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Analog Devices Inc. LTC3118IUFD#PBF
- Part No.:
- LTC3118IUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3118IUFD#PBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 2A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:650
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Product details
Overview
LTC3118IUFD#PBF from Analog Devices (formerly Linear Technology) is a dual-input, synchronous buck-boost DC/DC converter with integrated PowerPath™ control. It delivers up to 2A output current across 2V–18V programmable VOUT while accepting 2.2V–18V on either VIN1 or VIN2, enabling seamless operation above, below, or equal to output voltage - ideal for backup power systems with wall adapter and Li-ion inputs.
For engineers reviewing the LTC3118IUFD#PBF datasheet, LTC3118IUFD#PBF pinout, LTC3118IUFD#PBF application, or LTC3118IUFD#PBF equivalent, key selection factors include dual-input priority/ideal-diode mode behavior, 1.2MHz fixed-frequency PWM vs. 50µA Burst Mode quiescent current, independent RUN pin UVLO programming, and thermal performance in the 4mm × 5mm QFN package with exposed PGND pad.
Technical Context
The LTC3118IUFD#PBF employs a current-mode, monolithic buck-boost architecture with four internal N-channel MOSFETs (RDS(ON) = 80–120 mΩ) and dual bootstrapped gate drivers (BST1/BST2). Its proprietary switch algorithm enables continuous regulation during input-to-output crossover without subharmonic oscillation or output transients.
It integrates two independent charge-pump paths (CP1/CN1 for VIN1; CP2/CN2 for VIN2), CM1/CM2 filtering for MOSFET common-source nodes, and accurate 1.22V RUN comparators with 170mV hysteresis per input - supporting user-defined UVLO thresholds via resistor dividers on RUN1/RUN2.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.2V to 18V on VIN1 or VIN2 - supports wide-source flexibility including single-cell Li-ion, 12V rails, and industrial adapters. |
| Output Voltage Range | 2V to 18V (programmable via FB divider) - enables direct generation of 3.3V, 5V, or 12V outputs without post-regulation. |
| Max Output Current | 2A continuous - sufficient for powering microcontrollers, FPGAs, and communication modules from dual sources. |
| Switching Frequency | Fixed 1.2MHz ±200kHz - minimizes external component size while maintaining high efficiency (>94% at 1A, 5VOUT). |
| IQ in Burst Mode | 50µA (active input) / 5µA (inactive input) - extends battery life in always-on backup systems. |
| Shutdown Current | 2µA - ensures negligible drain during system sleep or fault conditions. |
| Operating Temp Range | –40°C to +125°C junction - qualified for industrial and automotive under-hood environments. |
Pinout & Package
The LTC3118IUFD#PBF is housed in a thermally enhanced 24-lead 4mm × 5mm plastic QFN package with an exposed PGND pad (Pin 25) that must be soldered to the PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SEL (Pin 1) | Input source selection control | Logic low = VIN1 priority; logic high = ideal diode mode (auto-select higher valid input). |
| VIN1 (Pin 2) | Primary input supply | Lower RDS(ON) path (80 mΩ); preferred for high-efficiency critical sources like main batteries. |
| RUN1 (Pin 3) | VIN1 enable & UVLO threshold input | 1.22V threshold with 170mV hysteresis; resistor divider sets custom turn-on voltage ≥2.2V. |
| RUN2 (Pin 4) | VIN2 enable & UVLO threshold input | Independent 1.22V threshold with hysteresis; enables asymmetric startup sequencing. |
| VCC (Pin 5) | Internal LDO output | 3.8V ±0.3V regulated supply for gate drivers; can be back-driven up to 5.5V. |
| MODE (Pin 6) | Operation mode select | Ground = Burst Mode (low IQ); VCC = forced PWM (low-noise, fixed frequency). |
| GND (Pin 7) | Signal reference ground | Must connect directly to low-impedance ground plane; separate from PGND routing. |
| VC (Pin 8) | Error amplifier output | Compensation node for voltage loop; RC network sets pole-zero placement. |
| FB (Pin 9) | Feedback input | 1.0V reference; VOUT = 1.0V × (1 + R1/R2); supports 2V–18V output programming. |
| V1GD (Pin 10) | VIN1 good indicator | Open-drain output pulled low when VIN1 > UVLO and RUN1 > 1.22V - enables system-level status monitoring. |
| V2GD (Pin 11) | VIN2 good indicator | Open-drain output pulled low when VIN2 > UVLO and RUN2 > 1.22V - supports dual-source health reporting. |
| PGD (Pin 12) | Power good indicator | Open-drain output pulled low when VOUT ≥ 94% of programmed value - confirms regulation stability. |
| VOUT (Pin 13) | Regulated output | Delivers up to 2A; requires ≥47µF ceramic output capacitance placed adjacent to IC. |
| SW2 (Pin 14) | Boost-side switch node | Connects to inductor output side; high dI/dt node requiring short, wide PCB traces. |
| BST2 (Pin 15) | SW2 high-side gate drive supply | Requires 0.1µF capacitor between BST2 and SW2; critical for N-MOSFET gate turn-on. |
