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Analog Devices Inc. LTC1439CG#PBF
- Part No.:
- LTC1439CG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 36-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1439CG#PBF.pdf
- Description:
- IC REG CTRLR BUCK 36SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,085
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Product details
Overview
LTC1439CG#PBF from Analog Devices (formerly Linear Technology) is a dual synchronous step-down switching regulator controller driving external N-channel MOSFETs in a phase-lockable fixed-frequency architecture. It delivers two independently regulated outputs (1.19V–9V), supports Adaptive Power™ mode for ultrahigh efficiency down to 1% load, and integrates a 0.5A low-noise linear regulator for VPP or audio supply - used in notebook computers and portable instrumentation.
For engineers reviewing the LTC1439CG#PBF datasheet, LTC1439CG#PBF pinout, LTC1439CG#PBF application, or LTC1439CG#PBF equivalent, key selection criteria include programmable fixed frequency (112–138 kHz base, PLL-extendable), dual N-MOSFET synchronous drive capability, remote sense support on VOSENSE2, and logic-controlled micropower shutdown (IQ < 30 µA).
Technical Context
The LTC1439CG#PBF implements a current-mode, constant-frequency step-down control architecture with independent error amplifiers per channel. Each channel uses an external current-sense resistor (RSENSE) and adjustable ITH voltage to regulate peak inductor current, while SFB1 forces continuous operation on Channel 1 when secondary winding feedback is required.
Its Adaptive Power™ topology dynamically routes gate drive between TGL/TGS pins to switch between high-current synchronous mode (TGL+BG) and low-current diode-assisted mode (TGS only), maintaining fixed frequency down to ~1% of full load. The integrated 5V INTVCC LDO and EXTVCC switchover circuit enable efficient self-biasing from regulated outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 30V operating, 36V absolute max - supports wide-input battery and DC distribution systems. |
| Switching Frequency | 112–138 kHz (COSC = 100 pF), PLL-extendable to 240 kHz - enables EMI control and layout optimization. |
| Output Voltage Range | 1.19V to 9V via VPROG1/VPROG2 or external resistive dividers - supports 3.3V/5V standard rails and adjustable supplies. |
| Efficiency Mode | Adaptive Power™ maintains fixed frequency down to ~1% load - avoids audible noise and output ripple spikes of burst mode. |
| Shutdown Current | < 30 µA (IQ) with RUN/SS1 & RUN/SS2 low - enables long battery life in portable devices. |
| Auxiliary Regulator | 0.5A linear regulator with AUXON control and 12V/1.19V selectable output - provides low-noise VPP or analog supply without external op-amps. |
| Operating Temp | 0°C to 70°C (Commercial grade, CG suffix) - validated for notebook, PDA, and industrial portable equipment. |
Pinout & Package
Package: 28-lead plastic SSOP (G package), RoHS-compliant, lead-free (PbF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE+ 1 / SENSE+ 2 | Current sense comparator non-inverting input | Connects to high-side of RSENSE to set current limit threshold (ΔVSENSE(MAX) = 150 mV typical). |
| SENSE– 1 / SENSE– 2 | Current sense comparator inverting input | Connects to low-side of RSENSE; internal offset defines trip point - no external amplifier needed. |
| VPROG1 / VPROG2 | Output voltage programming select | DC voltage level selects 3.3V (VPROG < VINTVCC/3), 5V (VPROG > VINTVCC/1.5), or adjustable mode (open). |
| VOSENSE2 | Remote output voltage sensing input (Channel 2) | Enables Kelvin sensing for precision regulation - required for remote sense configuration on second output. |
| RUN/SS1 / RUN/SS2 | Soft-start timing and enable control | Capacitor-to-ground sets ramp time (~0.5 s/µF); <1.3V disables respective channel; both low = full shutdown. |
| TGL1/TGL2, BG1/BG2 | High-current gate drivers | TGL drives top N-MOSFET (floating); BG drives bottom N-MOSFET - supports synchronous rectification up to 400 kHz. |
| TGS1/TGS2 | Low-current top-MOSFET driver | Enables Adaptive Power™ mode - replaces TGL during light load to reduce gate charge loss and maintain fixed frequency. |
| SFB1 | Secondary winding feedback control | Pulling below 1.19V forces Channel 1 into continuous conduction - critical for transformer-coupled auxiliary rail regulation. |
