My Inquiry
My Account
Analog Devices Inc. LTC3421EUF#PBF
- Part No.:
- LTC3421EUF#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC3421EUF#PBF.pdf
- Description:
- IC REG BOOST ADJ 1A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,241
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3421EUF#PBF from Analog Devices is a micropower synchronous boost DC/DC converter with true output disconnect, 0.10Ω NMOS switch, 0.14Ω PMOS synchronous rectifier, 12µA Burst Mode quiescent current, and programmable 0.5V–4.5V input / 2.4V–5.25V output operation - used in handheld computers, GPS receivers, and battery backup supplies.
For engineers reviewing the LTC3421EUF#PBF datasheet, LTC3421EUF#PBF pinout, LTC3421EUF#PBF application, or LTC3421EUF#PBF equivalent, key selection considerations include guaranteed 1V start-up, 3MHz programmable switching frequency, true output disconnect capability, programmable current limit (1–4.2A), and thermal-limited operation in compact 4mm × 4mm QFN.
Technical Context
The LTC3421EUF#PBF employs current-mode, fixed-frequency PWM control with adaptive slope compensation and lossless inductor current sensing. Its independent start-up oscillator enables operation from 0.85V VIN, and internal bootstrapping allows self-powering from VOUT once VOUT exceeds VIN by 0.3V.
It integrates dual MOSFETs (NMOS switch + PMOS synchronous rectifier), a 1.22V buffered reference, open-drain LBO comparator, and programmable functions via RT (frequency), ILIM (current limit), SS (soft-start), BURST (mode threshold), and SYNC (external clock synchronization).
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 partial discharge operation. |
| Output Voltage Range | 2.4V to 5.25V - adjustable via external resistor divider; feedback reference = 1.22V ±2.4%. |
| Max Continuous Output Current | 1.5A - at VIN ≥ 2.4V, VOUT = 3.3V, fSW = 1MHz; limited by NMOS RDS(ON) = 0.10Ω and thermal design. |
| Quiescent Current (Burst Mode) | 12µA - enables >1000-hour battery life in low-duty-cycle portable systems. |
| Switching Frequency | Up to 3MHz - programmable via RT resistor; supports ultra-small inductors (e.g., 4.7µH) and ceramic output caps. |
| Start-Up Voltage | 0.88V (min) - guaranteed start from single-cell alkaline/NiMH under light load. |
| Shutdown Current | <1µA - ensures zero-load battery drain during system sleep. |
Pinout & Package
Package: 24-lead (4mm × 4mm) plastic QFN with exposed thermal pad (Pin 25 = GND). Thermally enhanced for θJA = 35°C/W on 4-layer board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (1) | Feedback Input | Connects to resistor divider tap; regulates output via 1.22V reference; input bias current ≤50nA. |
| SHDN (2) | Shutdown Control | Active-low enable; <0.25V disables IC; >1.0V enables; hysteresis allows operation down to 0.5V VIN after start-up. |
| VREF (3) | Buffered Reference Output | 1.22V ±2.4% source/sink (±100µA/8µA); requires 0.1µF decoupling; enabled only when ENB = high. |
| ENB (4) | VREF Enable | High = enables VREF and low-battery comparator; low = disables VREF and reduces IQ by ~5µA. |
| RT (5) | Oscillator Frequency Set | Resistor-to-GND sets fSW = 28.1 MHz / RT(kΩ); supports 300kHz–3MHz range. |
| SS (6) | Soft-Start Timing | Capacitor-to-GND sets tSS = CSS(µF) × 320 ms; internal 2.5µA current source charges 0.8–1.6V range. |
| SYNC (7) | External Clock Input | Accepts 100ns–2µs pulses; synchronizes internal oscillator; must be grounded if unused. |
| ILIM (8) | Peak Current Limit Set | Resistor-to-GND programs ILIM = 150A/kΩ; sets NMOS peak switch current (1–4.2A typical). |
| BURST (9) | Burst Mode Threshold | RC network sets average load current threshold for automatic Burst Mode entry/exit; manual control via GND/VOUT tie. |
| GND (10, 25) | Signal & Thermal Ground | Pins 10 and 25 connect to PCB ground plane; exposed pad (25) must be soldered for thermal performance. |
| PGND (11–13) | Power Ground Return | NMOS source terminals; low-inductance connection critical for EMI and efficiency. |
| SW (14–16) | Switch Node | Connects to inductor; handles high di/dt; requires snubbing or Schottky clamp if VOUT > 4.3V. |
