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Analog Devices Inc. LTC3850EGN#PBF
- Part No.:
- LTC3850EGN#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3850EGN#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:143
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Product details
Overview
LTC3850EGN#PBF from Analog Devices is a dual, 2-phase synchronous step-down switching controller driving all-N-channel MOSFET stages. It delivers up to 95% efficiency, supports 250kHz–780kHz phase-lockable fixed-frequency operation, and features ±1% 0.8V reference accuracy. Used in high-density DC power distribution systems requiring tightly regulated dual outputs (e.g., 3.3V/2.5V @ 5A each).
For engineers reviewing the LTC3850EGN#PBF datasheet, LTC3850EGN#PBF pinout, LTC3850EGN#PBF application, or LTC3850EGN#PBF equivalent, key selection considerations include dual-phase current-mode control, RSENSE/DCR sensing flexibility, OPTI-LOOP® compensation for wide output capacitor/ESR tolerance, independent soft-start/tracking, and automotive-grade AEC-Q100 qualification (LTC3850I variants).
Technical Context
The LTC3850EGN#PBF implements constant-frequency current-mode control with two independent 180° out-of-phase channels, minimizing input ripple and supply-induced noise. Each channel uses a transconductance error amplifier (2.2 mmho gm), precision 0.8V reference (±1% over temp), and programmable current-sense threshold (20/40/60 mV via ILIM pin).
It integrates dual N-channel gate drivers (TG/BG) with 25ns transition times, anti-shoot-through logic, dropout detection with forced top-FET off for bootstrap capacitor recharge, and selectable operating modes (Burst Mode®, pulse-skipping, or continuous conduction) via MODE/PLLIN pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Dual synchronous buck controller - drives external high-side and low-side N-MOSFETs per channel. |
| Input Voltage Range | 4V to 24V (28V absolute max) - supports 12V intermediate bus and multi-cell Li-ion battery inputs. |
| Output Voltage Accuracy | ±1% at 0.8V feedback reference - ensures tight regulation across load, line, and temperature for critical digital rails. |
| Switching Frequency | 250kHz to 780kHz, phase-lockable - enables EMI reduction via synchronization and optimization of size vs. efficiency trade-off. |
| Current Sensing | RSENSE or DCR - allows flexible, low-loss inductor current sensing without dedicated sense resistors. |
| Soft-Start/Tracking | Independent TK/SS pins per channel - enables controlled ramp-up or voltage sequencing between dual outputs. |
| Power Good Output | Open-drain PGOOD with ±7.5% trip window and 17µs mask timer - provides reliable system-level power sequencing and fault indication. |
Pinout & Package
Package: 28-pin narrow plastic SSOP (GN), 4mm × 5.5mm body, exposed pad not present. Thermal resistance θJA = 95°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2 | Channel enable control | Independent shutdown: >1.22V enables; <1.1V disables. Internal 0.5µA pull-up + 4.5µA active pull-up. |
| TK/SS1, TK/SS2 | Soft-start & tracking input | Internal 1.3µA current charges external capacitor; regulates VFB to TK/SS voltage during ramp-up. |
| SENSE1+/2+, SENSE1−/2− | Current sense comparator inputs | Differential inputs for RSENSE or DCR networks; bias current ±2µA; common-mode range up to 5.5V. |
| VFB1, VFB2 | Error amplifier feedback input | Receives resistor-divided output voltage; referenced to precise 0.8V internal bandgap. |
| ITH1, ITH2 | Error amp output / current threshold | Controls peak inductor current; gm = 2.2 mmho; voltage range 0.7V–1.6V maps to full current scale. |
| TG1, TG2 / BG1, BG2 | Top/bottom gate drivers | N-channel drivers: TG swing = INTVCC + SW node; BG swing = PGND to INTVCC; RUP/RDOWN ≤ 2.6Ω/1.1Ω. |
| BOOST1, BOOST2 | Floating bootstrap supply | Connects to (+) terminal of bootstrap capacitor; swings from ~INTVCC − 0.7V to VIN + INTVCC. |
| SW1, SW2 | Switch node connection | Direct connection to inductor; voltage swing from ~−0.7V (body diode drop) to VIN. |
| PGOOD | Power-good indicator | Open-drain output pulled low when either VOUT deviates >±7.5% from setpoint after 17µs debounce. |
| MODE/PLLIN | Mode select & sync input | Selects Burst Mode® (float), pulse-skipping (tied to INTVCC), or forced CCM (tied to SGND); accepts external clock for PLL sync. |
| FREQ/PLLFLTR | Oscillator programming & PLL filter | DC voltage sets frequency (250–780kHz); also serves as PLL loop filter node when synchronized. |
| ILIM | Current limit threshold select | Tie to SGND/FLOAT/INTVCC to set max sense threshold to 20/40/60mV - configures foldback protection level. |
