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Analog Devices Inc. LTC1649IS#TRPBF
- Part No.:
- LTC1649IS#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1649IS#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,208
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Product details
Overview
LTC1649IS#TRPBF from Analog Devices (formerly Linear Technology) is a high-efficiency, voltage-mode PWM step-down switching regulator controller optimized for 3.3V input and 1.26V–2.5V output at up to 20A. It drives dual N-channel MOSFETs with integrated 5V charge-pump gate drive, achieves ±1% output regulation over line/load/temperature, operates at 200kHz fixed frequency, and supports industrial temperature range (–40°C to +85°C). It enables compact, high-power local regulation in low-voltage microprocessor power supplies.
For engineers reviewing the LTC1649IS#TRPBF datasheet, LTC1649IS#TRPBF pinout, LTC1649IS#TRPBF application, or LTC1649IS#TRPBF equivalent, key selection considerations include its 16-lead SO package, no external sense resistor requirement, IMAX-adjustable current limit, soft-start capacitor control, and synchronous buck architecture enabling >90% efficiency at 15A in 3.3V-to-2.5V conversion.
Technical Context
The LTC1649IS#TRPBF implements a voltage-mode PWM control architecture with a fixed 200kHz oscillator and internal 1.26V reference trimmed to ±0.5%. Its feedback loop uses an error amplifier (gm = 650 µmho) with external COMP-network compensation, while MIN/MAX comparators provide fast over/under-voltage protection at ±3% thresholds relative to VFB.
It integrates a charge pump generating regulated 5V at CPOUT (4.8–5.2V) to power PVCC2 and VCC, and relies on an external flying capacitor (C+/C–) and bootstrap diode/capacitor network to generate PVCC1 ≥ VIN + 5V for high-side gate drive. Current limiting uses Q1's RDS(ON) as a sensing element via IFB/IMAX pins-no sense resistor required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7V to 5V - supports 3.3V nominal rail with margin for droop; absolute max 6V. |
| Output Voltage Range | 1.26V to 2.5V - set by external FB resistor divider; VFB = 1.265V ±1.5mV. |
| Max Output Current | 20A - achievable with appropriately sized external N-MOSFETs and inductor. |
| Switching Frequency | 200kHz (typ) - fixed internal oscillator minimizes EMI filtering complexity and inductor size. |
| Regulation Accuracy | ±1% over line, load, and temperature - ensures stable core voltage for sensitive logic/microprocessors. |
| Gate Drive Capability | 5V logic-level drive for both high-side (G1) and low-side (G2) N-MOSFETs - eliminates need for P-channel or ultra-low-VGS(th) devices. |
| Shutdown Quiescent Current | <25µA - enables low-power standby in battery-backed or energy-sensitive systems. |
Pinout & Package
Package: 16-lead narrow SO (Small Outline), RoHS-compliant, surface-mount. Thermal resistance θJA = 110°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| G1 | High-side MOSFET gate driver output | Swings from PVCC1 to GND; drives Q1 gate; disabled in shutdown. |
| PVCC1 | Power supply for G1 driver | Must be ≥ VIN + 5V; generated externally via bootstrap charge pump from switching node. |
| GND | System ground reference | Low-impedance connection point for signal/power grounds; single-point star grounding required. |
| FB | Feedback input | Resistor-divider node setting VOUT = 1.265V × (1 + R1/R2); precision reference input. |
| SHDN | Active-low shutdown control | TTL-compatible; >50µs low pulse forces shutdown; quiescent current drops to <25µA. |
| SS | Soft-start timing and current-limit compensation | Capacitor to GND sets startup ramp time and stabilizes ILIM loop during overload transitions. |
| VIN | Main input power supply | 2.7–5V primary input; powers internal charge pump; bypass with 1µF ceramic capacitor. |
| C– / C+ | Flying capacitor terminals | 1µF ceramic capacitor connected between C+ and C– enables internal 5V charge pump at CPOUT. |
| G2 | Low-side MOSFET gate driver output | Swings from PVCC2 to GND; drives Q2 gate; disabled in shutdown. |
| PVCC2 | Power supply for G2 driver | Supplied by CPOUT (5V); bypass with 10µF capacitor; doubles as CPOUT reservoir. |
| VCC | Internal analog/digital circuit supply | Powered from CPOUT; requires RC filter (e.g., 22Ω + 10µF) due to noise sensitivity. |
| IFB | Current-sense input | Connects to switched node (Q1 source/Q2 drain) via 1kΩ resistor; senses Q1 RDS(ON) drop for current limiting. |
