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Analog Devices Inc. LTC3858EGN-1#TRPBF
- Part No.:
- LTC3858EGN-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3858EGN-1#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,802
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Product details
Overview
LTC3858EGN-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 from 4V–38V input, supports RSENSE or DCR current sensing, operates with 170μA quiescent current (one channel active), and features out-of-phase operation to reduce input ripple-used in battery-powered digital systems and distributed power architectures.
For engineers reviewing the LTC3858EGN-1#TRPBF datasheet, LTC3858EGN-1#TRPBF pinout, LTC3858EGN-1#TRPBF application, or LTC3858EGN-1#TRPBF equivalent, key selection criteria include its dual-channel phase control, OPTI-LOOP® compensation for wide capacitor/ESR tolerance, programmable 50kHz–900kHz switching frequency, selectable light-load modes (Burst Mode®, pulse-skipping, forced continuous), and integrated short-circuit latchoff with independent soft-start.
Technical Context
The LTC3858EGN-1#TRPBF implements a constant-frequency current-mode architecture with two 180° out-of-phase controllers, minimizing input capacitor ESR losses and supply-induced noise. Its error amplifier drives ITH pins to set peak current thresholds, while independent VFB1/VFB2 inputs monitor regulated outputs against a precision 0.800V 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, supports EXTVCC switchover at 4.7V, and includes dedicated PLLIN/MODE pin for external synchronization or light-load mode selection (Burst Mode®, pulse-skipping, or forced continuous).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4V to 38V - supports wide-input industrial, automotive, and battery chemistries including 12V/24V buses and Li-ion stacks. |
| VOUT Range | 0.8V to 24V - enables generation of core logic (e.g., 1.2V), I/O (3.3V), and intermediate rails (8.5V, 12V) from single controller. |
| IQ (One Channel Active) | 170μA - extends runtime in always-on battery systems such as portable instrumentation or remote sensors. |
| Switching Frequency | 50kHz to 900kHz - programmable via FREQ pin resistor; allows optimization of size (high-freq) vs. efficiency (mid-freq) and EMI compliance. |
| Current Sensing | RSENSE or DCR - eliminates need for lossy sense resistors when using inductor DCR, improving full-load efficiency. |
| Phase Operation | 180° out-of-phase - halves required input capacitance and reduces RMS input ripple current by ~30% vs. in-phase dual controllers. |
| 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. |
Pinout & Package
Package: 28-Lead Plastic SSOP (narrow), 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 (+) input | Connects to high-side of RSENSE or DCR network; sets current limit threshold with SENSE– and ITH voltage. |
| SENSE1–, SENSE2– | Differential current sense (–) input | Bias current source activates above INTVCC – 0.5V; enables accurate sensing across wide common-mode range (–0.3V to 28V). |
| FREQ | Oscillator frequency programming | 20μA internal pull-up; resistor to GND sets frequency from 50kHz–900kHz; direct tie to GND/INTVCC selects fixed 350kHz/535kHz. |
| PLLIN/MODE | Synchronization & light-load mode select | Accepts external clock for phase-locking; ground = Burst Mode®, INTVCC = forced continuous, 1.2V–(INTVCC–1.3V) = pulse-skipping. |
| RUN1, RUN2 | Independent channel enable | Logic-level shutdown: <1.26V disables one channel; both <0.7V enters 8μA shutdown with INTVCC LDO off. |
| SS1, SS2 | Soft-start & short-circuit timer | Internal 1μA pull-up charges external capacitor for controlled ramp; >2V arms latchoff; falling below 1.5V triggers shutdown on sustained overcurrent. |
| VFB1, VFB2 | Feedback input | Compares output divider voltage to 0.800V reference; ±1% accuracy over –40°C to 125°C ensures stable regulation. |
| PGOOD1 | Power-good indicator | Open-drain output pulled low when VFB1 deviates >±10% from target - used for sequencing or system enable signaling. |
| TG1, TG2 / BG1, BG2 | Top/bottom gate drivers | TG swing = INTVCC – 0.5V superimposed on SW node; BG swing = 0V to INTVCC; 2.5Ω/1.5Ω (TG), 2.4Ω/1.1Ω (BG) drive capability. |
