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Analog Devices Inc. LTC3251EMSE#PBF
- Part No.:
- LTC3251EMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3251EMSE#PBF.pdf
- Description:
- IC REG CHG PUMP ADJ 500MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:538
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Product details
Overview
LTC3251EMSE#PBF from Analog Devices (formerly Linear Technology) is a 2-phase, spread spectrum charge pump step-down DC/DC converter delivering up to 500mA at fixed 1.5V output from 2.7V–5.5V input, with no inductor required. It achieves twice the efficiency of LDOs, operates in Super Burst mode with 10µA quiescent current, and features short-circuit and overtemperature protection - ideal for space-constrained, battery-powered handheld devices.
For engineers reviewing the LTC3251EMSE#PBF datasheet, LTC3251EMSE#PBF pinout, LTC3251EMSE#PBF application, or LTC3251EMSE#PBF equivalent, key selection considerations include its 10-pin MSOP package with exposed GND pad, 2-phase spread spectrum architecture for ultra-low EMI, programmable operating modes (Shutdown, Continuous Spread Spectrum, Burst, Super Burst), and precise 1.44V–1.56V output regulation under 500mA load at VIN ≥ 3.5V.
Technical Context
The LTC3251EMSE#PBF implements dual-phase switched-capacitor fractional conversion: two interleaved charge pumps operate 180° out-of-phase to deliver continuous current transfer, minimizing input/output ripple and enabling high efficiency without magnetics. Its spread spectrum oscillator sweeps switching frequency between 0.7MHz and 2MHz (typical 1.0–1.6MHz), reducing peak EMI by >20dBm versus fixed-frequency converters.
Regulation is achieved via internal error amplifier comparing FB voltage (0.78–0.82V) against a precision reference; for fixed-output variants like LTC3251EMSE#PBF, feedback is internal and MODE pin disables spread spectrum. Operating mode is selected via CMOS-compatible MD0/MD1 pins with defined thresholds (0.4–0.8V low, 0.8–1.2V high), supporting shutdown (00), Burst (01), Continuous Spread Spectrum (10), and Super Burst (11).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.5V ±3% (1.44V–1.56V) across 0–500mA load and 3.5V–5.5V input; enables direct replacement of 1.5V LDOs with higher efficiency. |
| Input Voltage Range | 2.7V–5.5V - supports single-cell Li-ion (2.7–4.2V) and triple-cell NiMH (3.0–4.5V) battery inputs without external regulators. |
| Max Output Current | 500mA in Continuous or Burst Mode; limited to 40mA in Super Burst Mode - balances runtime vs. transient response for portable systems. |
| Quiescent Current | 10µA in Super Burst Mode, 35µA in Burst Mode, 3–5mA in Continuous Mode - extends battery life in always-on sensor nodes. |
| Switching Frequency | Spread spectrum range 0.7–2MHz (typ 1.0–1.6MHz); fixed 1.3–2MHz when spread spectrum disabled - avoids narrowband EMI compliance failures. |
| Thermal Protection | Auto-shutdown at ~160°C junction, restart at ~150°C - prevents permanent damage during sustained overload or poor PCB thermal design. |
| Package | 10-pin MSOP with exposed GND pad (Pin 11), θJA = 40°C/W - requires soldered thermal pad for full 500mA capability and safe operation at 85°C ambient. |
Pinout & Package
Package: 10-lead plastic MSOP (MSE) with thermally enhanced exposed GND pad (Pin 11), JEDEC MO-187 variant. Requires PCB land pattern per Analog Devices layout guidelines, including soldered GND pad for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (MD0) | Mode Control Input | CMOS logic input; sets operating mode with MD1 (00=Shutdown, 01=Burst, 10=Continuous Spread Spectrum, 11=Super Burst). |
| Pin 2 (VIN) | Main Power Input | 2.7V–5.5V supply input; must be bypassed with ≥1µF ceramic capacitor to GND to suppress high-frequency transients. |
| Pin 3 (C1+) | Flying Capacitor 1 Anode | Connects to positive terminal of 1µF flying capacitor C1; experiences high dv/dt - keep trace short and shielded from sensitive nodes. |
| Pin 4 (C1−) | Flying Capacitor 1 Cathode | Connects to negative terminal of C1; forms first phase of dual charge pump; polarity reversal possible - use non-polar ceramic only. |
| Pin 5 & Pin 11 (GND) | Power Ground | Common return for VIN, VOUT, and flying capacitors; Pin 11 is exposed thermal pad - must be soldered to solid ground plane. |