| IMAX | Current-limit threshold set | Internal 12µA pull-down; external resistor or voltage defines peak current trip point. |
| COMP | Error amplifier output / loop compensation | External RC+C network sets phase margin and transient response; connects to FB amplifier output. |
| CPOUT | Regulated 5V charge-pump output | 4.8–5.2V at up to 50mA; powers PVCC2, VCC, and optionally external circuitry. |
Key Features
| Feature | Design Value |
|---|---|
| No external current-sense resistor | Uses RDS(ON) of high-side MOSFET (Q1) for current limiting - reduces BOM count, PCB area, and conduction loss. |
| Synchronous buck topology | Replaces freewheeling diode with low-RDS(ON) N-MOSFET (Q2) - improves efficiency to >90% at 15A and enables bidirectional output current capability. |
| Integrated 5V charge pump | Generates regulated 5V gate drive from as low as 2.7V input - enables use of standard logic-level N-MOSFETs without external boost supplies. |
| ±1% output regulation | Maintains tight VOUT accuracy across –40°C to +85°C, full line (2.7–5V), and 0–20A load - critical for low-voltage microprocessor core rails. |
| Fixed 200kHz switching frequency | Minimizes external component count and simplifies EMI filtering - avoids variable-frequency jitter and enables predictable inductor sizing. |
Applications
| Microprocessor Core Supply | Industrial Distributed Power |
|---|---|
Use Scenario: Providing tightly regulated 2.5V/15A power to a high-performance DSP or FPGA core in an industrial PLC. IC Role / Device Role / Timing Role: Primary step-down controller managing high-current, low-voltage DC-DC conversion with fast transient response. Use Value: Enables reliable operation under dynamic load steps (e.g., 0→10A in <20µs) with <250mV output deviation, thanks to synchronous architecture and COMP-loop optimization. | Use Scenario: Local regulation of 1.8V/12A from a 3.3V backplane in a modular telecom shelf. IC Role / Device Role / Timing Role: Point-of-load (POL) controller delivering isolated, high-efficiency power with minimal layout footprint. Use Value: Eliminates need for external sense resistors and discrete gate drivers - reduces bill-of-materials and thermal stress in dense board layouts. |
| Low-Voltage Logic Rail | High-Power Embedded System |
Use Scenario: Generating 1.26V/10A for ARM-based SoC memory interface (LPDDR4) in medical imaging equipment. IC Role / Device Role / Timing Role: Precision voltage-mode controller ensuring sub-1% ripple and monotonic startup via SS pin. Use Value: Achieves ±1% regulation over temperature without calibration - meets stringent IEC 60601-1 stability requirements for safety-critical subsystems. | Use Scenario: Powering multiple 2.5V/8A subsystems (GPU, AI accelerator) from shared 3.3V intermediate bus in autonomous vehicle ECU. IC Role / Device Role / Timing Role: High-current POL controller supporting parallel-phase operation via external synchronization (not internal). Use Value: Delivers >90% efficiency across 1–15A load range - reduces thermal load and cooling requirements in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-efficiency, high-current buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3776 | Higher integration: includes MOSFET drivers with adaptive dead-time control; supports up to 30A; requires external VREF for <1.2V outputs. | Targeted at higher-current, multi-phase designs; lacks integrated charge pump - needs external 5V bias for gate drive. | Select LTC3776 when scaling beyond 20A or requiring multi-phase interleaving; LTC1649IS#TRPBF remains optimal for cost-sensitive, single-phase 15–20A 3.3V-input applications. |
| TPS546B24A | Digital PWM controller with PMBus interface; 0.6–5.5V output; built-in nonvolatile memory for configuration; no integrated charge pump. | Designed for programmable, telemetry-enabled systems; requires external 5V supply for gate drivers and communication interface. | Choose TPS546B24A for designs needing remote monitoring, fault logging, or dynamic voltage scaling; LTC1649IS#TRPBF suits analog-controlled, fixed-output industrial systems where simplicity and proven reliability are prioritized. |
Compared with LTC3776 and TPS546B24A, the LTC1649IS#TRPBF offers lower system cost and reduced external component count for fixed 1.26–2.5V outputs at ≤20A, leveraging its self-contained 5V charge pump and resistor-programmed feedback - ideal for analog-intensive, high-reliability embedded power rails.
