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Analog Devices Inc. LTC3789IUFD#PBF
- Part No.:
- LTC3789IUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3789IUFD#PBF.pdf
- Description:
- IC REG CTRLR BUCK-BOOST 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,036
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Product details
Overview
LTC3789IUFD#PBF from Analog Devices (formerly Linear Technology) is a high-performance, synchronous 4-switch buck-boost controller IC designed for wide-input, wide-output voltage regulation in automotive and industrial power systems. It operates from 4V to 38V input, delivers up to 38V output with ±1% accuracy, supports phase-lockable 200–600kHz switching, and enables seamless transitions between buck, boost, and buck-boost modes without output disturbance - ideal for 12V/24V battery-powered telecom and vehicle electronics.
For engineers reviewing the LTC3789IUFD#PBF datasheet, LTC3789IUFD#PBF pinout, LTC3789IUFD#PBF application, or LTC3789IUFD#PBF equivalent, key selection criteria include its single-inductor architecture supporting VIN above/below/equal to VOUT, programmable input/output current limiting, true soft-start with short-circuit protection in boost mode, and dual LDO support (INTVCC/EXTVCC) for optimized thermal performance in QFN packaging.
Technical Context
The LTC3789IUFD#PBF implements a constant-frequency current-mode control architecture with independent valley-current sensing in buck mode and peak-current sensing in boost mode, enabling precise regulation across all operating regions. Its proprietary four-switch topology uses two independent gate drivers (TG1/BG1 and TG2/BG2) with integrated charge pumps and internal 5.5V LDOs to sustain top-side N-MOSFET biasing during extended duty cycles.
Mode selection and synchronization are handled via the MODE/PLLIN pin, supporting forced continuous conduction (for EMI-sensitive designs) or pulse-skipping operation (for light-load efficiency), while FREQ pin programming allows precise oscillator tuning from 200kHz to 600kHz using a single external resistor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 38V - supports direct connection to automotive batteries (9–16V nominal) and industrial 24V/36V rails without pre-regulation. |
| Output Voltage Accuracy | ±1% over 0.8V–38V - ensures stable reference for precision analog or digital loads without post-regulation trimming. |
| Switching Frequency | 200kHz–600kHz (phase-lockable) - balances efficiency vs. size: 200kHz enables low-loss magnetics; 600kHz minimizes inductor/capacitor footprint. |
| Efficiency | Up to 98% - achieved via synchronous rectification and low RDS(on) driver outputs (2.6Ω pull-up / 1.5Ω pull-down). |
| Operating Temperature | –40°C to +125°C - qualified for under-hood automotive and industrial environments with junction-to-ambient θJA = 34°C/W (QFN package). |
| Current Sense Threshold | Programmable 48–160mV (via ILIM pin) - sets average input/output current limit with <10% variation over temperature. |
| PGOOD Accuracy | ±10% of setpoint - provides reliable system-level power sequencing and fault detection with 20µs debounce. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN with exposed thermal pad (Pin 29 = SGND). Requires soldering of exposed pad to PCB ground plane for rated thermal performance (θJA = 34°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VFB (Pin 26) | Error amplifier feedback input | Compares output voltage divider signal to 0.8V internal reference; determines regulation setpoint. |
| SS (Pin 27) | Soft-start ramp control | Internal 3µA current charges external capacitor to linearly ramp VOUT from 0V to final value; prevents inrush. |
| SENSE+ / SENSE– (Pins 28, 1) | Valley/peak current sense inputs | Detect inductor current via external shunt; enable cycle-by-cycle current limiting in buck/boost modes. |
| ITH (Pin 2) | Error amplifier output | Controls current comparator threshold; directly programs peak/valley current trip point proportional to VITH. |
| MODE/PLLIN (Pin 4) | Mode select / sync input | Tied to SGND → forced CCM; tied to INTVCC → pulse-skipping; driven externally → PLL synchronization. |
| FREQ (Pin 5) | Oscillator frequency set | 10µA sink current sets voltage across external resistor; determines switching frequency from 200–600kHz. |
| RUN (Pin 6) | Enable/disable control | Threshold = 1.22V (±150mV hysteresis); pulls down to <0.5V for shutdown with <40µA quiescent current. |
| TG1/BG1, TG2/BG2 (Pins 23,20,14,16) | Top/bottom gate drivers | Drive external N-MOSFETs with 25ns rise/fall times; BOOST1/BOOST2 pins supply floating bias for high-side switches. |
| PGOOD (Pin 25) | Power-good indicator | Open-drain output asserted low when VFB deviates >±10% from target; includes 20µs blanking after startup. |
Key Features
| Feature | Design Value |
|---|---|
| Single-inductor buck-boost topology | Eliminates need for separate buck + boost converters; reduces BOM count, board area, and magnetic component cost. |
| Seamless region transition | No output voltage glitch or discontinuity when crossing between buck, buck-boost, and boost modes - critical for stable rail generation. |
| True soft-start and VOUT short protection | Prevents inrush current and limits fault current even during boost-mode short circuits - protects MOSFETs and load. |
| VOUT disconnected from VIN during shutdown | Ensures zero output leakage when disabled - essential for battery-backed systems requiring ultra-low standby drain. |
| Internal 5.5V LDO with EXTVCC switchover | Reduces IC self-heating by allowing INTVCC to be powered from regulated VOUT instead of raw VIN when EXTVCC > 4.8V. |
Applications
| Automotive Infotainment Power Supply | Industrial 24V-to-12V/15V DC-DC Converter |
|---|---|
Use Scenario: Regulating stable 12V rail from variable 9–16V vehicle battery for head-unit processors and displays. IC Role / Device Role / Timing Role: 4-switch buck-boost controller managing bidirectional energy flow with no intermediate conversion stages. Use Value: Maintains regulated output during cold-crank (4.5V) and load-dump (38V) transients without dropout or overvoltage damage. | Use Scenario: Generating isolated 12V/15V supplies from unregulated 24V factory bus for PLC I/O modules. IC Role / Device Role / Timing Role: Primary controller driving external N-MOSFETs in synchronous 4-switch configuration with programmable current limit. Use Value: Delivers >95% efficiency at full load while supporting remote sensing and PGOOD sequencing for multi-rail systems. |
