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Analog Devices Inc. LTC1439IGW#PBF
- Part No.:
- LTC1439IGW#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 36-BSOP (0.295", 7.50mm Width)
- Datasheet:
-
LTC1439IGW#PBF.pdf
- Description:
- IC REG CTRLR BUCK 36SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,855
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Product details
Overview
LTC1439IGW#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 regulated outputs (1.19V–9V), supports 3.5V–30V input, maintains constant frequency down to ~1% load via Adaptive Power™ mode, and integrates a 0.5A low-noise linear regulator for VPP or audio supply - used in portable instrumentation and battery-powered DC distribution systems.
For engineers reviewing the LTC1439IGW#PBF datasheet, LTC1439IGW#PBF pinout, LTC1439IGW#PBF application, or LTC1439IGW#PBF equivalent, key selection criteria include programmable output voltage selection (via VPROG pins), remote sense capability on VOSENSE2, PLL synchronization support, ultralow shutdown current (<30µA), and dual-channel independent soft-start control (RUN/SS1 & RUN/SS2).
Technical Context
The LTC1439IGW#PBF implements a current-mode, constant-frequency dual buck controller with independent error amplifiers, adaptive gate drive (TGL/TGS/BG), and secondary feedback (SFB1) forcing continuous operation under light loads. Its Adaptive Power™ architecture dynamically switches between large- and small-MOSFET drive paths to sustain 400kHz operation down to ~1% rated load while minimizing switching losses.
It features a built-in 5V internal LDO (INTVCC), EXTVCC switchover at 4.7V, auxiliary PNP-based linear regulator (AUXDR/AUXFB) with 12V or 1.19V output options, and integrated power-on reset (POR2) with 65536-cycle delay (~300ms at 125kHz). The PLLIN/PLL LPF interface enables external clock synchronization with ±30% frequency tuning range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 30V (36V absolute max); supports wide-input industrial and battery-powered systems. |
| Switching Frequency | 112–138kHz (typical, COSC = 100pF); PLL-tunable up to ±30% for EMI reduction or multi-rail synchronization. |
| Output Voltage Range | 1.19V to 9V; pin-selectable 3.3V/5V or adjustable via external resistive divider on VOSENSE2. |
| Shutdown Current | <30µA (IQ); enables micropower standby in portable devices with logic-controlled RUN/SS pins. |
| Efficiency at Light Load | Ultrahigh efficiency maintained down to ~1% load via Adaptive Power™ mode - avoids Burst Mode discontinuity. |
| Auxiliary Regulator | 0.5A linear regulator with selectable 12V (internal divider) or 1.19V (external divider) output; low-noise supply for VPP or audio rails. |
| Operating Temperature | –40°C to +85°C (Industrial grade); validated for extended ambient environments without derating. |
Pinout & Package
Package: 36-lead plastic SSOP (GW package), 0.025" pitch, JEDEC MS-013AC. Thermal resistance θJA = 85°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS1, RUN/SS2 | Soft-start & enable control | Capacitor-to-ground sets ramp time (~0.5s/µF); <1.3V forces shutdown of respective channel. |
| SENSE+1/2, SENSE−1/2 | Current-sense differential inputs | Measure voltage across external RSENSE; set peak-current limit (ΔVSENSE(MAX) = 150mV typ). |
| VOSENSE2 | Remote output voltage sense | Connects to external resistive divider for precise regulation of second output; enables remote sensing. |
| VPROG1, VPROG2 | Output voltage programming | DC voltage selects 3.3V (low), 5V (high), or adjustable (open) for respective controller outputs. |
| PLLIN, PLL LPF | Phase-locked loop interface | Accepts external sync clock (PLLIN); PLL LPF controls oscillator frequency (0–2.4V = –30% to +30% fOSC). |
| AUXDR, AUXFB, AUXON | Auxiliary regulator interface | AUXDR drives PNP base; AUXFB is feedback node; AUXON enables/disables regulator with 1.19V threshold. |
| POR2 | Power-on reset output | Open-drain signal asserted when VOUT2 drops >7.5%; releases after 65536 oscillator cycles (~300ms @125kHz). |
| TGL1/2, BG1/2, TGS1/2 | Gate drivers | TGL/BG drive large N-MOSFETs; TGS drives small N-MOSFET for Adaptive Power™ low-load operation. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive Power™ architecture | Automatically toggles between TGL/BG (high-current) and TGS (low-current) drive paths to sustain fixed-frequency operation down to ~1% load - eliminates Burst Mode noise and improves transient response. |
