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Analog Devices Inc. LTC1439EG#PBF
- Part No.:
- LTC1439EG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 36-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1439EG#PBF.pdf
- Description:
- IC REG CTRLR BUCK 36SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,852
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Product details
Overview
LTC1439EG#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 (e.g., 5V/3.3V), 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 notebook computers and portable instrumentation.
For engineers reviewing the LTC1439EG#PBF datasheet, LTC1439EG#PBF pinout, LTC1439EG#PBF application, or LTC1439EG#PBF equivalent, key selection criteria include programmable output voltage (1.19V–9V), PLL-synchronizable oscillator (112–240 kHz), remote sense capability on VOSENSE2, foldback current limiting option, and logic-controlled micropower shutdown (IQ < 30 µA).
Technical Context
The LTC1439EG#PBF implements a current-mode, dual-channel step-down control architecture with independent error amplifiers, ITH1/ITH2 compensation nodes, and adaptive gate drive routing between TGL/TGS/BG outputs. Its Adaptive Power™ stage dynamically selects between high-current synchronous (TGL1/BG1) and low-current diode-assisted (TGS1) operation based on inductor current reversal detection and RSENSE voltage hysteresis.
It features a secondary feedback input (SFB1) forcing continuous operation on Channel 1 regardless of main output load, a dedicated POR2 timer (65536 cycles ≈ 300 ms at 125 kHz), and an auxiliary linear regulator controlled via AUXON/AUXFB/AUXDR pins - supporting either 12V (internal divider) or adjustable outputs (external divider) with ≤1.24V reference accuracy.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 30V (36V absolute max); enables direct battery-input operation in 12V/24V portable systems. |
| Output Voltage Range | 1.19V to 9V per channel; set via VPROG1/VPROG2 pins or external resistive divider on VOSENSE2. |
| Oscillator Frequency | 112–138 kHz (free-running), up to 240 kHz with PLL; programmable via COSC capacitor and lockable to external clock. |
| Efficiency Mode | Adaptive Power™ maintains fixed frequency down to ~1% rated load; eliminates burst-mode noise in sensitive analog/audio rails. |
| Shutdown Current | <30 µA (IQ); achieved by pulling RUN/SS1 and RUN/SS2 below 1.3V - critical for battery longevity in standby. |
| Auxiliary Regulator | 0.5A linear output; supports 12V (internal 11.5–12.5V divider) or adjustable voltages via AUXFB feedback. |
| Remote Sense | VOSENSE2 pin enables Kelvin sensing on Channel 2; compensates for PCB trace IR drop in high-current 3.3V/5V rails. |
Pinout & Package
Package: 36-lead plastic SSOP (GW package), RoHS-compliant, moisture-sensitive level 3. 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 (~0.5 s/µF); <1.3V forces shutdown of respective channel; both low disables entire IC. |
| SENSE+1/2, SENSE−1/2 | Current-sense differential inputs | Measure voltage across external RSENSE; built-in offset sets trip threshold (130–180 mV) for overcurrent protection. |
| VOSENSE2 | Remote output voltage feedback | Connects to external resistor divider on Channel 2 output; enables precision regulation despite PCB trace resistance. |
| TGL1/TGL2, BG1/BG2 | Main synchronous gate drives | TGLx drives top N-MOSFET gate; BGx drives bottom N-MOSFET gate; both swing 0V to INTVCC (≈5V). |
| TGS1/TGS2 | Low-current top-gate drive | Drives small N-MOSFET + Schottky diode in Adaptive Power™ mode; disabled during high-load synchronous operation. |
| SFB1 | Secondary winding feedback | Pull below 1.19V to force Channel 1 into continuous conduction - ensures regulation under light/no main-load conditions. |
| POR2 | Power-on reset output | Open-drain signal asserted when VOUT2 drops >7.5%; releases after 65536 oscillator cycles once regulation restored. |
| AUXON, AUXFB, AUXDR | Auxiliary regulator interface | AUXON enables regulator (1.19V threshold); AUXFB is feedback node; AUXDR sinks base current of external PNP pass transistor. |
