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Analog Devices Inc. LTC3561AIDD#TRPBF
- Part No.:
- LTC3561AIDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3561AIDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1A 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,110
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Product details
Overview
LTC3561AIDD#TRPBF from Analog Devices (formerly Linear Technology) is a constant-frequency, current-mode synchronous step-down DC/DC converter optimized for medium-power portable applications. It operates from 2.5V to 5.5V input, delivers up to 1A output current, supports user-configurable switching frequency up to 4MHz, and regulates output voltage from 0.8V to 5.5V using an external resistor divider. Its integrated 0.15Ω P-channel and 0.13Ω N-channel MOSFETs enable high-efficiency power conversion in space-constrained devices such as digital cameras and cellular handsets.
For engineers reviewing the LTC3561AIDD#TRPBF datasheet, LTC3561AIDD#TRPBF pinout, LTC3561AIDD#TRPBF application, or LTC3561AIDD#TRPBF equivalent, key selection considerations include its 8-lead 3mm × 3mm DFN package with exposed PGND pad, 0.8V feedback reference, 1µA shutdown current, 330µA quiescent current, and support for ceramic output capacitors without external compensation components.
Technical Context
The LTC3561AIDD#TRPBF implements a current-mode control architecture with external compensation via the ITH pin, enabling transient response optimization across diverse load and output capacitor conditions. Its oscillator frequency is set by an external RT resistor connected to the SHDN/RT pin, supporting programmable operation from ~200kHz to 4MHz.
Dropout operation is achieved via 100% duty cycle with continuous conduction of the internal P-channel MOSFET, while undervoltage lockout disables operation below ~2.1V VIN. The device integrates separate PVIN (power supply) and SVIN (signal supply) rails, requiring SVIN ≥ PVIN, and features dedicated SGND and PGND pins with mandatory low-impedance PCB connection between them and the exposed thermal pad (Pin 9).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 5.5V - supports single-cell Li-ion, Li-polymer, and multi-cell alkaline/NiMH battery inputs |
| Output Current | Up to 1A - sufficient for core logic, memory, and peripheral rails in portable electronics |
| Switching Frequency | Up to 4MHz - enables use of sub-2mm-height inductors and compact ceramic capacitors |
| Feedback Reference Voltage | 0.8V ±2% - sets precise output regulation point with minimal divider current error |
| Top/Bottom RDS(ON) | 0.15Ω / 0.13Ω - minimizes conduction loss and improves full-load efficiency to 96% |
| Quiescent Current | 330µA - extends battery runtime in active standby modes |
| Shutdown Current | <1µA - preserves battery charge during system sleep or off-state |
Pinout & Package
Package: 8-lead 3mm × 3mm plastic DFN with exposed PGND thermal pad (Pin 9), rated for –40°C to +125°C junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SHDN/RT (Pin 1) | Combined shutdown control and oscillator timing input | Pulling to SVIN disables all circuitry; resistor to GND sets switching frequency (e.g., 125kΩ ≈ 2.5MHz) |
| SGND (Pin 2) | Signal ground reference | Must be tied to PGND via low-inductance path; serves as return for VFB, ITH, and SVIN decoupling |
| SW (Pin 3) | Switch node connection | Drives external inductor; swings from PVIN to PGND; requires tight layout to minimize EMI and ringing |
| PGND (Pin 4) | Main power ground | Return path for high-current inductor and output capacitor; must connect to exposed pad (Pin 9) |
| PVIN (Pin 5) | Main power input | Supplies gate drive and high-side switch; requires local 0.1µF ceramic bypass to PGND |
| SVIN (Pin 6) | Signal power supply | Powers internal analog circuitry (error amp, reference, logic); must be ≥ PVIN and decoupled to SGND |
| VFB (Pin 7) | Feedback input | Compares divided output voltage against 0.8V reference; ±0.1µA input bias enables high-resistor-divider designs |
| ITH (Pin 8) | Error amplifier output and compensation node | Controls peak inductor current; external RC network tunes loop stability and transient response |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Eliminates external Schottky diode, reducing BOM count and improving light-load efficiency |
| OPTI-LOOP® compensation | Enables stable operation with wide range of ceramic, tantalum, or polymer output capacitors |
| 100% duty-cycle dropout mode | Maintains regulated output down to VIN ≈ VOUT + (IOUT × RDS(ON)), critical for battery end-of-life operation |
| Short-circuit protection | Current-limiting architecture prevents damage during output fault conditions |
| Stable with ceramic capacitors | No minimum ESR requirement simplifies filtering design and reduces cost/height vs. electrolytic solutions |
Applications
| Digital Camera Power Rail | Cellular Phone Baseband Core |
|---|---|
Use Scenario: Powers image sensor and ISP core requiring clean, adjustable 1.2V–1.8V at up to 1A with fast load transient response. IC Role / Device Role / Timing Role: Primary buck regulator delivering tightly regulated core voltage with <100mV droop under 1A load step. Use Value: 4MHz operation allows 1.0µH inductor and 10µF ceramic output capacitor, minimizing board area and height in ultra-thin camera modules. |
Use Scenario: Supplies application processor core voltage in GSM/WCDMA smartphones operating from single-cell Li-ion battery (3.0–4.2V). IC Role / Device Role / Timing Role: High-efficiency step-down converter maintaining 1.0V–1.3V output across battery discharge curve. Use Value: 0.15Ω/0.13Ω RDS(ON) and 330µA quiescent current extend talk time by >15% versus comparable 2MHz converters. |
| Notebook Computer I/O Rail | Handheld Instrument LCD Bias |
Use Scenario: Generates 3.3V or 5V auxiliary rail for USB controllers, card readers, and display interfaces in fanless notebooks. IC Role / Device Role / Timing Role: Compact, thermally efficient buck converter mounted near load to minimize voltage drop and noise coupling. Use Value: Exposed PGND pad and 43°C/W θJA enable 1A continuous operation without heatsink in 3mm × 3mm footprint. |