| Dual independent soft-start | RUN/SS1 and RUN/SS2 pins allow staggered or simultaneous startup of two outputs - prevents inrush current stacking in multi-rail systems. |
| Secondary winding feedback (SFB1) | Forces continuous conduction mode on Channel 1 regardless of main output loading - ensures stable regulation in flyback-derived auxiliary supplies. |
| Integrated POR2 timer | Generates system-level reset signal delayed by exactly 65536 oscillator cycles after VOUT2 reaches regulation - provides deterministic, clock-synchronized power sequencing. |
| Logic-controlled auxiliary regulator | AUXON pin enables/disables 0.5A linear regulator with 1.19V threshold - allows software-controlled VPP generation or low-noise analog supply gating. |
Applications
| Portable Instrumentation | Battery-Powered DC Distribution |
|---|---|
Use Scenario: Handheld multimeters and portable oscilloscopes requiring clean, isolated 3.3V digital and 5V analog rails from a single Li-ion cell or 12V battery pack. IC Role / Device Role / Timing Role: Dual synchronous buck controller generating tightly regulated, remotely sensed outputs with independent soft-start and low-noise auxiliary supply for ADC reference. Use Value: Adaptive Power™ sustains fixed-frequency operation during battery discharge, avoiding audible noise and ensuring consistent EMI profile across full SoC operating range. | Use Scenario: Distributed power architecture in ruggedized field equipment where multiple subsystems draw from a common 24V bus with varying load profiles. IC Role / Device Role / Timing Role: Primary DC-DC controller managing two independent downstream rails (e.g., 5V FPGA core, 3.3V I/O) with SFB1-assisted secondary winding regulation for isolated auxiliary bias. Use Value: PLL synchronization aligns switching edges across multiple LTC1439IGW#PBF units - reducing aggregate ripple and simplifying EMI filter design in multi-board systems. |
| Notebook Subsystem Power | Low-Noise Audio Supply Generation |
Use Scenario: Embedded controller power in thin-and-light notebooks where thermal headroom is limited and dynamic load steps occur during CPU/GPU state transitions. IC Role / Device Role / Timing Role: Dual-phase controller delivering 1.19V core and 3.3V memory rails with remote sense, foldback current limiting, and programmable soft-start timing. Use Value: 99% duty cycle dropout operation extends usable battery life; low IQ (<30µA) shutdown preserves charge during sleep states. | Use Scenario: High-fidelity portable audio DACs requiring ultra-low-noise 5V supply decoupled from noisy digital switching rails. IC Role / Device Role / Timing Role: Auxiliary linear regulator (AUXDR/AUXFB) configured as 5V low-dropout source using external PNP pass device and precision feedback. Use Value: PSRR >60dB at 1kHz (per datasheet Fig. 20) suppresses switching noise coupling into analog signal path - measurable improvement in THD+N. |
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 |
|---|---|---|---|
| LTC3779EUF#PBF | Single-channel, 2-phase interleaved controller; supports higher VIN (4–38V), includes MOSFET drivers with 3A peak sink/source; no integrated auxiliary LDO. | Designed for high-current single-output applications (e.g., 12V→1.2V @30A); lacks dual independent outputs and SFB1 functionality. | Select when needing higher current per rail and interleaved ripple cancellation - not suitable for dual-rail independent regulation. |
| MP2918GL-Z | Dual-channel controller with integrated MOSFET drivers (no external FETs required); fixed 500kHz fSW; no PLL sync, no auxiliary LDO, no SFB1 pin. | Targeted at cost-sensitive consumer power supplies; lacks remote sensing, programmable voltage selection, and industrial temp grade. | Choose for simplified BOM and layout in non-critical commercial applications - not recommended for industrial or low-noise designs. |
Compared with LTC3779EUF#PBF and MP2918GL-Z, the LTC1439IGW#PBF uniquely combines dual independent outputs with remote sensing, Adaptive Power™ light-load optimization, PLL synchronization, and an integrated auxiliary linear regulator - making it optimal for space-constrained, multi-rail industrial and portable systems requiring deterministic timing and low-noise bias.
