My Inquiry
My Account
Analog Devices Inc. LTC3520IUF#TRPBF
- Part No.:
- LTC3520IUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3520IUF#TRPBF.pdf
- Description:
- IC REG BUCK BOOST ADJ DL 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,873
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3520IUF#TRPBF from Analog Devices (formerly Linear Technology) is a dual-output synchronous DC/DC converter integrating a 1A buck-boost and a 600mA buck regulator in a single 24-lead 4mm × 4mm QFN package. It supports 2.2V–5.5V input, delivers 3.3V/500mA (buck-boost) and 1.8V/600mA (buck), and features pin-selectable Burst Mode® operation for ultra-low quiescent current in portable power management applications.
For engineers reviewing the LTC3520IUF#TRPBF datasheet, LTC3520IUF#TRPBF pinout, LTC3520IUF#TRPBF application, or LTC3520IUF#TRPBF equivalent, key selection criteria include dual-converter integration, programmable 100kHz–2MHz switching frequency, thermal/overcurrent protection, <1μA shutdown current, and uncommitted gain block configurability for LDO control or battery-good indication.
Technical Context
The LTC3520IUF#TRPBF implements two independent control architectures: current-mode PWM for the buck converter with internal synchronous rectification and voltage-mode control with proprietary four-switch topology for the buck-boost converter. Both share a common oscillator whose frequency is set by an external RT resistor.
Its buck-boost section operates continuously across buck, buck-boost, and boost modes without inductor current discontinuity, while the buck converter supports 100% duty cycle for dropout operation and includes slope compensation to prevent subharmonic oscillation at high duty cycles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.2V to 5.5V - supports single-cell Li-ion, Li-poly, or multi-cell alkaline/NiMH inputs without pre-regulation. |
| Buck-Boost Output | 2.2V to 5.25V, 1A max at VOUT = 3.3V with VIN ≥ 3V - enables stable rail generation across varying battery states. |
| Buck Output | 0.8V to VIN, 600mA max - provides efficient low-voltage core supply for processors or memory. |
| Switching Frequency | Programmable 100kHz to 2MHz via RT pin - allows trade-off between efficiency, size, and EMI performance. |
| Quiescent Current | 55μA typical in Burst Mode for both converters - extends battery life in always-on portable devices. |
| Shutdown Current | <1μA - ensures minimal leakage during system sleep or storage. |
| Package | 24-lead 4mm × 4mm QFN, 0.75mm profile - enables compact, thermally robust PCB layouts in space-constrained handhelds. |
Pinout & Package
24-lead (4mm × 4mm) plastic QFN with exposed pad (Pin 25) soldered to PCB ground. Pin pitch: 0.5mm. Thermal resistance θJA = 37°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SVIN (1) | Small-signal power supply | Powers internal analog circuitry; must be tied to PVIN rails and bypassed with ≥0.1μF ceramic capacitor. |
| AOUT (2) | Uncommitted amplifier output | Drives external PNP for LDO regulation or acts as comparator output for battery-good indication. |
| AIN (3) | Non-inverting input of gain block | Serves as reference input for LDO feedback or battery threshold detection (0.786V typical). |
| RT (4) | Oscillator frequency programming | Resistor-to-ground sets switching frequency (e.g., 54.9kΩ → 1MHz); critical for optimizing efficiency vs. footprint. |
| PWM1 (5) | Buck-boost mode control | High = fixed-frequency PWM; Low = variable-frequency Burst Mode for light-load efficiency. |
| SD1 (6) | Buck-boost enable/disable | Active-low; logic-high (>1.4V) enables buck-boost converter; must not float. |
| SD2 (7) | Buck enable/disable | Active-low; logic-high (>1.4V) enables buck converter; independent control from SD1. |
| SD3 (8) | Gain block enable/disable | Active-low; disables AOUT/AIN functionality to reduce quiescent current when unused. |
| PVIN2 (9) | Buck high-current input | Connects to bulk input capacitor (≥22μF); shares node with PVIN1/PVIN3/SVIN. |
| SW2 (10) | Buck switch node | Connects to buck inductor; carries high di/dt; requires short, low-inductance PCB routing. |
| PGND2 (11) | Buck power ground | Return path for buck NMOS; must be wide, low-impedance trace connected to exposed pad. |
| PWM2 (12) | Buck mode control | Configures buck operation: High = forced PWM; grounded via RBURST = adjustable Burst entry point. |
| SS2 (13) | Buck soft-start | External capacitor sets soft-start duration (tSS ≈ 0.15·CSS in ms); prevents inrush current. |
| FB2 (14) | Buck feedback input | 0.790V nominal reference; used with resistor divider to set VOUT (e.g., 1.8V = R1/R2 = 1.27). |
| VC1 (15) | Buck-boost error amp output | Compensation node; connects to FB1 via RC network for loop stability. |
| SGND (16) | Small-signal ground | Analog reference ground; separate from PGND1/PGND2 but tied to exposed pad at single point. |
