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Analog Devices Inc. LTC3850IGN#PBF
- Part No.:
- LTC3850IGN#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3850IGN#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,999
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Product details
Overview
LTC3850IGN#PBF from Analog Devices is a dual, 2-phase synchronous step-down switching controller driving all-N-channel MOSFET stages. It delivers ±1% 0.8V output voltage accuracy, phase-lockable 250–780kHz fixed-frequency operation, and supports RSENSE/DCR current sensing. Used in high-efficiency dual-rail power supplies for notebook computers and portable instruments.
For engineers reviewing the LTC3850IGN#PBF datasheet, LTC3850IGN#PBF pinout, LTC3850IGN#PBF application, or LTC3850IGN#PBF equivalent, key selection criteria include dual-channel out-of-phase timing to reduce input capacitance, OPTI-LOOP® compensation for transient optimization across varied output ESR, and independent TK/SS pins enabling precise soft-start or tracking control.
Technical Context
The LTC3850IGN#PBF implements constant-frequency current-mode control with two independent 180° out-of-phase channels, each featuring an error amplifier, slope-compensated current comparator, and anti-shoot-through logic. Its ITH pin directly sets peak inductor current via transconductance amplifier (2.2 mmho) and supports current foldback during short-circuit conditions.
It integrates dual N-channel gate drivers (TG/BG) with 1.1–2.6 Ω on-resistance, 25 ns rise/fall times, and synchronized dead-time control. The MODE/PLLIN pin selects among Burst Mode®, pulse-skipping, or forced continuous conduction - with PLL synchronization capability up to 780 kHz when driven externally.
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 (30V max for LTC3850I grade) - supports wide battery chemistries and intermediate bus rails. |
| Output Voltage Accuracy | ±1% at 0.8V reference - ensures tight regulation for core logic and memory rails. |
| Switching Frequency | 250–780kHz, phase-lockable - enables EMI reduction via synchronization and trade-off between efficiency and magnetics size. |
| Current Sensing | RSENSE or DCR - flexible layout options with ±2 µA sense pin bias current and selectable 20/40/60 mV max thresholds via ILIM pin. |
| Soft-Start/Tracking | Independent 1.3 µA TK/SS charge current per channel - enables programmable ramp rate or master-slave voltage tracking. |
| Power Good Output | Open-drain PGOOD with ±7.5% trip window and 17 µs mask timer - provides reliable system sequencing and fault indication. |
Pinout & Package
The LTC3850IGN#PBF is packaged in a 28-pin narrow plastic SSOP (GN package), 4mm × 9.7mm body, with exposed pad not present. Pin 14 is ILIM (not EXTVCC), confirming it is the standard LTC3850 variant (not -1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2 | Channel enable/disable inputs | Independent 1.22 V threshold with 80 mV hysteresis - allows staggered startup or fault isolation per rail. |
| TK/SS1, TK/SS2 | Soft-start/tracking control | 1.3 µA internal pull-up - sets output ramp rate or replicates master rail's VFB via resistor divider. |
| SENSE1+/–, SENSE2+/– | Current sense differential inputs | Accepts RSENSE or DCR networks; ±2 µA bias enables accurate low-side sensing without offset errors. |
| VFB1, VFB2 | Error amplifier feedback inputs | Monitor remote output voltage via resistive divider; referenced to precision 0.8 V internal bandgap. |
| ITH1, ITH2 | Error amplifier output / current limit threshold | Directly controls peak inductor current; transconductance = 2.2 mmho - defines loop gain and transient response. |
| TG1, TG2 / BG1, BG2 | Top/bottom gate drivers | Drive N-MOSFET gates with 25 ns transition time and anti-shoot-through logic - eliminates cross-conduction risk. |
| MODE/PLLIN | Mode selection & sync input | Selects Burst Mode® (float), pulse-skip (INTVCC), or forced CCM (SGND); accepts external clock for PLL lock. |
| FREQ/PLLFLTR | Oscillator programming / PLL filter | DC voltage sets frequency (250–780 kHz); also serves as PLL loop filter node when synchronized. |
| PGOOD | Power-good status indicator | Open-drain output pulled low if either VOUT deviates >±7.5% - enables safe system power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® compensation | Enables stable loop tuning across wide range of output capacitor ESR (e.g., ceramic vs. polymer) without redesigning compensation network. |
| 180° out-of-phase dual operation | Reduces RMS input ripple current by ~30%, allowing smaller input bulk capacitors and lower EMI on shared input bus. |
| Independent channel control | RUN and TK/SS pins per channel allow asymmetric startup sequencing, independent shutdown, and mixed-mode operation (e.g., one channel in Burst Mode®, other in CCM). |
| Pre-biased output support | Enables safe startup into pre-charged output capacitors - prevents reverse current flow and avoids damaging downstream loads. |
| AEC-Q100 qualified (I-grade) | Rated for –40°C to +85°C ambient with validated reliability - suitable for automotive infotainment and ADAS subsystems. |
Applications
| High-Efficiency Notebook Power | Portable Instrument Dual-Rail Supply |
|---|---|
Use Scenario: Dual-output DC/DC supply generating 3.3V @ 5A and 2.5V @ 5A from 12V intermediate bus in ultraportable notebooks. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing two independent regulated rails with 180° phase shift to minimize input ripple and thermal stress. Use Value: Achieves up to 95% peak efficiency and reduces required input capacitance by 40% versus single-phase design - extending battery runtime and shrinking PCB area. | Use Scenario: Precision dual-rail supply for handheld oscilloscope front-end analog circuitry requiring clean 3.3V and 1.8V rails. IC Role / Device Role / Timing Role: Dual-channel controller with independent soft-start and tracking - ensures controlled power-up sequence and matched voltage ramps to avoid latch-up. Use Value: OPTI-LOOP® compensation maintains stability with low-ESR ceramic output caps; ±1% output accuracy guarantees ADC reference integrity and signal chain linearity. |
| Battery-Operated Digital Systems | DC Power Distribution Systems |
