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Analog Devices Inc. LTC3522EUD#TRPBF
- Part No.:
- LTC3522EUD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LTC3522EUD#TRPBF.pdf
- Description:
- IC REG BUCK BOOST ADJ DL 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,801
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Product details
Overview
LTC3522EUD#TRPBF from Analog Devices (formerly Linear Technology) is a dual-output synchronous DC/DC converter integrating a 400mA buck-boost and a 200mA buck regulator in a single 3mm × 3mm QFN package. It operates from 2.4V to 5.5V input, delivers 3.3V/400mA (buck-boost) and 1.8V/200mA (buck), and supports pin-selectable Burst Mode® for ultra-low quiescent current in battery-powered portable electronics.
For engineers reviewing the LTC3522EUD#TRPBF datasheet, LTC3522EUD#TRPBF pinout, LTC3522EUD#TRPBF application, or LTC3522EUD#TRPBF equivalent, key selection considerations include independent shutdown control (SHDN1/SHDN2), dual Power Good indicators (PGOOD1/PGOOD2), 1MHz fixed-frequency PWM operation, 25μA combined quiescent current in Burst Mode, and seamless 4-switch buck-boost mode transitions across VIN–VOUT relationships.
Technical Context
The LTC3522EUD#TRPBF implements two independent switching regulators: a voltage-mode controlled 4-switch buck-boost with proprietary mode-transition logic (buck → buck-boost → boost), and a current-mode synchronous buck with 100% duty-cycle capability. Both share a single 1MHz oscillator and internal soft-start (600μs nominal).
It integrates dual error amplifiers (voltage-mode for buck-boost, transconductance for buck), internal slope compensation, average + peak current limiting on both channels, reverse current limiting (250mA typical), and open-drain PGOOD comparators with 7.7%–12% regulation thresholds and 2.5% hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.4V to 5.5V - supports single-cell Li-ion (2.7V–4.2V) and regulated 3.3V/5V rails without external LDO pre-regulation. |
| Buck-Boost Output | 2.2V to 5.25V at up to 400mA - maintains regulation when VIN < VOUT (boost), VIN ≈ VOUT (buck-boost), or VIN > VOUT (buck). |
| Buck Output | 0.6V to VIN at up to 200mA - supports 100% duty cycle for dropout extension, critical for battery end-of-life operation. |
| Quiescent Current (Burst) | 25μA total for both converters - enables multi-week standby in portable medical instruments and handheld devices. |
| Switching Frequency | 0.8MHz to 1.33MHz (typ. 1MHz) - balances small external inductor size (e.g., 4.7μH) and high efficiency (>90% at 100mA load). |
| Protection Features | Thermal shutdown (150°C), overcurrent (average + peak), reverse current limit (250mA), UVLO (2.3V), and independent PGOOD fault reporting. |
| Package | 16-pin 3mm × 3mm × 0.75mm QFN with exposed thermal pad - requires PCB ground connection for thermal dissipation and EMI reduction. |
Pinout & Package
Package: 16-lead (3mm × 3mm) plastic QFN, 0.75mm height, exposed pad (Pin 17) electrically connected to GND per datasheet requirement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB1 (Pin 1) | Buck-boost feedback input | Resistor-divider node setting VOUT1 = 1.00V × (1 + R2/R1); 0.97V–1.03V reference tolerance ensures ±2% output accuracy. |
| PWM (Pin 2) | Mode select control | Low = Burst Mode (25μA IQ) for both converters; High = forced 1MHz PWM for low-noise operation - no floating allowed. |
| GND (Pin 3) | Small-signal reference ground | Separate from power grounds (PGND1/PGND2); must be star-connected to minimize noise coupling into FB/PGOOD paths. |
| PGOOD2 (Pin 4) | Buck converter status flag | Open-drain output pulls low if VOUT2 is >7.7% below regulation, during OT/UVLO, or buck current limit - enables power sequencing. |
| FB2 (Pin 5) | Buck feedback input | Resistor-divider node setting VOUT2 = 0.594V × (1 + R2/R1); 0.582V–0.606V reference tolerance enables precise low-VOUT regulation. |
| PGOOD1 (Pin 6) | Buck-boost converter status flag | Open-drain output pulls low if VOUT1 is >10%–12% below regulation (Burst/PWM modes differ), during OT/UVLO, or buck-boost current limit. |
| SHDN1 (Pin 7) | Buck-boost enable/disable | Active-low; >1.4V = enabled, <0.4V = disabled - allows independent power rail control without affecting buck channel. |
| PVIN1 (Pin 8) | Buck-boost high-side power input | Must be tied to PVIN2; requires local 4.7μF ceramic bypass capacitor with short, low-inductance path to PGND2. |
| PGND2 (Pin 9) | Buck-boost switch C return path | High-current ground for SW1B node; PCB trace must be wide/short to minimize voltage bounce during switching transitions. |
| SW1B (Pin 10) | Buck-boost switch node B | Connects to one terminal of buck-boost inductor (L1); carries bidirectional current during buck-boost mode transitions. |
| SW1A (Pin 11) | Buck-boost switch node A | Connects to other terminal of buck-boost inductor (L1); forms 4-switch topology with SW1B, PVIN1, and VOUT1. |