| BST1 (Pin 16) | VIN1/VIN2 high-side gate drive supply | Shared boot node for A1/A2 switches; 0.1µF cap to SW1 required. |
| SW1 (Pin 17) | Buck-side switch node | Connects to inductor input side; ties to both VIN1 and VIN2 paths via internal MOSFETs. |
| VIN2 (Pin 18) | Secondary input supply | Higher RDS(ON) path (120 mΩ); suitable for auxiliary or backup sources where slight efficiency loss is acceptable. |
| CP2 (Pin 19) | VIN2 charge-pump positive | Toggles between VIN2 and VIN2+VCC during VIN2 operation; drives A2 gate. |
| CN2 (Pin 20) | VIN2 charge-pump negative | Driven between GND and VCC during VIN2 operation; 10nF cap to CP2 forms flying capacitor. |
| CM2 (Pin 21) | VIN2 MOSFET common-source filter | 47nF cap to PGND reduces switching noise coupling into VIN2 path. |
| CM1 (Pin 22) | VIN1 MOSFET common-source filter | 47nF cap to PGND suppresses noise from VIN1 path; improves EMI performance. |
| CN1 (Pin 23) | VIN1 charge-pump negative | Driven between GND and VCC during VIN1 operation; 10nF cap to CP1 forms flying capacitor. |
| CP1 (Pin 24) | VIN1 charge-pump positive | Toggles between VIN1 and VIN1+VCC during VIN1 operation; drives A1 gate. |
| PGND (Pin 25) | Power ground | Exposed thermal pad; must be soldered to solid copper area for thermal dissipation and low-impedance return path. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-input PowerPath™ control | Enables automatic switchover between primary and backup sources without external OR-ing FETs or controllers. |
| Programmable VIN UVLO thresholds | RUN1/RUN2 pins support independent, resistor-set turn-on voltages - critical for asymmetric battery chemistries. |
| Integrated charge-pump gate drives | Eliminates need for external bootstrap diodes/caps; supports 100% duty cycle in boost mode. |
| Output disconnect in shutdown | VOUT is actively isolated from inputs during shutdown - prevents backfeed and leakage in standby. |
| Short-circuit & thermal protection | Auto-recoverable current limiting and thermal shutdown prevent damage during overload or poor heatsinking. |
| Soft-start timing | 1ms internal soft-start prevents inrush current - eliminates need for external timing components. |
Applications
| Industrial Backup Power | Automotive Telematics |
|---|---|
Use Scenario: Industrial PLC with primary 24V rail and supercapacitor backup during AC mains failure. IC Role / Device Role / Timing Role: Dual-input buck-boost regulator maintaining 5V system rail during seamless transition from main to reserve power. Use Value: Eliminates discrete diode-OR losses (≥0.3V drop), extends backup runtime by >30% versus Schottky solutions. | Use Scenario: Automotive infotainment head unit powered by 12V battery and USB-C PD port. IC Role / Device Role / Timing Role: Priority-mode converter selecting battery when ignition is on, switching to USB-C when engine off. Use Value: Prevents battery drain during parked state while enabling firmware updates via USB-C without accessory battery. |
| Medical Portable Monitor | IoT Edge Gateway |
Use Scenario: Battery-powered patient monitor with wall adapter charging and hot-swap capability. IC Role / Device Role / Timing Role: Ideal diode-mode regulator sourcing 3.3V from either Li-ion pack or 5V adapter - no manual switching required. Use Value: Enables zero-downtime operation during adapter insertion/removal; maintains real-time sensor data logging. | Use Scenario: Cellular-connected smart meter with primary Li-SOCl₂ battery and solar-assisted charging. IC Role / Device Role / Timing Role: Buck-boost converter generating stable 3.3V from variable solar input (3–15V) and battery (2.8–3.6V). Use Value: Supports >94% peak efficiency across full input range - maximizes energy harvest and extends 10-year field life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-input buck-boost applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX77818EWL+ | Single-input buck-boost with integrated battery charger; no dual-input PowerPath™; 3A max output; 2.5MHz switching. | Designed for portable devices with battery charging, not backup switchover systems. | Select when battery management (charge/fuel gauge) is required alongside regulation - not for true dual-source redundancy. |
| TPS63070DDCR | Single-input buck-boost only; no VIN1/VIN2 selection logic; 2.4A max; 2.4MHz; no RUN pin UVLO programming. | Cost-optimized for space-constrained consumer electronics; lacks input supervision and priority control. | Choose for simple single-rail conversion where dual-source autonomy is unnecessary and BOM cost is critical. |
Compared with MAX77818EWL+ and TPS63070DDCR, the LTC3118IUFD#PBF uniquely provides hardware-based dual-input arbitration, independent UVLO configuration per source, and seamless crossover regulation - making it the only option for mission-critical backup power where input source independence and deterministic switchover are mandatory.
