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Analog Devices Inc. LTC3789IGN#PBF
- Part No.:
- LTC3789IGN#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3789IGN#PBF.pdf
- Description:
- IC REG CTRLR BUCK-BOOST 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,034
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Product details
Overview
LTC3789IGN#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 seamless buck/boost/buck-boost transitions, and integrates quad N-channel MOSFET drivers with internal 5.5V LDO. It is used in 12V battery-powered telecom systems requiring stable 12V output across varying battery states.
For engineers reviewing the LTC3789IGN#PBF datasheet, LTC3789IGN#PBF pinout, LTC3789IGN#PBF application, or LTC3789IGN#PBF equivalent, key selection criteria include its 200–600kHz phase-lockable oscillator, programmable input/output current sensing, true soft-start, PGOOD monitoring, and compatibility with both QFN and SSOP packages - critical for thermal management and layout flexibility in high-density DC/DC designs.
Technical Context
The LTC3789IGN#PBF implements a constant-frequency current-mode control architecture with dual independent current-sense paths: valley-current sensing in buck mode and peak-current sensing in boost mode, coordinated via an integrated state machine that manages four external N-MOSFETs. Its MODE/PLLIN pin selects between forced continuous conduction mode (for EMI-sensitive applications) and pulse-skipping mode (for light-load efficiency).
It features two independent gate drive stages (TG1/BG1 and TG2/BG2), each supporting floating bootstrap operation with internal charge pumps to sustain top-side drive during 100% duty-cycle conditions. The IC uses a single-inductor, four-switch topology enabling VIN above, below, or equal to VOUT without discontinuity or audible noise during region transitions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 38V - supports full automotive battery range (cold crank to load dump) without external pre-regulation. |
| Output Voltage Accuracy | ±1% over 0.8V–38V - ensures precise regulation for sensitive analog or digital loads without trimming. |
| Switching Frequency | 200kHz–600kHz, phase-lockable - enables EMI filtering optimization and synchronization with system clocks. |
| Current Sensing | Programmable input/output average current limit via ILIM pin - allows configurable overcurrent protection for battery charging or load management. |
| Efficiency | Up to 98% - achieved via synchronous rectification and low RDS(on) driver outputs (1.5Ω pull-down, 2.6Ω pull-up). |
| Thermal Performance | θJA = 80°C/W (SSOP) - requires standard PCB copper area for 125°C junction operation at 5A load. |
| PGOOD Threshold | ±10% of regulated VOUT - provides reliable power-good signaling for microcontroller reset sequencing. |
Pinout & Package
The LTC3789IGN#PBF is housed in a 28-lead narrow plastic SSOP package (GN), measuring 10.2mm × 5.3mm × 1.75mm, with exposed pad not present (unlike QFN variant). Pin functions are identical to the QFN version but mapped to different physical locations per SSOP top view.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VFB (Pin 1) | Error amplifier feedback input | Connects to resistor divider on VOUT; sets regulation point with 0.8V internal reference and ±1% accuracy. |
| SS (Pin 2) | Soft-start control | Internal 3µA current charges external capacitor; controls VOUT ramp rate and prevents inrush current. |
| SENSE+ / SENSE– (Pins 3, 4) | Valley/peak current sense inputs | Detect inductor current via shunt resistor; enable cycle-by-cycle current limiting in buck and boost modes. |
| ITH (Pin 5) | Error amplifier output | Directly programs current comparator threshold; used for compensation and current loop stability. |
| SGND (Pin 6) | Small-signal ground | Must be isolated from PGND; connects to CIN negative terminals and feedback network ground. |
| MODE/PLLIN (Pin 7) | Mode selection / sync input | Tie to SGND for forced CCM; to INTVCC for pulse-skipping; apply external clock for synchronization. |
| FREQ (Pin 8) | Oscillator frequency set | 10µA sink current; resistor to ground sets nominal frequency from 200kHz to 600kHz. |
| RUN (Pin 9) | Enable control | 1.22V turn-on threshold with 150mV hysteresis; pulls down to <0.5V for shutdown and <10µA quiescent current. |
| VINSNS / VOUTSNS (Pins 10, 11) | Buck-boost transition detection | Monitor VIN and VOUT to determine operating region (buck, boost, or buck-boost) and adjust switching logic. |
| ILIM (Pin 12) | Average current limit select | Three-state logic (SGND/float/INTVCC) sets max average current sense threshold: 48/90/130mV. |