| POR2 | Power-on reset output (open-drain) | Asserts low when VOUT2 drops >7.5%; releases after 65536 oscillator cycles - provides reliable system power sequencing. |
| LBI/LBO | Low-battery detect input/output | LBI compares to 1.19V reference; LBO sinks current when LBI falls below threshold - enables battery monitoring without external comparators. |
Key Features
| Feature | Design Value |
|---|---|
| Dual synchronous step-down control | Independent regulation of two outputs using external N-MOSFETs - eliminates need for dual discrete controllers. |
| Adaptive Power™ architecture | Automatic transition between TGL+BG (high load) and TGS-only (light load) - sustains fixed frequency and high efficiency across 100:1 load range. |
| Programmable soft start | RUN/SS capacitor sets controlled current ramp - prevents inrush current and output overshoot during power-up. |
| Integrated 0.5A linear regulator | AUXON-gated, AUXFB-sensed PNP-based regulator - delivers low-noise 12V or 1.19V output without external pass transistor biasing circuitry. |
| Phase-locked loop (PLL) | PLLIN and PLL LPF pins enable synchronization to external clock - essential for multi-rail systems requiring deterministic switching alignment. |
Applications
| Battery-Powered Notebook Systems | Portable Test Instruments |
|---|---|
Use Scenario: Dual-rail power for CPU core (3.3V) and I/O (5V) in space-constrained notebooks with Li-ion battery input (7–28V). IC Role / Device Role / Timing Role: Primary dual-output DC/DC controller managing synchronous buck conversion, adaptive load scaling, and POR sequencing. Use Value: Adaptive Power™ extends battery runtime by sustaining >90% efficiency at light loads; remote sense on VOSENSE2 ensures ±0.8% load regulation under dynamic current steps. | Use Scenario: Precision analog front-end and digital logic supply in handheld DMMs or spectrum analyzers powered from 4×AA batteries. IC Role / Device Role / Timing Role: Dual-channel regulator delivering clean 3.3V for ADC/DAC and 5V for microcontroller, with auxiliary 12V VPP for LCD bias. Use Value: Integrated 0.5A linear regulator provides 12V VPP with <20 mV ripple; LBI/LBO enables battery fuel gauging without extra components. |
| Industrial Portable Data Loggers | DC Power Distribution Modules |
Use Scenario: Wide-input (3.5–30V) field-deployed logger using supercapacitor backup and isolated sensor interfaces. IC Role / Device Role / Timing Role: Main power controller enabling seamless transition between line and backup power, with SFB1-driven secondary winding regulation. Use Value: SFB1 pin forces continuous operation on Channel 1 during backup mode - guarantees stable 5V rail even with transformer-coupled auxiliary windings. | Use Scenario: Centralized 24V-to-3.3V/5V conversion in modular PLC backplanes or telecom shelf management units. IC Role / Device Role / Timing Role: High-efficiency dual-output controller supporting hot-swap, remote sense, and synchronized switching across multiple boards. Use Value: PLL synchronization eliminates beat frequencies between adjacent modules; EXTVCC switchover allows self-powered bias from local 5V rail. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1439IG#PBF | Extended temperature range (–40°C to 85°C); same pinout and electrical specs. | Required for industrial or automotive-adjacent environments where ambient exceeds 70°C. | Select LTC1439IG#PBF when operating in extended temperature conditions; otherwise LTC1439CG#PBF is optimal for commercial-grade cost-sensitive designs. |
| MP2918GL-Z | Single-chip dual buck controller with integrated MOSFETs; no external gate drivers; lower max VIN (28V). | Reduces BOM count but sacrifices flexibility in MOSFET selection and thermal management. | Choose MP2918GL-Z for compact, low-component-count designs; LTC1439CG#PBF remains preferred when discrete MOSFET optimization, wide VIN, or Adaptive Power™ efficiency is critical. |
Compared with LTC1439IG#PBF, the LTC1439CG#PBF trades extended temperature rating for lower cost and identical functionality in commercial environments; versus MP2918GL-Z, it retains design flexibility through external MOSFET drive and wider input range (36V abs max), at the expense of higher board area and component count.
Availability
LTC1439CG#PBF is available at Aetrix Electronics and suitable for notebook computers, portable test instruments, and industrial data loggers requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.
