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Analog Devices Inc. LTC3129IUD#PBF
- Part No.:
- LTC3129IUD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LTC3129IUD#PBF.pdf
- Description:
- IC REG BUCK BST ADJ 200MA 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:7,552
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Product details
Overview
LTC3129IUD#PBF from Analog Devices (formerly Linear Technology) is a monolithic synchronous buck-boost DC/DC converter optimized for ultra-low-power energy harvesting systems. It delivers up to 200mA output current, operates across 1.92V–15V input and 1.4V–15.75V output ranges, features 1.3µA Burst Mode quiescent current, and integrates programmable maximum power point control (MPPC) for photovoltaic or thermoelectric sources. It is used in wireless sensor nodes where input voltage may fall below, exceed, or equal the regulated output.
For engineers reviewing the LTC3129IUD#PBF datasheet, LTC3129IUD#PBF pinout, LTC3129IUD#PBF application, or LTC3129IUD#PBF equivalent, key selection criteria include its 1.2MHz fixed-frequency PWM architecture, accurate RUN pin threshold (1.22V typ), 10nA shutdown current, thermal shutdown protection, and compatibility with single-inductor buck-boost topologies requiring minimal external components.
Technical Context
The LTC3129IUD#PBF employs average current mode control with an internally compensated transconductance error amplifier and proprietary switch sequencing to enable seamless transitions between buck, boost, and pass-through modes-eliminating sub-harmonic oscillation and output transients. Its 1.2MHz oscillator enables use of compact 10µH inductors and ceramic capacitors while maintaining high efficiency across wide VIN/VOUT ratios.
It integrates dual bootstrapped gate drivers (BST1/BST2), a 4.1V internal LDO for VCC generation, and dedicated MPPC and RUN comparators with hysteresis. The device supports user-selectable Burst Mode® (via PWM pin) for ultra-low IQ, and includes a power-good (PGOOD) open-drain indicator referenced to the FB-set output voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 1.92V–15V after startup; 2.42V min for initial turn-on - supports direct connection to partially discharged batteries or low-voltage harvesters. |
| VOUT Range | 1.4V–15.75V via external FB divider - enables regulation above, below, or equal to VIN without topology change. |
| Max Output Current | 200mA in buck mode (VIN > VOUT); reduced in boost due to duty-cycle and RDS(ON) losses - sufficient for RF transceivers and microcontrollers. |
| Quiescent Current | 1.3µA in Burst Mode - extends battery or harvester lifetime in intermittently active IoT endpoints. |
| Switching Frequency | 1.2MHz (typ), ±20% - balances EMI, inductor size (10µH typical), and efficiency across load range. |
| MPPC Input Voltage | 1.175V (typ) reference - sets VIN regulation point for maximum power extraction from PV cells or TEGs. |
| Shutdown Current | <10nA - ensures near-zero drain during system sleep, critical for multi-year battery operation. |
Pinout & Package
Package: 16-lead (3mm × 3mm) plastic QFN with exposed PGND pad (Pin 17). Thermally enhanced for 125°C junction operation; exposed pad must be soldered to PCB ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BST1 (Pin 1) | Bootstrap supply for SW1 high-side driver | Connects via 22nF capacitor to SW1; enables NMOS gate drive above VIN - essential for buck operation. |
| VIN (Pin 2) | Main input supply rail | Accepts 1.92V–15V; requires ≥4.7µF local ceramic decoupling - powers internal circuitry and switches. |
| VCC (Pin 3) | Internal LDO output (4.1V typ) | Supplies internal logic and gate drivers; can be back-driven up to 5.5V - allows hybrid power architectures. |
| RUN (Pin 4) | Enable comparator input | Turns on VCC at 0.9V (typ), enables switching at 1.22V (typ) with 80mV hysteresis - enables precise input UVLO programming. |
| MPPC (Pin 5) | Maximum Power Point Control reference | Programs VIN regulation point (VIN = 1.175V × [1+R5/R6]) - maximizes power from non-ideal sources like solar cells. |
| GND (Pin 6) | Signal ground reference | Low-impedance return for FB, RUN, PWM; must be shorted to PGND plane to minimize noise coupling. |
| FB (Pin 7) | Feedback input to error amplifier | Senses VOUT via resistor divider; 1.175V (typ) reference sets output voltage - determines regulation accuracy and stability. |
| PWM (Pin 10) | Mode select control | Low = Burst Mode (1.3µA IQ); High = fixed 1.2MHz PWM - selects trade-off between efficiency and output ripple. |
| PGOOD (Pin 11) | Open-drain power-good indicator | Pulls low when VOUT falls >7.5% below setpoint - provides system-level fault signaling without additional ICs. |
