continuous inductor current. |
| 2 | SGND | power_in | Small-signal ground that must be routed separately from high current grounds and electrically connected to pins 3 and 21 for proper operation. |
| 3 | SGND | power_in | Small-signal ground that must be routed separately from high current grounds and electrically connected to pin 2 and pin 21 for proper operation. |
| 4 | RUN | input | Digital run control input where forcing the pin below 1.16V shuts down the controller and below 0.7V shuts down the entire LTC3891 to about 14µA quiescent current. |
| 5 | SENSE- | input | The (-) input to the differential current comparator, which supplies power to the current comparator when greater than INTVCC - 0.5V. |
| 6 | SENSE+ | input | The (+) input to the differential current comparator, normally connected to the DCR sensing network or current sensing resistor, which together with ITH and offsets sets the current trip threshold. |
| 7 | VFB | input | Receives the remotely sensed feedback voltage from an external resistive divider across the output, regulated to the 0.8V reference. |
| 8 | ITH | passive | Error amplifier output and switching regulator compensation point, where the current comparator trip point increases with this control voltage. |
| 9 | PGOOD | output | Open-drain logic output that is pulled to ground when the VFB voltage is not within 10% of its set point. |
| 10 | TG | output | High current gate drive for the top N-channel MOSFET, a floating driver with a voltage swing equal to INTVCC superimposed on the SW voltage. |
| 11 | SW | passive | Switch node connection to the inductor. |
| 12 | BOOST | power_out | Bootstrapped supply to the topside floating driver, with a voltage swing from INTVCC to (VIN + INTVCC) and a Schottky diode tied between BOOST and INTVCC. |
| 13 | BG | output | High current gate drive for the bottom (synchronous) N-channel MOSFET, with a voltage swing from ground to INTVCC. |
| 14 | INTVCC | power_out | Output of the internal linear low dropout regulator that powers the driver and control circuits, which must be decoupled to PGND with a minimum of 2.2µF ceramic or other low ESR capacitor. |
| 15 | EXTVCC | power_in | External power input to an internal LDO connected to INTVCC that bypasses the VIN-powered LDO when EXTVCC is higher than 4.7V, and must not float or exceed 14V. |
| 16 | PGND | power_in | Driver power ground connected to the source of the bottom synchronous N-channel MOSFET and the (-) terminal of CIN. |
| 17 | VIN | power_in | Main supply pin that requires a bypass capacitor tied between this pin and the SGND pins, with an input supply operating range of 4V to 60V. |
| 18 | ILIM | input | Current comparator sense voltage range input where tying the pin to SGND, FLOAT or INTVCC sets the maximum current sense threshold to one of three levels. |
| 19 | TRACK/SS | input | External tracking and soft-start input to which the LTC3891 regulates VFB to the smaller of 0.8V or the TRACK/SS voltage, with an internal 10µA pull-up current source. |
| 20 | FREQ | input | Frequency control pin for the internal VCO, where grounding forces 350kHz, INTVCC forces 535kHz, and a resistor to GND programs other frequencies between 50kHz and 900kHz. |
| 21 | SGND | power_in | Exposed pad that is small-signal ground and must be soldered to PCB ground for rated thermal performance. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Analog Devices |
