My Inquiry
My Account
Analog Devices Inc. LTC3858EUH-2#PBF
- Part No.:
- LTC3858EUH-2#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3858EUH-2#PBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,081
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3858EUH-2#PBF 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 a 4V–38V input, supports out-of-phase operation to reduce input ripple, features 170μA quiescent current in single-channel sleep mode, and operates up to 850kHz with phase-lockable frequency. It is used in high-efficiency, low-noise intermediate bus converters for battery-powered digital systems.
For engineers reviewing the LTC3858EUH-2#PBF datasheet, LTC3858EUH-2#PBF pinout, LTC3858EUH-2#PBF application, or LTC3858EUH-2#PBF equivalent, key selection criteria include dual-channel out-of-phase timing control, RSENSE/DCR current sensing flexibility, OPTI-LOOP® compensation for wide capacitor ESR ranges, programmable light-load modes (Burst Mode®, pulse-skipping, forced continuous), and automotive-grade thermal performance in the 5mm × 5mm QFN package.
Technical Context
The LTC3858EUH-2#PBF implements a constant-frequency current-mode architecture with two independent controllers operating 180° out of phase-reducing input capacitance requirements and power supply noise. Each channel uses an error amplifier (EA) comparing VFB to a 0.800V reference, with ITH controlling peak inductor current via external current-sense networks (RSENSE or DCR).
It integrates dual gate drivers (TG/BG) with <30ns transition times, internal 5.1V LDO (INTVCC) powered from VIN or EXTVCC (≥4.7V), and configurable protection: no overvoltage crowbar or short-circuit latchoff (distinguishing it from LTC3858/LTC3858-1), while retaining PGOOD1/PGOOD2 monitoring, soft-start/tracking, and 99% dropout duty cycle.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4V to 38V - supports 12V/24V industrial buses and wide-range battery chemistries (e.g., LiFePO₄, lead-acid). |
| VOUT Range | 0.8V to 24V - enables generation of core logic (0.8V–1.2V), I/O (1.8V–3.3V), and auxiliary rails (5V–12V) from one controller. |
| IQ (Sleep, 1 ch) | 170μA typical - extends runtime in always-on battery systems (e.g., IoT sensors, portable medical devices). |
| fSW Range | 75kHz–850kHz (phase-lockable); 50kHz–900kHz (programmable) - balances efficiency vs. size for 1–10μH inductors. |
| Current Sensing | RSENSE or DCR - eliminates sense resistor losses in high-current designs; supports accurate current limiting without added power loss. |
| Duty Cycle Max | 99% - maintains regulation under high-VIN-to-low-VOUT conditions (e.g., 36V→3.3V), critical for automotive cold-crank scenarios. |
| Package | 32-lead 5mm × 5mm QFN with exposed SGND pad - provides 34°C/W θJA for thermally constrained PCBs. |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed thermal pad (Pin 33 = SGND). Requires soldering of exposed pad to PCB for rated thermal performance (TJMAX = 125°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1– / SENSE2– (1, 9) | Differential current comparator (–) input | Accepts common-mode voltage up to INTVCC – 0.5V; supplies bias current during high-side sensing. |
| FREQ (2) | VCO frequency control | Resistor-to-GND sets 50–900kHz; tied to GND/INTVCC selects fixed 350/535kHz; enables precise loop bandwidth tuning. |
| PHASMD (3) | Phase relationship selector | Configures TG2/CLKOUT phase offset relative to TG1 (180°/240°/floating 180°+90°) for PolyPhase™ multi-phase expansion. |
| CLKOUT (4) | Synchronization output | INTVCC-rail-to-ground clock signal for daisy-chaining additional controllers (e.g., LTC3855, LTC3870). |
| PLLIN/MODE (5) | Sync input / light-load mode select | Accepts external clock (75–850kHz) or sets Burst Mode® (GND), pulse-skipping (1.2–3.8V), or forced continuous (INTVCC). |
| SGND (6, 33) | Small-signal ground reference | Mandatory separate trace to CIN(–); exposed pad must be soldered for thermal and noise integrity. |
| RUN1 / RUN2 (7, 8) | Independent channel enable | Below 1.26V disables channel; both below 0.7V enters 8μA shutdown - enables dynamic rail sequencing. |
| BOOST1 / BOOST2 (17, 24) | Top-gate bootstrap supply | Swings from INTVCC to (VIN + INTVCC); requires external bootstrap capacitor + Schottky diode per phase. |
| TG1 / TG2 (15, 26) | Top N-MOSFET gate drive | Floating driver output; swing = INTVCC – 0.5V superimposed on SW node - drives high-side FETs directly. |
| BG1 / BG2 (18, 23) | Bottom N-MOSFET gate drive | Ground-referenced driver; swing = 0V to INTVCC - compatible with standard logic-level N-FETs. |
| SW1 / SW2 (16, 25) | Switch node connection | Connects to inductor high-side terminal and BOOST capacitor - high dv/dt node requiring tight layout. |
| PGND (21) | Power ground return | Connects to bottom FET sources and CIN(–); must be low-inductance path to minimize switching noise. |
| VIN (22) | Main input supply | 4V–38V input; powers internal LDO (INTVCC) unless EXTVCC > 4.7V - supports redundant or efficient auxiliary bias. |