Key Features
| Feature | Design Value |
|---|---|
| Phase-Lockable Oscillator | PLLIN and PLL LPF pins allow synchronization to external clock source - essential for EMI reduction in multi-rail systems. |
| Adaptive Power™ Architecture | Automatically switches between TGL/BG (high-current) and TGS (low-current) drive paths - sustains fixed-frequency operation down to ~35 mA (1% of 3.5A). |
| Dual Remote Sensing | VOSENSE2 pin provides Kelvin feedback for Channel 2; SFB1 forces continuous mode on Channel 1 - improves load regulation across wide current range. |
| Integrated POR Timer | POR2 output delays system enable by exactly 65536 oscillator cycles (~300 ms at 125 kHz) - ensures stable VOUT2 before downstream logic powers up. |
| Logic-Controlled Auxiliary Regulator | AUXON pin enables/disables 0.5A linear regulator with <1.24V reference tolerance - ideal for clean VPP generation or low-noise audio bias rails. |
Applications
| Notebook Power Management | Portable Instrumentation |
|---|---|
Use Scenario: Dual-rail power for CPU core (3.3V) and I/O (5V) in space-constrained notebooks with battery input. IC Role / Device Role / Timing Role: Primary dual-channel buck controller managing high-efficiency DC/DC conversion with Adaptive Power™ to suppress audible noise during light-load states. Use Value: Maintains 90%+ efficiency at 100 mA load and eliminates burst-mode ripple - critical for display backlight and audio subsystem stability. | Use Scenario: Precision analog front-end and microcontroller supply in handheld test equipment powered by Li-ion battery. IC Role / Device Role / Timing Role: Generates low-noise 3.3V digital rail and clean 12V analog supply (via AUX regulator) with remote sensing to compensate for board-level voltage drop. Use Value: VOSENSE2 feedback and AUXFB-controlled 12V output deliver <0.8% load regulation - enabling 16-bit ADC accuracy without additional post-regulation. |
| Battery-Operated Medical Devices | DC Power Distribution Systems |
Use Scenario: Long-life wearable monitor requiring ultra-low shutdown current and reliable power sequencing. IC Role / Device Role / Timing Role: Dual-output controller with micropower shutdown (<30 µA) and POR2-driven system reset - ensures safe boot and extended battery runtime. Use Value: RUN/SS1/SS2 logic control and POR2 delay guarantee deterministic power-up sequence - meeting IEC 62304 safety-critical timing requirements. | Use Scenario: Centralized 48V-to-12V/5V conversion in industrial rack-mounted equipment with multiple distributed loads. IC Role / Device Role / Timing Role: High-voltage input buck controller supporting 30V max VIN and synchronized operation across multiple LTC1439 units via PLLIN. Use Value: PLL synchronization reduces beat-frequency EMI; wide input range accommodates 48V nominal with ±20% variation - eliminating need for pre-regulator stage. |
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 |
|---|---|---|---|
| LTC3723EG#PBF | Single-channel, higher VIN (4–38V), no integrated auxiliary regulator, supports MOSFET drivers only (no linear aux) | Lacks dual-output capability and 0.5A linear regulator - requires external LDO for VPP/audio rails | Select when only one high-current rail is needed and system already includes discrete 12V generation |
| MP2918GL-Z | Dual-channel, 4.5–32V input, integrated MOSFET drivers only, no PLL sync, no auxiliary regulator | No SFB1 forcing, no POR2 timer, no remote sense on second channel - less suitable for precision load regulation | Choose for cost-sensitive, non-safety-critical applications where EMI synchronization and auxiliary supply are not required |
Compared with LTC3723EG#PBF and MP2918GL-Z, the LTC1439EG#PBF uniquely combines dual-channel synchronous control, Adaptive Power™ fixed-frequency light-load operation, SFB1-enforced regulation, and integrated 0.5A linear regulator - making it optimal for battery-powered systems demanding low noise, precise sequencing, and auxiliary rail integration.