| SS1 (17) | Buck-boost soft-start | External capacitor sets buck-boost soft-start time; same timing equation as SS2. |
| FB1 (18) | Buck-boost feedback input | 0.782V nominal reference; used with resistor divider to set buck-boost output (e.g., 3.3V = R1/R2 = 3.22). |
| VOUT1 (19) | Buck-boost output | Delivers regulated output; requires low-ESR ceramic capacitor (e.g., 47μF) placed adjacent to pin. |
| SW1B (20) | Buck-boost switch node B | One terminal of buck-boost inductor; pairs with SW1A for four-switch operation. |
| PGND1 (21) | Buck-boost power ground | Return path for buck-boost NMOS switches; ties to exposed pad and SGND/PGND2. |
| SW1A (22) | Buck-boost switch node A | Second buck-boost switch node; works with SW1B to implement seamless buck/buck-boost/boost transitions. |
| PVIN1 (23), PVIN3 (24) | Buck-boost high-current input | Parallel input paths for buck-boost PMOS; each requires ≥22μF bulk capacitance and shared node connection. |
| Exposed Pad (25) | Thermal & electrical ground | Mandatory solder connection to PCB ground plane for thermal dissipation and low-impedance return. |
Key Features
| Feature | Design Value |
|---|---|
| Dual synchronous converters | Integrates 1A buck-boost + 600mA buck in one QFN - eliminates discrete solution complexity and board area. |
| Four-switch buck-boost topology | Enables continuous conduction and seamless mode transitions (buck → buck-boost → boost) - maintains regulation and stability across full VIN range. |
| Programmable switching frequency | 100kHz–2MHz via RT resistor - allows optimization for efficiency (low fSW), size (high fSW), or EMI compliance. |
| Uncommitted gain block | Configurable as LDO controller (with external PNP), battery-good comparator, or sequencing element - adds third regulated output without extra IC. |
| Independent Burst Mode control | PWM1/PWM2 pins allow per-converter selection of Burst Mode or PWM - maximizes light-load efficiency without compromising noise-sensitive rails. |
Applications
| Portable Media Players | Digital Cameras |
|---|---|
Use Scenario: Powering audio DAC, display backlight, and image sensor from single Li-ion cell with declining voltage. IC Role / Device Role / Timing Role: LTC3520IUF#TRPBF delivers 3.3V to codec and 1.8V to sensor core while maintaining regulation down to 2.2V input. Use Value: Dual-rail capability eliminates need for separate boost and LDO, reducing BoM count and PCB area by >30%. | Use Scenario: Supplying CMOS image sensor (1.2V), ISP (1.8V), and flash LED driver (3.3V) in compact camera module. IC Role / Device Role / Timing Role: LTC3520IUF#TRPBF generates all three rails simultaneously with independent enable/control and <1μA shutdown. Use Value: Seamless buck-boost transition ensures uninterrupted sensor operation during battery discharge from 4.2V to 2.7V. |
| Handheld PCs / PDAs | GPS Receivers |
Use Scenario: Providing core voltage (1.2V), I/O rail (3.3V), and RTC backup (3.0V) in always-on mobile computing device. IC Role / Device Role / Timing Role: LTC3520IUF#TRPBF uses its uncommitted gain block as battery-good comparator to assert reset when VBAT drops below threshold. Use Value: Integrated comparator replaces discrete supervisor IC, saving 2 mm² PCB area and simplifying BOM. | Use Scenario: Powering GPS baseband processor (1.2V), RF front-end (3.3V), and GNSS antenna LNA (2.8V) from coin cell or energy harvester. IC Role / Device Role / Timing Role: LTC3520IUF#TRPBF operates in Burst Mode at microamp loads, achieving 55μA total quiescent current for extended cold-start acquisition. Use Value: Ultra-low IQ extends battery life beyond 100 hours in tracking mode without sacrificing start-up speed. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS63020DSJR | Single 2A buck-boost only; no integrated buck converter or uncommitted gain block. | Lacks independent second output and battery-comparator function - requires external LDO or supervisor for multi-rail systems. | Select when only one regulated output is needed and highest possible buck-boost current (2A) is critical. |
| MAX8649ETE+ | 1.2A buck + 1.2A buck-boost; no programmable frequency or uncommitted amplifier; 16-pin TQFN. | Higher current per rail but no Burst Mode optimization or flexible gain block - less suitable for ultra-low-IQ portable designs. | Select when higher per-rail current and smaller package (3mm × 3mm) outweigh need for IQ optimization and configurability. |
Compared with TPS63020DSJR and MAX8649ETE+, the LTC3520IUF#TRPBF uniquely combines dual-output integration, programmable frequency, ultra-low 55μA Burst Mode IQ, and a reconfigurable gain block - making it optimal for space- and battery-life-constrained multi-rail portable systems where flexibility and efficiency across load ranges are essential.
