My Inquiry
My Account
Analog Devices Inc. LTC3778EF#TRPBF
- Part No.:
- LTC3778EF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LTC3778EF#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,579
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3778EF#TRPBF from Analog Devices (formerly Linear Technology) is a wide-input synchronous step-down DC/DC controller IC for high-efficiency power conversion in memory and automotive systems. It delivers true valley current mode control without requiring an external sense resistor, supports 4V–36V input, 0.6V–(0.9)VIN output, 2%–90% duty cycle at 200kHz, ≤100ns minimum on-time, and ±1% 0.6V reference - enabling precise DDR memory and battery charger regulation.
For engineers reviewing the LTC3778EF#TRPBF datasheet, LTC3778EF#TRPBF pinout, LTC3778EF#TRPBF application, or LTC3778EF#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed ceramic-capacitor-compatible operation, real-world soft-start and overvoltage protection behavior, and two rigorously cross-checked alternative controllers for similar high-voltage synchronous buck applications.
Technical Context
The LTC3778EF#TRPBF implements a valley current mode architecture with a one-shot timer controlling top MOSFET on-time, where tON is set by ION pin current and VON pin voltage. It supports both discontinuous and forced-continuous conduction modes via the FCB pin, and uses Kelvin sensing across either an optional external resistor or the bottom MOSFET's RDS(ON).
Fault protection includes internal foldback current limiting, output overvoltage detection (±10% window), input undervoltage lockout (3.4V–4.0V), and programmable short-circuit shutdown timing. Power sequencing is enabled by RUN/SS pin-controlled soft-start with ~3s/µF ramp time and latch-off functionality.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4V to 36V - enables direct connection to 12V/24V automotive and industrial rails without pre-regulation. |
| VOUT Range | 0.6V to (0.9)×VIN - supports DDR1/2/3 memory supplies and adjustable logic rails down to sub-1V. |
| Reference Voltage | ±1% at 0.6V - ensures tight output regulation critical for low-voltage memory and processor cores. |
| tON(MIN) | ≤100ns - allows stable operation at high VIN/VOUT ratios (e.g., 24V→1.2V) without pulse-skipping instability. |
| Switching Frequency | Adjustable via RON on ION pin - maintains ~constant frequency across input/output variations when VON tied to VOUT. |
| Package | 20-Lead TSSOP (0.65mm pitch, 6.5mm × 4.4mm) - surface-mount compatible with standard reflow profiles and IPC-7351B land patterns. |
| Operating Temp | –40°C to 85°C ambient - qualified for industrial and automotive under-hood environments per datasheet Grade E. |
Pinout & Package
Package: 20-Lead Plastic TSSOP (F package), 0.65mm lead pitch, 6.5mm × 4.4mm body, exposed pad for thermal enhancement (not electrically connected).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS (1) | Run enable & soft-start ramp input | Capacitor-to-ground sets soft-start time (~3s/µF); <0.8V forces shutdown; rising edge above 1.5V initiates switching with clamped ITH. |
| VON (2) | On-time comparator trip point | Defines tON slope; grounded = 0.7V default; tied to INTVCC = 2.4V; clamped between 0.7V–2.4V for robust frequency setting. |
| PGOOD (3) | Open-drain power-good flag | Pulled low when VFB exits ±10% regulation window - enables system-level sequencing and fault reporting. |
| VRNG (4) | Sense voltage range scaling input | 10× nominal sense voltage (e.g., 1V → 100mV); sets current limit threshold; defaults to 70mV (GND) or 140mV (INTVCC). |
| ITH (5) | Error amplifier output & current limit control | 0–2.4V control voltage sets valley current threshold; 0.8V = zero current; used for compensation and current foldback. |
| FCB (6) | Forced continuous mode select | Ground = continuous mode at light load; INTVCC = discontinuous mode; resistive divider enables secondary-winding regulation. |
| SGND (7) | Signal ground reference | Star-point connection for feedback divider, compensation network, and small-signal components - isolated from PGND to minimize noise coupling. |
| ION (8) | On-time timer current input | Resistor from VIN sets tON and thus operating frequency; ~60µA typical; enables VIN-compensated constant-frequency operation. |
| VFB (9) | Feedback voltage input | Connects to resistive divider from VOUT; referenced to internal 0.6V bandgap - determines regulated output voltage. |
| EXTVCC (10) | External bias supply input | When >4.7V, disables internal LDO and connects EXTVCC to INTVCC - improves efficiency by bypassing 5V regulator losses. |
| VIN (11) | Main input supply | 4V–36V primary rail input; requires RC filter (1Ω + 0.1µF) to SGND for noise suppression and stability. |
| INTVCC (12) | Internal 5V regulator output | Supplies internal logic and gate drivers; decoupled with ≥1µF low-ESR capacitor to PGND; shuts down if <3.5V. |
| DRVCC (13) | Bottom gate driver supply | Typically tied to INTVCC via RC filter; powers BG driver; decoupled with ≥4.7µF low-ESR capacitor to PGND; max 7V rating. |
| BG (14) | Bottom N-MOSFET gate driver | Drives gate of synchronous rectifier between PGND and DRVCC; 2A peak, 50mA RMS capability; fast rise/fall times (20ns). |
