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Analog Devices Inc. LTC3421EUF#TRPBF
- Part No.:
- LTC3421EUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3421EUF#TRPBF.pdf
- Description:
- IC REG BOOST ADJ 1A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:7,378
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Product details
Overview
LTC3421EUF#TRPBF from Analog Devices is a micropower synchronous boost converter IC with true output disconnect, 0.5V–4.5V input range, 2.4V–5.25V adjustable output, up to 1.5A continuous output current, and 3MHz switching frequency-designed for battery-powered handheld computers and GPS receivers.
For engineers reviewing the LTC3421EUF#TRPBF datasheet, LTC3421EUF#TRPBF pinout, LTC3421EUF#TRPBF application, or LTC3421EUF#TRPBF equivalent, key selection considerations include guaranteed 1V start-up, 12µA Burst Mode quiescent current, programmable current limit and soft-start, synchronous rectification efficiency up to 96%, and thermal-enhanced 4mm × 4mm QFN package with exposed ground pad.
Technical Context
The LTC3421EUF#TRPBF implements current-mode, fixed-frequency PWM control with an integrated 0.10Ω N-channel MOSFET switch and 0.14Ω P-channel synchronous rectifier. Its independent start-up oscillator enables operation from as low as 0.88V input, and internal bootstrapping allows self-powering from VOUT once VOUT exceeds VIN by 0.3V.
It supports automatic or manual Burst Mode® operation, with programmable transition threshold via external resistor on BURST pin, and includes lossless current sensing, adaptive slope compensation, zero-current detection for discontinuous conduction, and antiringing control-enabling stable, high-efficiency operation across wide load and input voltage ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 0.5V to 4.5V - supports single- or dual-cell alkaline/NiMH and Li-ion battery inputs without external LDO pre-regulation. |
| Output Voltage Range | 2.4V to 5.25V - adjustable via external resistor divider; 1.22V feedback reference enables precise regulation. |
| Max Continuous Output Current | 1.5A - achievable at typical conditions (VIN ≥ 1.2V, VOUT = 3.3V); limited by NMOS current limit setting and thermal design. |
| Switching Frequency | Up to 3MHz - programmable via RT pin resistor; supports small inductors and ceramic capacitors for compact layout. |
| Burst Mode Quiescent Current | 12µA - minimizes standby power draw in portable devices; extends battery life during light-load sleep states. |
| Start-Up Input Voltage | 0.88V (min) - enables reliable start-up from deeply discharged batteries or energy-harvesting sources. |
| True Output Disconnect | Yes - eliminates body diode conduction path; prevents reverse current flow and ensures VOUT = 0V in shutdown. |
Pinout & Package
Package: 24-lead (4mm × 4mm) plastic QFN with exposed thermal pad (Pin 25), θJA = 35°C/W on 4-layer board. Exposed pad must be soldered to PCB ground plane for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (1) | Feedback input | Connects to resistor divider tap; regulates output via 1.22V internal reference; sets output voltage accuracy and loop stability. |
| SHDN (2) | Shutdown control | Logic-level enable: <0.25V disables IC; >1.0V enables; hysteresis allows operation down to 0.5V VIN after startup. |
| VREF (3) | Buffered reference output | 1.22V ±1% source/sink (±100µA/8µA); requires 0.1µF decoupling; enabled only when ENB = high. |
| ENB (4) | VREF and comparator enable | Controls VREF output and low-battery comparator activation; reduces quiescent current by ~5µA when grounded. |
| RT (5) | Oscillator frequency programming | Resistor-to-ground sets fOSC = 28.1kΩ/RT (kHz); enables precise noise/EMI control and inductor size optimization. |
| SS (6) | Soft-start timing | Capacitor-to-ground programs soft-start time (t = CSS × 320 ms); prevents inrush current and stabilizes startup transient. |
| SYNC (7) | External clock synchronization | Accepts 100ns–2µs pulses; allows EMI reduction via frequency alignment with system clock or other converters. |
| ILIM (8) | Peak current limit programming | Resistor-to-ground sets ILIM = 150kΩ/R (A); protects switch and inductor under overload or short-circuit. |
| BURST (9) | Burst Mode threshold control | RC network sets average load current threshold for automatic mode transition; manual control via grounding or VOUT tie. |
| GND (10,25) | Signal and thermal ground | Exposed pad (Pin 25) is primary thermal path; both pins must connect to low-impedance ground plane near compensation components. |
| PGND (11–13) | Power ground return | Direct return path for NMOS source; must be routed with minimal inductance to reduce switching noise and improve efficiency. |
