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Analog Devices Inc. LT1339ISW#TRPBF
- Part No.:
- LT1339ISW#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
LT1339ISW#TRPBF.pdf
- Description:
- IC REG CTLR BST/FWRD CONV 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,091
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Product details
Overview
LT1339ISW#TRPBF from Analog Devices (formerly Linear Technology) is a high-power synchronous current-mode DC/DC controller designed for buck, inverting, and negative-output converters up to 60V input. It drives dual N-channel MOSFETs with adaptive nonoverlapping gate drive, supports programmable average current limiting (120 mV threshold), 150 kHz synchronizable oscillator, and operates across –40°C to +85°C. Used in telecom power supplies and industrial control systems requiring robust overcurrent protection.
For engineers reviewing the LT1339ISW#TRPBF datasheet, LT1339ISW#TRPBF pinout, LT1339ISW#TRPBF application, or LT1339ISW#TRPBF equivalent, key selection criteria include its 60V max input voltage, dual N-MOSFET synchronous drive capability, programmable average current limit, soft-start control via SS pin, and phase-reversal support for inverting topologies.
Technical Context
The LT1339ISW#TRPBF implements constant-frequency current-mode control with an internal transconductance error amplifier (1200–3200 µmho gm), 1.25 V reference at VFB, and dual-stage current sensing: peak limit (170–190 mV) and programmable average limit (110–130 mV at sense inputs, 2.5 V at IAVG pin). Its oscillator supports free-run or external sync up to 150 kHz with timing set by RCT/CCT network.
It integrates adaptive nonoverlapping logic preventing shoot-through, minimum off-time protection (~1 µs), undervoltage lockout (9.0–9.75 V falling threshold, 350 mV hysteresis), and phase-reversal functionality via PHASE pin grounding to swap top/bottom driver roles-enabling flexible topology configuration including boost and inverting converters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | –0.3 V to 60 V on sense inputs; 12VIN supply: –0.3 V to 20 V - enables direct interface with high-voltage rails without level-shifting. |
| Operating Frequency | Programmable up to 150 kHz with ±5% accuracy - sets switching loss vs. magnetics size trade-off; supports synchronization to external clock. |
| Average Current Limit Threshold | 110–130 mV across sense resistor (typ. 120 mV) - provides stable DC load current regulation independent of duty cycle and inductor ripple. |
| Error Amplifier Reference | 1.242–1.258 V at VFB pin - defines output voltage setpoint with <±1% tolerance over temperature and line. |
| 5V Reference Output | 4.75–5.25 V at 10 mA DC load - powers external circuitry (e.g., feedback dividers, logic) without requiring auxiliary LDO. |
| Gate Drive Capability | Drives up to 10,000 pF total gate capacitance with 11–12 V on/off swing - supports high-current discrete MOSFETs in multi-amp designs. |
| Temperature Range | –40°C to +85°C (I-grade) - qualified for industrial and telecom environments with no derating required. |
Pinout & Package
LT1339ISW#TRPBF is housed in a 20-lead plastic SO Wide (SW) package with exposed thermal pad, compatible with standard SOIC-20W footprints and rated for θJA = 85°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SYNC (1) | Oscillator synchronization input | TTL-compatible rising-edge trigger; enables precise frequency alignment with system clocks or other regulators. |
| 5VREF (2) | 5 V regulated output | Stable 5 V supply for external biasing; delivers up to 10 mA DC, disabled during shutdown. |
| CT (3) | Oscillator timing node | Connects to timing capacitor (CCT) and pull-up resistor (RCT); sets operating frequency and sync response. |
| SL/ADJ (4) | Slope compensation adjustment | Allows external resistor divider to add duty-cycle-dependent slope compensation above 50% duty. |
| IAVG (5) | Average current limit integrator | 50 kΩ internal impedance node; external capacitor sets averaging bandwidth; short to SGND disables function. |
| SS (6) | Soft-start ramp generator | Sources ~8 µA to external capacitor; controls gradual VC clamp rise for controlled output voltage ramp-up. |
| VC (7) | Error amplifier output | Transconductance amplifier output; directly sets current comparator threshold and loop compensation point. |
| SGND (8) | Small-signal ground reference | Separate analog ground for feedback, reference, and error amp; must be star-connected to COUT negative. |
| VFB (9) | Error amplifier inverting input | Receives feedback voltage; 0.5 µA bias current ensures open-loop fault detection. |
| VREF (10) | Bandgap reference decoupling | Connects 0.1 µF bypass capacitor to stabilize internal 1.25 V reference. |
| SENSE+ (11) | Current sense amplifier inverting input | Connects to high-side of sense resistor; common-mode range extends to 60 V. |
| SENSE– (12) | Current sense amplifier noninverting input | Connects to low-side of sense resistor; enables bidirectional or high-side sensing configurations. |
| RUN/SHDN (13) | Enable/shutdown control | 1.25 V precision threshold with 25 mV hysteresis; supports both digital enable and analog UVLO monitoring. |
| PHASE (14) | Topology configuration control | Floating = buck mode; grounded = inverting/boost mode; swaps TG/BG driver assignments. |
