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Analog Devices Inc. LTC3125EDCB#TRPBF
- Part No.:
- LTC3125EDCB#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LTC3125EDCB#TRPBF.pdf
- Description:
- IC REG BOOST ADJ 1.2A 8DFN
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LTC3125EDCB#TRPBF from Analog Devices (formerly Linear Technology) is a synchronous step-up DC/DC converter with programmable average input current limit, designed for GSM/GPRS pulsed-load applications. It operates from 1.8V to 5.5V input, delivers up to 5.25V output, features 1.6MHz fixed-frequency switching, 1.2A peak switch current limit, and achieves up to 93% efficiency in compact portable power systems.
For engineers reviewing the LTC3125EDCB#TRPBF datasheet, LTC3125EDCB#TRPBF pinout, LTC3125EDCB#TRPBF application, or LTC3125EDCB#TRPBF equivalent, key selection criteria include input current limit accuracy (±5% at 500mA), output disconnect capability, Burst Mode® quiescent current (15μA), thermal shutdown behavior, and compatibility with low-ESR supercapacitor charging topologies.
Technical Context
The LTC3125EDCB#TRPBF uses current-mode PWM control with internal slope compensation and adaptive zero-current detection to maintain stability across wide load and input voltage ranges. Its lossless current sensing architecture enables precise average input current regulation via external PROG resistor feedback, independent of VIN/VOUT ratio.
It integrates dual MOSFETs - an N-channel main switch (RDS(ON) = 0.125Ω) and P-channel synchronous rectifier (RDS(ON) = 0.200Ω) - with anti-ringing control and soft-start circuitry. Output disconnect is implemented by disabling body diode conduction during shutdown, enabling true VOUT = 0V operation and inrush limiting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.8V to 5.5V - supports single-cell Li-ion, NiMH, and PCMCIA/CompactFlash bus inputs without external LDO pre-regulation. |
| Output Voltage Range | 2.0V to 5.25V - adjustable via FB resistive divider; enables direct 3.3V, 4.5V, or 5V rail generation for modems and radios. |
| Average Input Current Limit | 200mA to 1000mA - resistor-programmable with ±5% accuracy at 500mA; critical for staying within PC Card slot current limits. |
| Switching Frequency | 1.6MHz (typ) - enables use of small 2.2–4.7μH inductors and reduces solution footprint vs. lower-frequency boosters. |
| Peak Switch Current Limit | 1.2A (min), 1.8A (typ) - protects internal MOSFETs during GSM burst transients and short-circuit events. |
| Efficiency | Up to 93% - achieved via synchronous rectification and low RDS(ON) switches; minimizes thermal stress in space-constrained modules. |
| Quiescent Current (Burst Mode) | 15μA - extends battery life in standby mode while maintaining fast wake-up response for pulsed loads. |
| Shutdown Current | 0.01μA - ensures near-zero drain on reservoir capacitors during system sleep or transport. |
Pinout & Package
The LTC3125EDCB#TRPBF is housed in a thermally enhanced 8-lead (2mm × 3mm × 0.75mm) DFN package with exposed pad (Pin 9), which must be soldered to PCB ground for electrical continuity and thermal performance (θJA = 64°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1, Exposed Pad Pin 9) | Power and signal reference ground | Primary return path for all currents; exposed pad must be soldered to PCB ground plane for rated thermal performance and EMI suppression. |
| FB (Pin 2) | Feedback input to error amplifier | Senses output voltage via resistive divider; sets regulated VOUT from 2.0V to 5.25V; input bias current ≤50nA minimizes divider error. |
| PROG (Pin 3) | Average input current limit programming node | Sinks current proportional to sensed input current; external RPROG sets 200–1000mA limit range with ±5% accuracy at mid-scale. |
| VIN (Pin 4) | Main input supply connection | Accepts 1.8–5.5V; powers IC until VOUT > VIN + 0.25V, then auto-switches to VOUT for higher efficiency. |
| CS (Pin 5) | Current sense node | Connects directly to inductor; internal 60mΩ sense resistor between CS and VIN enables lossless input current monitoring. |
| SHDN (Pin 6) | Logic-controlled enable/disable input | Active-high (≥1V); pulls <0.35V to enter <1μA shutdown; tolerant of voltages above VIN/VOUT within absolute max ratings. |
| VOUT (Pin 7) | Regulated output and synchronous rectifier source | Provides regulated output; disconnects from VIN during shutdown via P-MOSFET gate control, preventing reverse current and enabling true 0V output. |