Availability
LTC1439EG#PBF is available at Aetrix Electronics and suitable for notebook computers, portable instrumentation, and battery-operated medical devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC1439EG#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, serving industrial, automotive, communications, and healthcare markets.
The LTC1439EG#PBF belongs to ADI's legacy Linear Technology power management portfolio, designed specifically for high-efficiency, low-noise dual-output DC/DC conversion in portable and battery-critical applications.
FAQ
What is the operating temperature range guaranteed for the LTC1439EG#PBF?
The LTC1439EG#PBF is specified and tested over the commercial temperature range of 0°C to 70°C. While performance over –40°C to 85°C is assured by design and characterization, only the 0°C to 70°C range is fully guaranteed per the datasheet. This makes LTC1439EG#PBF suitable for indoor portable electronics but not extended-temperature industrial deployments without validation.
How does the Adaptive Power™ mode in the LTC1439EG#PBF reduce audible noise compared to Burst Mode?
The LTC1439EG#PBF uses Adaptive Power™ to maintain constant switching frequency down to ~1% of full load by switching gate drive from TGL/BG to TGS outputs - avoiding the variable-frequency, low-duty-cycle pulses of Burst Mode that excite ceramic capacitor piezoelectric effects. This eliminates high-pitched whine in notebook speakers and displays, a key advantage of LTC1439EG#PBF in consumer portable designs.
Can the LTC1439EG#PBF generate a 12V auxiliary output without external components beyond the PNP transistor?
Yes - when AUXDR exceeds 9.5V, the LTC1439EG#PBF automatically connects its internal 11.5–12.5V resistive divider to AUXFB, enabling a precise 12V output using only an external PNP pass device (e.g., 2N2907A) and pull-up resistor on AUXDR. No external feedback resistors are needed for this configuration, simplifying layout and improving accuracy versus discrete divider solutions.
What is the function of the SFB1 pin on the LTC1439EG#PBF, and how is it used in secondary winding regulation?
The SFB1 pin on the LTC1439EG#PBF is a secondary winding feedback input tied exclusively to Channel 1. Pulling SFB1 below 1.19V forces continuous conduction mode regardless of main output loading - ensuring regulation stability when the primary output is lightly loaded or unpowered. In flyback-derived supplies, SFB1 connects to a resistive divider from the secondary winding to guarantee tight cross-regulation, a capability unique to LTC1439EG#PBF among dual controllers in its class.
Does the LTC1439EG#PBF support synchronization between multiple ICs, and what pins are involved?
Yes - the LTC1439EG#PBF supports phase-locked synchronization via its dedicated PLL circuit. The PLLIN pin accepts an external clock signal, while the PLL LPF pin serves as both phase detector output and oscillator control input (0–2.4V range). When locked, the top MOSFET turn-on aligns to the rising edge of the synchronizing signal - enabling coherent switching across multiple LTC1439EG#PBF units to minimize beat-frequency EMI in multi-rail systems.
LTC1439EG#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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 36-SSOP
LTC1439EG#PBF FAQ
1.How can I place an order for LTC1439EG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1439EG#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 LTC1439EG#PBF reliable?
The price and inventory of LTC1439EG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1439EG#PBF is usually 5 days.
3.What payment methods are accepted for LTC1439EG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1439EG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1439EG#PBF?
LTC1439EG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1439EG#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 LTC1439EG#PBF?
For technical support, including LTC1439EG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1439EG#PBF requirements.
6.How does Aetrix verify that LTC1439EG#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1439EG#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 LTC1439EG#PBF meets industry standards.
7.What is the process for return or replacement of LTC1439EG#PBF?
All LTC1439EG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1439EG#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 LTC1439EG#PBF part is unused and in its original packaging.
Return procedure for LTC1439EG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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