Availability
LTC1439IGW#PBF is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered DC distribution systems, and notebook subsystem power requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.
Supply support for LTC1439IGW#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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, acquired Linear Technology in 2017 to expand its power management portfolio.
The LTC1439IGW#PBF belongs to ADI's legacy Linear Technology high-efficiency DC-DC controller family, designed specifically for dual-output, low-noise, battery-operated applications demanding adaptive light-load efficiency and precise multi-rail sequencing.
FAQ
What is the maximum supported switching frequency for the LTC1439IGW#PBF?
The LTC1439IGW#PBF supports up to 400kHz maximum switching frequency, as specified in the Absolute Maximum Ratings and confirmed in the Applications Information section. Operation above 400kHz is not characterized and may compromise efficiency, thermal performance, and stability. The typical oscillator frequency is 112–138kHz (with COSC = 100pF), and PLL tuning extends this range by ±30% around the nominal value - but the 400kHz ceiling remains absolute.
Does the LTC1439IGW#PBF support remote voltage sensing on both outputs?
The LTC1439IGW#PBF supports remote voltage sensing only on the second output (VOSENSE2). The first output (Channel 1) uses internal sensing tied to SENSE−1, except in the LTC1438-ADJ variant - which is not applicable to the LTC1439IGW#PBF. VOSENSE2 accepts an external resistive divider for precise regulation of VOUT2, enabling compensation for PCB trace IR drop in high-current applications.
How does the Adaptive Power™ mode function in the LTC1439IGW#PBF?
Adaptive Power™ mode in the LTC1439IGW#PBF automatically routes gate drive from TGL1/TGL2 (large-MOSFET path) to TGS1/TGS2 (small-MOSFET path) when load current falls below ~1% of full scale. This preserves fixed-frequency operation and avoids Burst Mode discontinuities. Drive reverts to TGL when ITH exceeds 0.6V or RSENSE voltage exceeds 20mV - ensuring seamless transition across load ranges without external intervention.
Can the LTC1439IGW#PBF be synchronized to an external clock source?
Yes, the LTC1439IGW#PBF supports external clock synchronization via the PLLIN pin. When an external square wave is applied to PLLIN, the internal phase detector locks the oscillator to that frequency. The PLL LPF pin serves as both phase detector output and oscillator control node (0–2.4V range), allowing ±30% frequency adjustment. This feature is exclusive to the LTC1439 (not LTC1438) and is fully functional in the LTC1439IGW#PBF.
What is the purpose of the SFB1 pin on the LTC1439IGW#PBF?
The SFB1 pin on the LTC1439IGW#PBF is a secondary winding feedback input dedicated to Channel 1. Pulling SFB1 below 1.19V forces continuous conduction mode regardless of load - critical for maintaining regulation in flyback-derived auxiliary supplies where main output loading varies independently. It is not used for standard buck operation and must be tied to INTVCC or grounded depending on topology.
LTC1439IGW#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 36-BSOP (0.295", 7.50mm 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 36-SSOP
LTC1439IGW#PBF FAQ
1.How can I place an order for LTC1439IGW#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1439IGW#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 LTC1439IGW#PBF reliable?
The price and inventory of LTC1439IGW#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1439IGW#PBF is usually 5 days.
3.What payment methods are accepted for LTC1439IGW#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1439IGW#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1439IGW#PBF?
LTC1439IGW#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1439IGW#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 LTC1439IGW#PBF?
For technical support, including LTC1439IGW#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1439IGW#PBF requirements.
6.How does Aetrix verify that LTC1439IGW#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1439IGW#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 LTC1439IGW#PBF meets industry standards.
7.What is the process for return or replacement of LTC1439IGW#PBF?
All LTC1439IGW#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1439IGW#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 LTC1439IGW#PBF part is unused and in its original packaging.
Return procedure for LTC1439IGW#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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