| VOUT (Pin 12) | Regulated output voltage | Delivers up to 200mA; requires ≥4.7µF local ceramic capacitance - serves as main supply for downstream loads. |
| BST2 (Pin 13) | Bootstrap supply for SW2 high-side driver | Connects via 22nF capacitor to SW2; enables NMOS gate drive above VOUT - essential for boost operation. |
| SW2 (Pin 14) | Boost-mode switch node | Connects to one end of inductor; high dV/dt node - requires short, wide PCB trace to minimize EMI and losses. |
| PGND (Pin 15 & Exposed Pad 17) | Power ground return | Carries high-switching currents; exposed pad is mandatory thermal path - must be fully soldered to inner ground plane. |
| SW1 (Pin 16) | Buck-mode switch node | Connects to other end of inductor; high dV/dt node - same layout rules as SW2 for EMI control. |
Key Features
| Feature | Design Value |
|---|---|
| Single-inductor buck-boost topology | Eliminates need for separate buck/boost converters or complex transformer-based solutions - reduces BOM count and board area by >30%. |
| Programmable MPPC with 1.175V reference | Enables direct interface to photovoltaic panels or thermoelectric generators without external op-amps or ADCs - simplifies harvester front-end design. |
| Accurate RUN pin with 80mV hysteresis | Allows precise, stable startup/shutdown thresholds (e.g., 2.5V battery cutoff) - prevents brownout oscillation in marginal input conditions. |
| 1.2MHz fixed-frequency PWM + Burst Mode | Provides low-noise continuous switching or ultra-efficient light-load operation - selectable per application noise/efficiency requirements. |
| Integrated soft-start and loop compensation | Removes need for external compensation networks or timing capacitors - accelerates design cycle and improves production yield. |
| Thermally enhanced 3mm × 3mm QFN | θJA = 68°C/W (with proper pad soldering) - sustains 200mA output at 125°C ambient without derating in compact layouts. |
Applications
| Industrial Wireless Sensor Nodes | Solar Panel Post-Regulator/Charger |
|---|---|
|
Use Scenario: Batteryless temperature/humidity node powered by indoor light-harvesting PV cell. IC Role / Device Role / Timing Role: Primary DC/DC regulator that accepts 1.8–5V variable PV output and delivers stable 3.3V to MCU and BLE radio. Use Value: 1.3µA Burst Mode IQ and MPPC extend operational uptime under low-light conditions; seamless buck-boost avoids dead zones during dawn/dusk transitions. |
Use Scenario: Outdoor IoT gateway using small monocrystalline panel (VOC ≈ 8V) to charge Li-ion battery and power SoC. IC Role / Device Role / Timing Role: Energy-harvesting front-end that regulates panel output to constant 4.2V for battery charging IC. Use Value: Programmable MPPC tracks panel's IV curve to extract >95% of available power; 15V absolute max rating tolerates panel open-circuit voltage spikes. |
| Post-Regulator for Harvested Energy | Intrinsically Safe Power Supplies |
|
Use Scenario: Vibration-powered wireless transmitter in hazardous oil/gas facility, using piezoelectric harvester. IC Role / Device Role / Timing Role: Interface IC that conditions irregular AC from harvester into clean, regulated DC for ultra-low-power transceiver. Use Value: Wide 1.92V–15V input range accepts rectified AC peaks; 10nA shutdown current prevents leakage drain during idle periods. |
Use Scenario: Loop-powered field instrument in Zone 0/1 explosive atmosphere requiring <100mW total power budget. IC Role / Device Role / Timing Role: Isolated secondary-side regulator deriving 3.3V from 4–20mA loop supply via energy storage capacitor. Use Value: 1.3µA IQ and 10nA shutdown ensure compliance with IEC 60079-11 intrinsic safety limits; thermal shutdown prevents fault-induced ignition risk. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS63020DSJR | Higher 3A output capability; 2.5µA IQ; no integrated MPPC; 2.5V–12V input range | Better suited for higher-current portable devices; lacks native solar MPPT functionality | Select when >200mA load current or lower-cost industrial design is required; add external MPPT if needed. |
| LTC3129-1IUD#PBF | Fixed-output variants (e.g., 3.3V, 5V); eliminates FB divider; identical MPPC, RUN, and quiescent specs | Reduces component count in cost-sensitive, fixed-VOUT designs; no output adjustability | Select when output voltage is fixed and board space is constrained - saves two resistors and routing. |
Compared with TPS63020DSJR, the LTC3129IUD#PBF offers superior ultra-low-power performance and built-in MPPC for energy harvesting, while LTC3129-1IUD#PBF trades flexibility for simplicity in fixed-output deployments - both alternatives require layout review due to differing pinouts and thermal footprints.
