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Analog Devices Inc. LTC3858IGN-1#TRPBF
- Part No.:
- LTC3858IGN-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3858IGN-1#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,808
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Product details
Overview
LTC3858IGN-1#TRPBF from Analog Devices (formerly Linear Technology) is a dual-phase, synchronous step-down DC/DC controller IC driving two independent N-channel MOSFET stages. It delivers 0.8V–24V output voltage with 4V–38V input range, 170μA no-load quiescent current, and out-of-phase operation to reduce input ripple. Used in battery-powered digital systems requiring high-efficiency dual-rail power conversion.
For engineers reviewing the LTC3858IGN-1#TRPBF datasheet, LTC3858IGN-1#TRPBF pinout, LTC3858IGN-1#TRPBF application, or LTC3858IGN-1#TRPBF equivalent, key selection criteria include phase-lockable frequency (75–850 kHz), OPTI-LOOP® compensation, selectable light-load modes (Burst Mode®, pulse-skipping, forced continuous), and dual independent soft-start and latchoff protection.
Technical Context
The LTC3858IGN-1#TRPBF implements a constant-frequency current-mode architecture with two 180° out-of-phase controllers to minimize input capacitor ESR losses and power supply noise. Each channel features independent error amplifiers (ITH1/ITH2), differential current sensing (SENSE1±/SENSE2±), and precision 0.800V feedback reference.
It integrates dual gate drivers (TG1/BG1 and TG2/BG2) with 2.5Ω pull-up / 1.5Ω pull-down on top-side and 2.4Ω/1.1Ω on bottom-side drivers, plus internal LDOs for INTVCC generation from VIN or EXTVCC. Shutdown IQ is 8μA, and it supports programmable fixed frequency (50–900 kHz) or PLL synchronization.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 38V - supports wide intermediate bus and battery chemistries including 12V, 24V, and 36V systems. |
| Output Voltage Range | 0.8V to 24V - enables dual-rail generation (e.g., 3.3V/8.5V) with ±1% regulation accuracy over temperature. |
| No-Load Quiescent Current | 170μA (one channel active) - extends runtime in always-on battery-operated devices like portable instrumentation. |
| Switching Frequency Range | 75kHz to 850kHz (PLL-sync) or 50kHz to 900kHz (fixed) - allows optimization of size vs. efficiency; 180° phase shift reduces input capacitance requirements by ~50%. |
| Current Sensing | RSENSE or DCR - supports low-loss inductor-based sensing or precision shunt-based current monitoring with 43–57mV max threshold. |
| Protection Features | Output overvoltage (±10% PGOOD trip), short-circuit latchoff, dropout detection, and no current foldback during startup - ensures robust fault handling without compromising start-up reliability. |
| Soft-Start & Control | Independent SS1/SS2 pins with 1μA pull-up - enables programmable ramp time and dual-channel sequencing; latchoff arming at 2.0V, trip at 1.5V. |
Pinout & Package
Package: 28-Lead Plastic SSOP (0.150" width), RoHS-compliant, –40°C to +125°C operating junction temperature, θJA = 90°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1+, SENSE2+ | Differential current sense (+) inputs | Connect to DCR network or RSENSE top; set peak current limit jointly with ITH voltage and SENSE– offset. |
| SENSE1–, SENSE2– | Differential current sense (–) inputs | Reference point for current comparator; supplies bias current above INTVCC – 0.5V; enables accurate high-side sensing. |
| VFB1, VFB2 | Feedback voltage inputs | Monitor regulated output via external resistor divider; internal 0.800V reference enables precise output setting with ±1% tolerance. |
| ITH1, ITH2 | Error amplifier outputs | Control current limit threshold; voltage proportional to load demand; used for loop compensation and current mode stability. |
| TG1, TG2 | Top-gate drivers | Drive N-channel high-side MOSFET gates with floating 5.1V swing referenced to SW node; 25ns rise/fall time into 3.3nF. |
| BG1, BG2 | Bottom-gate drivers | Drive N-channel synchronous rectifiers with 0–5.1V swing referenced to PGND; 28ns rise / 13ns fall time into 3.3nF. |
| PGOOD1 | Power-good indicator | Open-drain output asserting low when VFB1 deviates >±10% from target; supports system enable sequencing and fault reporting. |
| SS1, SS2 | Soft-start/latchoff timing inputs | Capacitor-to-ground sets ramp time; internal 1μA pull-up enables linear VOUT rise; also discharges at 9μA during short-circuit for timed shutdown. |
| RUN1, RUN2 | Channel enable controls | Digital inputs: <1.26V disables individual channel; both <0.7V forces full shutdown with 8μA IQ - enables independent rail control and system-level power management. |
| FREQ, PLLIN/MODE | Oscillator control & sync interface | FREQ sets frequency via resistor (50–900 kHz); PLLIN/MODE selects Burst Mode® (GND), pulse-skip (1.2–3.8V), or forced continuous (INTVCC). |
