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Analog Devices Inc. LTC1871EMS#PBF
- Part No.:
- LTC1871EMS#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LTC1871EMS#PBF.pdf
- Description:
- IC REG CTRLR MULT TOP 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:446
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Product details
Overview
LTC1871EMS#PBF from Analog Devices (formerly Linear Technology) is a wide-input, current-mode DC/DC controller for boost, flyback, and SEPIC topologies, driving an external N-channel MOSFET without requiring a sense resistor. It operates from 2.5V to 36V input, delivers up to 92% duty cycle, supports 50kHz–1MHz programmable frequency, and features Burst Mode operation for <10μA shutdown current-ideal for battery-powered telecom and portable equipment.
For engineers reviewing the LTC1871EMS#PBF datasheet, LTC1871EMS#PBF pinout, LTC1871EMS#PBF application, or LTC1871EMS#PBF equivalent, key selection criteria include no-RSENSE operation via MOSFET RDS(ON) sensing, ±2% RUN threshold with 100mV hysteresis, 1.230V internal reference accuracy, INTVCC LDO output at 5.2V, and MODE/SYNC pin support for burst/continuous/synchronized modes.
Technical Context
The LTC1871EMS#PBF implements a constant-frequency, current-mode control architecture with slope compensation, where peak inductor current is sensed either across the MOSFET's RDS(ON) (for VSW ≤ 36V) or via an external source-resistor (for higher output voltages). Its error amplifier drives the ITH pin (0.3V–1.4V range) to set the current comparator threshold, enabling fast transient response and stable regulation.
Operation is managed by a PWM latch reset by the current comparator, with startup controlled by a micropower RUN pin comparator (1.248V falling threshold, 100mV hysteresis) and protection provided by FB overvoltage lockout (6.5% above 1.230V). The internal 5.2V LDO powers gate drive and logic, delivering up to 50mA with 280mV dropout at 20mA load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 36V - supports single-cell Li-ion up to 24V industrial rails without external regulators. |
| Output Topologies | Boost, flyback, SEPIC - enables flexible power architecture selection without changing controller IC. |
| Max Duty Cycle | 92% typical - allows high step-up ratios (e.g., 3.3V → 12V) in continuous conduction mode. |
| Frequency Range | 50kHz to 1MHz - set by single RT resistor; synchronization up to 1.3× fOSC reduces EMI through clock alignment. |
| Shutdown IQ | 10μA typical - enables multi-year battery life in always-on IoT sensor nodes. |
| Reference Voltage | 1.230V ±1% - ensures ±1.2% output voltage accuracy with standard 1% feedback resistors. |
| SENSE Threshold | 150mV typical - sets current limit when sensing via MOSFET RDS(ON); adjustable via external resistor for >36V outputs. |
| INTVCC Output | 5.2V ±0.2V - powers gate driver and internal logic; requires ≥4.7μF local ceramic/tantalum bypass. |
Pinout & Package
Package: 10-lead MSOP (3mm × 3mm), exposed pad, rated for –40°C to +85°C (E-grade).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN (1) | Enable/shutdown threshold input | 1.248V falling threshold with 100mV hysteresis; enables precise brown-in/brown-out control without external circuitry. |
| ITH (2) | Error amplifier output / current limit setpoint | 0.3V–1.4V analog control of peak switch current; used for loop compensation and soft-start. |
| FB (3) | Feedback input | Compares output divider voltage to 1.230V reference; triggers overvoltage lockout at +6.5% deviation. |
| FREQ (4) | Oscillator programming node | 0.62V nominal; RT-to-ground sets frequency from 50kHz–1MHz with ±10% tolerance. |
| MODE/SYNC (5) | Mode selection & clock sync input | Pull-down = Burst Mode; >2V DC = pulse-skip; external clock = synchronized operation up to 1.3× fOSC. |
| GND (6) | Power and signal ground reference | Common return for all internal circuits; must be low-impedance connection to minimize noise coupling. |