Availability
LTC3118IUFD#PBF is available at Aetrix Electronics and suitable for industrial backup power, automotive telematics, medical portable monitors, and IoT edge gateways requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3118IUFD#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices acquired Linear Technology in 2017 and maintains its high-performance power management portfolio with rigorous qualification standards and long-term product availability commitments.
The LTC3118IUFD#PBF belongs to Linear's PowerPath™ buck-boost family, engineered specifically for systems demanding autonomous dual-input power management with minimal external components and guaranteed reliability in harsh environments.
FAQ
What is the maximum continuous output current capability of the LTC3118IUFD#PBF?
The LTC3118IUFD#PBF delivers up to 2A continuous output current at 5VOUT with typical efficiency >94%. Peak inductor current limit is 3.6A (typ), but sustained 2A operation requires proper thermal design using the exposed PGND pad and adequate PCB copper area. Derating applies above 85°C ambient.
How does the SEL pin determine input source selection in the LTC3118IUFD#PBF?
When SEL is grounded, the LTC3118IUFD#PBF operates in VIN1 priority mode: it powers VOUT from VIN1 if RUN1 and VIN1 meet thresholds; otherwise it falls back to VIN2. When SEL is tied to VCC, it enters ideal diode mode and automatically selects the higher valid input (VIN1 or VIN2) that satisfies RUN and UVLO conditions - no software control needed.
Can the LTC3118IUFD#PBF generate a 3.3V output from a 2.7V input?
Yes. The LTC3118IUFD#PBF supports buck-boost operation down to 2.2V input and up to 18V output. With FB set for 3.3V (R1/R2 = 2.3), it regulates correctly from 2.7V VIN1 or VIN2 - confirmed in Typical Performance Characteristics (Figure G04, G05). Efficiency drops at light loads but remains >85% at 500mA.
What is the purpose of the CM1 and CM2 pins on the LTC3118IUFD#PBF?
CM1 and CM2 are common-source filter pins for the VIN1→SW1 and VIN2→SW1 N-channel MOSFETs respectively. Each requires a 47nF capacitor to PGND to reduce high-frequency noise coupling from the switching nodes into the input supplies - critical for meeting CISPR-22/32 conducted EMI limits in sensitive applications.
Does the LTC3118IUFD#PBF support output disconnect during shutdown?
Yes. The LTC3118IUFD#PBF features active output disconnect: when both RUN1 and RUN2 are pulled below 0.2V, internal switches isolate VOUT from VIN1 and VIN2, preventing backfeed and reducing system standby current to <2µA - essential for battery-powered devices requiring zero-load leakage.
LTC3118IUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.2V
- Voltage - Input (Max):
- 18V
- Voltage - Output (Min/Fixed):
- 2V
- Voltage - Output (Max):
- 18V
- Current - Output:
- 2A
- Frequency - Switching:
- 1.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x5)
LTC3118IUFD#PBF FAQ
1.How can I place an order for LTC3118IUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3118IUFD#PBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LTC3118IUFD#PBF reliable?
The price and inventory of LTC3118IUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3118IUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3118IUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3118IUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3118IUFD#PBF?
LTC3118IUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3118IUFD#PBF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LTC3118IUFD#PBF?
For technical support, including LTC3118IUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3118IUFD#PBF requirements.
6.How does Aetrix verify that LTC3118IUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3118IUFD#PBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LTC3118IUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3118IUFD#PBF?
All LTC3118IUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3118IUFD#PBF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LTC3118IUFD#PBF part is unused and in its original packaging.
Return procedure for LTC3118IUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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