Use Scenario: Provides adjustable 2.5V–5.5V bias for TFT-LCD source drivers in portable test equipment with strict EMI limits. IC Role / Device Role / Timing Role: Low-noise, high-frequency DC/DC converter minimizing conducted emissions into sensitive analog measurement circuits. Use Value: 4MHz switching moves fundamental noise above 10MHz, easing compliance with CISPR-22 Class B radiated emission requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62130ARGTR | Fixed 3.3V output (non-adjustable); 3MHz max frequency; 0.12Ω/0.09Ω RDS(ON); 1.2A rating | Requires redesign of feedback network; better suited for fixed-voltage systems with higher current margin | Select if output voltage is fixed and 1.2A headroom is needed; verify thermal performance in same DFN package |
| MP2143GJ-Z | 2.5–5.5V input; 0.8V reference; 3MHz max; 0.14Ω/0.11Ω RDS(ON); 1.2A rating; no SVIN/PVIN separation | Lacks dual-supply isolation; simpler layout but less noise immunity in mixed-signal systems | Choose when SVIN/PVIN separation is unnecessary and cost sensitivity outweighs analog noise isolation needs |
Compared with TPS62130ARGTR and MP2143GJ-Z, the LTC3561AIDD#TRPBF provides unique SVIN/PVIN rail separation for improved analog noise rejection, guaranteed 4MHz operation for smallest passive size, and industry-leading 1µA shutdown current-making it optimal for battery-critical, space-constrained, mixed-signal portable designs.
Availability
LTC3561AIDD#TRPBF is available at Aetrix Electronics and suitable for digital cameras, cellular phones, and handheld instruments requiring stable component supply with guaranteed long-term availability and full industrial temperature range support.
Supply support for LTC3561AIDD#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 (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management ICs, serving precision instrumentation, communications, and industrial markets.
The LTC3561AIDD#TRPBF belongs to Linear's µPower synchronous buck converter family, designed specifically for battery-powered portable electronics where small size, high efficiency across load range, and ultra-low quiescent current are essential.
FAQ
What is the maximum supported switching frequency for the LTC3561AIDD#TRPBF?
The LTC3561AIDD#TRPBF supports a user-configurable switching frequency up to 4MHz, set by an external resistor on the SHDN/RT pin. While 4MHz operation is guaranteed by design, production testing is performed at lower frequencies (e.g., 2.5MHz with 125kΩ RT), and duty cycle limitations apply at maximum frequency-particularly at high VIN/VOUT ratios per the fO(MAX) ≈ 6.67 × VOUT/VIN(MAX) constraint.
Does the LTC3561AIDD#TRPBF require external catch diodes?
No, the LTC3561AIDD#TRPBF does not require an external catch diode because it integrates synchronous N-channel MOSFET rectification. An optional Schottky diode may be added in parallel with the SW node for marginal efficiency gains in pulse-skipping mode, but this is discouraged due to increased leakage current at high temperature and potential EMI/ringing issues-especially with ceramic capacitors.
How is output voltage programmed on the LTC3561AIDD#TRPBF?
The LTC3561AIDD#TRPBF output voltage is programmed using an external resistive divider from VOUT to SGND, with the midpoint connected to the VFB pin. The formula is VOUT ≈ 0.8V × (1 + R2/R1), where R1 connects VFB to SGND and R2 connects VOUT to VFB. Feedback current is limited to ±0.1µA, allowing high-value resistors (e.g., 118kΩ/16.9kΩ for 2.5V) to minimize quiescent loss.
What is the purpose of separate PVIN and SVIN pins on the LTC3561AIDD#TRPBF?
The LTC3561AIDD#TRPBF uses separate PVIN (power input) and SVIN (signal power) pins to isolate high-current switching paths from sensitive analog circuitry. PVIN supplies the gate drivers and power switches, while SVIN powers the error amplifier, reference, and logic-reducing noise coupling and improving regulation accuracy. SVIN must be ≥ PVIN and decoupled separately to SGND.
Can the LTC3561AIDD#TRPBF operate with ceramic output capacitors only?
Yes, the LTC3561AIDD#TRPBF is explicitly designed to be stable with ceramic output capacitors, eliminating minimum ESR requirements. Its OPTI-LOOP® architecture and accessible ITH pin allow loop compensation tuning across capacitor types and values. However, layout best practices-including short traces, proper grounding, and local 0.1µF ceramic bypass near VFB-are essential to prevent instability caused by parasitic inductance.
LTC3561AIDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 5V
- Current - Output:
- 1A
- Frequency - Switching:
- 2.5MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (3x3)
LTC3561AIDD#TRPBF FAQ
1.How can I place an order for LTC3561AIDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3561AIDD#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 LTC3561AIDD#TRPBF reliable?
The price and inventory of LTC3561AIDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3561AIDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3561AIDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3561AIDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3561AIDD#TRPBF?
LTC3561AIDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3561AIDD#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 LTC3561AIDD#TRPBF?
For technical support, including LTC3561AIDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3561AIDD#TRPBF requirements.
6.How does Aetrix verify that LTC3561AIDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3561AIDD#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 LTC3561AIDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3561AIDD#TRPBF?
All LTC3561AIDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3561AIDD#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 LTC3561AIDD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3561AIDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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