| VOUT (17, 19, 20) | Main Output Power | Delivers regulated output; powers internal circuitry when VOUT > VIN + 0.3V; requires local 4.7µF ceramic cap. |
| VOUTS (18) | Output Sense | Direct connection to output filter capacitor; improves regulation accuracy by eliminating PCB trace IR drop. |
| VIN (21) | Input Supply | Accepts 0.5–4.5V; requires ≥4.7µF ceramic decoupling close to pin. |
| LBO (22) | Low-Battery Open-Drain Output | Pulls low when LBI < 0.6V; sinks up to 20mA; active only during wake cycles in Burst Mode. |
| LBI (23) | Low-Battery Input | Comparator input with 0.6V threshold (±30mV hysteresis); powered from VIN or VOUT (whichever higher). |
| VC (24) | Error Amplifier Output | Compensation node; connects to RC network for loop stability; clamped during Burst Mode to retain voltage. |
Key Features
| Feature | Design Value |
|---|---|
| True Output Disconnect | Eliminates body-diode conduction path - enables zero-VOUT shutdown and prevents backfeed from output capacitors. |
| Inrush Current Limiting | Internal soft-start and controlled peak-current ramp prevent input surge during power-on, protecting batteries and input filters. |
| Programmable Burst Mode Threshold | RC network on BURST pin sets precise average load current crossover point between high-efficiency Burst Mode and low-noise PWM mode. |
| 1.22V Buffered Reference | Stable, low-noise reference usable for external circuitry (e.g., ADC references, sensor biasing) with ±100µA sourcing capability. |
| Antiringing Control | Integrated damping reduces SW-node ringing in DCM, lowering EMI without external components. |
Applications
| Handheld Computers | GPS Receivers |
|---|---|
Use Scenario: Powering 3.3V logic and RF front-end from single-cell alkaline or NiMH battery (0.8–1.5V). IC Role / Device Role / Timing Role: Primary step-up regulator delivering stable 3.3V with <12µA quiescent current during standby polling intervals. Use Value: Extends battery life beyond 100 hours in intermittent-use navigation devices while maintaining fast wake-up response. | Use Scenario: Generating 3.3V supply for GPS baseband processor and LNA from partially discharged Li-ion cell (2.7–4.2V). IC Role / Device Role / Timing Role: Synchronous boost converter operating in PWM mode during acquisition, then switching to Burst Mode during tracking. Use Value: Achieves >92% efficiency at 100mA load and maintains regulation down to 2.4V input - critical for cold-start GPS lock. |
| Battery Backup Supplies | Cordless Phones |
Use Scenario: Providing uninterrupted 5V rail during main power failure using supercapacitor or secondary Li-ion cell. IC Role / Device Role / Timing Role: Bidirectional-capable boost controller that sustains VOUT even when VIN drops below 0.5V post-failure. Use Value: Guarantees 1V start-up and true output disconnect - prevents backup energy leakage while enabling seamless switchover. | Use Scenario: Supplying 3.3V to digital baseband and 5V to analog audio codec from two AA cells (2.0–3.0V). IC Role / Device Role / Timing Role: Dual-output capable boost converter (via VOUTS feedback and external divider) powering multiple subsystems. Use Value: Delivers up to 1.5A continuous current with <1% load regulation - supports burst transmit power without brownout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61099YFFR | Lower IQ (300nA shutdown, 400nA operation), fixed 3.3V/5V outputs, no programmable current limit or SYNC. | Best for ultra-low-power always-on sensors; lacks adjustable output and external frequency sync. | Select when minimal quiescent current dominates over flexibility and output adjustability. |
| MAX17222ETA+T | Higher max output current (2A), integrated soft-start, but no true output disconnect or LBO/LBI comparator. | Suitable for higher-current portable displays; missing battery monitoring and zero-VOUT shutdown. | Choose when output current >1.5A is required and battery monitoring is handled externally. |
Compared with TPS61099YFFR and MAX17222ETA+T, the LTC3421EUF#PBF uniquely combines true output disconnect, programmable current limit, integrated low-battery detection, and 3MHz synchronization - making it optimal for space-constrained, multi-rail, battery-critical systems requiring both efficiency and functional integration.