| VIN | Main input supply | Primary power source for INTVCC LDO (4.8–5.2V) and internal circuitry; decouple with 0.1–1µF to PGND. |
| INTVCC | Internal 5V regulator output | Supplies gate drivers and analog circuits; requires 4.7µF low-ESR capacitor to PGND. |
| SGND | Signal ground reference | Reference for all small-signal pins (VFB, ITH, SENSE); connect to PGND at single point near IC. |
| PGND | Power ground return | Return path for bottom FET sources, CIN(−), CVCC(−); must be low-inductance connection to minimize noise. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® compensation | Enables stable loop response across wide range of output capacitance (10µF–1000µF) and ESR (0.5mΩ–100mΩ), eliminating need for custom compensation per design. |
| Dual 180° phased operation | Reduces RMS input ripple current by ~70% vs. single-phase, allowing smaller input capacitors and lower EMI in compact layouts. |
| Pre-biased output start-up | Supports safe start-up into pre-charged outputs without reverse current flow - essential for hot-swap and rail-sequencing applications. |
| Current foldback limiting | Reduces MOSFET thermal stress during short-circuit by scaling peak current down as sensed voltage exceeds programmed threshold (20/40/60mV). |
| AEC-Q100 qualified variants | LTC3850I versions meet automotive reliability requirements (–40°C to 125°C junction), enabling use in infotainment and ADAS power supplies. |
Applications
| High-Efficiency Dual-Rail Notebook Power | Industrial DC Distribution System |
|---|---|
Use Scenario: Powering CPU core (1.8V) and I/O (3.3V) rails in ultra-thin notebooks with strict thermal and efficiency targets. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing independent voltage rails with coordinated soft-start and power-good sequencing. Use Value: Achieves >92% efficiency at 5A per rail under 12V input, reducing heat dissipation and extending battery life while meeting Intel VR14/VR12.5 compliance. | Use Scenario: Generating isolated 5V and 3.3V supplies from a 24V industrial bus for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: High-reliability dual-output controller supporting wide input range (4V–24V), pre-biased start-up, and robust current limiting in harsh environments. Use Value: Delivers ±1% output accuracy across –40°C to 85°C ambient, with foldback protection preventing field failures during cable short events. |
| Portable Medical Instrumentation | Automotive Infotainment Power Supply |
Use Scenario: Providing clean, low-noise 3.3V and 2.5V rails for ADCs, DACs, and RF front-ends in handheld ultrasound and ECG devices. IC Role / Device Role / Timing Role: Dual-channel controller operating in pulse-skipping mode to minimize audible noise while maintaining tight regulation during variable load conditions. Use Value: Enables <30mVpp output ripple at light loads and eliminates coil whine - critical for clinical-grade signal integrity and user experience. | Use Scenario: Powering display controller, audio DSP, and CAN interface in automotive head units with 12V battery input and transient immunity requirements. IC Role / Device Role / Timing Role: AEC-Q100-qualified dual buck controller with 30V absolute max input rating and integrated UVLO hysteresis for cold-crank resilience. Use Value: Maintains regulation during 4.5V–30V battery transients and supports seamless start-stop operation without rail collapse or reset events. |
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 |
|---|---|---|---|
| MP2918GL-Z | Single-chip dual-phase controller with integrated MOSFETs (30V/15A); no external ILIM configuration; fixed 600kHz freq. | Lower BOM count but limited thermal headroom above 8A total; no DCR sensing support. | Choose MP2918GL-Z for space-constrained, medium-current designs where integration outweighs flexibility. |
| LTC3838EGN#PBF | Single-output version with identical pinout, control architecture, and OPTI-LOOP®; lacks second channel and associated pins (RUN2, TK/SS2, etc.). | Used when only one regulated rail is needed; shares layout compatibility for scalable platform design. | Choose LTC3838EGN#PBF for cost-sensitive single-rail applications leveraging same design knowledge and layout reuse. |
Compared with MP2918GL-Z and LTC3838EGN#PBF, the LTC3850EGN#PBF uniquely balances external power stage flexibility, dual independent control, and automotive-ready ruggedness - making it optimal for high-reliability, thermally demanding dual-rail systems where discrete MOSFET selection and thermal management are critical.