| SW (Pin 8) | Switch node | Drives external inductor; internal anti-ringing resistor suppresses high-frequency ringing during DCM operation to reduce EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable Average Input Current Limit | Enables compliance with PCMCIA/CompactFlash slot current limits (e.g., 500mA max) while supporting 2A GSM pulse bursts using reservoir capacitance. |
| Output Disconnect in Shutdown | Eliminates body diode conduction path, allowing VOUT to fully discharge and preventing backfeed into VIN - essential for safe hot-swap and multi-rail sequencing. |
| Burst Mode® Operation | Maintains 15μA quiescent current at light loads while preserving fixed-frequency PWM loop dynamics, avoiding output voltage transients during mode transitions. |
| Internal Current Sense Resistor | 60mΩ integrated sense element between CS and VIN removes need for external sense resistor, reducing BOM count, board area, and power loss. |
| Thermal Shutdown Protection | Activates at ~160°C junction temperature, disabling all switches and discharging soft-start capacitor; resumes operation after ~15°C cooldown. |
| Soft-Start Circuitry | Ramps peak inductor current from 0 to 1.8A over ~0.5ms, preventing inrush into large output capacitors and enabling reliable start-up under heavy pulsed loads. |
Applications
| GSM/GPRS PCMCIA Modem Power | Supercapacitor Charging |
|---|---|
Use Scenario: Powering a GSM/GPRS modem card inserted into a notebook PC's PCMCIA slot, where host bus supplies only 3.3V/500mA but modem requires 4.5V/2A pulsed bursts. IC Role / Device Role / Timing Role: Step-up converter with precise input current limiting and output disconnect, acting as a pulsed-load buffer between limited-source bus and high-demand RF module. Use Value: Enables direct interface without violating PCMCIA spec; maintains stable 4.5V output during 577μs/2A transmission bursts using 2200μF tantalum reservoir. | Use Scenario: Charging a 10F supercapacitor from a 3.3V Li-ion battery to power emergency locator beacon with 2.5V logic and 1A pulse capability. IC Role / Device Role / Timing Role: Constant-current/constant-voltage charger with programmable input current limit, regulating charge rate to avoid battery sag and ensure full capacitor utilization. Use Value: Delivers controlled 2.5V output with <1% ripple; supports >100,000 charge cycles; eliminates need for external current-sense amplifier or discrete FET controller. |
| Wireless Emergency Locator | Portable Radio Transceiver |
Use Scenario: Providing regulated 3.3V/500mA output from a 2.5–5V variable input (e.g., solar-charged battery) to power GPS + RF transmitter in remote asset tracker. IC Role / Device Role / Timing Role: Wide-input boost regulator with ultra-low quiescent current, managing intermittent energy harvesting and burst transmission duty cycles. Use Value: Achieves >90% efficiency at 100mA load; draws only 15μA in Burst Mode during GPS acquisition; supports cold-start from 1.8V battery depletion. | Use Scenario: Supplying 4.5V to a handheld UHF radio transceiver requiring 500mA continuous and 1.5A peak during TX, powered from two AA alkaline cells (1.8–3.2V). IC Role / Device Role / Timing Role: High-efficiency synchronous boost converter with thermal protection and short-circuit robustness for rugged field operation. Use Value: Sustains 4.5V output across full battery range; survives accidental antenna short; shuts down safely at 125°C junction temp without latch-up. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-up converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61200DRCT | Fixed 5V output; no programmable input current limit; 1.5A peak switch current; 3.3μA shutdown current. | Lacks precision input current regulation - unsuitable for PCMCIA-compliant GSM burst buffering. | Select only when fixed-output voltage and minimal quiescent current are prioritized over input current control. |
| MAX17062ETA+ | 2.5V–5.5V input; 2.5V–5.5V output; 1.2A peak current; includes I2C interface for dynamic current limit adjustment. | Requires digital configuration; larger 16-pin TQFN package; higher BOM complexity due to external MOSFETs. | Choose when programmability via I2C and wider output adjust range justify added design overhead and cost. |
Compared with TPS61200DRCT and MAX17062ETA+, the LTC3125EDCB#TRPBF uniquely combines resistor-programmable input current limiting, true output disconnect, and 1.6MHz operation in a 2mm × 3mm DFN - making it optimal for space-constrained, pulsed-load applications where bus compliance and low-noise shutdown are mandatory.