| VOUT1 (Pin 12) | Buck-boost regulated output | Delivers 2.2V–5.25V; requires low-ESR ceramic output capacitor (e.g., 4.7μF) placed adjacent to pin with direct PGND1 return. |
| PGND1 (Pin 13) | Shared power ground | Return path for buck rectifier, buck-boost switch B, and internal circuitry - must be connected to GND and exposed pad. |
| SW2 (Pin 14) | Buck switch node | Connects to buck inductor (L2); carries unidirectional current in buck topology - no reverse conduction path required. |
| PVIN2 (Pin 15) | Buck input & internal VCC supply | Primary power input for buck stage and internal bias; requires 4.7μF+ ceramic bypass; must tie to PVIN1 in layout. |
| SHDN2 (Pin 16) | Buck enable/disable | Active-low; >1.4V = enabled, <0.4V = disabled - enables independent control of 1.8V/200mA rail in multi-rail systems. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent regulators | Single-chip solution eliminates discrete buck + buck-boost ICs, reducing BOM count, board area, and design complexity in space-constrained portable designs. |
| Seamless 4-switch buck-boost topology | Proprietary mode transition avoids discontinuities in inductor current and loop gain - maintains stability and efficiency across VIN/VOUT crossover points. |
| 100% duty-cycle buck operation | Extends usable battery voltage range down to VOUT + RDS(ON) × IOUT, delaying system shutdown during deep discharge in Li-ion applications. |
| 25μA combined Burst Mode IQ | Enables >10-year theoretical battery life in always-on sensor nodes or medical monitors drawing <10μA average system current. |
| Independent PGOOD outputs | Allows safe power sequencing (e.g., enable VOUT1 before VOUT2) and fault isolation - critical for FPGA, DSP, or multi-core SoC power domains. |
| Integrated soft-start (600μs) | Prevents inrush current damage to input capacitors and avoids brown-out on shared supplies - no external components required. |
Applications
| Flash-Based MP3 Players | Medical Instruments |
|---|---|
Use Scenario: Portable audio player powered by single-cell Li-ion battery (2.7V–4.2V) requiring stable 3.3V for NAND flash and 1.8V for DSP core. IC Role / Device Role / Timing Role: LTC3522EUD#TRPBF provides dual regulated rails with dynamic input tracking - buck-boost maintains 3.3V as battery discharges, buck delivers 1.8V with 100% duty cycle at end-of-life. Use Value: Eliminates need for separate boost + LDO, reduces solution size by 40%, and extends playback time via ultra-low 25μA Burst Mode quiescent current. |
Use Scenario: Handheld blood glucose meter with LCD display, microcontroller, and analog front-end, operating from coin cell or rechargeable battery. IC Role / Device Role / Timing Role: LTC3522EUD#TRPBF generates 3.3V for MCU/peripherals and 1.8V for precision ADC reference - independent SHDN pins allow selective rail shutdown during sleep. Use Value: Dual PGOOD flags enable reliable power-up sequencing; thermal/overcurrent protection ensures safety-critical reliability; 3mm × 3mm footprint fits compact casework. |
| Digital Cameras | Personal Navigation Devices |
Use Scenario: Compact digital camera with CMOS image sensor (2.8V), ISP (1.2V), and SD card interface (3.3V), powered by dual-cell Li-ion pack. IC Role / Device Role / Timing Role: LTC3522EUD#TRPBF's buck-boost channel delivers 3.3V from 5.5V–8.4V input; buck channel supplies 1.2V via external resistor divider on FB2. Use Value: Seamless buck-boost mode transition prevents image corruption during zoom/focus motor surges; 1MHz switching minimizes EMI near sensitive analog video paths. |
Use Scenario: GPS-enabled handheld navigator using SiRFstar IV chipset (1.8V core, 3.3V RF/IO) and OLED display (3.3V), powered by 3.7V Li-ion. IC Role / Device Role / Timing Role: LTC3522EUD#TRPBF independently powers 3.3V GPS RF section and 1.8V baseband processor - PWM pin forces low-noise 1MHz mode during signal acquisition. Use Value: Independent shutdown (SHDN1/SHDN2) enables GPS-only or display-only operation; 2.4V–5.5V input range accommodates USB charging and battery voltage sag. |
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-inductor dual-output (buck-boost + buck), 3A peak, 2.5V–5.5V input, no independent PGOOD or shutdown pins. | Lacks per-rail enable and fault reporting - unsuitable for sequenced or safety-critical power domains. | Select when cost and single-inductor simplicity outweigh need for independent rail control and diagnostics. |
| MAX8646ETE+ | Two independent buck converters (1.2A + 0.6A), 2.5V–5.5V input, integrated MOSFETs, but no buck-boost capability. | Cannot regulate above input voltage - requires pre-boost stage for 3.3V output from 2.7V Li-ion. | Select only if both rails are step-down only and higher current (≥600mA) is required per channel. |
Compared with TPS63020DSJR and MAX8646ETE+, the LTC3522EUD#TRPBF uniquely combines buck-boost + buck topologies with independent enable, PGOOD, and mode control - making it optimal for portable systems needing flexible VIN–VOUT relationships and robust power sequencing.
