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Analog Devices Inc. LT3844EFE#TRPBF
- Part No.:
- LT3844EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3844EFE#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,095
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Product details
Overview
LT3844EFE#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 LT3844EFE#TRPBF datasheet, LT3844EFE#TRPBF pinout, LT3844EFE#TRPBF application, or LT3844EFE#TRPBF equivalent, key selection considerations include its 16-pin TSSOP package with exposed thermal pad, ±1.3% reference accuracy, 100mV current sense threshold, programmable soft-start, and internal high-voltage bias regulator enabling simple gate drive for high-side N-MOSFETs.
Technical Context
The LT3844EFE#TRPBF implements a constant-frequency, current-mode PWM control architecture with slope and antislope compensation to prevent subharmonic oscillation across duty cycles. Its error amplifier (transconductance: 270–410 µS) sets peak inductor current via the VC pin, while the SENSE+ and SENSE– inputs monitor differential voltage across an external sense resistor with 100mV threshold unaffected by duty cycle.
It integrates a high-voltage linear regulator powering VCC (6.25–8.3V output), a bootstrapped TG driver (9.8V typical ON voltage, 40ns rise/fall time), and independent UVLO on VIN, VCC, and BOOST pins (e.g., VIN UVLO rising threshold = 3.8V, hysteresis = 670mV). Burst Mode® is enabled via BURST_EN pin grounding and reduces total supply current to 120µA at light loads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 60V - supports wide-range industrial and automotive supplies without pre-regulation |
| Operating Frequency | 100kHz to 500kHz (programmable via fSET resistor) - enables noise-sensitive layout and EMI control |
| Reference Accuracy | ±1.3% over temperature - ensures stable output regulation across –40°C to 125°C junction range |
| Current Sense Threshold | 100mV (typical) - sets precise, duty-cycle-independent current limit for short-circuit protection |
| Burst Mode Quiescent Current | 120µA - maintains high efficiency at light loads without external circuitry |
| Shutdown Current | 10µA - enables ultra-low-power system standby states |
| Package | 16-lead thermally enhanced TSSOP with exposed SGND pad - provides low θJA (40°C/W) for medium-power operation |
Pinout & Package
LT3844EFE#TRPBF is housed in a 16-lead plastic TSSOP package (FE grade) with exposed thermal pad (Pin 17) soldered to PCB SGND for optimal thermal performance and electrical grounding. The package measures 5mm × 4.4mm × 1.1mm and is rated for –40°C to 125°C operating junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (1) | Main input supply rail | Accepts 4V–60V; powers internal HV regulator and supplies gate drive energy during start-up |
| SHDN (2) | Enable/disable control | 1.35V rising threshold with 120mV hysteresis; pulls IC into 10µA shutdown when <0.7V |
| CSS (3) | Soft-start timing node | Charged by internal 2µA source; controls output voltage slew rate and prevents inrush current |
| BURST_EN (4) | Burst Mode enable | Ground to activate low-IQ mode; connect to VFB/VCC to disable |
| VFB (5) | Feedback reference comparator input | Compares resistive divider output to 1.231V internal reference; regulates output voltage |
| VC (6) | Error amplifier output | Sets peak switch current per cycle; integrator pole placement optimizes transient response |
| SYNC (7) | External clock input | Accepts 100kHz–600kHz sync signal; requires RSET set 10–25% below sync frequency |
| fSET (8) | Oscillator programming | Resistor-connected pin sets base frequency; required even when SYNC is used |
| SGND (9,17) | Signal ground reference | Low-noise analog ground; connects to –VOUT side of output caps; exposed pad must be soldered |
| SENSE– (10) | Current sense negative input | Connects to VOUT side of sense resistor in buck topology; defines 100mV current limit threshold |
| SENSE+ (11) | Current sense positive input | Connects to inductor side of sense resistor; differential input rejects common-mode noise |
| PGND (12) | Power ground return | High-current return for VCC regulator and internal SW pull-down switch; decouple VCC to this pin |
| VCC (13) | Bias supply output | 6.25–8.3V regulated output; powers internal logic and charges BOOST capacitor via external diode |
| SW (14) | Switch node connection | Connects to MOSFET drain, Schottky cathode, and inductor; swings from VIN to ~–0.3V |
| TG (15) | Bootstrapped gate driver | Drives N-MOSFET gate with 9.8V typical ON voltage; requires short, wide trace to minimize inductance |
| BOOST (16) | Bootstrap capacitor supply | Referenced to SW; charges CBOOST during MOSFET off-time; max voltage = VIN + VCC |
Key Features
| Feature | Design Value |
|---|---|
| Programmable fixed-frequency operation | 100kHz–500kHz via external RSET - enables EMI optimization and predictable loop design |
| Antislope compensation | Maintains constant 100mV current limit across all duty cycles - eliminates need for dynamic sense resistor scaling |
| Internal high-voltage bias regulator | Generates VCC from VIN up to 60V - eliminates external bias supply in most applications |
| Thermally enhanced TSSOP package | 16-pin with exposed SGND pad (θJC = 10°C/W) - supports >50W continuous operation with proper PCB copper |
| Independent UVLO on VIN, VCC, BOOST | Three-tier lockout (e.g., VCC UVLO rising = 6.25V) - ensures safe startup and fault recovery |
Applications
| Industrial Power Distribution | 42V Automotive Systems |
|---|---|
Use Scenario: Distributed 24V/48V bus powering PLC I/O modules, motor drivers, and sensors in factory automation cabinets. IC Role / Device Role / Timing Role: Step-down controller regulating 48V bus to 12V/5V rails with programmable frequency synchronized to system clock to avoid beat frequencies. Use Value: 60V absolute max input withstands load-dump transients; Burst Mode® extends battery runtime in always-on monitoring nodes. | Use Scenario: Onboard charger auxiliary supply converting 42V battery to 12V for infotainment, ADAS cameras, and gateway ECUs. IC Role / Device Role / Timing Role: High-efficiency buck controller driving large N-MOSFETs with integrated gate driver and thermal shutdown for under-hood reliability. Use Value: 125°C junction rating and robust UVLO hysteresis ensure operation during cold cranking and hot soak conditions. |