| VIN, PGND, SGND | Main input, power ground, signal ground | VIN powers internal LDOs; PGND returns bottom-FET sources; SGND is isolated analog reference - critical for noise-sensitive current sensing. |
| INTVCC, EXTVCC | Internal LDO output & external bias input | INTVCC = 5.1V ±1.1% output powering logic/drivers; EXTVCC >4.7V bypasses VIN LDO - improves efficiency when using regulated auxiliary supply. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Minimizes required output capacitance and enables stable loop response across wide COUT/ESR variations - eliminates trial-and-error tuning for ceramic or polymer capacitors. |
| Out-of-Phase Dual Control | 180° phase shift between channels cuts RMS input ripple current by ~70%, reducing input capacitor count and size while lowering EMI. |
| Low-IQ Sleep Mode | 170μA quiescent current per active channel extends battery life in standby - achieved by disabling non-essential circuitry while maintaining regulation. |
| Independent Short-Circuit Latchoff | Each channel uses dedicated SS pin discharge (9μA) and voltage thresholds (arm at 2.0V, latch at 1.5V) - prevents single-fault propagation and enables selective rail recovery. |
| Programmable Light-Load Operation | Selectable Burst Mode®, pulse-skipping, or forced continuous conduction via PLLIN/MODE pin - balances efficiency vs. output ripple for varying load profiles. |
| Robust Gate Drivers | TG/BG drivers deliver 2.5Ω/1.5Ω (top), 2.4Ω/1.1Ω (bottom) on-resistance with <30ns transition times - ensures fast switching and minimal dead-time losses in high-frequency designs. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Dual-rail power for SoC (1.1V core) and display interface (3.3V I/O) in head-unit ECUs with 12V battery input and thermal constraints. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller delivering tightly regulated, low-noise 1.1V and 3.3V rails with phase interleaving to suppress conducted EMI. Use Value: 170μA IQ extends sleep-mode battery life; 180° phase shift reduces input cap count by 2×; PGOOD1 enables safe processor reset sequencing. |
Use Scenario: Distributed 5V and 24V rails in modular PLC backplane where space, thermal performance, and fault isolation are critical. IC Role / Device Role / Timing Role: Dual independent buck controller generating isolated 5V logic and 24V sensor excitation from 48V intermediate bus. Use Value: Independent RUN1/RUN2 enables hot-swap capability; latchoff protection prevents cascade failure; wide 4V–38V VIN accommodates brownout conditions. |
| Portable Medical Imaging | Test & Measurement Equipment |
|
Use Scenario: Battery-powered ultrasound front-end requiring ultra-low-noise 1.8V ADC supply and 5V FPGA rail with strict standby current limits. IC Role / Device Role / Timing Role: Dual-channel controller with Burst Mode® operation minimizing light-load losses and OPTI-LOOP® ensuring fast transient response to pulsed imaging loads. Use Value: 8μA shutdown IQ preserves battery charge during idle; independent SS1/SS2 enables staggered rail ramp-up to avoid inrush current peaks. |
Use Scenario: Precision bench power supply with dual adjustable outputs (±15V analog, 3.3V digital) fed from universal AC/DC adapter. IC Role / Device Role / Timing Role: High-accuracy dual buck controller supporting remote sensing (VFB1/VFB2), programmable frequency (to avoid sensitive bands), and overvoltage lockout. Use Value: 0.800V ±1% reference enables <±0.5% output accuracy; PGOOD1 and OV protection meet safety compliance (IEC 61000-4-5); EXTVCC option improves overall system efficiency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2918GL-Z | Single-chip dual-phase controller with integrated MOSFET drivers; 4.5–28V VIN; fixed 0.6V reference; no EXTVCC support; lower IQ (120μA) but no Burst Mode®. | Targeted at cost-sensitive consumer power modules; lacks independent latchoff, soft-start, and PLL sync - unsuitable for safety-critical or high-reliability systems. | Choose MP2918GL-Z only for compact, low-cost 12V-input applications where feature parity is not required and layout space is constrained. |
| LTC3857EUFD-1#TRPBF | Same architecture but in 28-pin QFN (4mm × 5mm); identical electrical specs; θJA = 43°C/W vs. 90°C/W for SSOP; exposed pad requires PCB thermal relief. | Better thermal performance for high-current (>5A/channel) or high-ambient designs; incompatible pinout - not drop-in replacement for SSOP footprint. | Choose LTC3857EUFD-1#TRPBF when thermal dissipation is limiting and board layout allows QFN rework; otherwise retain LTC3858IGN-1#TRPBF for proven SSOP manufacturability. |
Compared with MP2918GL-Z, LTC3858IGN-1#TRPBF offers superior fault protection, flexible light-load operation, and wider input range; versus LTC3857EUFD-1#TRPBF, it trades thermal performance for legacy SSOP compatibility and easier hand-soldering in prototyping.