| Package | QFN-20-EP(3x4) |
| Category | Power Management ICs |
| Pins | 21 |
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 Operating Voltage Range | VIN | 4 | 60 | V | 3 | ||
| Regulated Feedback Voltage | VFB | 0.792 | 0.8 | 0.808 | V | ITH Voltage = 1.2V; -40C to 85C; LTC3891E, LTC3891I | 3 |
| Feedback Current | IFB | -50 | 50 | nA | Note 4 | 3 | |
| Reference Voltage Line Regulation | VREFLNREG | 0.002 | 0.02 | %/V | VIN = 4.5V to 60V; Note 4 | 3 | |
| Output Voltage Load Regulation | VLOADREG | 0.01 | 0.1 | % | Measured in Servo Loop; ΔITH Voltage = 1.2V to 0.7V | 3 | |
| Input DC Supply Current, Pulse Skip or Forced Continuous Mode | IQ | 2 | mA | VFB = 0.83V (No Load) | 3 | ||
| Input DC Supply Current, Sleep Mode | IQ | 50 | 75 | µA | Sleep Mode VFB = 0.83V (No Load) | 3 | |
| Input DC Supply Current, Shutdown | IQ | 14 | 25 | µA | RUN = 0V | 3 | |
| Feedback Overvoltage Protection | VOVL | 7 | 10 | 13 | % | Measured at VFB Relative to Regulated VFB | 3 |
| SENSE+ Pin Current | ISENSE+ | -1 | 1 | µA | 3 | ||
| Maximum Duty Factor | DFMAX | 98 | 99 | % | In Dropout | 3 | |
| Soft-Start Charge Current | ITRACK/SS | 7 | 10 | 14 | µA | VTRACK = 0V | 3 |
| RUN Pin On Threshold | VRUN | 1.15 | 1.21 | 1.27 | V | VRUN Rising | 3 |
| Maximum Current Sense Threshold | VSENSE(MAX) | 22 | 30 | 36 | mV | VFB = 0.7V, VSENSE- = 3.3V, ILIM = 0 | 3 |
| Maximum Current Sense Threshold | VSENSE(MAX) | 43 | 50 | 57 | mV | VFB = 0.7V, VSENSE- = 3.3V, ILIM = INTVCC | 3 |
| Maximum Current Sense Threshold | VSENSE(MAX) | 64 | 75 | 85 | mV | VFB = 0.7V, VSENSE- = 3.3V, ILIM = FLOAT | 3 |
| INTVCC Internal VCC Voltage (VIN) | VINTVCCVIN | 4.85 | 5.1 | 5.35 | V | 6V < VIN < 60V, VEXTVCC = 0V | 4 |
| INTVCC Load Regulation (VIN) | VLDOVIN | 0.7 | 1.1 | % | ICC = 0mA to 50mA, VEXTVCC = 0V | 4 | |
| Internal VCC Voltage (EXTVCC) | VINTVCCEXT | 4.85 | 5.1 | 5.35 | V | 6V < VEXTVCC < 13V | 4 |
| INTVCC Load Regulation (EXTVCC) | VLDOEXT | 0.6 | 1.1 | % | ICC = 0mA to 50mA, VEXTVCC = 8.5V | 4 | |
| EXTVCC Switchover Voltage | VEXTVCC | 4.5 | 4.7 | 4.9 | V | ICC = 0mA to 50mA, EXTVCC Ramping Positive | 4 |
| Low Fixed Frequency | fLOW | 320 | 350 | 380 | kHz | VFREQ = 0V; PLLIN/MODE = DC Voltage | 4 |
| High Fixed Frequency | fHIGH | 485 | 535 | 585 | kHz | VFREQ = INTVCC; PLLIN/MODE = DC Voltage | 4 |
| Programmable Frequency | f65kΩ | 375 | 440 | 505 | kHz | RFREQ = 65k; PLLIN/MODE = DC Voltage | 4 |
| Synchronizable Frequency | fSYNC | 75 | 750 | kHz | PLLIN/MODE = External Clock | 4 | |
| PGOOD Voltage Low | VPGL | 0.2 | 0.4 | V | IPGOOD = 2mA | 4 | |
| PGOOD Leakage Current | IPGOOD | -1 | 1 | µA | VPGOOD = 5V | 4 | |
| PGOOD Trip Level, VFB Ramping Negative | VPG | -13 | -10 | -7 | % | VFB Ramping Negative | 4 |
| PGOOD Trip Level, VFB Ramping Positive | VPG | 7 | 10 | 13 | % | VFB Ramping Positive | 4 |
CAD (KiCad official)
- Symbol:
LTC3891EUDC#TRPBF - Footprint:
Package_DFN_QFN:QFN-20-1EP_3x4mm_P0.5mm_EP1.65x2.65mm - 3D model: QFN-20-EP(3x4) (KiCad packages3D, STEP)
- 3D model files:
ltc3891eudc-trpbf-etched.step/ltc3891eudc-trpbf-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);ltc3891eudc-trpbf.step/ltc3891eudc-trpbf.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Analog Devices datasheet (32 pp, sha256
21a46463d6a45e3c, retrieved 2026-10-28, tier: manufacturer) - 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).