| SW (14–16) | Switch node | Drives external inductor; high dv/dt node requiring tight layout; Schottky clamp required if VOUT > 4.3V to meet 6V abs max rating. |
| VOUT (17,19,20) | Main output and bootstrap supply | Delivers regulated output; powers internal circuitry once VOUT > VIN + 0.3V; requires local 4.7µF ceramic bypass. |
| VOUTS (18) | Remote output sense | Connects directly to output capacitor; improves load regulation by compensating for PCB trace IR drop. |
| VIN (21) | Input supply | Accepts 0.5V–4.5V; requires ≥4.7µF ceramic input capacitor placed adjacent to pin for low-ESR filtering. |
| LBO (22) | Low-battery open-drain flag | Pulls low when LBI < 0.6V; sinks up to 20mA; active only during wake cycles in Burst Mode. |
| LBI (23) | Low-battery comparator input | 0.6V threshold with 30mV hysteresis; operates from VIN or VOUT (whichever higher); enabled when ENB = high in back-fed mode. |
| VC (24) | Error amplifier output | Compensation node for loop stability; connects to RC network; clamped during Burst Mode to preserve charge. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated 0.14Ω P-MOSFET eliminates body diode conduction, enabling true output disconnect and up to 96% efficiency at 1A. |
| Programmable inrush limiting | Soft-start capacitor (SS pin) controls ramp rate; combined with current limit programming (ILIM pin), prevents input surge during cold start. |
| Ultra-low quiescent current | 12µA in Burst Mode and <1µA in shutdown-critical for multi-year battery life in always-on sensors and backup supplies. |
| Guaranteed 1V start-up capability | Independent start-up oscillator initiates conversion from 0.88V typical, supporting single-cell alkaline/NiMH and energy harvesting applications. |
| Thermally enhanced QFN package | 4mm × 4mm footprint with exposed GND pad (θJC = 2.6°C/W) enables >1A continuous operation without heatsink in compact portable designs. |
Applications
| Handheld Computers | Cordless Phones |
|---|---|
Use Scenario: Powering 3.3V logic and RF sections from two AA/AAA cells (2.0V–3.0V). IC Role / Device Role / Timing Role: Primary step-up DC/DC converter providing regulated 3.3V rail with true output disconnect during sleep mode. Use Value: 12µA Burst Mode current extends battery runtime; 3MHz switching enables use of 4.7µH inductor and 22µF ceramic output cap for ultra-thin form factor. | Use Scenario: Boosting single-cell NiMH (1.2V nominal) to 3.3V for baseband processor and display backlight driver. IC Role / Device Role / Timing Role: High-efficiency synchronous boost regulator with programmable soft-start to prevent audio pop during power-on. Use Value: 0.88V start-up ensures operation even with aged batteries; inrush limiting avoids brown-out in shared battery systems. |
| GPS Receivers | Battery Backup Supplies |
Use Scenario: Generating stable 3.3V supply from lithium coin cell (2.0V–3.0V) for GNSS module with intermittent 50mA peak loads. IC Role / Device Role / Timing Role: Micropower boost converter with low-noise fixed-frequency operation and fast load transient response. Use Value: Synchronizable oscillator (SYNC pin) eliminates beat frequencies with GPS baseband clock; <1µA shutdown current preserves coin cell for years. | Use Scenario: Maintaining SRAM or real-time clock (RTC) voltage during main power failure using supercapacitor or backup battery. IC Role / Device Role / Timing Role: Bidirectional-capable boost converter that sustains VOUT from secondary source (e.g., VOUT > VIN) during main supply dropout. Use Value: Self-powering from VOUT once established allows continued operation with VIN as low as 0.5V; true disconnect prevents backup source drain during normal operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61099YFFR | Lower max output current (1A vs 1.5A); fixed 3.3V/5V options only; no VOUTS sense pin; 1.2V min start-up. | Less suitable for high-current or precision-adjustable outputs; lacks remote sense for high-accuracy regulation under PCB IR drop. | Select LTC3421EUF#TRPBF when adjustable output, true disconnect, or >1A load capability is required. |
| MAX17222ETA+ | Higher quiescent current (800nA shutdown, 2.5µA operating); 0.7V min start-up; no programmable current limit or SYNC pin. | Better for ultra-low-power always-on sensors but lacks burst-mode efficiency at medium loads and EMI control features. | Choose LTC3421EUF#TRPBF for applications needing <12µA light-load IQ, 3MHz switching, or programmable protection thresholds. |
Compared with TPS61099YFFR and MAX17222ETA+, the LTC3421EUF#TRPBF delivers superior light-load efficiency via 12µA Burst Mode, full output adjustability, true output disconnect, and comprehensive programmability (frequency, current limit, soft-start, Burst threshold)-making it optimal for space-constrained, battery-sensitive systems demanding long runtime and flexible power architecture.
