My Inquiry
My Account
Analog Devices Inc. LT3742EUF#PBF
- Part No.:
- LT3742EUF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LT3742EUF#PBF.pdf
- Description:
- IC REG CTRLR BUCK 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:731
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3742EUF#PBF from Analog Devices (formerly Linear Technology) is a dual, 2-phase, fixed-frequency current-mode step-down DC/DC switching controller driving external high-side N-channel MOSFETs. It features 500kHz operation, 180° out-of-phase control, 0.8V ±1.5% reference, internal boost regulator for gate drive (VIN + 7V), and independent RUN/SS pins for per-channel enable and soft-start. It is used in high-efficiency, low-noise dual-output power supplies for satellite set-top boxes and automotive systems.
For engineers reviewing the LT3742EUF#PBF datasheet, LT3742EUF#PBF pinout, LT3742EUF#PBF application, or LT3742EUF#PBF equivalent, key selection considerations include phase interleaving for input ripple reduction, dual independent regulation capability, gate drive bias generation, UVLO programmability, and thermal performance in the 4mm × 4mm QFN package.
Technical Context
The LT3742EUF#PBF integrates two independent current-mode controllers sharing a master 1MHz oscillator that generates two 500kHz, 180°-phase-shifted clock signals. Each channel includes dedicated error amplifiers (transconductance = 250 µmho), current sense amplifiers with ±5% matching, and open-collector PG outputs referenced to 0.8V FB with ±10% window detection.
Its internal boost regulator (SWB switch, BIAS output) delivers VIN + 7V (typ.) to drive N-MOSFET gates, enabling low dropout and 100% duty cycle operation. Protection includes undervoltage lockout (1.25V threshold with 3µA hysteresis current), thermal shutdown, and cycle-by-cycle current limiting via 50–70mV sense threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 500kHz fixed - enables compact magnetics and predictable EMI filtering design. |
| Phase Relationship | 180° out-of-phase operation - reduces input RMS ripple current by ~55%, allowing smaller input capacitors. |
| Reference Voltage | 0.800V ±1.5% - sets precise output voltage accuracy across temperature and line/load conditions. |
| Gate Drive Bias | VIN + 7V (typ.) - ensures full enhancement of high-side N-MOSFETs even at low input voltages. |
| Shutdown Current | 20µA - minimizes system standby power in battery-backed or always-on applications. |
| Current Sense Threshold | 50–70mV (guaranteed min/max) - defines peak inductor current limit with minimal sensing loss. |
| Operating Temp Range | –40°C to 125°C junction - supports automotive under-hood and industrial embedded environments. |
Pinout & Package
The LT3742EUF#PBF is housed in a thermally enhanced 24-lead 4mm × 4mm × 0.75mm plastic QFN package with exposed pad (Pin 25) soldered to PCB ground for electrical and thermal integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| G1, G2 (Pins 1, 6) | High-current gate drivers | Floating outputs swinging between BIAS and SW pins - directly drive external N-MOSFET gates with fast rise/fall times (40ns/60ns). |
| VIN (Pin 2) | Main power input | Supplies internal circuitry; requires local bypass capacitor - minimum operating voltage is 4V. |
| UVLO (Pin 3) | Programmable undervoltage lockout | Resistor-divider input; 1.25V threshold with 3µA hysteresis sink - disables controllers below safe input level. |
| BIAS (Pin 4) | Boost-regulated gate drive rail | Output of internal charge pump - provides VIN + 7V to ensure robust N-MOSFET turn-on and 100% duty cycle capability. |
| SWB (Pin 5) | Internal boost switch collector | Drives external Schottky diode in boost stage - current-limited to 250–500mA for reliable bias generation. |
| RUN/SS1, RUN/SS2 (Pins 16, 15) | Per-channel enable & soft-start | 1µA internal pull-up; 0.5V threshold - enables independent startup sequencing and user-programmable ramp time via external capacitor. |
| PG1, PG2 (Pins 17, 14) | Open-collector power-good indicators | Assert low when FB is outside ±10% of 0.8V - used for output monitoring, fault signaling, and supply sequencing. |
| VC1, VC2 (Pins 18, 13) | Error amplifier compensation nodes | Connect series RC to ground - sets loop stability and transient response for each independent control loop. |
| FB1, FB2 (Pins 19, 12) | Feedback inputs | Regulated to 0.800V - resistor dividers set output voltage; matching within ±4mV ensures balanced dual-output tracking. |