| PGND (15) | Power ground return | Low-impedance return for bottom FET source and driver circuits; connects to VIN decoupling cap negative. |
| BG (16) | Bottom gate driver output | 11–12 V swing, 70–200 ns rise/fall; drives N-MOSFET source-connected to PGND. |
| 12VIN (17) | Main supply input | Powers internal logic and drivers; requires ≥1 µF bypass to PGND; max 20 V rating. |
| TS (18) | Topside switch node reference | Connects to source of top FET and switch node; withstands up to 60 V common-mode voltage. |
| TG (19) | Top gate driver output | 11–12 V swing, 130–200 ns rise/fall; drives N-MOSFET gate referenced to TS node. |
| VBOOST (20) | Bootstrap supply input | Accepts bootstrapped voltage (≥12 V typical); powers TG driver during high-side conduction. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable average current limiting | Enables precise DC load current regulation independent of inductor ripple and duty cycle - critical for battery charging and motor control where average current defines performance. |
| Adaptive nonoverlapping gate drive | Automatically adjusts dead time between TG and BG transitions based on actual FET switching behavior - eliminates need for fixed dead-time tuning and prevents shoot-through under varying load/temperature conditions. |
| Phase reversal via PHASE pin | Single-pin topology reconfiguration allows same IC to implement buck, inverting, or negative-output converters - reduces BOM count and design reuse effort. |
| Soft start gated by UVLO and shutdown | SS capacitor discharge during UVLO or SHDN ensures graceful recovery without output overshoot or inrush current spikes - improves system reliability during brownouts or sequencing events. |
| High-voltage sense amplifier inputs | SENSE+/– tolerate up to 60 V common-mode voltage - permits direct high-side current sensing in 48 V telecom or industrial bus applications without isolation or level-shifting. |
Applications
| 48V Telecom Power Supplies | Industrial Control Systems |
|---|---|
Use Scenario: Step-down conversion from 48 V DC distribution bus to 5 V/12 V logic rails in base station power shelves. IC Role / Device Role / Timing Role: Synchronous buck controller managing dual N-MOSFET power stage with 20 A output capability and precise average current limiting for redundancy monitoring. Use Value: Enables >90% efficiency at full load while maintaining tight current regulation across temperature, supporting hot-swap and N+1 redundant architectures. |
Use Scenario: Regulated 24 V output from 48 V or 60 V industrial bus for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: High-reliability DC/DC controller with UVLO hysteresis and phase-reversal support for isolated or non-isolated distributed supplies. Use Value: Delivers stable operation across wide ambient temperatures (–40°C to +85°C) and withstands bus transients up to 60 V - meeting EN 61000-4-5 surge immunity requirements. |
| Lead-Acid Battery Backup Systems | Automotive and Heavy Equipment |
Use Scenario: Bidirectional buck-boost converter managing charge/discharge between 36 V battery bank and 12 V loads in UPS or solar hybrid inverters. IC Role / Device Role / Timing Role: Configurable controller using PHASE pin and average current limit to enforce safe charge current limits and prevent battery over-discharge. Use Value: Programmable average current limit (120 mV threshold) provides accurate battery current regulation without external op-amps or DACs - reducing component count and calibration complexity. |
Use Scenario: 24 V to 5 V/3.3 V conversion for infotainment head units and ADAS ECUs in commercial vehicles with wide input range (18–32 V nominal, up to 60 V load dump). IC Role / Device Role / Timing Role: Robust synchronous controller with 60 V sense input tolerance and 1.25 V precision RUN/SHDN threshold for supply sequencing and cold-crank detection. Use Value: Undervoltage lockout with 350 mV hysteresis prevents erratic operation during engine cranking; 12VIN supply range supports direct connection to vehicle battery rail. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage synchronous controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3891EFE#PBF | Higher integration: includes 5 V bias regulator, integrated MOSFET drivers, and PMBus interface; 60 V max input, but fixed 1.2 V reference (not 1.25 V). | Targets digitally managed power systems; lacks PHASE pin for topology reversal; optimized for compact, high-density designs. | Select when digital telemetry, smaller solution size, or integrated bias supply are priorities - not for analog-only or phase-reversal use cases. |
| LM5116MH/NOPB | Lower max input (100 V), but only peak current mode (no average current limit); no 5 VREF output; uses external VREF instead of internal 1.25 V. | Designed for high-input-voltage industrial converters; requires external current-sense amplifier for average limit; less suitable for telecom or battery systems needing precise DC current control. | Select for >60 V input applications where average current limiting is not required - avoid when 120 mV average limit threshold or 5 VREF sourcing are mandatory. |
Compared with LTC3891EFE#PBF and LM5116MH/NOPB, the LT1339ISW#TRPBF uniquely combines programmable average current limiting, phase-reversal capability, and a self-contained 5 V reference - making it optimal for analog-controlled, topology-flexible, medium-power telecom and industrial DC/DC designs where precision DC current regulation is essential.
