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LTC4040EUFD#TRPBF
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Analog Devices Battery Management, VQFN-24-EP(4x5). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
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README
markdownLTC4040EUFD#TRPBF
Analog Devices · Battery Management · VQFN-24-EP(4x5)
LTC4040EUFD#TRPBF from Analog Devices, in a VQFN-24-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 | VSYS | power_out | System voltage output that powers the external load from the input supply or the backup battery and charges the battery when input power is available; bypass with a low-ESR ceramic capacitor of at least 100µF to GND. |
| 2 | PROG | passive | Charge current program pin where an external resistor to ground sets full-scale charge current; it servos to 0.8V at full scale, with BAT-to-PROG current ratio internally set to 2500. |
| 3 | CLPROG | output | VSYS current monitor output whose voltage equals 32 times the VIN-to-CLN differential, and charge current is reduced when it reaches 0.8V. |
| 4 | CHGOFF | input | Battery charger disable input: tie to GND to enable the charger or to a voltage above 1.2V to disable it, and do not leave it unconnected. |
| 5 | BSTOFF | input | Backup boost converter disable input: tie to GND to enable backup or to a voltage above 1.2V to disable it, and do not leave it unconnected. |
| 6 | VIN | power_in | Input supply pin that can be driven directly when OVP is not used, otherwise an external N-channel FET is connected between the supply output VPWR and this pin. |
| 7 | CLN | input | Negative terminal of the external input current-limit sense resistor between VIN and CLN, which regulates the sense drop to 25mV and does not limit system current if the drop exceeds 25mV. |
| 8 | CHRG | output | Open-drain charge status output, typically pulled up to a reference voltage, that is pulled low during charging until charge current falls below C/8. |
| 9 | FAULT | output | Open-drain fault status output, typically pulled up to a reference voltage, that is pulled low on a temperature fault or bad-battery fault during charging. |
| 10 | RSTFB | input | High-impedance input to the reset comparator with a 0.74V falling threshold and 20mV hysteresis, using an external divider between VSYS, RSTFB and GND. |
| 11 | RST | output | Open-drain reset output pulled to ground whenever RSTFB falls below 0.74V and becoming high impedance 232ms after RSTFB recovers. |
| 12 | F2 | input | Logic input selecting battery chemistry, where logic high selects Li-Ion and logic low selects LiFePO4, and it must not be left unconnected. |
| 13 | F1 | input | Logic input selecting one of four charge voltage settings for the chosen chemistry, and it must not be left unconnected. |
| 14 | F0 | input | Logic input selecting one of four charge voltage settings for the chosen chemistry, and it must not be left unconnected. |
| 15 | IGATE | output | Gate drive from an internal charge pump for the external N-channel pass FETs, where the first FET (VPWR to VIN) is part of the optional OVP and the second FET (VIN to VSYS) is mandatory for backup disconnect. |
| 16 | OVSNS | input | Overvoltage protection sense input that connects through a 6.2k resistor to the input connector and FET drain if OVP is used, or is shorted to VIN if not; IGATE is pulled to GND when it exceeds about 6V. |
| 17 | NTC | passive | Thermistor monitoring input that uses a low-drift bias resistor from VIN and a thermistor to GND to pause charging when the battery is too hot or too cold, and should be grounded if NTC is not used. |