Use Scenario: Power management for ARM-based industrial handheld with Li-ion battery input (4–24V) and multiple SoC voltage domains. IC Role / Device Role / Timing Role: Wide-input dual controller supporting RSENSE/DCR sensing and Burst Mode® for ultra-low quiescent current (<30 µA shutdown). Use Value: Extends battery life via adaptive light-load efficiency modes; 0.8V reference enables direct generation of sub-1V core voltages with minimal dropout loss. | Use Scenario: Redundant 24V-to-12V/5V conversion in telecom shelf power distribution with strict thermal and reliability requirements. IC Role / Device Role / Timing Role: Dual-phase controller operating in forced CCM with external clock sync - ensures deterministic timing and EMI compliance across parallel modules. Use Value: Phase-locking enables coherent interleaving across multiple LTC3850IGN#PBF units; AEC-Q100 qualification validates long-term field reliability under thermal cycling. |
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 MOSFET drivers only; no external gate drive flexibility; fixed 600kHz frequency. | Targeted at cost-sensitive consumer power supplies; lacks RSENSE/DCR selectability and independent TK/SS control. | Choose MP2918GL-Z only if board space is critical and external MOSFET drive is unnecessary. |
| LTC3833EUF#PBF | Single-channel, 2-phase controller (not dual independent channels); no second VFB/ITH/TK-SS set; supports only one output rail. | Suitable for high-current single-rail applications (e.g., CPU core); cannot generate two independent regulated outputs. | Choose LTC3833EUF#PBF only when dual-phase operation on a single rail is required - not for dual-output systems. |
Compared with MP2918GL-Z and LTC3833EUF#PBF, the LTC3850IGN#PBF uniquely supports two fully independent, phase-shifted buck regulators with separate feedback, soft-start, and mode control - essential for multi-rail systems requiring sequencing, tracking, or asymmetric load handling.
Availability
LTC3850IGN#PBF is available at Aetrix Electronics and suitable for notebook computers, portable instrumentation, and battery-operated digital devices requiring stable component supply, automotive-grade reliability, and dual-rail power management.
Supply support for LTC3850IGN#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 is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3850IGN#PBF belongs to Analog Devices' Power by Linear™ controller family, designed specifically for high-efficiency, multi-phase, synchronous DC/DC conversion in space- and thermally-constrained applications.
FAQ
What is the maximum input voltage rating for the LTC3850IGN#PBF?
The LTC3850IGN#PBF has an absolute maximum input supply voltage (VIN) rating of 28V. For the I-grade version (as indicated by "IGN"), transient input voltage up to 34V is allowed for <500ms when INTVCC ≥ 5V. Continuous operation must remain within 4V to 24V for optimal performance and reliability. Always observe derating guidelines in the official datasheet for thermal and lifetime considerations.
Does the LTC3850IGN#PBF support pre-biased output startup?
Yes, the LTC3850IGN#PBF supports pre-biased output startup. Its control architecture prevents reverse current flow during startup into an already charged output capacitor. This is achieved through coordinated gate timing and reverse-current detection (IREV comparator), making LTC3850IGN#PBF suitable for hot-swap and redundant power systems where output rails may be live prior to controller enable.
How does the ILIM pin function on the LTC3850IGN#PBF?
On the LTC3850IGN#PBF, the ILIM pin (Pin 14) sets the maximum current sense threshold for both channels. Tying ILIM to SGND, FLOAT, or INTVCC selects 20mV, 40mV, or 60mV thresholds respectively - enabling optimization of current-sense resolution and noise immunity. This differs from the LTC3850-1 variant, where Pin 14 is EXTVCC; the IGN suffix confirms this is the standard LTC3850, not the -1 version.
Can the LTC3850IGN#PBF synchronize to an external clock?
Yes, the LTC3850IGN#PBF can synchronize to an external clock via the MODE/PLLIN pin. When an external clock signal is applied to MODE/PLLIN, the internal oscillator locks to it using an integrated phase-locked loop (PLL). The FREQ/PLLFLTR pin simultaneously serves as the PLL loop filter node. Supported input clock frequencies align with the internal 250–780kHz range, enabling coherent interleaving in multi-controller systems.
What package type is used for the LTC3850IGN#PBF?
The LTC3850IGN#PBF uses a 28-lead narrow plastic SSOP (GN package), measuring 4mm × 9.7mm with 0.635mm lead pitch. It is lead-free, RoHS-compliant, and rated for –40°C to +85°C operation. Unlike QFN variants (UFD/UF), the GN package has no exposed thermal pad - thermal management relies on copper pour under the leads and proper PCB layout per AN136.
LTC3850IGN#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 ~ 30V
- 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
LTC3850IGN#PBF FAQ
1.How can I place an order for LTC3850IGN#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3850IGN#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 LTC3850IGN#PBF reliable?
The price and inventory of LTC3850IGN#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3850IGN#PBF is usually 5 days.
3.What payment methods are accepted for LTC3850IGN#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3850IGN#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3850IGN#PBF?
LTC3850IGN#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3850IGN#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 LTC3850IGN#PBF?
For technical support, including LTC3850IGN#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3850IGN#PBF requirements.
6.How does Aetrix verify that LTC3850IGN#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3850IGN#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 LTC3850IGN#PBF meets industry standards.
7.What is the process for return or replacement of LTC3850IGN#PBF?
All LTC3850IGN#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3850IGN#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 LTC3850IGN#PBF part is unused and in its original packaging.
Return procedure for LTC3850IGN#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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