| Avionics Power Conversion | Telecom Intermediate Bus |
Use Scenario: 28V aircraft bus conversion to isolated 5V/3.3V for flight control computers and navigation sensors. IC Role / Device Role / Timing Role: Controller for non-isolated buck converter implementing MIL-STD-704 compliant transient response with fast line/load regulation. Use Value: Current-mode control delivers <10µs load transient recovery; ±1.3% reference ensures ADC reference stability. | Use Scenario: 48V intermediate bus regulator supplying 12V to server PSUs and optical transceivers in data center racks. IC Role / Device Role / Timing Role: Fixed-frequency controller synchronized to system clock to reduce conducted EMI in dense board layouts. Use Value: 500kHz max switching frequency allows smaller magnetics; 16-pin TSSOP simplifies automated assembly and thermal management. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage current-mode controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3890EMSE#PBF | Dual-output, 60V input, integrated MOSFET drivers, no Burst Mode®; higher pin count (28-MSOP) | Required for dual-rail systems (e.g., ±12V); lacks ultra-low-IQ light-load operation | Select when dual outputs or higher integration justify added complexity and cost |
| LM5116MH/NOPB | 65V input, 100kHz–1MHz programmable frequency, no integrated VCC regulator, requires external bias | Suitable for higher-frequency designs (>500kHz); needs external VCC supply or bootstrap diode network | Select when >500kHz operation or TI ecosystem compatibility is prioritized over single-supply simplicity |
Compared with LTC3890EMSE#PBF and LM5116MH/NOPB, the LT3844EFE#TRPBF offers the lowest quiescent current (120µA Burst Mode®), integrated VCC regulator eliminating external bias components, and proven thermal performance in 16-pin TSSOP - making it optimal for cost-sensitive, medium-power, single-output industrial and automotive converters where light-load efficiency and layout simplicity are critical.
Availability
LT3844EFE#TRPBF is available at Aetrix Electronics and suitable for industrial power distribution, 42V automotive subsystems, and avionics power conversion requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LT3844EFE#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) acquired Linear Technology in 2017 and maintains its legacy high-performance power management portfolio with full datasheet, simulation model, and application support.
The LT3844EFE#TRPBF belongs to Linear's high-voltage current-mode controller product line, designed specifically for rugged, medium-power DC/DC conversion in harsh environments including automotive, industrial, and aerospace applications.
FAQ
What is the maximum input voltage rating for the LT3844EFE#TRPBF?
The LT3844EFE#TRPBF has an absolute maximum input voltage (VIN) rating of 65V, with continuous operation supported up to 60V. This allows reliable use in 42V automotive systems and industrial 48V buses, including tolerance for load-dump transients. Operation below 4V is only possible after initial start-up if VCC is externally powered.
How does the LT3844EFE#TRPBF achieve current limit independence from duty cycle?
The LT3844EFE#TRPBF uses antislope compensation: while slope compensation adds an artificial ramp to the sensed current waveform to prevent subharmonics, a matching ramp is simultaneously added to the current limit threshold. This preserves the 100mV sense threshold across all duty cycles - a key differentiator from basic current-mode controllers where current limit degrades at high duty.
Can the LT3844EFE#TRPBF drive synchronous rectification?
No, the LT3844EFE#TRPBF is designed for nonsynchronous operation and drives only a high-side N-channel MOSFET. It does not provide a low-side gate drive signal or dead-time control required for synchronous rectification. For synchronous buck applications, consider the pin-compatible LTC3800 family or LTC3890 series instead.
What is the purpose of the exposed pad (Pin 17) on the LT3844EFE#TRPBF?
The exposed pad (Pin 17) on the LT3844EFE#TRPBF is internally connected to SGND and must be soldered to the PCB ground plane. It serves dual functions: providing a low-inductance, low-resistance analog ground reference for sensitive feedback and current sense circuitry, and acting as the primary thermal path - reducing θJA to 40°C/W and enabling >50W operation with adequate copper area.
How is Burst Mode® operation enabled or disabled on the LT3844EFE#TRPBF?
Burst Mode® operation on the LT3844EFE#TRPBF is controlled by the BURST_EN pin (Pin 4): connect it to SGND to enable low-quiescent-current operation (120µA), or connect it to VFB or VCC to disable Burst Mode® and force continuous PWM operation. Disabling Burst Mode® eliminates low-load output ripple but increases light-load current consumption to ~20µA (VIN) + ~100µA (VCC).
LT3844EFE#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
LT3844EFE#TRPBF FAQ
1.How can I place an order for LT3844EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3844EFE#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 LT3844EFE#TRPBF reliable?
The price and inventory of LT3844EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3844EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3844EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3844EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3844EFE#TRPBF?
LT3844EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3844EFE#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 LT3844EFE#TRPBF?
For technical support, including LT3844EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3844EFE#TRPBF requirements.
6.How does Aetrix verify that LT3844EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3844EFE#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 LT3844EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3844EFE#TRPBF?
All LT3844EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3844EFE#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 LT3844EFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3844EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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