| 18 | BSTFB | input | Feedback input for the backup boost regulator that servos to 0.8V during steady-state backup operation. |
| 19 | PFI | input | High-impedance power-fail comparator input with a 1.19V falling threshold and 30mV hysteresis that sets the input voltage below which boost backup starts. |
| 20 | PFO | output | Open-drain power-fail status output that is pulled to ground when PFI is below its falling threshold and becomes high impedance once PFI rises above the rising threshold. |
| 21 | SW | passive | Switch node for the buck charger and boost backup converter, requiring a 1µH to 2.2µH inductor connected from SW to BAT. |
| 22 | SW | passive | Switch node for the buck charger and boost backup converter, requiring a 1µH to 2.2µH inductor connected from SW to BAT. |
| 23 | BAT | bidirectional | Single-cell Li-Ion or LiFePO4 battery connection that supplies VSYS through the boost converter in backup and is charged from VSYS through the buck charger; bypass with a low-ESR ceramic capacitor of at least 10µF to GND. |
| 24 | VSYS | power_out | System voltage output that powers the external load from the input supply or the backup battery and charges the battery when input power is available; bypass with a low-ESR ceramic capacitor of at least 100µF to GND. |
| 25 | GND | power_in | Exposed pad that must be soldered to the PCB to provide a low electrical and thermal impedance connection to ground. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Analog Devices |
| Package | VQFN-24-EP(4x5) |
| Category | Power Management (PMIC) |
| Pins | 25 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| VIN Input Voltage Range | VIN | 3.5 | 5.5 | V | 3 | ||
| VBAT Battery Voltage Range (Backup Boost Input) | VBAT | 2.7 | 5 | V | 3 | ||
| BAT Quiescent Current, Normal Mode | IBATQ | 45 | 70 | µA | Normal Mode (VPFI = 2V), Battery Charger Timed Out | 3 | |
| BAT Quiescent Current, Shutdown | IBATQ | 1.5 | 3 | µA | Shutdown (BSTOFF = CHGOFF = 1) | 3 | |
| VIN Quiescent Current, Shutdown | IINQ | 3.5 | 7 | µA | Shutdown (BSTOFF = CHGOFF=1) | 3 | |
| BAT Regulated Output Voltage for LiFePO4 Option | VCHG | 3.42 | 3.45 | 3.48 | V | F2 = 0, F1 = 0, F0 = 0 | 3 |
| BAT Regulated Output Voltage for LiFePO4 Option | VCHG | 3.47 | 3.5 | 3.53 | V | F2 = 0, F1 = 0, F0 = 1 | 3 |
| BAT Regulated Output Voltage for LiFePO4 Option | VCHG | 3.52 | 3.55 | 3.58 | V | F2 = 0, F1 = 1, F0 = 0 | 3 |
| BAT Regulated Output Voltage for LiFePO4 Option | VCHG | 3.57 | 3.6 | 3.63 | V | F2 = 0, F1 = 1, F0 = 1 | 3 |
| BAT Regulated Output Voltage for Li-Ion Option | VCHG | 3.92 | 3.95 | 3.98 | V | F2 = 1, F1 = 0, F0 = 0 | 3 |
| BAT Regulated Output Voltage for Li-Ion Option | VCHG | 3.97 | 4 | 4.03 | V | F2 = 1, F1 = 0, F0 = 1 | 3 |
| BAT Regulated Output Voltage for Li-Ion Option | VCHG | 4.02 | 4.05 | 4.08 | V | F2 = 1, F1 = 1, F0 = 0 | 3 |
| BAT Regulated Output Voltage for Li-Ion Option | VCHG | 4.07 | 4.1 | 4.13 | V | F2 = 1, F1 = 1, F0 = 1 | 3 |
| Regulated Battery Charge Current | ICHG | 950 | 1000 | 1050 | mA | RPROG = 2k | 3 |
| VSYS-to-VBAT Differential Undervoltage Lockout Threshold (Falling) | 40 | 50 | 60 | mV | 3 | ||
| VSYS-to-BAT Differential Undervoltage Lockout Threshold (Rising) | 125 | 145 | 165 | mV | 3 | ||
| Input Current Limit Threshold Voltage | VIN, VCLN | 23.5 | 25 | 26.5 | mV | 3 | |
| Recharge Battery Threshold Voltage (relative to VCHG) | VRECHG | 94.2 | 95 | 95.8 | % | F2 = 0 and F1 = 1 | 3 |
| Recharge Battery Threshold Voltage (relative to VCHG) | VRECHG | 96.7 | 97.5 | 98.3 | % | All other cases | 3 |