| Pin 6 (C2−) | Flying Capacitor 2 Cathode | Connects to negative terminal of second 1µF flying capacitor C2; interleaved with C1 to cancel input/output ripple. |
| Pin 7 (VOUT) | Regulated Output | 1.5V output capable of 500mA; disconnected from VIN during shutdown; requires ≥10µF low-ESR (<0.08Ω) ceramic capacitor. |
| Pin 8 (C2+) | Flying Capacitor 2 Anode | Connects to positive terminal of C2; completes second phase of charge pump; same layout constraints as C1+. |
| Pin 9 (MD1) | Mode Control Input | CMOS logic input paired with MD0; threshold 0.4–0.8V (low), 0.8–1.2V (high); floating state prohibited - tie to VIN or GND. |
| Pin 10 (MODE) | Spread Spectrum Enable | On LTC3251-1.5 variants: low = spread spectrum enabled (reduced EMI), high = fixed 1.6MHz operation; no effect in Super Burst mode. |
Key Features
| Feature | Design Value |
|---|---|
| Inductorless Architecture | Eliminates magnetic components and associated EMI, board area, and cost - enables ultra-thin portable designs with <1mm profile. |
| 2-Phase Spread Spectrum | Reduces peak input/output noise by >20dBm versus fixed-frequency converters, easing EMC certification for handheld radios and wearables. |
| Super Burst Mode | Draws only 10µA supply current while sustaining 40mA output - extends shelf life and standby time in IoT endpoint devices. |
| Soft-Start Circuitry | Linearly ramps output current over ~500µs at turn-on - prevents inrush into large output capacitors and avoids system brownouts. |
| Integrated Protection | Short-circuit current limit (~800mA) and thermal shutdown (160°C) prevent field failures without external circuitry - improves BOM reliability. |
Applications
| Handheld Medical Sensors | Wearable Fitness Trackers |
|---|---|
|
Use Scenario: Compact pulse oximeter using single-cell Li-ion battery requiring stable 1.5V rail for analog front-end and BLE radio. IC Role / Device Role / Timing Role: Primary 1.5V power supply replacing inefficient LDO; delivers 300mA with <15mV ripple in Burst Mode during active sensing. Use Value: Doubles battery runtime versus LDO solution and eliminates inductor-induced EMI that corrupts weak optical signals. |
Use Scenario: Always-on heart rate monitor with motion sensors and Bluetooth Low Energy, powered by coin cell or micro-LiPo. IC Role / Device Role / Timing Role: Ultra-low-quiescent 1.5V regulator operating in Super Burst Mode (10µA IQ) during sleep, waking on motion interrupt. Use Value: Enables multi-week operation on 30mAh battery by minimizing idle current while maintaining fast wake-up (<1ms) from shutdown. |
| Industrial Handheld Scanners | Portable Audio DAC Supplies |
|
Use Scenario: Rugged barcode scanner with laser diode driver and ARM Cortex-M4 MCU, powered by 3.7V Li-ion pack. IC Role / Device Role / Timing Role: High-current 1.5V supply for laser driver bias and ADC reference, operating in Continuous Spread Spectrum mode. Use Value: Delivers clean 500mA with <35mV ripple and passes CISPR-22 Class B emissions without shielding or ferrites. |
Use Scenario: Portable USB-C DAC with ESS Sabre DAC requiring ultra-low-noise 1.5V analog supply independent of noisy digital rails. IC Role / Device Role / Timing Role: Dedicated low-EMI 1.5V analog supply; spread spectrum disabled (fixed 1.6MHz) to avoid beat frequencies with DAC clock. Use Value: Provides 1.5V rail with <10mV RMS noise (measured 10Hz–100kHz), improving DAC SNR by 3dB versus standard charge pumps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down charge pump applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX8815AETE+T | Fixed 1.5V output, 400mA max, 2.5V–5.5V input, 25µA Burst IQ, no Super Burst mode | Lacks Super Burst mode and spread spectrum; higher IQ limits ultra-low-power use cases | Select when lower cost and simpler mode control outweigh need for 10µA IQ or EMI reduction |
| TPS60403DBVR | Adjustable 1.5–5V output, 60mA max, 1.6–5.5V input, 120µA IQ, no spread spectrum | Lower current rating and no EMI-reduction features; requires external resistors for 1.5V setting | Choose for low-cost, low-current applications where board space allows discrete feedback network |
Compared with MAX8815AETE+T and TPS60403DBVR, the LTC3251EMSE#PBF uniquely combines 500mA capability, 10µA Super Burst IQ, and 2-phase spread spectrum - making it the only option meeting stringent EMI and battery-life requirements in premium portable medical and audio devices.