| IOSENSE+ / IOSENSE– (Pins 13, 14) | Input/output average current sense | Supports battery charge/discharge current monitoring with dedicated amplifier and programmable gain. |
| TRIM (Pin 15) | Reference trim disable | Must tie to GND; floating causes undefined regulation behavior. |
| PGOOD (Pin 28) | Open-drain power-good flag | Asserts low when VFB deviates >±10% from target; includes 20µs debounce to reject transients. |
| TG1/BG1/TG2/BG2 (Pins 26,23,17,19) | N-MOSFET gate drivers | Drive external high-side and low-side switches; TG outputs swing referenced to SW node; BG outputs swing 0–INTVCC. |
| BOOST1/BOOST2 (Pins 25,18) | Floating bootstrap supplies | Charge pump-supported rails for top-gate drive; swing from INTVCC to (VIN + INTVCC) or (VOUT + INTVCC). |
| SW1/SW2 (Pins 27,16) | Switch node connections | Connect to inductor ends; handle full VIN or VOUT swing plus diode drop; require low-inductance layout. |
Key Features
| Feature | Design Value |
|---|---|
| Single-inductor 4-switch topology | Enables continuous regulation across VIN < VOUT, VIN = VOUT, and VIN > VOUT without mode-hopping artifacts or output glitches. |
| True soft-start and short-circuit protection | Prevents inrush current in all operating modes including boost; maintains protection even during VOUT short events. |
| VIN-disconnect during shutdown | Isolates output from input when disabled - eliminates standby leakage and supports hot-swap applications. |
| Internal 5.5V LDO with EXTVCC switchover | Reduces IC power dissipation by allowing INTVCC to be powered from VOUT or auxiliary rail when >4.8V. |
| No reverse current at startup | Prevents backfeed from output to input during initial power-up - essential for battery backup and redundant supply systems. |
Applications
| Automotive Infotainment Power Supply | Industrial 24V Distributed Bus Converter |
|---|---|
Use Scenario: Regulating stable 12V/5A output from a 9V–16V vehicle battery under cold-crank and load-dump conditions. IC Role / Device Role / Timing Role: Primary buck-boost controller managing four external MOSFETs, coordinating seamless transitions between buck and boost regions as battery voltage fluctuates. Use Value: Eliminates need for separate buck and boost converters; maintains uninterrupted power to head-unit processors and displays during engine start. | Use Scenario: Converting 24V industrial bus to 15V for PLC I/O modules with tight ripple and transient response requirements. IC Role / Device Role / Timing Role: High-efficiency synchronous controller implementing fixed-frequency current-mode regulation with programmable current limits. Use Value: Delivers >95% efficiency at full load while meeting EN55022 Class B conducted EMI due to phase-lockable 400kHz operation. |
| High-Power Portable Test Equipment | Telecom Remote Radio Unit (RRU) Power |
Use Scenario: Providing adjustable 5V–24V output from a 12V Li-ion battery pack in handheld spectrum analyzers. IC Role / Device Role / Timing Role: Wide-range buck-boost controller with output voltage programming via DAC-controlled VFB divider. Use Value: Enables single-battery operation across multiple instrument configurations without hardware change or efficiency penalty. | Use Scenario: Generating 28V/3A from a 48V telecom -48VDC supply for RF power amplifiers in outdoor base stations. IC Role / Device Role / Timing Role: Robust buck-boost controller with PGOOD monitoring, thermal shutdown, and reverse-current blocking during brownout. Use Value: Ensures clean, glitch-free 28V rail during grid fluctuations; supports remote fault reporting via open-drain PGOOD signal. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3789EUFD#PBF | Same die, 28-lead 4mm×5mm QFN package with exposed thermal pad (θJA = 34°C/W vs 80°C/W). | Better thermal performance for high-current (>4A), space-constrained layouts; requires soldered exposed pad. | Select when board-level thermal resistance is <25°C/W and layout allows QFN reflow. |
| LTC3891IGN#PBF | Pin-compatible upgrade with wider 4.5V–60V input, integrated 5V/100mA bias supply, and improved light-load efficiency. | Supports higher-voltage industrial and solar-battery systems; reduces external component count. | Choose for new designs requiring extended input range or simplified biasing without EXTVCC routing. |
Compared with LTC3789EUFD#PBF, the LTC3789IGN#PBF offers lower assembly cost and legacy SSOP footprint compatibility but requires more PCB copper for thermal management; compared with LTC3891IGN#PBF, it lacks integrated bias supply and has narrower input range, making it suitable for cost-sensitive, established 12V/24V platforms where design reuse is prioritized.