Availability
LTC3125EDCB#TRPBF is available at Aetrix Electronics and suitable for GSM/GPRS modem power, supercapacitor charging, and portable radio transceiver applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LTC3125EDCB#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 acquired Linear Technology in 2017 and maintains its legacy of high-performance analog and power management ICs with rigorous automotive and industrial qualification standards.
The LTC3125EDCB#TRPBF belongs to Linear's high-efficiency synchronous boost converter product line, engineered specifically for pulsed-load, power-limited environments such as wireless modems, emergency locators, and energy-harvesting systems.
FAQ
What is the minimum input voltage required for the LTC3125EDCB#TRPBF to start switching?
The LTC3125EDCB#TRPBF has a minimum start-up voltage of 1.6V (typical) and 1.8V (guaranteed). Below this threshold, the device remains in undervoltage lockout and will not initiate switching, even if SHDN is asserted. This ensures reliable cold-start capability from partially discharged batteries while preventing erratic operation near cutoff.
How does the LTC3125EDCB#TRPBF achieve output disconnect during shutdown?
The LTC3125EDCB#TRPBF achieves true output disconnect by actively controlling the gate of its internal P-channel synchronous rectifier to block body diode conduction. When SHDN is pulled low, the P-MOSFET is fully turned off, isolating VOUT from VIN and allowing VOUT to discharge to 0V without reverse current flow - a feature absent in most basic boost converters.
Can the LTC3125EDCB#TRPBF operate with VIN greater than VOUT?
Yes, the LTC3125EDCB#TRPBF supports VIN > VOUT operation - it regulates output voltage even when input exceeds the programmed VOUT. However, efficiency drops significantly and maximum output current capability is reduced; the device transitions to pass-through-like behavior with increased conduction losses in both MOSFETs.
What is the purpose of the CS pin on the LTC3125EDCB#TRPBF?
The CS pin on the LTC3125EDCB#TRPBF serves as the current sense node, directly connecting to the inductor. An internal 60mΩ resistor between CS and VIN enables lossless input current measurement - eliminating external sense resistors and associated power loss, while providing the signal for average input current regulation and peak current limiting.
Does the LTC3125EDCB#TRPBF require external compensation components?
No, the LTC3125EDCB#TRPBF features fully internal loop compensation optimized for stability with output capacitors ≥150μF and very low ESR - typical of tantalum and supercapacitor banks. No external compensation network is needed, simplifying design and reducing bill-of-materials for pulsed-load applications.
LTC3125EDCB#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN 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):
- 1.8V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2V
- Voltage - Output (Max):
- 5.25V
- Current - Output:
- 1.2A (Switch)
- Frequency - Switching:
- 1.6MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (2x3)
LTC3125EDCB#TRPBF FAQ
1.How can I place an order for LTC3125EDCB#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3125EDCB#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 LTC3125EDCB#TRPBF reliable?
The price and inventory of LTC3125EDCB#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3125EDCB#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3125EDCB#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3125EDCB#TRPBF transactions.
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4.How is shipping managed for LTC3125EDCB#TRPBF?
LTC3125EDCB#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3125EDCB#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 LTC3125EDCB#TRPBF?
For technical support, including LTC3125EDCB#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3125EDCB#TRPBF requirements.
6.How does Aetrix verify that LTC3125EDCB#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3125EDCB#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 LTC3125EDCB#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3125EDCB#TRPBF?
All LTC3125EDCB#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3125EDCB#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 LTC3125EDCB#TRPBF part is unused and in its original packaging.
Return procedure for LTC3125EDCB#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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