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Analog Devices Inc. LTC3727LXEG-1#PBF
- Part No.:
- LTC3727LXEG-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC3727LXEG-1#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,145
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Product details
Overview
LTC3727LXEG-1#PBF from Analog Devices (formerly Linear Technology) is a dual-phase, constant-frequency, current-mode synchronous step-down switching regulator controller driving two independent N-channel MOSFET stages. It supports 4V–32V input, 0.8V–14V output per channel, ±1.5% VOUT accuracy, and operates out-of-phase to reduce input RMS current and EMI. It is used in high-efficiency dual-rail power supplies for telecom base stations and automotive infotainment systems.
For engineers reviewing the LTC3727LXEG-1#PBF datasheet, LTC3727LXEG-1#PBF pinout, LTC3727LXEG-1#PBF application, or LTC3727LXEG-1#PBF equivalent, key selection considerations include its 28-pin SSOP package, 120ns minimum on-time, OPTI-LOOP® compensation, phase-lockable 250kHz–550kHz frequency range, and dual-channel independent soft-start via RUN/SS pins.
Technical Context
The LTC3727LXEG-1#PBF implements a dual-channel, interleaved, constant-frequency current-mode architecture with 180° phase offset between channels. Each channel features independent error amplifiers (ITH1/ITH2), differential current sense inputs (SENSE1±/SENSE2±), and dedicated gate drivers (TG1/BG1/TG2/BG2) supporting up to 99.4% duty cycle in dropout.
It integrates a precision 0.8V reference, power-good monitoring (±7.5% trip), overvoltage protection (0.84–0.88V threshold), and selectable operation modes: forced continuous (FCB < 0.8V) or Burst Mode® (FCB = 0.8–6.3V). The PLLIN/PLLFLTR interface enables external synchronization or DC voltage-controlled frequency tuning from 250kHz to 550kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4V to 32V - supports 12V/24V automotive and telecom battery inputs without pre-regulation. |
| VOUT Range | 0.8V to 14V - programmable dual outputs for core logic (0.8V–1.2V) and I/O rails (3.3V/5V/12V). |
| Output Accuracy | ±1.5% over temperature - ensures stable regulation across –40°C to 85°C industrial operating range. |
| Min On-Time | 120ns - enables high step-down ratios (e.g., 24V→1.2V at 500kHz) without pulse-skipping instability. |
| Switching Freq | 250kHz–550kHz (phase-lockable) - balances efficiency vs. size; 550kHz allows <10µH inductors in space-constrained designs. |
| IQ (Shutdown) | 20µA - minimizes standby power loss in always-on automotive subsystems. |
| PGOOD Threshold | ±7.5% of set VOUT - provides reliable system power sequencing and fault detection for downstream processors. |
Pinout & Package
Package: 28-lead plastic SSOP (G package), 5.3mm × 10.2mm, exposed pad not present. Thermal resistance θJA = 95°C/W. Compatible with standard reflow profiles (lead-free #PBF).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS1 (Pin 1) | Soft-start & enable control | Charging capacitor sets ramp time; <1.0V disables Channel 1; internal 1.2µA current source enables controlled startup. |
| SENSE1+ / SENSE1– (Pins 2,3) | Differential current sense inputs | Measure voltage across RSENSE; set peak inductor current limit (max 135mV) with ±60µA input bias. |
| VOSENSE1 (Pin 4) | Remote feedback input | Connects to resistor divider on VOUT1; referenced to 0.8V internal bandgap for precise regulation. |
| PLLFLTR (Pin 5) | PLL loop filter / freq control | DC voltage (0–2.4V) sets oscillator frequency; also accepts AC sync signal for PLL locking. |
| PLLIN (Pin 6) | External sync input | 50kΩ internal pull-down; rising edge synchronizes Channel 1 top-gate turn-on; open = min frequency mode. |
| FCB (Pin 7) | Forced continuous control | <0.8V forces PWM mode on both channels; 0.8–6.3V enables Burst Mode®; must not float. |
| ITH1 (Pin 8) | Error amplifier output | Controls current limit threshold; voltage increase raises peak inductor current; used for OPTI-LOOP® compensation. |
| SGND (Pin 9) | Small-signal ground | Reference for all analog circuitry; must be routed separately from PGND to avoid noise coupling into feedback path. |
| 3.3VOUT (Pin 10) | Integrated LDO output | Supplies 10mA (50mA peak) at 3.3V ±2.5%; powers auxiliary circuitry or level-shifters without external regulator. |
| ITH2 (Pin 11) | Error amplifier output | Independent control of Channel 2 current limit; identical function to ITH1 but isolated for dual-rail flexibility. |
| VOSENSE2 (Pin 12) | Remote feedback input | Same role as VOSENSE1 but for Channel 2; enables independent regulation of second output rail. |
| SENSE2– / SENSE2+ (Pins 13,14) | Differential current sense inputs | Identical to SENSE1±; supports independent current limiting per channel with shared or separate RSENSE. |
| PGOOD (Pin 15) | Open-drain status output | Pulled low if either VOSENSE deviates >±7.5%; requires external pull-up to ≤7V; 10µs response time. |
| TG1 (Pin 16) | Top-gate driver output | Floating high-side driver; swing = INTVCC – 0.5V above SW1; drives N-MOSFET gate with 50–90ns rise/fall (3300pF load). |
| SW1 (Pin 17) | Switch node connection | Connects to inductor and external Schottky diode anode; voltage swings from –0.3V to VIN. |