Availability
LTC3858IGN-1#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, and portable medical imaging systems requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.
Supply support for LTC3858IGN-1#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 high-performance power management portfolio with rigorous automotive and industrial qualification standards.
The LTC3858 family was designed for high-efficiency, dual-rail DC/DC conversion in space-constrained, thermally demanding applications - emphasizing low IQ, robust fault handling, and flexible control architecture for battery and intermediate-bus systems.
FAQ
What is the minimum input voltage supported by the LTC3858IGN-1#TRPBF?
The LTC3858IGN-1#TRPBF supports a minimum input voltage of 4V, enabling reliable operation from partially discharged 12V lead-acid or 3S Li-ion batteries. Below 4V, undervoltage lockout (UVLO) engages at 3.6V (rising) to prevent erratic behavior or incomplete regulation.
Does the LTC3858IGN-1#TRPBF support synchronization to an external clock source?
Yes, the LTC3858IGN-1#TRPBF supports external clock synchronization via the PLLIN/MODE pin. When driven with a clean TTL/CMOS clock signal (75–850 kHz), the internal phase-locked loop aligns the rising edge of TG1 to the external clock's rising edge - essential for noise-sensitive mixed-signal systems.
How does the LTC3858IGN-1#TRPBF implement short-circuit protection?
The LTC3858IGN-1#TRPBF uses independent short-circuit latchoff per channel: once the SS pin voltage exceeds 2.0V (arming threshold), a 9μA discharge current pulls SS down during overvoltage faults. If SS falls below 1.5V, the channel latches off until VIN or RUN is cycled - preventing thermal runaway without affecting the other channel.
Can the LTC3858IGN-1#TRPBF operate with only one output enabled?
Yes, the LTC3858IGN-1#TRPBF supports independent channel control: pulling RUN1 low disables Channel 1 while Channel 2 remains fully operational with 170μA IQ, and vice versa. Both RUN pins must be pulled below 0.7V to enter full shutdown (8μA IQ), preserving design flexibility for partial-rail operation.
What is the purpose of the EXTVCC pin on the LTC3858IGN-1#TRPBF?
The EXTVCC pin on the LTC3858IGN-1#TRPBF accepts an external 4.7–14V supply to power the internal 5.1V INTVCC LDO, bypassing the VIN-based regulator. This improves system efficiency when a clean, regulated auxiliary rail (e.g., from a secondary converter) is available - reducing heat and input current draw from the main supply.
LTC3858IGN-1#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 38V
- Frequency - Switching:
- 105kHz ~ 835kHz, 350kHz ~ 535kHz
- Duty Cycle (Max):
- 99.4%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SSOP
LTC3858IGN-1#TRPBF FAQ
1.How can I place an order for LTC3858IGN-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3858IGN-1#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 LTC3858IGN-1#TRPBF reliable?
The price and inventory of LTC3858IGN-1#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3858IGN-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3858IGN-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3858IGN-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3858IGN-1#TRPBF?
LTC3858IGN-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3858IGN-1#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 LTC3858IGN-1#TRPBF?
For technical support, including LTC3858IGN-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3858IGN-1#TRPBF requirements.
6.How does Aetrix verify that LTC3858IGN-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3858IGN-1#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 LTC3858IGN-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3858IGN-1#TRPBF?
All LTC3858IGN-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3858IGN-1#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 LTC3858IGN-1#TRPBF part is unused and in its original packaging.
Return procedure for LTC3858IGN-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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