| GATE (7) | N-channel MOSFET gate driver output | Capable of driving QG up to 37nC at 300kHz; rise/fall times <100ns into 3300pF load. |
| INTVCC (8) | Internal 5.2V LDO output | Supplies gate driver and logic; bypass with ≥4.7μF capacitor; short to VIN only if VIN ≤ 7V. |
| VIN (9) | Main supply input | Accepts 2.5V–36V; powers internal bias circuits and supplies current to INTVCC LDO. |
| SENSE (10) | Current sense input | Accepts VDS of power MOSFET (max 36V) or source-shunt resistor; includes leading-edge blanking. |
Key Features
| Feature | Design Value |
|---|---|
| No RSENSE operation | Uses MOSFET RDS(ON) for current sensing - eliminates 5–15% power loss and PCB area of discrete shunt. |
| Burst Mode efficiency | Reduces quiescent current to 250μA at light loads - extends battery runtime in standby states. |
| Programmable frequency | Single RT resistor sets 50kHz–1MHz range - balances switching loss vs. magnetics size for each design. |
| Overvoltage protection | FB pin lockout at +6.5% deviation - prevents damage to downstream 5V/3.3V logic during regulation failure. |
| Wide temperature grade | E-grade (–40°C to +85°C) - qualified for commercial and industrial portable equipment environments. |
| Low dropout INTVCC | 280mV dropout at 20mA - maintains gate drive strength even as input drops near 5V. |
Applications
| Telecom Power Supplies | Portable Electronic Equipment |
|---|---|
Use Scenario: 48V telecom line card with 3.3V/5V point-of-load conversion requiring high reliability and low standby loss. IC Role / Device Role / Timing Role: Current-mode controller managing boost converter with synchronous rectification and remote sensing. Use Value: No-RSENSE operation improves full-load efficiency by 2–3% versus resistor-based controllers; Burst Mode cuts idle power to <1mW. | Use Scenario: USB-C powered portable monitor with variable input (5V–20V) and regulated 12V backlight supply. IC Role / Device Role / Timing Role: SEPIC controller enabling buck-boost operation across entire USB PD voltage range. Use Value: 92% max duty cycle and 2.5V minimum start-up allow operation down to single-cell Li-ion (2.7V); 10μA shutdown preserves battery charge during sleep. |
| Industrial Sensors | Medical Handheld Devices |
Use Scenario: Battery-operated wireless vibration sensor node with 10-year lifetime target and intermittent RF transmission. IC Role / Device Role / Timing Role: Boost controller powering 3.3V microcontroller and 2.5V ADC from 2xAA alkaline (1.8V–3.2V). Use Value: 2.5V minimum input and 10μA shutdown enable full utilization of battery capacity; RUN pin hysteresis prevents oscillation near end-of-life voltage. | Use Scenario: Portable ultrasound probe requiring clean 5V rail for analog front-end and low-noise 1.8V for FPGA core. IC Role / Device Role / Timing Role: Flyback controller generating isolated 5V/1.8V outputs from 7.4V Li-Po pack. Use Value: Synchronization capability (via MODE/SYNC) aligns switching to system clock - reducing beat frequencies in sensitive analog signal paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3757EMS#PBF | Higher input range (4.5V–100V), integrated high-side gate driver, no internal LDO; requires external bias supply. | Targeted at high-voltage industrial flyback/boost; lacks no-RSENSE feature and Burst Mode. | Select LT3757EMS#PBF only for >40V input applications where LTC1871EMS#PBF's 36V SENSE limit is exceeded. |
| TPS40210DRCT | Fixed 1.25V reference, no internal LDO, requires external VDD bias; lower max duty cycle (85%). | Designed for cost-sensitive consumer boost converters; no RUN pin hysteresis or FB overvoltage lockout. | Choose TPS40210DRCT for non-critical, low-cost designs where 10μA shutdown and ±1% reference are not required. |
Compared with LT3757EMS#PBF and TPS40210DRCT, the LTC1871EMS#PBF uniquely combines no-RSENSE operation, 2.5V start-up, integrated 5.2V LDO, and programmable Burst Mode - making it optimal for compact, battery-efficient boost/SEPIC systems below 36V output.