Availability
LTC3850EGN#PBF is available at Aetrix Electronics and suitable for notebook computing, industrial DC distribution, and portable medical instrumentation requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant alternatives.
Supply support for LTC3850EGN#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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3850EGN#PBF belongs to Analog Devices' Power by Linear™ family of high-efficiency DC/DC controllers, engineered for demanding multi-rail power conversion in space- and thermal-constrained applications where precision, reliability, and flexibility are paramount.
FAQ
What is the maximum input voltage rating for the LTC3850EGN#PBF?
The LTC3850EGN#PBF has an absolute maximum input voltage (VIN) rating of 28V. Its operational input range is 4V to 24V, with transient capability up to 28V for <500ms when INTVCC ≥ 5V. This makes the LTC3850EGN#PBF suitable for 24V industrial buses and multi-cell Li-ion battery systems while ensuring robustness against line transients.
Does the LTC3850EGN#PBF support DCR current sensing?
Yes, the LTC3850EGN#PBF fully supports DCR current sensing on both channels via its differential SENSE+ and SENSE− inputs. The device's current comparators accept common-mode voltages up to 5.5V and feature low bias current (±2µA), enabling accurate inductor DCR-based sensing without additional amplification or calibration - a key advantage for high-efficiency, low-component-count designs.
How does the ILIM pin configure current limit thresholds on the LTC3850EGN#PBF?
The ILIM pin on the LTC3850EGN#PBF selects one of three maximum current sense thresholds: tie to SGND for 20mV, leave floating for 40mV, or tie to INTVCC for 60mV. This directly sets the foldback protection level for both channels, allowing designers to match MOSFET RDS(on) and sense resistor values without changing compensation - a critical feature for optimizing thermal performance during overload conditions.
Can the LTC3850EGN#PBF operate with pre-biased outputs?
Yes, the LTC3850EGN#PBF supports pre-biased output start-up. When enabled, the controller prevents reverse current flow during start-up by disabling bottom-FET turn-on until the output voltage rises above the feedback divider's setpoint. This avoids output voltage collapse and potential damage to downstream circuitry - essential for hot-swap, redundant supply, and modular power system applications using the LTC3850EGN#PBF.
What package type is used for the LTC3850EGN#PBF?
The LTC3850EGN#PBF uses a 28-pin narrow plastic SSOP (GN) package measuring 4mm × 5.5mm with standard gull-wing leads. It is lead-free, RoHS-compliant, and rated for operation from –40°C to 85°C ambient. Unlike QFN variants (UFD/UF), the GN package lacks an exposed thermal pad, resulting in higher θJA (95°C/W), which must be accounted for in thermal design when using the LTC3850EGN#PBF.
LTC3850EGN#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SSOP (0.154", 3.90mm 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 ~ 24V
- Frequency - Switching:
- 250kHz ~ 780kHz
- Duty Cycle (Max):
- 97.2%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SSOP
LTC3850EGN#PBF FAQ
1.How can I place an order for LTC3850EGN#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3850EGN#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 LTC3850EGN#PBF reliable?
The price and inventory of LTC3850EGN#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3850EGN#PBF is usually 5 days.
3.What payment methods are accepted for LTC3850EGN#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3850EGN#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3850EGN#PBF?
LTC3850EGN#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3850EGN#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 LTC3850EGN#PBF?
For technical support, including LTC3850EGN#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3850EGN#PBF requirements.
6.How does Aetrix verify that LTC3850EGN#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3850EGN#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 LTC3850EGN#PBF meets industry standards.
7.What is the process for return or replacement of LTC3850EGN#PBF?
All LTC3850EGN#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3850EGN#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 LTC3850EGN#PBF part is unused and in its original packaging.
Return procedure for LTC3850EGN#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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