| BOOST1 (Pin 18) | Bootstrap supply | Connects to bootstrap capacitor between BOOST1 and SW1; supplies floating gate drive for TG1. |
| BG1 (Pin 19) | Bottom-gate driver output | Ground-referenced driver; swing = 0V to INTVCC; 40–90ns rise/fall; drives synchronous N-MOSFET source. |
| PGND (Pin 20) | Power ground | Return path for bottom MOSFETs, Schottky cathodes, and CIN (–); must be low-inductance plane tied to SGND at single point. |
| INTVCC (Pin 21) | Internal LDO output | 7.5V ±1% regulated supply (7.2–7.8V); powers drivers and analog circuits; bypass with ≥4.7µF tantalum. |
| EXTVCC (Pin 22) | External VCC input | When >7.3V, bypasses internal LDO to improve efficiency; max 8.5V; internal switch connects to INTVCC. |
| BG2 (Pin 23) | Bottom-gate driver output | Identical to BG1 but for Channel 2; supports independent synchronous rectification per phase. |
| VIN (Pin 24) | Main input supply | Primary power input (4–32V); requires local 10µF ceramic bypass to PGND near pin. |
| BOOST2 (Pin 25) | Bootstrap supply | Same function as BOOST1 but for Channel 2; requires separate bootstrap cap and Schottky diode. |
| SW2 (Pin 26) | Switch node connection | Same function as SW1 but for Channel 2; connects to second inductor and rectifier. |
| TG2 (Pin 27) | Top-gate driver output | Same function as TG1 but for Channel 2; floating driver referenced to SW2. |
| RUN/SS2 (Pin 28) | Soft-start & enable control | Independent control of Channel 2 startup; identical timing and shutdown behavior as RUN/SS1. |
Key Features
| Feature | Design Value |
|---|---|
| Out-of-phase dual-channel operation | Reduces input RMS current by ~39% (e.g., 2.53A → 1.55A), enabling smaller, lower-cost input capacitors and lower EMI. |
| OPTI-LOOP® compensation | Allows stable transient response across wide range of output capacitance (e.g., 22µF ceramic to 470µF polymer) and ESR values. |
| Adjustable soft-start via RUN/SS pins | Independent capacitor-based ramp per channel prevents inrush current conflicts during multi-rail power-up sequencing. |
| Dual independent current limit control | Separate SENSE± pairs and ITH outputs allow asymmetric current limits (e.g., 5A on VOUT1, 4A on VOUT2) for mixed-load systems. |
| Integrated 3.3V/10mA LDO | Eliminates need for external 3.3V bias supply for level shifters, ADC references, or supervisory ICs in compact designs. |
| Dropout protection with 99.4% duty cycle | Maintains regulation down to VIN – VOUT ≈ 0.1V; internal dropout detector pulses top-FET off briefly every 10 cycles to recharge bootstrap caps. |
Applications
| Telecom Power Supply | Automotive Infotainment |
|---|---|
Use Scenario: Dual-rail 12V/5V converter powering DSP, FPGA, and display interface in 48V telecom shelf. IC Role / Device Role / Timing Role: Dual-phase controller managing interleaved buck stages with synchronized switching to minimize input ripple. Use Value: Reduces 48V input capacitor RMS current from 2.53A to 1.55A, cutting input EMI and allowing use of cheaper 105°C X7R ceramics instead of polymer caps. | Use Scenario: 12V battery-fed dual-output supply for head unit MCU (1.2V), memory (1.8V), and USB ports (5V) in vehicle cabin. IC Role / Device Role / Timing Role: High-efficiency synchronous controller with Burst Mode® for low-idle current and ±1.5% accuracy across –40°C to 85°C. Use Value: 20µA shutdown IQ extends battery life in parked mode; 99.4% duty cycle maintains 5V output even during cold-crank (6.5V battery dip). |
| Distributed DC System | Notebook Computing |
Use Scenario: Central 24V-to-5V/3.3V converter feeding multiple PCBs in industrial PLC backplane. IC Role / Device Role / Timing Role: Phase-lockable controller synchronized to system clock to eliminate beat frequencies and simplify EMI filtering. Use Value: PLLIN input allows fixed 400kHz operation locked to 1MHz master clock, reducing conducted emissions by >10dB in 150kHz–30MHz CISPR-22 band. | Use Scenario: Dual-phase 19V adapter input to 1.2V CPU core and 5V peripheral rail in ultrabook motherboard. IC Role / Device Role / Timing Role: Interleaved controller with independent RUN/SS pins enabling staggered startup to avoid inrush current peaks. Use Value: Independent soft-start prevents 12A combined inrush; 120ns min on-time supports 1.2V/20A output at 500kHz with 0.47µH inductors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3727LXEUH-1#PBF | Same silicon, 32-pin 5mm×5mm QFN package with exposed thermal pad (θJA = 34°C/W vs. 95°C/W). | Higher power density and better thermal performance required for >10W/channel continuous operation. | Select when board space is constrained and thermal dissipation >1.5W per channel is expected. |
| LTC3727-1#PBF | Wider VIN (4–36V), ±1% VREF accuracy, latch-off UVLO, 180ns min on-time, no integrated 3.3V LDO. | Used where higher input voltage margin (e.g., 36V industrial) or tighter regulation (<±1%) is mandatory. | Select when 36V max input or sub-1% accuracy outweighs need for integrated 3.3V bias rail. |
Compared with LTC3727LXEUH-1#PBF, the LTC3727LXEG-1#PBF offers lower cost and simpler layout in SSOP but sacrifices thermal performance; compared with LTC3727-1#PBF, it trades UVLO latch-off and tighter accuracy for integrated 3.3V LDO and lower minimum on-time-critical for high-step-down notebook applications.
