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Analog Devices Inc. LTC3858EUH#TRPBF
- Part No.:
- LTC3858EUH#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3858EUH#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:6,022
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Product details
Overview
LTC3858EUH#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 3.3V/5A and 8.5V/3.5A outputs from a 4V–38V input, features 170μA quiescent current in single-channel sleep mode, 0.8V reference accuracy (±1.5%), and out-of-phase operation to reduce input ripple. It is used in battery-powered digital systems requiring high-efficiency dual-rail power conversion.
For engineers reviewing the LTC3858EUH#TRPBF datasheet, LTC3858EUH#TRPBF pinout, LTC3858EUH#TRPBF application, or LTC3858EUH#TRPBF equivalent, key selection considerations include its dual-channel phase control, RSENSE/DCR current sensing flexibility, OPTI-LOOP® compensation for wide output capacitor ESR ranges, programmable 50kHz–900kHz switching frequency, and latch-off short-circuit protection with adjustable soft-start timing.
Technical Context
The LTC3858EUH#TRPBF implements a constant-frequency current-mode architecture with two independent controllers operating 180° out of phase-reducing input capacitance requirements and supply-induced noise. Each channel uses an error amplifier (EA) comparing VFB to a precision 0.800V reference, with ITH voltage setting peak inductor current via differential current comparators referenced to SENSE+ and SENSE− pins.
It supports three light-load modes via PLLIN/MODE pin configuration: Burst Mode® (ground), pulse-skipping (intermediate voltage), or forced continuous (INTVCC). Internal LDOs power gate drivers from either VIN or EXTVCC (≥4.7V), and dropout detection enables 99% duty cycle operation while maintaining bootstrap capacitor recharge integrity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4V to 38V - supports wide intermediate bus voltages and battery chemistries including 12V, 24V, and 28V systems. |
| VOUT Range | 0.8V to 24V - enables precise regulation of logic rails (e.g., 3.3V, 5V, 8.5V) and higher-voltage analog supplies. |
| IQ (Sleep, 1 ch) | 170μA typical - extends runtime in battery-operated devices without compromising transient response. |
| fSW Range | 50kHz to 900kHz - programmable via FREQ pin resistor or external sync; enables optimization of size vs. efficiency trade-offs. |
| Reference Voltage | 0.800V ±1.5% over –40°C to 125°C - ensures stable output regulation across automotive and industrial temperature ranges. |
| Current Sensing | RSENSE or DCR - supports low-loss inductor-based sensing or precision shunt-based current monitoring per channel. |
| Duty Cycle Max | 99.4% - maintains regulation during deep dropout conditions (e.g., VIN ≈ VOUT + VF). |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed thermal pad (Pin 33 = SGND), rated for –40°C to 125°C junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1– / SENSE2– (1, 9) | Differential current sense (–) input | Provides common-mode bias point for current comparator; sources current when > INTVCC – 0.5V. |
| FREQ (2) | Oscillator frequency control | Sets switching frequency via resistor-to-GND (50–900kHz); tied to GND/INTVCC for fixed 350/535kHz. |
| PHASMD (3) | Phase relationship selector | Configures TG2 and CLKOUT phase offset relative to TG1 (180°/240° or 60°/120° or 180°/90°). |
| CLKOUT (4) | Master clock output | Drives daisy-chained controllers; swings rail-to-rail between INTVCC and SGND. |
| PLLIN/MODE (5) | Sync input / light-load mode select | Accepts external clock for synchronization; selects Burst Mode®, pulse-skip, or forced continuous operation. |
| SGND (6, 33) | Small-signal ground reference | Must be isolated from PGND; exposed pad requires PCB soldering for thermal performance. |
| RUN1 / RUN2 (7, 8) | Independent channel enable | Shuts down individual controller below 1.23V; full shutdown below 0.7V (IQ = 8μA). |
| BOOST1 / BOOST2 (17, 24) | Top-gate bootstrap supply | Provides floating bias for TG drivers; swings from INTVCC to (VIN + INTVCC). |
| TG1 / TG2 (15, 26) | Top N-MOSFET gate drive | High-current floating driver output; swing = INTVCC – 0.5V superimposed on SW node. |
| SW1 / SW2 (16, 25) | Switch node connection | Connects to inductor and bootstrap diode/capacitor; handles high dv/dt transitions. |
| BG1 / BG2 (18, 23) | Bottom N-MOSFET gate drive | Ground-referenced driver; swing = 0V to INTVCC; drives synchronous rectifier gates. |
| PGND (21) | Power ground return | Connects to bottom MOSFET sources and CIN (–) terminals; separate from SGND path. |
| VIN (22) | Main input supply | Primary power source for internal LDOs and gate drivers; bypassed to SGND with ceramic capacitor. |
