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Analog Devices Inc. LT3844IFE#TRPBF
- Part No.:
- LT3844IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3844IFE#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,715
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Product details
Overview
LT3844IFE#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode DC/DC controller for step-down, step-up, inverting, and SEPIC topologies. It operates from 4V to 60V input, delivers up to 36V output, supports 100kHz–500kHz programmable frequency, features Burst Mode® operation (120µA quiescent current), and drives external N-channel MOSFETs in industrial power distribution and 42V automotive systems.
For engineers reviewing the LT3844IFE#TRPBF datasheet, LT3844IFE#TRPBF pinout, LT3844IFE#TRPBF application, or LT3844IFE#TRPBF equivalent, key selection criteria include its 60V max VIN rating, ±1.3% reference accuracy, 100mV current sense threshold, thermal shutdown, and 16-pin TSSOP package with exposed SGND pad for enhanced thermal performance.
Technical Context
The LT3844IFE#TRPBF implements fixed-frequency current-mode control with slope/antislope compensation to prevent subharmonic oscillation across duty cycles. Its error amplifier (270–410 µS transconductance) regulates via VC pin voltage, directly setting peak inductor current per cycle.
Burst Mode® operation engages below ~15% load by latching VC voltage and disabling switching when VC drops 150mV below latch level-reducing VIN supply current to 120µA while maintaining regulation. Internal high-voltage bias regulator powers gate drive from VIN up to 60V, and BOOST pin supplies bootstrapped TG driver referenced to SW node.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4V to 60V - supports wide-input industrial and 42V automotive rails without pre-regulation |
| Output Voltage Max | 36V - enables high-side step-down conversion from 48V telecom or avionics buses |
| Operating Frequency | 100kHz to 500kHz (programmable via fSET resistor) - balances efficiency, size, and EMI in medium-power designs |
| Current Sense Threshold | 100mV (typical) - sets precise overcurrent protection independent of duty cycle due to antislope compensation |
| Reference Accuracy | ±1.3% (over –40°C to 125°C) - ensures stable output regulation across automotive temperature range |
| Quiescent Current | 120µA in Burst Mode® - extends battery life in always-on 12V/24V systems during light-load standby |
| Shutdown Current | 10µA - enables ultra-low-power system-level disable without auxiliary LDO |
| Package | 16-Lead Thermally Enhanced TSSOP with Exposed SGND Pad - provides 10°C/W θJC for reliable 50W operation |
Pinout & Package
LT3844IFE#TRPBF is housed in a 16-lead plastic TSSOP package (FE grade) with exposed pad (Pin 17) internally connected to SGND. The thermally enhanced layout requires soldering the exposed pad to PCB ground for optimal thermal performance (θJA = 40°C/W, θJC = 10°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (1) | Main input supply rail | Accepts 4V–60V; powers internal bias regulator and supplies gate drive energy via BOOST path |
| SHDN (2) | Enable/disable control | 1.35V rising threshold with 120mV hysteresis; pulls VIN current to ~9µA in shutdown |
| CSS (3) | Soft-start timing | 2µA current source charges external capacitor to ramp VFB reference and limit inrush current |
| BURST_EN (4) | Burst Mode® enable | Ground = enable; VCC/VFB = disable - controls low-load efficiency mode independently of regulation loop |
| VFB (5) | Feedback input | Compares output voltage (via resistive divider) to 1.231V internal reference; error signal drives VC |
| VC (6) | Error amplifier output | DC voltage sets peak inductor current per cycle; clamped at –100mV during Burst Mode® to minimize ripple |
| SYNC (7) | External clock input | Accepts 100kHz–600kHz sync signal; allows noise-sensitive system-level clock alignment |
| fSET (8) | Oscillator programming | Resistor sets nominal frequency; required even when SYNC is active to define base oscillator range |
| SGND (9,17) | Signal ground reference | Low-noise analog ground for feedback, sense, and error amp; must be isolated from PGND in layout |
| SENSE– (10) | Current sense negative | Connects to VOUT side of sense resistor; common-mode range up to 36V supports high-side sensing |
| SENSE+ (11) | Current sense positive | Connects to inductor side of sense resistor; 100mV differential threshold enables accurate current limiting |