| SENSE1±, SENSE2± (Pins 21,20 & 10,11) | Differential current sense inputs | Monitor inductor current for cycle-by-cycle limiting - ±5% matching between channels enables accurate current sharing. |
| SW1, SW2 (Pins 24, 7) | Switch node connections | Connect to MOSFET sources, inductors, and catch diodes - high dv/dt nodes requiring careful layout and grounding. |
| Exposed Pad (Pin 25) | Thermal & electrical ground | Mandatory PCB solder connection - provides primary thermal path and low-impedance ground return for all internal circuits. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 2-phase interleaved control | Guaranteed 180° phase shift reduces input RMS current by >50%, lowering capacitor size, cost, and EMI. |
| Integrated gate drive boost regulator | Generates VIN + 7V bias rail without external components - enables efficient high-side N-MOSFET use and 100% duty cycle. |
| Independent per-channel enable & soft-start | RUN/SS pins allow staggered startup, ratiometric tracking, or individual shutdown - critical for power sequencing in multi-rail systems. |
| Accurate dual power-good monitoring | PG1/PG2 open-collector outputs with ±10% window relative to 0.8V reference - support fault detection and inter-rail coordination. |
| Robust current sensing architecture | 50–70mV guaranteed sense threshold with ±5% channel-to-channel matching - ensures consistent current limiting and load balancing. |
Applications
| Satellite Set-Top Box Power Supply | Automotive Infotainment System |
|---|---|
Use Scenario: Dual-rail power delivery (8V @ 4A and 5V @ 4A) from 12V vehicle battery or 14V supply in cable/satellite receiver headend units. IC Role / Device Role / Timing Role: Dual step-down controller managing independent buck stages with interleaved switching to minimize input ripple and EMI. Use Value: Reduces input capacitor RMS current from ~1.8A to ~0.8A, enabling smaller 1206/0805 ceramic caps and meeting CISPR-25 Class 5 conducted emissions limits. | Use Scenario: Powering display logic (5V) and RF tuner (8V) in automotive infotainment head units with wide input range (6–16V battery transients). IC Role / Device Role / Timing Role: Dual-phase controller providing regulated rails with independent sequencing and thermal protection during cold-crank (4.5V) or load-dump (30V) events. Use Value: UVLO programmability (via R-divider on Pin 3) and –40°C to 125°C operation ensure reliable startup and regulation across automotive temperature and voltage extremes. |
| Distributed Telecom Power System | Super Capacitor Charging Module |
Use Scenario: Local DC/DC conversion at board level for FPGA I/O banks (1.8V) and memory interfaces (1.2V) fed from 48V intermediate bus. IC Role / Device Role / Timing Role: Dual controller operating in independent mode - one channel regulates 1.8V, the other 1.2V, both using external MOSFETs for efficiency scalability. Use Value: Per-channel RUN/SS and PG pins enable firmware-controlled power-up order and fault isolation - critical for hot-swap and redundancy schemes. | Use Scenario: Constant-current/constant-voltage charging of 2.7V/10F supercapacitor banks from 5–30V input in energy harvesting or backup power systems. IC Role / Device Role / Timing Role: Controller configured in constant-current mode via SENSE pin feedback - uses current-mode architecture for precise charge current regulation. Use Value: 50–70mV current sense threshold and cycle-by-cycle limiting provide accurate, stable charge current control without external op-amps or DACs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3855EUFD#PBF | Single-channel, 2-phase synchronous controller with integrated MOSFET drivers; no internal boost regulator - requires external gate drive supply. | Designed for synchronous rectification; lacks independent dual-output capability and per-channel PG/RUN pins. | Choose LTC3855EUFD#PBF only when synchronous operation and higher efficiency at light loads are prioritized over dual independent regulation. |
| MP8770GQ-Z | Dual monolithic buck converter (integrated MOSFETs); fixed 500kHz frequency; no BIAS/SWB pins or programmable UVLO. | Lower component count but limited to ≤6A total output; no external MOSFET flexibility or 100% duty cycle support. | Choose MP8770GQ-Z for space-constrained, cost-sensitive designs where integrated FETs and simplified layout outweigh configurability needs. |
Compared with LTC3855EUFD#PBF and MP8770GQ-Z, the LT3742EUF#PBF uniquely combines dual independent current-mode control, internal gate-drive boost, programmable UVLO, and 180° interleaving - making it optimal for high-reliability, high-flexibility dual-output systems requiring external MOSFETs and wide input range.