Availability
LTC3727LXEG-1#PBF is available at Aetrix Electronics and suitable for telecom infrastructure, automotive electronics, and distributed DC power systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC3727LXEG-1#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTC3727LXEG-1#PBF belongs to Linear's high-efficiency DC/DC controller product line, designed specifically for demanding dual-rail, high-current, low-noise power conversion in space- and thermally-constrained environments.
FAQ
What is the maximum input voltage rating for the LTC3727LXEG-1#PBF?
The LTC3727LXEG-1#PBF has an absolute maximum input voltage (VIN) rating of 32V. Operation beyond this voltage risks permanent damage. Its functional input range is specified from 4V to 32V, making it suitable for 12V and 24V automotive and industrial bus systems. The device includes undervoltage lockout (UVLO) that disables operation below 3.5V (typical) to prevent erratic startup.
Does the LTC3727LXEG-1#PBF support external frequency synchronization?
Yes, the LTC3727LXEG-1#PBF supports external frequency synchronization via the PLLIN pin. When an external clock signal is applied to PLLIN, the internal phase-locked loop aligns the rising edge of Channel 1's top-gate signal to that clock's rising edge. The PLLIN pin has a 50kΩ internal pull-down, and the device can lock across its full 250kHz–550kHz operating range. Open-circuiting PLLIN forces minimum frequency operation.
How does the LTC3727LXEG-1#PBF implement overvoltage protection?
The LTC3727LXEG-1#PBF includes dedicated overvoltage protection that monitors both VOSENSE1 and VOSENSE2 pins. If either feedback voltage exceeds +7.5% of the nominal output (i.e., >0.84V for a 0.8V reference), the top MOSFET is immediately turned off and the bottom MOSFET is turned on to discharge the output. This fast-acting comparator responds within nanoseconds and is independent of the main control loop, providing robust protection against transient overshoots and fault conditions.
Can the LTC3727LXEG-1#PBF operate in single-phase mode?
No, the LTC3727LXEG-1#PBF is inherently a dual-phase controller and cannot be configured for true single-phase operation. However, Channel 2 can be disabled by pulling RUN/SS2 below 1.0V, leaving only Channel 1 active. In this configuration, the device still occupies the same footprint and retains dual-phase pinout, but delivers single-rail output. For dedicated single-phase designs, Analog Devices recommends the LTC3726 or LTC3855 families.
What is the purpose of the FCB pin on the LTC3727LXEG-1#PBF?
The FCB (Forced Continuous Control) pin on the LTC3727LXEG-1#PBF serves two functions: (1) forcing both channels into continuous conduction mode when pulled below 0.8V, useful for regulating secondary windings or avoiding discontinuous operation; and (2) selecting Burst Mode® operation when held between 0.8V and ~6.3V. It must never be left floating, as undefined voltage may cause erratic mode switching or instability in the LTC3727LXEG-1#PBF control loop.
LTC3727LXEG-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-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:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 28V
- Frequency - Switching:
- 255kHz ~ 530kHz
- Duty Cycle (Max):
- 99.4%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SSOP
LTC3727LXEG-1#PBF FAQ
1.How can I place an order for LTC3727LXEG-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3727LXEG-1#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 LTC3727LXEG-1#PBF reliable?
The price and inventory of LTC3727LXEG-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3727LXEG-1#PBF is usually 5 days.
3.What payment methods are accepted for LTC3727LXEG-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3727LXEG-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
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LTC3727LXEG-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3727LXEG-1#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 LTC3727LXEG-1#PBF?
For technical support, including LTC3727LXEG-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3727LXEG-1#PBF requirements.
6.How does Aetrix verify that LTC3727LXEG-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3727LXEG-1#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 LTC3727LXEG-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC3727LXEG-1#PBF?
All LTC3727LXEG-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3727LXEG-1#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 LTC3727LXEG-1#PBF part is unused and in its original packaging.
Return procedure for LTC3727LXEG-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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