Availability
LTC3129IUD#PBF is available at Aetrix Electronics and suitable for industrial wireless sensor nodes, solar panel post-regulators, and intrinsically safe power supplies requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC3129IUD#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 (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, industrial automation, and energy harvesting markets.
The LTC3129 product line was designed specifically for ultra-low-power, wide-input-range DC/DC conversion in energy-constrained environments - emphasizing micropower operation, MPPC integration, and robustness in intermittent power source applications.
FAQ
What is the minimum input voltage required to start up the LTC3129IUD#PBF?
The LTC3129IUD#PBF requires a minimum VIN of 2.42V (typical) to initiate startup. Once operating, it sustains regulation down to 1.92V (after bootstrapping), enabling use with partially discharged batteries or low-output harvesters. This dual-threshold behavior is enforced by internal UVLO circuitry with 100mV hysteresis.
How does the MPPC function work in the LTC3129IUD#PBF?
The MPPC pin on the LTC3129IUD#PBF references an internal 1.175V threshold. When connected to a resistor divider from VIN to GND, it regulates VIN to VIN = 1.175V × (1 + Rtop/Rbottom). This servo action maximizes power extraction from non-ideal sources like solar cells by holding them at their peak power point voltage.
Can the LTC3129IUD#PBF operate with input voltage equal to output voltage?
Yes, the LTC3129IUD#PBF supports pass-through operation where VIN ≈ VOUT. Its proprietary four-switch buck-boost architecture enables seamless transitions between buck, boost, and 1:1 modes without output glitches or discontinuities - critical for stable powering of MCUs during battery voltage decay.
What is the purpose of the BST1 and BST2 pins on the LTC3129IUD#PBF?
BST1 and BST2 are bootstrap supplies for the high-side NMOS gate drivers controlling SW1 and SW2, respectively. Each requires a 22nF capacitor connected between the pin and its corresponding switch node. They enable efficient gate drive above VIN (BST1) or VOUT (BST2), essential for low RDS(ON) conduction in buck and boost phases.
Does the LTC3129IUD#PBF require external compensation components?
No, the LTC3129IUD#PBF integrates full loop compensation for its average current mode control architecture. No external capacitors or resistors are needed for stability - only standard input/output ceramic capacitors and a single inductor are required, reducing design complexity and bill-of-materials cost.
LTC3129IUD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.92V
- Voltage - Input (Max):
- 15V
- Voltage - Output (Min/Fixed):
- 1.4V
- Voltage - Output (Max):
- 15.75V
- Current - Output:
- 200mA
- Frequency - Switching:
- 1.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN (3x3)
LTC3129IUD#PBF FAQ
1.How can I place an order for LTC3129IUD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3129IUD#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 LTC3129IUD#PBF reliable?
The price and inventory of LTC3129IUD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3129IUD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3129IUD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3129IUD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3129IUD#PBF?
LTC3129IUD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3129IUD#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 LTC3129IUD#PBF?
For technical support, including LTC3129IUD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3129IUD#PBF requirements.
6.How does Aetrix verify that LTC3129IUD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3129IUD#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 LTC3129IUD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3129IUD#PBF?
All LTC3129IUD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3129IUD#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 LTC3129IUD#PBF part is unused and in its original packaging.
Return procedure for LTC3129IUD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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