| SW1, SW2 | Switch node connection | Direct connection to inductor and MOSFET sources/drains; rated –5V to 40V; requires low-inductance layout for EMI and efficiency. |
| INTVCC / EXTVCC | Internal LDO output / external bias input | INTVCC = 5.1V ±1.1%; EXTVCC switchover at 4.7V (250mV hysteresis); enables efficient self-bias from output rail. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Allows stable loop response across wide range of output capacitor values (10μF–1000μF) and ESR (0.5mΩ–100mΩ), reducing design iteration time. |
| Out-of-Phase Dual Control | Reduces RMS input ripple current by ~30%, enabling smaller input bulk capacitors and lower EMI filter component stress. |
| Independent Soft-Start & Latchoff | Each channel has dedicated SS pin with arming/latchoff thresholds (2.0V/1.5V), enabling staggered startup and isolated fault containment. |
| Low Dropout Operation | 99.4% max duty cycle allows operation with VIN as low as VOUT + 0.2V (e.g., 3.3V out from 3.6V input), critical for battery end-of-life support. |
| Three Light-Load Modes | Burst Mode® (highest efficiency at µA loads), pulse-skipping (low-noise mid-load), forced continuous (lowest output ripple) - selectable per system requirement. |
Applications
| Industrial Power Distribution | Automotive Infotainment Systems |
|---|---|
Use Scenario: Distributed 12V-to-3.3V/8.5V conversion in PLC backplanes or sensor hubs with strict thermal limits. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing two independent rails with coordinated phase timing to minimize input ripple. Use Value: 170μA IQ extends uptime in battery-backed modules; out-of-phase operation cuts input cap size by 40% vs. single-phase solutions. | Use Scenario: Powering display logic, audio codecs, and MCU cores in head units where cold-crank (4.5V) and load dump (38V) must be tolerated. IC Role / Device Role / Timing Role: High-vin dual controller providing regulated 1.2V (core), 3.3V (I/O), and 5V (USB) rails with independent RUN pin control for subsystem power gating. Use Value: 4V–38V input range covers full automotive transients; PGOOD1 enables safe sequencing; latchoff protects against shorted display cables. |
| Portable Medical Instrumentation | Telecom Line Cards |
Use Scenario: Battery-powered ultrasound or patient monitor requiring ultra-low standby power and clean analog supplies. IC Role / Device Role / Timing Role: Dual controller generating low-noise 3.3V (digital) and 5V (analog front-end) rails with Burst Mode® enabled for sub-mA loads. Use Value: 8μA shutdown current preserves battery charge during sleep; OPTI-LOOP® ensures stability with ceramic caps near sensitive ADCs. | Use Scenario: Intermediate bus conversion (–48V or +12V input) to multiple point-of-load rails on high-density line cards. IC Role / Device Role / Timing Role: Dual-phase controller driving discrete MOSFETs for 1.8V FPGA core and 3.3V interface rails with phase-lock to system clock for EMI reduction. Use Value: PLLIN/MODE sync capability aligns switching edges to avoid beat frequencies; RSENSE/DCR flexibility simplifies BOM across variants. |
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 | Integrated MOSFETs (40V, 12A), fixed 500kHz freq, no EXTVCC, no PLL sync, lower IQ (120μA one channel) | Targeted at space-constrained, medium-power apps (<10A/rail); lacks phase sync and wide-VIN flexibility | Select MP2918GL-Z only if board area is critical and input range ≤28V; not suitable for automotive cold-crank or telecom transients. |
| LTC3858IUFD-1#TRPBF | Same silicon, QFN-28 package (4mm×5mm), θJA = 43°C/W vs. SSOP's 90°C/W, identical electrical specs | Better thermal performance in high-power density layouts; same pinout but different footprint and soldering requirements | Choose LTC3858IUFD-1#TRPBF for thermally constrained designs; requires PCB rework due to QFN vs. SSOP land pattern mismatch. |
Compared with MP2918GL-Z, LTC3858EGN-1#TRPBF offers wider VIN (4–38V vs. 4.5–28V), external MOSFET flexibility, and phase synchronization-critical for EMI-sensitive telecom systems. Versus LTC3858IUFD-1#TRPBF, the SSOP variant trades thermal performance for easier hand-soldering and legacy board compatibility.