Availability
LTC3421EUF#TRPBF is available at Aetrix Electronics and suitable for handheld computers, GPS receivers, and battery backup supplies requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LTC3421EUF#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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3421EUF#TRPBF belongs to the Linear Technology (now part of Analog Devices) µPower DC/DC converter family, engineered specifically for ultra-low-quiescent-current, high-efficiency boost regulation in portable and energy-constrained applications.
FAQ
What is the minimum input voltage required for the LTC3421EUF#TRPBF to start switching?
The LTC3421EUF#TRPBF guarantees start-up from 0.88V input voltage (typical 1.0V) with light load, enabled by its dedicated start-up oscillator. This allows reliable operation from single-cell alkaline, NiMH, or partially discharged Li-ion sources where conventional boost converters fail to initiate.
Does the LTC3421EUF#TRPBF support true output disconnect, and how is it implemented?
Yes, the LTC3421EUF#TRPBF provides true output disconnect by integrating a P-channel MOSFET synchronous rectifier with controlled gate drive that eliminates body diode conduction. When disabled, VOUT drops to 0V with no reverse current from output to input-critical for battery backup isolation and preventing leakage in shutdown states.
How does the LTC3421EUF#TRPBF achieve 12µA quiescent current in Burst Mode operation?
The LTC3421EUF#TRPBF achieves 12µA quiescent current in Burst Mode by disabling the oscillator, error amplifier, and most internal bias circuits while maintaining only essential monitoring functions. The VC pin is clamped to preserve compensation network charge, and the device wakes periodically to service the output-minimizing both switching and static losses.
Can the LTC3421EUF#TRPBF operate with an output voltage higher than its input voltage, and what happens to power sourcing?
Yes, the LTC3421EUF#TRPBF operates with VOUT > VIN and automatically transitions to self-powering from VOUT once VOUT exceeds VIN by 0.3V. At that point, internal circuitry draws supply current from VOUT-not VIN-allowing VIN to drop as low as 0.5V without affecting regulation or functionality.
What is the purpose of the VOUTS (Pin 18) on the LTC3421EUF#TRPBF, and how should it be connected?
The VOUTS pin on the LTC3421EUF#TRPBF is a dedicated remote output sense terminal. It must be connected directly to the positive terminal of the main output filter capacitor-bypassing PCB trace resistance-to enable accurate load regulation and compensate for IR drop between the IC and load, especially critical in high-current or long-trace applications.
LTC3421EUF#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-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 0.5V
- Voltage - Input (Max):
- 4.5V
- Voltage - Output (Min/Fixed):
- 2.4V
- Voltage - Output (Max):
- 5.25V
- Current - Output:
- 1A (Switch)
- Frequency - Switching:
- 100kHz ~ 3MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x4)
LTC3421EUF#TRPBF FAQ
1.How can I place an order for LTC3421EUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3421EUF#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 LTC3421EUF#TRPBF reliable?
The price and inventory of LTC3421EUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3421EUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3421EUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3421EUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3421EUF#TRPBF?
LTC3421EUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3421EUF#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 LTC3421EUF#TRPBF?
For technical support, including LTC3421EUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3421EUF#TRPBF requirements.
6.How does Aetrix verify that LTC3421EUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3421EUF#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 LTC3421EUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3421EUF#TRPBF?
All LTC3421EUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3421EUF#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 LTC3421EUF#TRPBF part is unused and in its original packaging.
Return procedure for LTC3421EUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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