Availability
LTC1871EMS#PBF is available at Aetrix Electronics and suitable for telecom power supplies, portable electronic equipment, industrial sensors, medical handheld devices, and battery-backed instrumentation requiring stable component supply across extended production lifecycles.
Supply support for LTC1871EMS#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 semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC1871EMS#PBF belongs to ADI's legacy Linear Technology power management portfolio, designed specifically for high-efficiency, low-quiescent-current DC/DC controllers in space-constrained, battery-sensitive applications.
FAQ
What is the minimum input voltage required for LTC1871EMS#PBF to start switching?
The LTC1871EMS#PBF has a guaranteed minimum operating input voltage of 2.5V. Startup occurs when the RUN pin voltage exceeds its rising threshold of 1.348V, which corresponds to VIN ≥ 2.5V with appropriate resistor divider scaling. Below this, the IC remains in shutdown with 10μA quiescent current. This enables direct operation from single-cell Li-ion or two alkaline cells.
Can LTC1871EMS#PBF be used in flyback topology with primary-side sensing?
Yes, the LTC1871EMS#PBF supports flyback operation using primary-side sensing by connecting the SENSE pin to the drain of the primary MOSFET. It provides internal leading-edge blanking and current-mode control optimized for discontinuous conduction mode (DCM) flyback. For secondary-side regulation, an optocoupler feedback path to the FB pin is required, as documented in Linear's Application Note 105.
Does LTC1871EMS#PBF require an external bootstrap capacitor?
No, the LTC1871EMS#PBF does not require an external bootstrap capacitor. Its GATE driver is directly powered by the internal 5.2V INTVCC LDO, which is supplied from VIN. A minimum 4.7μF ceramic or tantalum capacitor must be placed between INTVCC and GND to handle gate drive transients - but no floating bootstrap node or capacitor is needed.
How is output voltage accuracy affected by FB pin current in LTC1871EMS#PBF designs?
The FB pin draws only 18–60nA, so with standard 1% feedback resistors (e.g., R1 = 12.1kΩ, R2 = 37.4kΩ), the resulting voltage divider error is <0.05%. This ensures the 1.230V ±1% internal reference dominates overall output accuracy. To maintain ±1.2% total output tolerance, use ≤1% resistors and keep trace impedance low at the FB node.
What happens to LTC1871EMS#PBF when the MODE/SYNC pin is left unconnected?
When the MODE/SYNC pin is left unconnected, its internal 50kΩ pull-down resistor pulls it to ground, enabling Burst Mode operation. In this mode, the controller cycles between short bursts of switching and extended sleep periods at light loads, reducing quiescent current to 250μA and improving light-load efficiency - a key feature of the LTC1871EMS#PBF for battery longevity.
LTC1871EMS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Boost, Flyback, SEPIC
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 2.5V ~ 36V
- Frequency - Switching:
- 50kHz ~ 1MHz
- Duty Cycle (Max):
- 92%
- Synchronous Rectifier:
- No
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP
LTC1871EMS#PBF FAQ
1.How can I place an order for LTC1871EMS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1871EMS#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 LTC1871EMS#PBF reliable?
The price and inventory of LTC1871EMS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1871EMS#PBF is usually 5 days.
3.What payment methods are accepted for LTC1871EMS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1871EMS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1871EMS#PBF?
LTC1871EMS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1871EMS#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 LTC1871EMS#PBF?
For technical support, including LTC1871EMS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1871EMS#PBF requirements.
6.How does Aetrix verify that LTC1871EMS#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1871EMS#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 LTC1871EMS#PBF meets industry standards.
7.What is the process for return or replacement of LTC1871EMS#PBF?
All LTC1871EMS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1871EMS#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 LTC1871EMS#PBF part is unused and in its original packaging.
Return procedure for LTC1871EMS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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