Availability
LTC1649IS#TRPBF is available at Aetrix Electronics and suitable for industrial automation, telecom infrastructure, and high-performance computing applications requiring stable component supply, extended temperature operation (–40°C to +85°C), and long-term production continuity.
Supply support for LTC1649IS#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) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC1649IS#TRPBF belongs to ADI's legacy Linear Technology Power Management product line, engineered specifically for high-efficiency, high-current, low-input-voltage DC-DC conversion in space-constrained industrial and computing systems.
FAQ
What is the operating temperature range of the LTC1649IS#TRPBF?
The LTC1649IS#TRPBF is specified for industrial temperature operation from –40°C to +85°C. This rating is confirmed in the Absolute Maximum Ratings table and Electrical Characteristics section of the official datasheet, where "LTC1649I" grade denotes the industrial temperature version. The "IS" suffix in LTC1649IS#TRPBF explicitly identifies this temperature grade.
Does the LTC1649IS#TRPBF require an external current-sense resistor?
No, the LTC1649IS#TRPBF does not require an external current-sense resistor. It implements current limiting by monitoring the voltage drop across the RDS(ON) of the high-side N-channel MOSFET (Q1) via the IFB pin. This method eliminates power loss and board space associated with a dedicated sense resistor, as documented in the Applications Information section under "Current Limit Loop".
What package type is used for the LTC1649IS#TRPBF?
The LTC1649IS#TRPBF is housed in a 16-lead narrow SO (Small Outline) plastic package, as stated in the "PACKAGE/ORDER INFORMATION" section and confirmed in the top-view pin diagram. This surface-mount package has standard SOIC dimensions and is RoHS-compliant, with thermal resistance θJA = 110°C/W.
How does the LTC1649IS#TRPBF generate gate drive voltage for the high-side MOSFET?
The LTC1649IS#TRPBF generates high-side gate drive voltage (PVCC1) using an external bootstrap charge pump: a Schottky diode (DCP) and capacitor connected between CPOUT and the source of Q1. When Q2 conducts, the capacitor charges to ~5V; when Q1 turns on, its source rises to VIN, lifting PVCC1 to ~VIN + 5V - sufficient to fully enhance standard 5V logic-level N-MOSFETs, as detailed in the "MOSFET Gate Drive" subsection.
What is the typical efficiency of an LTC1649IS#TRPBF-based converter at 15A output?
A typical LTC1649IS#TRPBF-based 3.3V-to-2.5V converter achieves >90% efficiency at 15A output load, as shown in Figure 1649 TA02 ("LTC1649 Efficiency") and confirmed in the "Features" summary. This efficiency level holds across 1A–10A and remains above 85% even at 20A, enabled by synchronous rectification and low-loss external MOSFET selection (e.g., IRF7801).
LTC1649IS#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 2.7V ~ 5V
- Frequency - Switching:
- 200kHz
- Duty Cycle (Max):
- 93%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
LTC1649IS#TRPBF FAQ
1.How can I place an order for LTC1649IS#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1649IS#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 LTC1649IS#TRPBF reliable?
The price and inventory of LTC1649IS#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1649IS#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1649IS#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1649IS#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1649IS#TRPBF?
LTC1649IS#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1649IS#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 LTC1649IS#TRPBF?
For technical support, including LTC1649IS#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1649IS#TRPBF requirements.
6.How does Aetrix verify that LTC1649IS#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1649IS#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 LTC1649IS#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1649IS#TRPBF?
All LTC1649IS#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1649IS#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 LTC1649IS#TRPBF part is unused and in its original packaging.
Return procedure for LTC1649IS#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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