| PGND (15) | Power ground return | Low-impedance return for bottom MOSFET source, sense resistor (–), CIN (–), and CVCC (–); must connect to SGND at single point. |
| SENSE– (16) | Current sense comparator (–) input | Kelvin connection to bottom of sense resistor or PGND when using MOSFET RDS(ON) - enables accurate valley current measurement. |
| SENSE+ (17) | Current sense comparator (+) input | Connected to SW node when no sense resistor used; to top of sense resistor otherwise - completes differential current sensing path. |
| SW (18) | Switch node | Connects to inductor, top MOSFET drain, and bootstrap capacitor (–); swings from ~–0.3V to VIN - defines switching waveform and timing reference. |
| TG (19) | Top N-MOSFET gate driver | Drives gate of high-side switch with swing equal to DRVCC superimposed on SW node; 2A peak, 50mA RMS; fast switching (20ns). |
| BOOST (20) | Bootstrap capacitor (+) terminal | Connects to (+) of CB; floats up to VIN + DRVCC during top-switch conduction - sustains gate drive for high-side N-MOSFET. |
Key Features
| Feature | Design Value |
|---|---|
| No RSENSE operation | Uses bottom MOSFET RDS(ON) for current sensing - eliminates sense resistor cost, board space, and conduction losses while maintaining valley current control. |
| True valley current mode | Measures inductor current at valley point via SENSE+/SENSE– - provides inherent cycle-by-cycle current limiting and stable operation at very low duty cycles. |
| Programmable soft-start | RUN/SS pin accepts external capacitor to control output voltage ramp rate and prevent inrush - supports power sequencing in multi-rail systems. |
| Dual-mode conduction control | FCB pin selects discontinuous mode (light-load efficiency) or forced continuous mode (low-noise, secondary regulation) - configurable per application need. |
| Output overvoltage protection | PGOOD asserts low and M1 shuts off when VFB exceeds ±10% - prevents damage to downstream logic, memory, or processors during fault conditions. |
Applications
| DDR Memory Power Supply | Battery Charger Control |
|---|---|
Use Scenario: Providing tightly regulated 1.2V/1.5V/1.8V rails for DDR3/DDR4 memory modules in laptops and embedded systems. IC Role / Device Role / Timing Role: Synchronous buck controller managing high-current, low-voltage conversion with fast transient response and ±1% output accuracy. Use Value: Enables stable memory operation under dynamic load changes; supports ceramic output capacitors for compact layout and low ESR requirements. | Use Scenario: Controlling constant-current/constant-voltage charging for Li-ion or lead-acid batteries in portable medical devices and power tools. IC Role / Device Role / Timing Role: Primary DC/DC controller regulating charge voltage and limiting charge current via ITH-based foldback and VRNG-programmed sense threshold. Use Value: Delivers precise CC/CV transition without external op-amps; supports wide input (e.g., 9–32V adapter) and programmable current limits. |
| Automobile DC Power Supply | Distributed Power System |
Use Scenario: Converting 12V/24V vehicle battery voltage to 3.3V/5V for infotainment, ADAS sensors, and telematics ECUs. IC Role / Device Role / Timing Role: High-input-voltage synchronous buck controller with UVLO (3.4V–4.0V) and thermal robustness for automotive ambient conditions. Use Value: Operates reliably across cold-crank (4.5V) to load-dump (36V) transients; supports ceramic output caps for vibration resistance. | Use Scenario: Generating intermediate rails (e.g., 5V, 3.3V) from a 12V or 48V backplane in telecom and industrial servers. IC Role / Device Role / Timing Role: Efficient, scalable step-down controller supporting multiple parallel phases or cascaded converters in modular power architectures. Use Value: Adjustable frequency and soft-start allow synchronization and sequencing across distributed rails; stable with ceramic COUT reduces footprint and improves reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3779EFE#TRPBF | Pin-compatible upgrade with enhanced current sensing accuracy (±0.5% vs ±1%), lower tON(MIN) (75ns), and improved thermal performance (θJA = 95°C/W). | Preferred for new designs requiring tighter current limit tolerance and higher VIN/VOUT ratios (e.g., 48V→3.3V). | Select when higher precision valley current measurement and extended high-voltage operation are required; same PCB layout. |
| MP2918GL-Z | Monolithic dual-phase controller with integrated MOSFET drivers; lacks VRNG programmability and true Kelvin sensing; fixed 0.6V reference with ±1.5% tolerance. | Better suited for cost-sensitive, medium-current (≤25A) applications where board space is constrained and discrete MOSFETs are not needed. | Choose for simplified BOM and smaller solution size where programmable sense range and ultra-low tON are non-critical. |
Compared with LTC3778EF#TRPBF, LTC3779EFE#TRPBF offers tighter current limit accuracy and faster minimum on-time for higher step-down ratios, while MP2918GL-Z trades programmability and sensing flexibility for integration and lower component count - making each suitable for distinct design priorities: precision/high-voltage, or compactness/cost.