| EXTVCC (20) | External bias input | Enables more efficient INTVCC sourcing from regulated output (e.g., 5V rail) when >4.7V. |
| INTVCC (19) | Internal LDO output | 5.1V ±1.1% regulated supply for control circuitry and gate drivers; requires ≥4.7μF ceramic decoupling. |
| VFB1 / VFB2 (11, 31) | Feedback voltage input | Compares output divider voltage to 0.800V reference; ±5nA input bias minimizes divider error. |
| ITH1 / ITH2 (12, 30) | Error amplifier output | Controls current limit threshold; voltage directly sets peak inductor current per channel. |
| SS1 / SS2 (13, 29) | Soft-start / latch-off timer | Internal 1μA pull-up charges external capacitor for linear VOUT ramp; also discharges at 9μA during fault. |
| PGOOD1 / PGOOD2 (14, 27) | Open-drain power-good indicator | Asserts low when VFB deviates >±10% from setpoint; includes 25μs fault delay and hysteresis. |
| ILIM (28) | Current limit range select | Three thresholds (GND/FLOAT/INTVCC) set max sense voltage: 22/43/64mV typical. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Minimizes required output capacitance by enabling stable loop response across wide COUT and ESR variations. |
| Out-of-Phase Dual Control | Reduces RMS input ripple current by ~30%, allowing smaller input capacitors and lower EMI emissions. |
| Programmable Light-Load Mode | Selects Burst Mode® (highest light-load efficiency), pulse-skipping (low-noise), or forced continuous (lowest ripple). |
| Short-Circuit Latch-Off Protection | Arms after SS voltage exceeds 2V; discharges SS capacitor at 9μA during fault; latches off at 1.5V threshold. |
| Dropout Detection & Recovery | Maintains 99% duty cycle while forcing periodic top-FET off-time to recharge bootstrap capacitors in dropout. |
| Flexible Current Sensing | Supports both discrete RSENSE (low-value shunt) and lossless DCR sensing networks per channel. |
Applications
| Industrial Embedded Power | Automotive Infotainment |
|---|---|
|
Use Scenario: Dual-rail power for FPGA + microcontroller subsystems in programmable logic controllers (PLCs) and motor drives. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller delivering 3.3V/5A and 5V/4A from 24V bus with tight cross-regulation. Use Value: Out-of-phase operation reduces input capacitor stress and EMI filter size; 170μA IQ extends standby time in always-on modules. |
Use Scenario: Power management for head-unit processors, display drivers, and audio amplifiers in 12V vehicle systems. IC Role / Device Role / Timing Role: Generates 1.2V core and 3.3V I/O rails from cold-crank tolerant 4V–38V input with robust short-circuit protection. Use Value: Latch-off protection prevents thermal runaway during load dump or connector faults; EXTVCC support improves overall system efficiency. |
| Battery-Powered Test Equipment | Distributed Telecom Power |
|
Use Scenario: Portable oscilloscopes and signal analyzers requiring clean, low-noise dual outputs from Li-ion battery packs. IC Role / Device Role / Timing Role: Controls two independent synchronous buck stages with selectable light-load modes to maximize battery life. Use Value: Burst Mode® operation achieves >85% efficiency at 1mA load; soft-start prevents inrush current during hot-swap battery insertion. |
Use Scenario: Intermediate bus conversion in 48V telecom systems powering multiple point-of-load regulators. IC Role / Device Role / Timing Role: Generates 12V and 5V intermediate rails with phase-lock capability to synchronize with system clock tree. Use Value: CLKOUT and PLLIN enable multi-phase coordination across boards; wide VIN accommodates 48V PoE++ and battery backup inputs. |
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 |
|---|---|---|---|
| MP8772GQ-Z (Monolithic Power) | Integrated power stage (MOSFETs built-in); 4.5V–36V VIN; fixed 500kHz fSW; no phase modulation or CLKOUT. | Lower BOM count but less flexible layout; no external current sensing option; limited to ≤12A per channel. | Choose MP8772GQ-Z for space-constrained designs where integration outweighs configurability needs. |
| ISL81601FRZ-T7A (Renesas) | Single-chip dual-phase controller with PMBus interface; 4.5V–60V VIN; supports DCM/CCM/Burst; integrated telemetry. | Requires digital control infrastructure; higher cost; adds firmware complexity for telemetry readback. | Choose ISL81601FRZ-T7A when remote monitoring, margining, or dynamic voltage scaling is required. |
Compared with MP8772GQ-Z and ISL81601FRZ-T7A, the LTC3858EUH#TRPBF offers unmatched analog configurability-supporting RSENSE/DCR sensing, user-defined soft-start timing, independent channel enable, and phase-offset programming-making it ideal for high-reliability analog-centric power designs where flexibility and proven ruggedness are critical.