Availability
LTC3789IGN#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial distributed power, and telecom RRU applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC3789IGN#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. (ADI) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and power management ICs, acquired Linear Technology in 2017 to expand its precision power portfolio.
The LTC3789 belongs to ADI's high-efficiency DC/DC controller product line, engineered for wide-input, wide-output voltage regulation in harsh environments such as automotive, industrial, and telecom infrastructure where reliability and seamless mode transitions are critical.
FAQ
What is the maximum input voltage rating for the LTC3789IGN#PBF?
The LTC3789IGN#PBF has an absolute maximum input supply voltage (VIN) rating of 40V. Its operational input range is specified from 4V to 38V, making it suitable for 24V and 36V industrial systems and 12V automotive applications with load-dump tolerance. Exceeding 40V risks permanent damage per Absolute Maximum Ratings.
Does the LTC3789IGN#PBF support external frequency synchronization?
Yes, the LTC3789IGN#PBF supports external frequency synchronization via the MODE/PLLIN pin. When an external clock signal is applied to this pin, the internal PLL locks to the incoming frequency within the 200kHz–600kHz range, forcing continuous conduction mode and eliminating beat frequencies in multi-converter systems.
How does the LTC3789IGN#PBF handle startup when VIN is near VOUT?
The LTC3789IGN#PBF automatically detects the buck-boost transition region using VINSNS and VOUTSNS pins and adjusts switching logic in real time. During startup, it begins in either buck or boost mode based on initial conditions and smoothly transitions into buck-boost operation without output disturbance or control-loop instability.
Can the LTC3789IGN#PBF regulate both input and output current simultaneously?
No, the LTC3789IGN#PBF supports either input current regulation (e.g., for battery charging) or output current regulation (e.g., for constant-current LED drivers), selected via the ILIM pin configuration. It does not implement dual-loop simultaneous regulation; the current sense path is shared and configured for one direction per application.
What is the purpose of the TRIM pin on the LTC3789IGN#PBF?
The TRIM pin on the LTC3789IGN#PBF must be tied to GND for normal operation. It disables internal reference trimming circuitry; leaving it floating may cause unpredictable output voltage regulation or failure to start. This pin has no user-adjustable function and serves only as a safety tie-down.
LTC3789IGN#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SSOP (0.154", 3.90mm Width)
- 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-SSOP
LTC3789IGN#PBF FAQ
1.How can I place an order for LTC3789IGN#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3789IGN#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 LTC3789IGN#PBF reliable?
The price and inventory of LTC3789IGN#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3789IGN#PBF is usually 5 days.
3.What payment methods are accepted for LTC3789IGN#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3789IGN#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3789IGN#PBF?
LTC3789IGN#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3789IGN#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 LTC3789IGN#PBF?
For technical support, including LTC3789IGN#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3789IGN#PBF requirements.
6.How does Aetrix verify that LTC3789IGN#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3789IGN#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 LTC3789IGN#PBF meets industry standards.
7.What is the process for return or replacement of LTC3789IGN#PBF?
All LTC3789IGN#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3789IGN#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 LTC3789IGN#PBF part is unused and in its original packaging.
Return procedure for LTC3789IGN#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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