Availability
LTC3421EUF#PBF 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 temperature.
Supply support for LTC3421EUF#PBF 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 precision instrumentation, industrial automation, communications, and aerospace markets.
The LTC3421EUF#PBF belongs to Analog Devices' µPower DC/DC converter product line, designed specifically for battery-powered portable electronics demanding ultra-low quiescent current, high light-load efficiency, and robust start-up from depleted cells.
FAQ
What is the minimum input voltage required for the LTC3421EUF#PBF to start up?
The LTC3421EUF#PBF guarantees start-up from 0.88V input (typical 0.85V) with light load, enabled by an independent start-up oscillator and internal charge pump. This allows reliable operation from deeply discharged single-cell alkaline or NiMH batteries, and is confirmed across –40°C to 85°C per Electrical Characteristics table.
Does the LTC3421EUF#PBF support true output disconnect, and how is it implemented?
Yes, the LTC3421EUF#PBF provides true output disconnect by actively controlling its internal P-channel synchronous rectifier to eliminate body-diode conduction. During shutdown, VOUT can fall to 0V without drawing current from VIN - verified in the "Output Disconnect and Inrush Limiting" section and confirmed by absence of reverse current in typical application waveforms.
Can the LTC3421EUF#PBF operate with input voltage lower than the output voltage?
Yes - once VOUT exceeds VIN by 0.3V, the LTC3421EUF#PBF powers itself from VOUT instead of VIN. This allows continued operation even if VIN drops as low as 0.5V, provided sufficient energy remains in the output capacitor and duty cycle limits (≤91%) are respected - explicitly stated in the Low Voltage Start-Up section.
What is the purpose of the VOUTS pin on the LTC3421EUF#PBF, and how should it be connected?
The VOUTS pin on the LTC3421EUF#PBF is a dedicated output sense terminal that must be connected directly to the output filter capacitor's positive terminal - not to the VOUT pins. This Kelvin connection eliminates PCB trace resistance error, improving load regulation accuracy to ±1% over full temperature and load range, as specified in the Pin Functions section.
How does the LTC3421EUF#PBF achieve 96% peak efficiency, and under what conditions is this measured?
The LTC3421EUF#PBF achieves up to 96% peak efficiency through synchronous rectification (0.10Ω NMOS + 0.14Ω PMOS), low-quiescent-current Burst Mode operation, and optimized gate drive. The 96% figure is measured at VIN = 2.4V, VOUT = 3.3V, IOUT = 500mA, fSW = 1MHz - shown in Figure 2 ("2-Cell to 3.3V Efficiency") of the datasheet, with test conditions explicitly documented.
LTC3421EUF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tube
- 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#PBF FAQ
1.How can I place an order for LTC3421EUF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3421EUF#PBF 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#PBF reliable?
The price and inventory of LTC3421EUF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3421EUF#PBF is usually 5 days.
3.What payment methods are accepted for LTC3421EUF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3421EUF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3421EUF#PBF?
LTC3421EUF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3421EUF#PBF 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#PBF?
For technical support, including LTC3421EUF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3421EUF#PBF requirements.
6.How does Aetrix verify that LTC3421EUF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3421EUF#PBF 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#PBF meets industry standards.
7.What is the process for return or replacement of LTC3421EUF#PBF?
All LTC3421EUF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3421EUF#PBF, 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#PBF part is unused and in its original packaging.
Return procedure for LTC3421EUF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3421EUF#PBF 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…