| PGND (12) | Power ground return | High-current return for VCC regulator and internal SW pull-down switch; ties to VCC decoupling cap |
| VCC (13) | Bias supply node | Internally regulated ~8V rail; can be back-driven from VOUT to reduce IC power loss and improve efficiency |
| SW (14) | Switch node | Connects to MOSFET drain and Schottky cathode; swings from VIN to ~–0.5V; drives BOOST capacitor charging |
| TG (15) | Bootstrapped gate driver | Supplies high-current pulses to N-MOSFET gate; requires short/wide trace to minimize ringing and shoot-through risk |
| BOOST (16) | Bootstrap supply | Charged from VCC via external diode; referenced to SW; supports >10V gate drive for low-RDS(on) MOSFETs |
Key Features
| Feature | Design Value |
|---|---|
| Antislope compensation | Maintains constant 100mV current limit threshold across all duty cycles - eliminates need for dynamic sense resistor scaling |
| Programmable UVLO | Configurable start-up and shutdown thresholds via external resistor dividers on SHDN pin - enables custom brown-in/brown-out behavior |
| Internal high-voltage bias regulator | Derives VCC and BOOST from VIN up to 60V - eliminates need for external bias supply in most 48V applications |
| Thermally enhanced TSSOP | Exposed SGND pad reduces junction-to-case thermal resistance to 10°C/W - sustains 50W continuous operation without heatsink |
| Short-circuit protection | Automatic cycle-skipping when SENSE+–SENSE– ≥100mV - limits fault current without external circuitry or latch-up |
| Soft-start with fault recovery | CSS pin discharges during UVLO events and short circuits - ensures controlled restart after faults without manual reset |
Applications
| Industrial Power Distribution | 42V Automotive Systems |
|---|---|
Use Scenario: Distributed 24V/12V power in factory automation PLCs and I/O modules fed from 48V DC bus. IC Role / Device Role / Timing Role: Step-down controller regulating isolated 12V rails for microcontrollers, sensors, and communication interfaces. Use Value: 60V VIN rating tolerates 48V bus transients; Burst Mode® maintains <120µA idle current for energy-efficient standby states. | Use Scenario: Onboard charger auxiliary supply and ADAS domain controller power in commercial vehicles with 42V architecture. IC Role / Device Role / Timing Role: High-efficiency buck controller converting 42V battery to 5V/3.3V for infotainment and radar processing units. Use Value: ±1.3% reference accuracy ensures stable MCU core voltage across –40°C to 125°C; thermal shutdown protects against engine bay overheating. |
| Avionics Power Conversion | Telecom 48V Intermediate Bus |
Use Scenario: Point-of-load regulation in airborne communication equipment requiring MIL-STD-704 compliant 28V input handling. IC Role / Device Role / Timing Role: Non-synchronous buck controller generating 15V/5V from aircraft 28V DC bus with transient immunity. Use Value: 100kHz–500kHz programmable frequency avoids sensitive RF bands; SYNC input enables deterministic EMI shaping. | Use Scenario: Intermediate bus converter in 48V server racks delivering 12V to VRMs and FPGA power stages. IC Role / Device Role / Timing Role: High-voltage buck controller driving paralleled N-MOSFETs for scalable 50W output with low component count. Use Value: TG driver supports >90nC gate charge; BOOST pin enables efficient high-side N-MOSFET use - reducing conduction losses vs. P-MOSFET. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3891EFE#PBF | Includes integrated 5V/100mA bias LDO and dual MOSFET drivers; wider 4.5V–60V VIN range; no Burst Mode® | Preferred for designs needing self-contained bias and synchronous rectification; higher BOM cost | Select LTC3891EFE#PBF when synchronous topology and integrated gate drive simplify layout and improve full-load efficiency. |
| LM5116PWPR | TI part with 6.5V–100V VIN, no integrated high-voltage bias regulator, requires external VCC supply, 50µA IQ in skip mode | Better suited for ultra-high-input applications (>60V); lacks antislope compensation and programmable UVLO | Choose LM5116PWPR only when input exceeds 60V or when external bias supply is already available and cost sensitivity outweighs feature set. |
Compared with LTC3891EFE#PBF, LT3844IFE#TRPBF offers lower quiescent current in Burst Mode® and simpler gate drive for non-synchronous designs; versus LM5116PWPR, it provides integrated bias regulation and antislope compensation but lacks >60V capability - making LT3844IFE#TRPBF optimal for 48V industrial/automotive buck controllers requiring precision, low-IQ, and thermal robustness.