Supply support for LTC1439CG#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) acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for legacy Linear products including the LTC series.
The LTC1439CG#PBF belongs to Linear's high-efficiency power management controller family, designed specifically for dual-output, battery-operated, and wide-input DC/DC applications demanding precision regulation, low quiescent current, and adaptive light-load performance.
FAQ
What is the maximum recommended switching frequency for the LTC1439CG#PBF?
The maximum recommended switching frequency for the LTC1439CG#PBF is 400 kHz. This limit balances gate charge losses against inductor size and ripple current. While the PLL can extend frequency to 240 kHz in synchronized mode, operation beyond 400 kHz risks reduced efficiency and thermal stress - confirmed in the Applications Information section and Figure 2 of the datasheet. The LTC1439CG#PBF achieves optimal efficiency at its base 112–138 kHz range with COSC = 100 pF.
Does the LTC1439CG#PBF support remote voltage sensing on both outputs?
The LTC1439CG#PBF supports remote voltage sensing only on Channel 2 via the VOSENSE2 pin. Channel 1 does not expose a dedicated VOSENSE1 pin except on the LTC1438-ADJ variant; for the LTC1439CG#PBF, Channel 1 sensing is internal and tied to SENSE–1. Remote sense on Channel 2 enables precise regulation under PCB trace IR drop - critical for high-current 3.3V/5V rails. The LTC1439CG#PBF datasheet explicitly confirms VOSENSE2 functionality and lists SENSE–1 as internally connected for Channel 1.
How does the Adaptive Power™ mode function in the LTC1439CG#PBF?
Adaptive Power™ mode in the LTC1439CG#PBF automatically switches gate drive from TGL1/TGL2 (high-current path) to TGS1/TGS2 (low-current path) when load drops below ~1% of full scale. This preserves fixed-frequency operation and avoids burst-mode noise/ripple. Transition triggers when current reversal is detected and sustained for one cycle, provided SENSE common-mode voltage >1.4V and SFB1 >1.19V. The LTC1439CG#PBF maintains >90% efficiency at 10 mA load - a key differentiator over standard controllers that default to burst mode at ~10% load.
Can the LTC1439CG#PBF generate a 12V auxiliary output?
Yes, the LTC1439CG#PBF can generate a regulated 12V auxiliary output using its integrated linear regulator block. When AUXDR exceeds 9.5V, the internal 12V resistive divider engages at AUXFB, setting the output to 12.0V ±0.5V (typical). An external PNP pass transistor (e.g., 2N2907A) is required, with base driven by AUXDR and collector tied to the 12V rail. The LTC1439CG#PBF datasheet confirms this behavior in the Electrical Characteristics table (VAUXFB = 12.0V) and Applications Information section.
What is the purpose of the SFB1 pin on the LTC1439CG#PBF?
The SFB1 pin on the LTC1439CG#PBF is a secondary winding feedback input that forces Channel 1 into continuous conduction mode when pulled below 1.19V. It is used exclusively with transformer-coupled auxiliary windings to guarantee regulation of the main output even when the auxiliary rail is lightly loaded. Unlike general-purpose feedback pins, SFB1 does not set voltage - it overrides Adaptive Power™ and burst mode to sustain synchronous switching. The LTC1439CG#PBF Functional Diagram and Pin Functions section confirm SFB1's role in dropout prevention for coupled-inductor topologies.
LTC1439CG#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 36-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 2
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 3.5V ~ 30V
- Frequency - Switching:
- Up to 400kHz
- Duty Cycle (Max):
- 99%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Power on Reset, Soft Start
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 36-SSOP
LTC1439CG#PBF FAQ
1.How can I place an order for LTC1439CG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1439CG#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 LTC1439CG#PBF reliable?
The price and inventory of LTC1439CG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1439CG#PBF is usually 5 days.
3.What payment methods are accepted for LTC1439CG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1439CG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1439CG#PBF?
LTC1439CG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1439CG#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 LTC1439CG#PBF?
For technical support, including LTC1439CG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1439CG#PBF requirements.
6.How does Aetrix verify that LTC1439CG#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1439CG#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 LTC1439CG#PBF meets industry standards.
7.What is the process for return or replacement of LTC1439CG#PBF?
All LTC1439CG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1439CG#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 LTC1439CG#PBF part is unused and in its original packaging.
Return procedure for LTC1439CG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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