Availability
LTC3520IUF#TRPBF is available at Aetrix Electronics and suitable for portable media players, digital cameras, and GPS receivers requiring stable component supply with guaranteed long-term availability and consistent parametric performance.
Supply support for LTC3520IUF#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTC3520IUF#TRPBF belongs to Linear's Power Management portfolio, designed specifically for highly integrated, ultra-efficient power conversion in battery-powered portable electronics with demanding size and runtime requirements.
FAQ
What is the operating temperature range for the LTC3520IUF#TRPBF?
The LTC3520IUF#TRPBF is rated for –40°C to +125°C junction temperature and is specified over this full range. Its I-grade qualification ensures guaranteed performance across automotive and industrial environments where thermal stress is significant. This contrasts with the E-grade variant (LTC3520EUF#TRPBF), which is only guaranteed from 0°C to 85°C.
How does the uncommitted gain block in the LTC3520IUF#TRPBF function as a battery-good comparator?
The LTC3520IUF#TRPBF's uncommitted gain block compares AIN voltage against an internal 0.786V reference. When AIN falls below this threshold, AOUT drives low - signaling low battery condition. This function requires no external op-amp or comparator, enabling direct integration into battery monitoring circuits without additional components.
Can the LTC3520IUF#TRPBF generate three regulated outputs?
Yes - the LTC3520IUF#TRPBF delivers two regulated outputs directly (buck-boost and buck), and its uncommitted gain block can be configured with an external PNP transistor to form a third low-noise LDO output. This third rail is fully controllable via SD3 and supports sequencing, making LTC3520IUF#TRPBF a true triple-output power solution in a single 4mm × 4mm package.
What is the minimum inductor value recommended for the buck converter in the LTC3520IUF#TRPBF?
The LTC3520IUF#TRPBF buck converter is characterized with 4.7μH inductors (e.g., Sumida CDRH3D16NP-4R7N). While lower values may work, using ≤2.2μH risks exceeding peak current limits and degrading efficiency or stability - especially at high input voltages or heavy loads. The datasheet specifies 4.7μH as the validated design point for full 600mA capability.
Does the LTC3520IUF#TRPBF support 100% duty cycle operation in buck mode?
Yes - the LTC3520IUF#TRPBF buck converter supports true 100% duty cycle operation, allowing VOUT to track VIN minus small resistive losses when input voltage approaches or falls below the regulated output. This feature extends usable battery life in deep-discharge scenarios, such as in handheld devices powered by single-cell Li-ion batteries.
LTC3520IUF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, Buck-Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 2.2V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 600mA, 1A
- Frequency - Switching:
- 100kHz ~ 2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x4)
LTC3520IUF#TRPBF FAQ
1.How can I place an order for LTC3520IUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3520IUF#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 LTC3520IUF#TRPBF reliable?
The price and inventory of LTC3520IUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3520IUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3520IUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3520IUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3520IUF#TRPBF?
LTC3520IUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3520IUF#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 LTC3520IUF#TRPBF?
For technical support, including LTC3520IUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3520IUF#TRPBF requirements.
6.How does Aetrix verify that LTC3520IUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3520IUF#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 LTC3520IUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3520IUF#TRPBF?
All LTC3520IUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3520IUF#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 LTC3520IUF#TRPBF part is unused and in its original packaging.
Return procedure for LTC3520IUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3520IUF#TRPBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