Availability
LTC3522EUD#TRPBF is available at Aetrix Electronics and suitable for flash-based MP3 players, portable medical instruments, digital cameras, and personal navigation devices requiring stable component supply with guaranteed long-term manufacturability.
Supply support for LTC3522EUD#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 semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3522EUD#TRPBF belongs to Linear's µPower DC/DC converter product line, designed specifically for ultra-low-power portable electronics where battery life, small size, and multi-rail flexibility are critical.
FAQ
What is the maximum output current capability of the LTC3522EUD#TRPBF buck-boost channel?
The LTC3522EUD#TRPBF buck-boost channel delivers up to 400mA continuous output current when VIN > 3V and VOUT = 3.3V, as specified in the Electrical Characteristics table. At lower input voltages or higher output voltages, the achievable current decreases due to thermal limits and switch RDS(ON) - e.g., ~300mA at VIN = 2.7V, VOUT = 3.3V. The device includes average and peak current limiting to protect against overload.
Does the LTC3522EUD#TRPBF support 100% duty-cycle operation on both channels?
Only the buck channel (VOUT2) of the LTC3522EUD#TRPBF supports true 100% duty-cycle operation to maintain regulation during battery dropout. The buck-boost channel does not operate in 100% duty cycle; instead, it uses a 4-switch topology that inherently regulates across VIN–VOUT crossovers without requiring 100% conduction - enabling seamless buck-to-boost transitions while maintaining efficiency.
How does the PWM pin affect operation of the LTC3522EUD#TRPBF?
The PWM pin on the LTC3522EUD#TRPBF selects between two global operating modes: when pulled low, both converters enter Burst Mode (25μA total IQ, variable frequency); when pulled high, both are forced into fixed 1MHz PWM mode for low-noise performance. The pin must never float and requires a solid logic-level drive - internal pull-ups/downs are not provided.
What are the thermal limitations of the LTC3522EUD#TRPBF in a 3mm × 3mm QFN package?
The LTC3522EUD#TRPBF features thermal shutdown at approximately 150°C junction temperature and is rated for operation from –40°C to +85°C ambient. Its θJA is 68°C/W; achieving full 400mA buck-boost output requires proper PCB layout - including soldering the exposed pad to a ≥100mm² copper pour and using ≥4 thermal vias - otherwise derating is necessary above 60°C ambient.
Can the LTC3522EUD#TRPBF generate non-standard output voltages like 2.5V or 1.2V?
Yes - the LTC3522EUD#TRPBF supports programmable outputs via external resistor dividers on FB1 (buck-boost) and FB2 (buck). For example, 2.5V on VOUT1 uses R2/R1 = (2.5V/1.00V) – 1 = 1.5; 1.2V on VOUT2 uses R2/R1 = (1.2V/0.594V) – 1 ≈ 1.02. Reference tolerances (±1.2% for buck-boost, ±2% for buck) ensure final accuracy within datasheet limits.
LTC3522EUD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-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):
- 2.4V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 200mA, 400mA
- Frequency - Switching:
- 1.07MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN (3x3)
LTC3522EUD#TRPBF FAQ
1.How can I place an order for LTC3522EUD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3522EUD#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 LTC3522EUD#TRPBF reliable?
The price and inventory of LTC3522EUD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3522EUD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3522EUD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3522EUD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3522EUD#TRPBF?
LTC3522EUD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3522EUD#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 LTC3522EUD#TRPBF?
For technical support, including LTC3522EUD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3522EUD#TRPBF requirements.
6.How does Aetrix verify that LTC3522EUD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3522EUD#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 LTC3522EUD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3522EUD#TRPBF?
All LTC3522EUD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3522EUD#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 LTC3522EUD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3522EUD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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