Availability
LT1339ISW#TRPBF is available at Aetrix Electronics and suitable for 48V telecom power supplies, industrial control systems, and lead-acid battery backup systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LT1339ISW#TRPBF 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 power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LT1339 belongs to ADI's legacy high-voltage synchronous controller product line, engineered specifically for industrial, telecom, and automotive power conversion where robustness, precision current regulation, and topology flexibility are critical.
FAQ
What is the maximum input voltage supported by the LT1339ISW#TRPBF?
The LT1339ISW#TRPBF supports up to 60 V on its current sense inputs (SENSE+ and SENSE–), and its 12VIN supply pin accepts –0.3 V to 20 V. The TS pin tolerates up to 60 V common-mode voltage, enabling direct interface with high-voltage buses. This makes the LT1339ISW#TRPBF suitable for 48 V telecom and industrial applications where transient overvoltage resilience is required.
How does the average current limit function work in the LT1339ISW#TRPBF?
The LT1339ISW#TRPBF implements average current limiting via the IAVG pin, which integrates the current sense amplifier output through an external capacitor. When the averaged signal exceeds 120 mV across the sense resistor, the VC pin is clamped, limiting output current regardless of duty cycle or inductor ripple. This function is disabled by shorting IAVG to SGND, and is confirmed in the Electrical Characteristics table (VIAVG = 2.5 V at IAVG pin).
Can the LT1339ISW#TRPBF be used in inverting or negative-output converter topologies?
Yes - the LT1339ISW#TRPBF supports inverting and negative-output configurations via the PHASE pin (Pin 14). When grounded, PHASE reverses the roles of TG and BG drivers, allowing the bottom FET to act as the main switch and the top FET as the synchronous rectifier. This capability is explicitly documented in the Pin Functions section and Typical Application schematics.
What is the purpose of the SL/ADJ pin on the LT1339ISW#TRPBF?
The SL/ADJ pin (Pin 4) provides user-adjustable slope compensation to stabilize current-mode control at duty cycles above 50%. Applying a resistive divider from 5VREF introduces additional ramp to the current comparator, preventing subharmonic oscillation. The datasheet confirms this function is optional - the pin may be floated or tied to 5VREF if no extra compensation is needed.
Does the LT1339ISW#TRPBF include an internal 5 V reference, and how is it used?
Yes - the LT1339ISW#TRPBF provides a regulated 5 V output at the 5VREF pin (Pin 2), specified from 4.75 V to 5.25 V under 10 mA DC load. It powers internal oscillator and logic circuits and can also bias external components such as feedback resistors or level-shifters. The 5VREF output is disabled during shutdown, as noted in the Features list and Electrical Characteristics table.
LT1339ISW#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Boost, Forward Converter
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- Up to 20V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- 90%
- Synchronous Rectifier:
- No
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Phase Control, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
LT1339ISW#TRPBF FAQ
1.How can I place an order for LT1339ISW#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1339ISW#TRPBF 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 LT1339ISW#TRPBF reliable?
The price and inventory of LT1339ISW#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1339ISW#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1339ISW#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1339ISW#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1339ISW#TRPBF?
LT1339ISW#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1339ISW#TRPBF 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 LT1339ISW#TRPBF?
For technical support, including LT1339ISW#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1339ISW#TRPBF requirements.
6.How does Aetrix verify that LT1339ISW#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1339ISW#TRPBF 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 LT1339ISW#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1339ISW#TRPBF?
All LT1339ISW#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1339ISW#TRPBF, 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 LT1339ISW#TRPBF part is unused and in its original packaging.
Return procedure for LT1339ISW#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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