# LTC3891EUDC#TRPBF
**Analog Devices** · DC-DC Controllers · QFN-20-EP(3x4)
LTC3891EUDC#TRPBF from Analog Devices, in a QFN-20-EP(3x4). 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 | PLLIN/MODE | input | External synchronization input to the phase detector and forced continuous mode input, with grounding selecting Burst Mode operation and tying to INTVCC forcing continuous inductor current. |
| 2 | SGND | power_in | Small-signal ground that must be routed separately from high current grounds and electrically connected to pins 3 and 21 for proper operation. |
| 3 | SGND | power_in | Small-signal ground that must be routed separately from high current grounds and electrically connected to pin 2 and pin 21 for proper operation. |
| 4 | RUN | input | Digital run control input where forcing the pin below 1.16V shuts down the controller and below 0.7V shuts down the entire LTC3891 to about 14µA quiescent current. |
| 5 | SENSE- | input | The (-) input to the differential current comparator, which supplies power to the current comparator when greater than INTVCC - 0.5V. |
| 6 | SENSE+ | input | The (+) input to the differential current comparator, normally connected to the DCR sensing network or current sensing resistor, which together with ITH and offsets sets the current trip threshold. |
| 7 | VFB | input | Receives the remotely sensed feedback voltage from an external resistive divider across the output, regulated to the 0.8V reference. |
| 8 | ITH | passive | Error amplifier output and switching regulator compensation point, where the current comparator trip point increases with this control voltage. |
| 9 | PGOOD | output | Open-drain logic output that is pulled to ground when the VFB voltage is not within 10% of its set point. |
| 10 | TG | output | High current gate drive for the top N-channel MOSFET, a floating driver with a voltage swing equal to INTVCC superimposed on the SW voltage. |
| 11 | SW | passive | Switch node connection to the inductor. |
| 12 | BOOST | power_out | Bootstrapped supply to the topside floating driver, with a voltage swing from INTVCC to (VIN + INTVCC) and a Schottky diode tied between BOOST and INTVCC. |
| 13 | BG | output | High current gate drive for the bottom (synchronous) N-channel MOSFET, with a voltage swing from ground to INTVCC. |
| 14 | INTVCC | power_out | Output of the internal linear low dropout regulator that powers the driver and control circuits, which must be decoupled to PGND with a minimum of 2.2µF ceramic or other low ESR capacitor. |
| 15 | EXTVCC | power_in | External power input to an internal LDO connected to INTVCC that bypasses the VIN-powered LDO when EXTVCC is higher than 4.7V, and must not float or exceed 14V. |
| 16 | PGND | power_in | Driver power ground connected to the source of the bottom synchronous N-channel MOSFET and the (-) terminal of CIN. |
| 17 | VIN | power_in | Main supply pin that requires a bypass capacitor tied between this pin and the SGND pins, with an input supply operating range of 4V to 60V. |
| 18 | ILIM | input | Current comparator sense voltage range input where tying the pin to SGND, FLOAT or INTVCC sets the maximum current sense threshold to one of three levels. |
| 19 | TRACK/SS | input | External tracking and soft-start input to which the LTC3891 regulates VFB to the smaller of 0.8V or the TRACK/SS voltage, with an internal 10µA pull-up current source. |
| 20 | FREQ | input | Frequency control pin for the internal VCO, where grounding forces 350kHz, INTVCC forces 535kHz, and a resistor to GND programs other frequencies between 50kHz and 900kHz. |
| 21 | SGND | power_in | Exposed pad that is small-signal ground and must be soldered to PCB ground for rated thermal performance. |
## Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Analog Devices |
| Package | QFN-20-EP(3x4) |
| Category | Power Management ICs |
| Pins | 21 |
## 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 Operating Voltage Range | VIN | 4 | | 60 | V | | 3 |
| Regulated Feedback Voltage | VFB | 0.792 | 0.8 | 0.808 | V | ITH Voltage = 1.2V; -40C to 85C; LTC3891E, LTC3891I | 3 |
| Feedback Current | IFB | -50 | | 50 | nA | Note 4 | 3 |
| Reference Voltage Line Regulation | VREFLNREG | | 0.002 | 0.02 | %/V | VIN = 4.5V to 60V; Note 4 | 3 |
| Output Voltage Load Regulation | VLOADREG | | 0.01 | 0.1 | % | Measured in Servo Loop; ΔITH Voltage = 1.2V to 0.7V | 3 |
| Input DC Supply Current, Pulse Skip or Forced Continuous Mode | IQ | | | 2 | mA | VFB = 0.83V (No Load) | 3 |
| Input DC Supply Current, Sleep Mode | IQ | | 50 | 75 | µA | Sleep Mode VFB = 0.83V (No Load) | 3 |
| Input DC Supply Current, Shutdown | IQ | | 14 | 25 | µA | RUN = 0V | 3 |
| Feedback Overvoltage Protection | VOVL | 7 | 10 | 13 | % | Measured at VFB Relative to Regulated VFB | 3 |
| SENSE+ Pin Current | ISENSE+ | -1 | | 1 | µA | | 3 |
| Maximum Duty Factor | DFMAX | 98 | 99 | | % | In Dropout | 3 |
| Soft-Start Charge Current | ITRACK/SS | 7 | 10 | 14 | µA | VTRACK = 0V | 3 |
| RUN Pin On Threshold | VRUN | 1.15 | 1.21 | 1.27 | V | VRUN Rising | 3 |
| Maximum Current Sense Threshold | VSENSE(MAX) | 22 | 30 | 36 | mV | VFB = 0.7V, VSENSE- = 3.3V, ILIM = 0 | 3 |
| Maximum Current Sense Threshold | VSENSE(MAX) | 43 | 50 | 57 | mV | VFB = 0.7V, VSENSE- = 3.3V, ILIM = INTVCC | 3 |
| Maximum Current Sense Threshold | VSENSE(MAX) | 64 | 75 | 85 | mV | VFB = 0.7V, VSENSE- = 3.3V, ILIM = FLOAT | 3 |
| INTVCC Internal VCC Voltage (VIN) | VINTVCCVIN | 4.85 | 5.1 | 5.35 | V | 6V < VIN < 60V, VEXTVCC = 0V | 4 |
| INTVCC Load Regulation (VIN) | VLDOVIN | | 0.7 | 1.1 | % | ICC = 0mA to 50mA, VEXTVCC = 0V | 4 |
| Internal VCC Voltage (EXTVCC) | VINTVCCEXT | 4.85 | 5.1 | 5.35 | V | 6V < VEXTVCC < 13V | 4 |
| INTVCC Load Regulation (EXTVCC) | VLDOEXT | | 0.6 | 1.1 | % | ICC = 0mA to 50mA, VEXTVCC = 8.5V | 4 |
| EXTVCC Switchover Voltage | VEXTVCC | 4.5 | 4.7 | 4.9 | V | ICC = 0mA to 50mA, EXTVCC Ramping Positive | 4 |
| Low Fixed Frequency | fLOW | 320 | 350 | 380 | kHz | VFREQ = 0V; PLLIN/MODE = DC Voltage | 4 |
| High Fixed Frequency | fHIGH | 485 | 535 | 585 | kHz | VFREQ = INTVCC; PLLIN/MODE = DC Voltage | 4 |
| Programmable Frequency | f65kΩ | 375 | 440 | 505 | kHz | RFREQ = 65k; PLLIN/MODE = DC Voltage | 4 |
| Synchronizable Frequency | fSYNC | 75 | | 750 | kHz | PLLIN/MODE = External Clock | 4 |
| PGOOD Voltage Low | VPGL | | 0.2 | 0.4 | V | IPGOOD = 2mA | 4 |
| PGOOD Leakage Current | IPGOOD | -1 | | 1 | µA | VPGOOD = 5V | 4 |
| PGOOD Trip Level, VFB Ramping Negative | VPG | -13 | -10 | -7 | % | VFB Ramping Negative | 4 |
| PGOOD Trip Level, VFB Ramping Positive | VPG | 7 | 10 | 13 | % | VFB Ramping Positive | 4 |
## CAD (KiCad official)
- Symbol: `LTC3891EUDC#TRPBF`
- Footprint: `Package_DFN_QFN:QFN-20-1EP_3x4mm_P0.5mm_EP1.65x2.65mm`
- 3D model: QFN-20-EP(3x4) (KiCad packages3D, STEP)
- 3D model files: `ltc3891eudc-trpbf-etched.step` / `ltc3891eudc-trpbf-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `ltc3891eudc-trpbf.step` / `ltc3891eudc-trpbf.glb` are the bare package body.
## Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- **Datasheet:** [Analog Devices datasheet](https://www.analog.com/media/en/technical-documentation/data-sheets/3891fa.pdf) (32 pp, sha256 `21a46463d6a45e3c`, retrieved 2026-10-28, tier: manufacturer)
- **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/ltc3891eudc-trpbf-datasheet.pdf)