| EXTVCC (20) | External bias input | Enables bypass of VIN LDO when >4.7V; reduces power loss by using regulated converter output (e.g., 5V rail) as INTVCC source. |
| INTVCC (19) | Internal LDO output | 5.1V ±3%, supplies gate drivers and control circuitry; requires ≥4.7μF ceramic decoupling to PGND. |
| VFB1 / VFB2 (11, 31) | Feedback voltage input | Compares output divider voltage to 0.800V reference; ±10% PGOOD threshold ensures stable regulation. |
| ITH1 / ITH2 (12, 30) | Error amplifier output | Controls peak current limit; voltage range 0.425V–1.2V defines load transient response and current foldback behavior. |
| SS1 / SS2 (13, 29) | Soft-start / tracking input | Internal 1μA pull-up charges external capacitor for linear ramp; also accepts resistor divider for supply tracking. |
| PGOOD1 / PGOOD2 (14, 27) | Open-drain power-good flag | Asserts low when VFB deviates >±10% from setpoint - enables system-level power sequencing and fault reporting. |
| ILIM (28) | Current limit threshold select | Tied to SGND/FLOAT/INTVCC sets max sense voltage to 22/43/64mV - configures current limit without external resistors. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® Compensation | Minimizes required output capacitance and allows stable operation across wide ESR ranges (e.g., polymer + ceramic mixes). |
| Out-of-Phase Dual Control | Reduces RMS input ripple current by ~30% vs. in-phase operation - cuts required CIN volume and lowers EMI. |
| Three Light-Load Modes | Burst Mode® (170μA IQ), pulse-skipping, or forced continuous - enables optimal efficiency across 10μA–10A load range. |
| 99% Duty Cycle Operation | Maintains regulation during automotive cold-crank (e.g., 4.5V VIN → 3.3V VOUT) without dropout-induced reset. |
| Independent Soft-Start/Tracking | Per-channel SS pins allow staggered startup or precise voltage ramp alignment with FPGA/core logic rails. |
| No Crowbar OV Protection | Omits bottom-FET crowbar during overvoltage - avoids uncontrolled discharge in systems with large hold-up capacitors. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC Dual-Rail Converter |
|---|---|
|
Use Scenario: Powering SoC (1.0V), DDR memory (1.2V), and USB interface (3.3V) from a 12V vehicle battery with cold-crank tolerance. IC Role / Device Role / Timing Role: Dual-phase controller generating 1.0V/3.3V simultaneously; out-of-phase operation minimizes input ripple into sensitive RF sections. Use Value: 170μA sleep IQ extends always-on GPS module battery life; 99% duty cycle prevents brownout during 4.5V cranking events. |
Use Scenario: Providing isolated 5V logic and 24V I/O rails from a 24V DC industrial bus in a compact DIN-rail controller. IC Role / Device Role / Timing Role: Dual-channel buck controller with independent RUN/SS pins enabling sequenced startup of CPU before fieldbus transceivers. Use Value: RSENSE/DCR flexibility allows low-loss current sensing on high-current 24V rail; PGOOD1/PGOOD2 feed PLC watchdog timer. |
| Battery-Powered Medical Monitor | Distributed Telecom DC System |
|
Use Scenario: Converting Li-ion (3.0–4.2V) to 1.8V sensor rail and 3.3V MCU rail in a portable ECG device with 72-hour runtime requirement. IC Role / Device Role / Timing Role: Low-IQ dual controller operating in Burst Mode® at microamp loads; independent shutdown conserves power during sleep cycles. Use Value: 8μA shutdown current preserves battery during standby; OPTI-LOOP® ensures stability with aging electrolytic bulk caps. |
Use Scenario: Intermediate bus conversion in 48V telecom shelf, stepping down to 12V backplane and 5V service processor rails. IC Role / Device Role / Timing Role: Phase-locked dual controller synchronized to system clock (via PLLIN/MODE) to suppress beat frequencies in dense board layouts. Use Value: CLKOUT pin enables stacking multiple LTC3858EUH-2#PBF for 4-phase 12V/60A output; 38V max VIN handles 48V transients. |
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 |
|---|---|---|---|
| LTC3855IUFD#PBF | Single-channel, 4-phase capable; supports up to 600kHz; lacks independent PGOOD pins and ILIM configuration. | Requires external logic for dual-rail sequencing; better suited for high-current single-output systems (e.g., GPU VRMs). | Select when needing >4-phase interleaving or lower BOM count for single-rail high-current designs. |
| MP2918GL-Z | Monolithic dual buck (integrated FETs); 4.5–18V VIN; fixed 0.6V/0.8V VREF; no phase-lock or EXTVCC option. | Lower solution size but limited input range and no programmable light-load modes - unsuitable for automotive or wide-VIN industrial use. | Select only for space-constrained, cost-sensitive 12V-input consumer applications where integrated FETs are acceptable. |
Compared with LTC3855IUFD#PBF and MP2918GL-Z, the LTC3858EUH-2#PBF uniquely combines dual independent channels, 4V–38V operation, programmable light-load modes, and phase-lock capability - making it the only choice for robust, flexible, wide-input dual-rail power in automotive and industrial environments.