Availability
LTC3251EMSE#PBF is available at Aetrix Electronics and suitable for handheld medical sensors, wearable fitness trackers, industrial handheld scanners, and portable audio DAC supplies requiring stable component supply, long-term lifecycle support, and guaranteed authentic sourcing.
Supply support for LTC3251EMSE#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.
The LTC3251EMSE#PBF belongs to ADI's legacy Linear Technology µPower DC/DC converter family, engineered specifically for ultra-low-noise, inductorless power in space- and battery-constrained portable electronics.
FAQ
What is the output voltage tolerance of the LTC3251EMSE#PBF under full load?
The LTC3251EMSE#PBF delivers a fixed 1.5V output with guaranteed regulation of ±3% (1.44V to 1.56V) across 0–500mA load current and 3.5V–5.5V input voltage, as specified in the Electrical Characteristics table under "VOUT Regulation Voltage (LTC3251-1.5)" with continuous or burst mode operation.
Can the LTC3251EMSE#PBF be used with a single-cell Li-ion battery?
Yes, the LTC3251EMSE#PBF supports input voltages from 2.7V to 5.5V, fully covering the discharge range of a single-cell Li-ion battery (2.7V–4.2V). Its minimum input requirement for 1.5V/500mA operation is VIN ≥ 3.5V per datasheet Note 4, making it compatible with Li-ion above ~30% state-of-charge.
How does the MODE pin function on the LTC3251EMSE#PBF?
On the LTC3251EMSE#PBF (a -1.5V fixed-output variant), the MODE pin enables or disables spread spectrum operation: logic low (≤30% VIN) enables random-frequency switching for low EMI; logic high (≥50% VIN) forces fixed 1.3–2MHz operation. MODE has no effect in Super Burst mode.
What is the recommended output capacitor for the LTC3251EMSE#PBF?
The LTC3251EMSE#PBF requires a minimum 10µF ceramic output capacitor with ESR ≤ 0.08Ω (e.g., X5R/X7R 1206 case). Lower ESR reduces output ripple and improves stability; tantalum or aluminum electrolytics are not recommended due to high ESR and instability risk.
Does the LTC3251EMSE#PBF require external feedback resistors?
No, the LTC3251EMSE#PBF is the fixed 1.5V output variant; internal feedback eliminates the need for external resistors. The FB pin (Pin 10) is unused on this version - unlike the adjustable LTC3251, which uses FB for resistor-divider programming.
LTC3251EMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Charge Pump
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.9V
- Voltage - Output (Max):
- 1.6V
- Current - Output:
- 500mA
- Frequency - Switching:
- 1MHz ~ 1.6MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LTC3251EMSE#PBF FAQ
1.How can I place an order for LTC3251EMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3251EMSE#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 LTC3251EMSE#PBF reliable?
The price and inventory of LTC3251EMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3251EMSE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3251EMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3251EMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3251EMSE#PBF?
LTC3251EMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3251EMSE#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 LTC3251EMSE#PBF?
For technical support, including LTC3251EMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3251EMSE#PBF requirements.
6.How does Aetrix verify that LTC3251EMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3251EMSE#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 LTC3251EMSE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3251EMSE#PBF?
All LTC3251EMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3251EMSE#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 LTC3251EMSE#PBF part is unused and in its original packaging.
Return procedure for LTC3251EMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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