Availability
LT3844IFE#TRPBF is available at Aetrix Electronics and suitable for industrial power distribution, 42V automotive systems, and telecom intermediate bus applications requiring stable component supply, extended temperature support (–40°C to 125°C), and long-term lifecycle continuity.
Supply support for LT3844IFE#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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LT® portfolio.
The LT3844IFE#TRPBF belongs to Linear's high-voltage DC/DC controller family, designed specifically for medium-power, non-synchronous buck, boost, and SEPIC converters in harsh environments where wide VIN range, precision regulation, and thermal resilience are critical.
FAQ
What is the maximum input voltage rating for the LT3844IFE#TRPBF?
The LT3844IFE#TRPBF has an absolute maximum input voltage (VIN) rating of 65V, with continuous operation supported up to 60V. This makes LT3844IFE#TRPBF suitable for 48V industrial and 42V automotive systems where bus transients must be tolerated without derating or external clamping.
Does the LT3844IFE#TRPBF support synchronous rectification?
No, the LT3844IFE#TRPBF is designed for nonsynchronous operation and drives only a single external N-channel MOSFET with its TG pin. It relies on an external Schottky diode for freewheeling. For synchronous rectification, consider the pin-compatible LT3800 series - the LT3844IFE#TRPBF does not integrate or control a bottom-side MOSFET.
How is Burst Mode® enabled or disabled on the LT3844IFE#TRPBF?
Burst Mode® is controlled by the BURST_EN pin (Pin 4): connect to SGND to enable, or to VCC/VFB to disable. When enabled, LT3844IFE#TRPBF reduces VIN supply current to 120µA at light loads by intermittently disabling switching - a key feature for battery-backed or always-on 12V/24V systems.
What is the purpose of the exposed pad (Pin 17) on the LT3844IFE#TRPBF package?
The exposed pad (Pin 17) on the LT3844IFE#TRPBF is internally connected to SGND and must be soldered to the PCB ground plane. It provides a low-thermal-resistance path (θJC = 10°C/W) to dissipate heat from the IC die, enabling reliable 50W operation in the 16-lead TSSOP without additional heatsinking.
Can the LT3844IFE#TRPBF operate with an input voltage below 7.5V?
Yes - the LT3844IFE#TRPBF can operate down to 4V VIN once started, but requires ≥7.5V to initiate startup unless VCC is externally driven above 6.5V. This dual-threshold behavior allows LT3844IFE#TRPBF to maintain regulation during brownout conditions after initial turn-on, improving system robustness in fluctuating power environments.
LT3844IFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost, SEPIC
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 60V
- Frequency - Switching:
- 300kHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- No
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT3844IFE#TRPBF FAQ
1.How can I place an order for LT3844IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3844IFE#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 LT3844IFE#TRPBF reliable?
The price and inventory of LT3844IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3844IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3844IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3844IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3844IFE#TRPBF?
LT3844IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3844IFE#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 LT3844IFE#TRPBF?
For technical support, including LT3844IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3844IFE#TRPBF requirements.
6.How does Aetrix verify that LT3844IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3844IFE#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 LT3844IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3844IFE#TRPBF?
All LT3844IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3844IFE#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 LT3844IFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3844IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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