| Telecom Distributed Power Architecture | Battery-Backed Medical Monitoring System |
Use Scenario: Providing 5V/3.3V rails from 48V telecom backplane with tight ripple and fast transient response. IC Role / Device Role / Timing Role: High-frequency (600kHz) current-mode controller enabling compact magnetics and low-output-capacitance design. Use Value: Achieves <200µs recovery from 50% load step with <150mV undershoot - meets GR-1089 immunity requirements. | Use Scenario: Dual-rail (±12V) power for portable ECG front-end amplifiers powered by Li-ion battery (3.0–4.2V). IC Role / Device Role / Timing Role: Buck-boost controller operating in pulse-skipping mode to extend battery life during sleep intervals. Use Value: Reduces no-load quiescent current to <60µA while maintaining ±1% output accuracy and reverse-current blocking. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3780EUFD#PBF | Fixed 300kHz frequency; no FREQ pin; no PGOOD; lower max input (36V); same QFN-28 package. | Lacks programmable frequency and power-good monitoring - suitable only for cost-sensitive, fixed-frequency designs. | Select when system timing is fixed and fault signaling is handled externally. |
| MPQ4333GL-AEC1-Z | Integrated MOSFETs (40V/5A); smaller 3x4mm QFN-22; AEC-Q100 Grade 1; no EXTVCC or IOSENSE pins. | Monolithic solution eliminates external FETs but sacrifices flexibility in current rating and thermal management. | Select for space-constrained automotive applications where 5A output suffices and layout simplicity is prioritized. |
Compared with LTC3780EUFD#PBF and MPQ4333GL-AEC1-Z, the LTC3789IUFD#PBF offers unique programmability (frequency, current limit, mode), dual LDO support for thermal optimization, and full 4-switch control for higher power scalability - making it optimal for demanding industrial and automotive platforms requiring design longevity and field adaptability.
Availability
LTC3789IUFD#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC power supplies, and telecom distributed DC systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3789IUFD#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTC3789IUFD#PBF belongs to Linear's high-efficiency DC/DC controller product line, engineered specifically for wide-input-range, single-inductor buck-boost applications in harsh environments where reliability, thermal performance, and seamless mode transitions are critical.
FAQ
What is the maximum input voltage rating for the LTC3789IUFD#PBF?
The LTC3789IUFD#PBF has an absolute maximum input voltage rating of 40V, with recommended continuous operation from 4V to 38V. Exceeding 40V may cause permanent damage. This rating enables robust operation during automotive load-dump events and industrial 36V rail surges, provided external TVS clamping is implemented per design guidelines.
Does the LTC3789IUFD#PBF support both buck and boost operation simultaneously?
Yes - the LTC3789IUFD#PBF implements a true 4-switch buck-boost topology that dynamically transitions between buck, buck-boost, and boost modes based on input-to-output voltage ratio. During buck-boost operation, it alternates between buck and boost sub-cycles within a single clock period, ensuring continuous regulation without output discontinuity or mode-switching artifacts.
How does the MODE/PLLIN pin configure operation of the LTC3789IUFD#PBF?
The MODE/PLLIN pin serves three functions: grounding it enables forced continuous conduction mode (CCM); tying it to INTVCC selects pulse-skipping mode for light-load efficiency; applying an external clock signal synchronizes the internal oscillator to that frequency while enforcing CCM. The pin features 220kΩ internal resistance and supports PLL lock across the full 200–600kHz range.
What thermal performance can be expected from the LTC3789IUFD#PBF in its QFN package?
The LTC3789IUFD#PBF in the 4mm × 5mm QFN package achieves θJA = 34°C/W when the exposed pad (Pin 29) is properly soldered to a minimum 100mm² copper pour on the PCB. This enables operation up to 125°C junction temperature at full load in ambient temperatures up to 85°C - verified per JEDEC JESD51-7 standards with 2-layer board layout.
Can the LTC3789IUFD#PBF regulate output current as well as output voltage?
Yes - the LTC3789IUFD#PBF supports programmable input or output average current regulation via the ILIM pin (tied to SGND, INTVCC, or left floating) and dedicated IOSENSE+/IOSENSE– pins. This enables battery charging, LED current control, or foldback current limiting - independent of voltage regulation - with thresholds adjustable from 48mV to 160mV and <10% drift over –40°C to +125°C.
LTC3789IUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Number of Outputs:
- 2
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 38V
- Frequency - Switching:
- 200kHz ~ 640kHz
- Duty Cycle (Max):
- 90%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LTC3789IUFD#PBF FAQ
1.How can I place an order for LTC3789IUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3789IUFD#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 LTC3789IUFD#PBF reliable?
The price and inventory of LTC3789IUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3789IUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3789IUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3789IUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3789IUFD#PBF?
LTC3789IUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3789IUFD#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 LTC3789IUFD#PBF?
For technical support, including LTC3789IUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3789IUFD#PBF requirements.
6.How does Aetrix verify that LTC3789IUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3789IUFD#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 LTC3789IUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3789IUFD#PBF?
All LTC3789IUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3789IUFD#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 LTC3789IUFD#PBF part is unused and in its original packaging.
Return procedure for LTC3789IUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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