Availability
LTC3858EGN-1#TRPBF is available at Aetrix Electronics and suitable for industrial power distribution, automotive infotainment systems, and portable medical instrumentation requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.
Supply support for LTC3858EGN-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 full product support, documentation, and manufacturing continuity for all Linear-branded power management ICs.
The LTC3858 family was designed for high-efficiency, dual-output, synchronous step-down conversion in space- and thermal-constrained systems-targeting applications where input voltage range, light-load efficiency, and fault robustness are critical.
FAQ
What is the maximum input voltage rating for the LTC3858EGN-1#TRPBF?
The LTC3858EGN-1#TRPBF has an absolute maximum input supply voltage (VIN) rating of 40V, with recommended operating range from 4V to 38V. This allows reliable operation across automotive cold-crank (down to ~4.5V) and load-dump (up to 38V) conditions, as well as industrial 24V and 36V bus systems. Exceeding 40V may cause permanent damage.
Does the LTC3858EGN-1#TRPBF support external synchronization of switching frequency?
Yes, the LTC3858EGN-1#TRPBF supports external synchronization via the PLLIN/MODE pin. When an external clock signal is applied, the internal phase-locked loop forces the rising edge of TG1 to align with the rising edge of that clock. The device accepts synchronizing frequencies from 75kHz to 850kHz, enabling EMI reduction in noise-sensitive systems like medical imaging or telecom infrastructure.
How does the short-circuit latchoff protection work on the LTC3858EGN-1#TRPBF?
The LTC3858EGN-1#TRPBF implements independent short-circuit latchoff per channel using the SS1/SS2 pins. Once the SS pin voltage exceeds 2.0V (arming threshold), a 9μA net discharge current pulls it down if VFB falls below 70% of regulation. If SS drops below 1.5V, the controller latches off until VIN or RUN is cycled. This prevents thermal runaway during sustained faults while allowing normal soft-start behavior.
Can the LTC3858EGN-1#TRPBF operate with only one output active?
Yes, the LTC3858EGN-1#TRPBF supports independent channel control: pulling RUN1 low disables Channel 1 while Channel 2 remains fully operational, and vice versa. In single-channel mode, quiescent current drops to 170μA (typical), and the unused channel's gate drivers, current sense, and feedback circuitry are disabled-enabling flexible power sequencing and partial-system operation in modular designs.
What is the purpose of the EXTVCC pin on the LTC3858EGN-1#TRPBF?
The EXTVCC pin on the LTC3858EGN-1#TRPBF provides an alternative power path for the internal 5.1V INTVCC LDO. When EXTVCC exceeds 4.7V (with 250mV hysteresis), the VIN-powered LDO shuts off and the EXTVCC LDO takes over-allowing efficient self-bias from a downstream converter output (e.g., 5V rail). This reduces overall system power loss and heat generation compared to powering INTVCC solely from the high-input bus.
LTC3858EGN-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
LTC3858EGN-1#TRPBF FAQ
1.How can I place an order for LTC3858EGN-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3858EGN-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 LTC3858EGN-1#TRPBF reliable?
The price and inventory of LTC3858EGN-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 LTC3858EGN-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3858EGN-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3858EGN-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3858EGN-1#TRPBF?
LTC3858EGN-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3858EGN-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 LTC3858EGN-1#TRPBF?
For technical support, including LTC3858EGN-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3858EGN-1#TRPBF requirements.
6.How does Aetrix verify that LTC3858EGN-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3858EGN-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 LTC3858EGN-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3858EGN-1#TRPBF?
All LTC3858EGN-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3858EGN-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 LTC3858EGN-1#TRPBF part is unused and in its original packaging.
Return procedure for LTC3858EGN-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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