Availability
LTC3858EUH#TRPBF is available at Aetrix Electronics and suitable for industrial embedded power, automotive infotainment, and battery-powered test equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC3858EUH#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 continues to develop and support its high-performance power management portfolio with emphasis on reliability, precision, and ruggedness.
The LTC3858EUH#TRPBF belongs to Linear's flagship polyphase controller family designed for demanding dual-rail DC/DC conversion in automotive, industrial, and telecom applications where efficiency, thermal resilience, and fault tolerance are non-negotiable.
FAQ
What is the maximum supported switching frequency for the LTC3858EUH#TRPBF?
The LTC3858EUH#TRPBF supports a programmable switching frequency from 50kHz to 900kHz using the FREQ pin resistor, and up to 850kHz when synchronized externally via the PLLIN/MODE pin. Its internal VCO allows precise tuning across this range without requiring external clock components, making the LTC3858EUH#TRPBF adaptable to diverse layout and filtering constraints.
Does the LTC3858EUH#TRPBF support both RSENSE and DCR current sensing?
Yes, the LTC3858EUH#TRPBF supports both RSENSE (shunt resistor) and DCR (inductor winding resistance) current sensing methods on each channel via dedicated SENSE+ and SENSE− pins. This dual-sensing capability allows designers to optimize for accuracy (RSENSE) or efficiency (DCR), and the ILIM pin selects one of three current threshold ranges to match the chosen sensing method.
How does the short-circuit latch-off protection work on the LTC3858EUH#TRPBF?
The LTC3858EUH#TRPBF implements independent latch-off protection per channel using the SS1/SS2 pins. After soft-start completes (SS voltage >2V), a short-circuit causes the SS pin to discharge at 9μA. If voltage falls below 1.5V, the controller shuts down permanently until VIN or RUN is cycled. This prevents thermal damage during sustained overloads, and the LTC3858EUH#TRPBF's dual-channel independence ensures one fault doesn't disable both rails.
Can the LTC3858EUH#TRPBF operate with only one channel enabled?
Yes, the LTC3858EUH#TRPBF supports independent channel control via RUN1 and RUN2 pins. Pulling RUN1 low disables Channel 1 while Channel 2 remains active, and vice versa. In single-channel operation, quiescent current drops to 170μA typical, extending battery life in partial-load scenarios - a key advantage of the LTC3858EUH#TRPBF over fixed dual-channel alternatives.
What is the purpose of the PHASMD pin on the LTC3858EUH#TRPBF?
The PHASMD pin configures the phase relationship between TG1, TG2, and CLKOUT. Grounding PHASMD sets TG2 and CLKOUT 180° and 60° out of phase with TG1; tying to INTVCC sets 240° and 120°; floating yields 180° and 90°. This flexibility allows designers to minimize input ripple, manage EMI, or align switching edges with other system clocks - a unique capability of the LTC3858EUH#TRPBF not found in most dual-phase controllers.
LTC3858EUH#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 32-WFQFN Exposed Pad
- 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:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC3858EUH#TRPBF FAQ
1.How can I place an order for LTC3858EUH#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3858EUH#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 LTC3858EUH#TRPBF reliable?
The price and inventory of LTC3858EUH#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3858EUH#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3858EUH#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3858EUH#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3858EUH#TRPBF?
LTC3858EUH#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3858EUH#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 LTC3858EUH#TRPBF?
For technical support, including LTC3858EUH#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3858EUH#TRPBF requirements.
6.How does Aetrix verify that LTC3858EUH#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3858EUH#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 LTC3858EUH#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3858EUH#TRPBF?
All LTC3858EUH#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3858EUH#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 LTC3858EUH#TRPBF part is unused and in its original packaging.
Return procedure for LTC3858EUH#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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