Availability
LT3742EUF#PBF is available at Aetrix Electronics and suitable for satellite set-top boxes, automotive infotainment systems, and distributed telecom power supplies requiring stable component supply, long-term lifecycle support, and AEC-Q200-aligned reliability.
Supply support for LT3742EUF#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 semiconductor leader specializing in high-performance analog, mixed-signal, and power management ICs. Formerly Linear Technology, ADI acquired the company in 2017 and maintains its legacy of precision power solutions.
The LT3742EUF#PBF belongs to ADI's PolyPhase® controller family, designed specifically for high-efficiency, low-noise, multi-phase and dual-output DC/DC conversion in demanding industrial, automotive, and communications applications.
FAQ
What is the maximum input voltage supported by the LT3742EUF#PBF?
The LT3742EUF#PBF has an absolute maximum VIN rating of 30V. Its functional operating range extends from 4V to 30V, with internal protection engaging below 4V (via UVLO) and above 30V (absolute max). For reliable regulation without pulse-skipping, VIN(MAX) depends on output voltage and minimum duty cycle (15%); e.g., for a 2.5V output, VIN should not exceed 19V to avoid skipping. The LT3742EUF#PBF remains functional up to 30V but may exhibit higher peak currents and erratic waveforms above the recommended operating limit.
Does the LT3742EUF#PBF support 100% duty cycle operation?
Yes, the LT3742EUF#PBF supports true 100% duty cycle operation. This is enabled by its internal boost regulator, which generates a gate drive bias of VIN + 7V at the BIAS pin - ensuring sufficient VGS for full enhancement of high-side N-channel MOSFETs even when VIN approaches the output voltage. The LT3742EUF#PBF achieves low-dropout behavior without requiring P-channel devices or external bias supplies.
How does the LT3742EUF#PBF reduce input ripple current?
The LT3742EUF#PBF reduces input ripple current by operating its two controllers 180° out of phase. This interleaving causes the input current pulses from each phase to cancel partially, lowering RMS input current by up to ~55% compared to single-phase dual controllers. In a typical 5V/3A + 3.3V/3A application from 12V, RMS input current drops from ~1.8A to ~0.8A - enabling smaller, lower-cost input capacitors and improved EMI performance. The LT3742EUF#PBF guarantees this phase relationship by design.
Can the LT3742EUF#PBF be used for single-output, higher-current applications?
Yes, the LT3742EUF#PBF can be configured for single-output, higher-current applications by paralleling both channels with shared feedback and synchronized operation. Its 180° phase shift inherently balances current between phases, reducing thermal stress and improving efficiency. External current-sharing resistors or inductor coupling may be used for tighter balance. The LT3742EUF#PBF's independent current sense paths and matched thresholds (±5%) make it well-suited for such high-current, interleaved buck designs - commonly deployed in CPU/GPU VRMs and high-power PoL converters.
What is the purpose of the SWB and BIAS pins on the LT3742EUF#PBF?
The SWB (Pin 5) and BIAS (Pin 4) pins form the internal gate-drive boost regulator. SWB is the collector of an internal NPN switch that drives an external Schottky diode and capacitor to generate a boosted voltage at BIAS. The BIAS pin outputs VIN + 7V (typ.), providing the elevated gate drive needed for high-side N-channel MOSFETs. This eliminates the need for external bootstrap circuits or P-channel devices. The LT3742EUF#PBF disables both controllers until BIAS reaches ~90% of regulation, ensuring robust MOSFET turn-on before switching begins.
LT3742EUF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 30V
- Frequency - Switching:
- 500kHz
- Duty Cycle (Max):
- 100%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Power Good
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x4)
LT3742EUF#PBF FAQ
1.How can I place an order for LT3742EUF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3742EUF#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 LT3742EUF#PBF reliable?
The price and inventory of LT3742EUF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3742EUF#PBF is usually 5 days.
3.What payment methods are accepted for LT3742EUF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3742EUF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3742EUF#PBF?
LT3742EUF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3742EUF#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 LT3742EUF#PBF?
For technical support, including LT3742EUF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3742EUF#PBF requirements.
6.How does Aetrix verify that LT3742EUF#PBF is sourced from the original manufacturer or authorized distributors?
All LT3742EUF#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 LT3742EUF#PBF meets industry standards.
7.What is the process for return or replacement of LT3742EUF#PBF?
All LT3742EUF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3742EUF#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 LT3742EUF#PBF part is unused and in its original packaging.
Return procedure for LT3742EUF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3742EUF#PBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