| Safety Timer Termination Period | tTERMINATE | 3.7 | 4.25 | 5 | Hours | Timer starts when VBAT = VCHG; F2 = 1 (Li-Ion) | 3 |
| Safety Timer Termination Period | tTERMINATE | 1.85 | 2.13 | 2.5 | Hours | Timer starts when VBAT = VCHG; F2 = 0 (LiFePO4) | 3 |
| Low Battery Threshold Voltage for Trickle Charge | VLOWBAT | 2.75 | 2.85 | 2.95 | V | VBAT Rising | 3 |
| Bad-Battery Termination Time | tBADBAT | 0.47 | 0.54 | 0.64 | Hours | VBAT < (VLOWBAT − ΔVLOWBAT) | 3 |
| End-of-Charge Indication PROG Pin Average Voltage | VC/8 | 90 | 100 | 110 | mV | PROG Pin Average Voltage | 3 |
| Step-Down (Buck) Converter Switching Frequency | fOSC(BUCK) | 1.96 | 2.25 | 2.65 | MHz | Normal Mode (VPFI > 1.21V) | 3 |
| PMOS Switch Current Limit | ILIM(BUCK) | 3 | 4.3 | A | 3 | ||
| NTC Cold Temperature Fault Threshold Voltage (Rising) | VCOLD | 75 | 76.5 | 78 | %VIN | Rising Voltage Threshold | 4 |
| NTC Hot Temperature Fault Threshold Voltage (Falling) | VHOT | 33.4 | 34.9 | 36.4 | %VIN | Falling Voltage Threshold | 4 |
| NTC Disable Threshold Voltage (Falling) | VDIS | 0.7 | 1.7 | 2.7 | %VIN | Falling Threshold | 4 |
| NTC Leakage Current | INTC | -20 | 20 | nA | 4 | ||
| BSTFB Reference Voltage | VBSTFB | 0.78 | 0.8 | 0.82 | V | 4 | |
| BSTFB Input Bias Current | IBSTFB | -20 | 20 | nA | 4 | ||
| Step-up (Boost) Converter Output Voltage Range | VSYS | 3.5 | 5 | V | 4 | ||
| Step-Up Converter Switching Frequency | fOSCBST | 0.98 | 1.125 | 1.33 | MHz | Backup Mode (VPFI < 1.17V) | 4 |
| NMOS Switch Current Limit | ILIMBST | 5.5 | 6.5 | 7.5 | A | 4 | |
| VSYS Overvoltage Shutdown Threshold | VOVSD | 5.3 | 5.5 | 5.7 | V | VSYS Rising | 4 |
| BAT Pin Undervoltage Lockout | VUVLO | 2.45 | 2.6 | V | VBAT Falling | 4 | |
| Maximum Boost Duty Cycle | DMAX | 88 | 93 | % | 4 | ||
| RSTFB Threshold (Falling) | 0.72 | 0.74 | 0.76 | V | 4 | ||
| RSTFB Pin Leakage Current | VRSTFB | -50 | 50 | nA | VRSTFB = 0.9V | 4 | |
| PFI Input Threshold (Falling Edge) | 1.17 | 1.19 | 1.21 | V | Initiates Backup Mode | 4 | |
| PFI Pin Leakage Current | -100 | 100 | nA | VPFI = 1.3V | 4 | ||
| Logic Low Input Leakage | IIL | -1 | 1 | µA | 4 | ||
| Logic High Input Leakage | IIH | -1 | 1 | µA | 4 | ||
| Overvoltage Protection Threshold (Rising) | VOV(CUTOFF) | 6.1 | 6.4 | 6.7 | V | Rising Threshold, ROVSNS = 6.2k | 5 |
| IGATE Voltage Under Load | VOVGT(LOAD) | 8 | 8.6 | V | 5V Through 6.2k Into OVSNS, IIGATE = 1µA | 5 | |
| Operating Junction Temperature Range | TJ | -40 | 125 | °C | Note 3 | 2 | |
| Storage Temperature Range | TSTG | -65 | 125 | °C | 2 | ||
| VIN (Transient) | VIN | -0.3 | 7 | V | t < 1ms, Duty Cycle < 1% | 2 | |
| VIN (Steady State), BAT, CLN, VSYS, BSTFB, NTC, OVSNS, CHRG, PFO, RST, FAULT | -0.3 | 6 | V | 2 | |||
| F0, F1, F2, BSTOFF, RSTFB, PFI, CHGOFF | -0.3 | V | Upper limit printed as Max (VIN, VBAT, VSYS) + 0.3V; not a fixed number | 2 | |||
| IOVSNS | IOVSNS | -10 | 10 | mA | 2 | ||
| ICHRG, IPFO, IRST, IFAULT | 10 | mA | 2 | ||||
| IPROG, ICLPROG | 1.1 | mA | 2 | ||||
| Thermal Resistance, Junction to Ambient | θJA | 43 | °C/W | 2 | |||
| Maximum Junction Temperature | TJMAX | 125 | °C | 2 |
CAD (KiCad official)
- Symbol:
LTC4040EUFD#TRPBF - Footprint:
Package_DFN_QFN:QFN-24-1EP_4x5mm_P0.5mm_EP2.65x3.65mm - 3D model: VQFN-24-EP(4x5) (KiCad packages3D, STEP)
- 3D model files:
ltc4040eufd-trpbf-etched.step/ltc4040eufd-trpbf-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);ltc4040eufd-trpbf.step/ltc4040eufd-trpbf.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Analog Devices datasheet (26 pp, sha256
957228362ca0845d, 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).