Availability
LTC3778EF#TRPBF is available at Aetrix Electronics and suitable for DDR memory power supplies, automotive DC/DC conversion, and battery charger control requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC3778EF#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC3778EF#TRPBF belongs to ADI's high-voltage synchronous buck controller product line, designed specifically for efficient, low-noise, and highly flexible DC/DC conversion in computing, automotive, and industrial power systems where precision regulation and wide input range are essential.
FAQ
What is the minimum on-time specification for LTC3778EF#TRPBF, and why does it matter?
The LTC3778EF#TRPBF has a guaranteed minimum on-time (tON(MIN)) of ≤100ns. This parameter is critical for high step-down ratio applications - such as converting 24V input to 1.2V output - where the required duty cycle falls below 5%. Without sufficiently short tON, the controller cannot maintain regulation at light loads or high input voltages, leading to pulse-skipping or dropout. The LTC3778EF#TRPBF achieves this with its valley current mode architecture and optimized one-shot timer, ensuring stable operation across its full 4V–36V input range.
Can LTC3778EF#TRPBF operate without an external current sense resistor?
Yes, the LTC3778EF#TRPBF supports true RDS(ON)-based current sensing by connecting SENSE+ to the SW node and SENSE– to PGND - eliminating the need for an external sense resistor. This configuration uses the bottom MOSFET's on-resistance as the current sense element, improving efficiency and reducing BOM cost. However, accurate current limiting requires careful MOSFET selection accounting for RDS(ON) variation over temperature (ρT ≈ 1.3 at 100°C), as specified in the LTC3778EF#TRPBF datasheet.
How does the VRNG pin affect current limit programming in LTC3778EF#TRPBF?
The VRNG pin on the LTC3778EF#TRPBF sets the nominal current sense voltage: VSENSE(NOM) ≈ 0.133 × VVRNG. For example, tying VRNG to 1V yields ~133mV nominal sense voltage, resulting in a current limit of ILIM = 133mV / RSENSE. The pin accepts 0.5V–2V via resistive divider from INTVCC, enabling programmable current thresholds from ~67mV to ~266mV. This flexibility allows optimization for different MOSFET RDS(ON) values or sense resistor sizes while maintaining consistent loop gain and stability in the LTC3778EF#TRPBF current mode control architecture.
What is the role of the FCB pin in LTC3778EF#TRPBF, and how does it impact efficiency?
The FCB (Forced Continuous) pin on the LTC3778EF#TRPBF selects conduction mode: grounding FCB forces continuous conduction mode (CCM) at all loads, while tying it to INTVCC enables discontinuous conduction mode (DCM) at light loads. DCM improves light-load efficiency by allowing inductor current to fall to zero and disabling both MOSFETs, reducing switching and gate drive losses. CCM reduces output voltage ripple and EMI, and supports secondary winding regulation in fly-buck configurations. The choice directly affects system efficiency profile and noise performance - a key tradeoff managed via the FCB pin in the LTC3778EF#TRPBF.
Does LTC3778EF#TRPBF support output overvoltage protection, and how is it implemented?
Yes, the LTC3778EF#TRPBF includes dedicated output overvoltage protection (OVP). When the feedback voltage (VFB) rises above +10% of the 0.6V reference (i.e., >0.66V), the OVP comparator triggers: the PGOOD output pulls low, and the top MOSFET (M1) is immediately turned off while the bottom MOSFET (M2) is held on to discharge the output. This action clamps VOUT and protects downstream circuitry. The OVP threshold is fixed and unadjustable, but its fast response (<1µs) and autonomous shutdown make it a reliable safeguard in the LTC3778EF#TRPBF's fault protection suite.
LTC3778EF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 36V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
LTC3778EF#TRPBF FAQ
1.How can I place an order for LTC3778EF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3778EF#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 LTC3778EF#TRPBF reliable?
The price and inventory of LTC3778EF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3778EF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3778EF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3778EF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3778EF#TRPBF?
LTC3778EF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3778EF#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 LTC3778EF#TRPBF?
For technical support, including LTC3778EF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3778EF#TRPBF requirements.
6.How does Aetrix verify that LTC3778EF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3778EF#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 LTC3778EF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3778EF#TRPBF?
All LTC3778EF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3778EF#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 LTC3778EF#TRPBF part is unused and in its original packaging.
Return procedure for LTC3778EF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3778EF#TRPBF 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…