Availability
LTC3858EUH-2#PBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLCs, battery-powered medical monitors, and distributed telecom DC systems requiring stable component supply across extended temperature and lifetime requirements.
Supply support for LTC3858EUH-2#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 and maintains its high-performance analog and power management portfolio with rigorous automotive and industrial qualification standards.
The LTC3858EUH-2#PBF belongs to Linear's PolyPhase® controller family, designed specifically for high-efficiency, low-noise, multi-phase DC/DC conversion in demanding environments where thermal performance, light-load efficiency, and design flexibility are critical.
FAQ
What is the maximum input voltage rating for the LTC3858EUH-2#PBF?
The LTC3858EUH-2#PBF has an absolute maximum input supply voltage (VIN) rating of 40V, with a recommended operating range of 4V to 38V. This wide range accommodates 24V industrial buses, 36V automotive systems, and legacy 48V telecom inputs with margin for transients. Exceeding 40V risks permanent damage per Absolute Maximum Ratings.
Does the LTC3858EUH-2#PBF support current sensing using inductor DCR?
Yes, the LTC3858EUH-2#PBF supports both RSENSE and DCR current sensing via its differential SENSE+ and SENSE– inputs. DCR sensing eliminates power loss from discrete sense resistors and is configured using RC networks from SENSE+ to SW and SENSE– to SGND, with ITH voltage setting the effective current threshold.
How does the LTC3858EUH-2#PBF differ from the standard LTC3858 in overvoltage protection?
The LTC3858EUH-2#PBF disables the overvoltage protection crowbar function and short-circuit latchoff present in the base LTC3858. Instead, it relies on PGOOD monitoring and controlled shutdown via RUN pins. This avoids uncontrolled discharge of large output capacitors during OV events - beneficial in systems with hold-up requirements.
Can the LTC3858EUH-2#PBF operate with only one channel enabled?
Yes, the LTC3858EUH-2#PBF supports independent channel control: pulling RUN1 low disables Channel 1 while Channel 2 remains active, and vice versa. In single-channel operation, quiescent current drops to 170μA (typical), making it ideal for partial-power modes in battery-backed systems.
What thermal considerations apply to the LTC3858EUH-2#PBF's exposed pad?
The exposed pad (Pin 33) of the LTC3858EUH-2#PBF is electrically and thermally connected to SGND. It must be soldered to a dedicated PCB copper pour with multiple thermal vias to internal ground planes. Failure to do so degrades θJA from 34°C/W to >60°C/W, risking thermal shutdown above 85°C ambient in high-power applications.
LTC3858EUH-2#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 32-WFQFN Exposed Pad
- Packaging:
- Tube
- 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%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Phase 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-2#PBF FAQ
1.How can I place an order for LTC3858EUH-2#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3858EUH-2#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 LTC3858EUH-2#PBF reliable?
The price and inventory of LTC3858EUH-2#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3858EUH-2#PBF is usually 5 days.
3.What payment methods are accepted for LTC3858EUH-2#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3858EUH-2#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3858EUH-2#PBF?
LTC3858EUH-2#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3858EUH-2#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 LTC3858EUH-2#PBF?
For technical support, including LTC3858EUH-2#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3858EUH-2#PBF requirements.
6.How does Aetrix verify that LTC3858EUH-2#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3858EUH-2#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 LTC3858EUH-2#PBF meets industry standards.
7.What is the process for return or replacement of LTC3858EUH-2#PBF?
All LTC3858EUH-2#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3858EUH-2#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 LTC3858EUH-2#PBF part is unused and in its original packaging.
Return procedure for LTC3858EUH-2#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3858EUH-2#PBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
