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Analog Devices Inc. LTC3878EGN#TRPBF
- Part No.:
- LTC3878EGN#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3878EGN#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:5,850
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Product details
Overview
LTC3878EGN#TRPBF from Analog Devices (formerly Linear Technology) is a synchronous step-down DC/DC controller IC optimized for high-frequency operation and fast transient response in high-ratio buck converters. It features no-RSENSE valley current mode control, 4V–38V input range, ±1% 0.8V reference, 43ns minimum on-time, and dual N-channel MOSFET gate drive - enabling efficient 1.2V/15A power delivery in communications infrastructure and embedded computing systems.
For engineers reviewing the LTC3878EGN#TRPBF datasheet, LTC3878EGN#TRPBF pinout, LTC3878EGN#TRPBF application, or LTC3878EGN#TRPBF equivalent, this page delivers verified technical context, validated pin functions, confirmed package mapping to 16-pin narrow SSOP, real-world efficiency curves at 400kHz, and two rigorously cross-checked alternative controllers with documented functional and application-level differences.
Technical Context
The LTC3878EGN#TRPBF implements constant-on-time valley current mode control using the bottom MOSFET's RDS(ON) as the current sense element - eliminating external sense resistors and slope compensation. Its one-shot timer sets tON via ION pin current, enabling pseudo-fixed frequency operation with VIN compensation.
It integrates dual gate drivers (TG/BG) with 1.2Ω/0.7Ω pull-down and 2.5Ω pull-up on-resistances, programmable current limit with foldback, output overvoltage protection, and forced continuous/discontinuous mode selection via FCB pin - all operating within –40°C to 85°C ambient temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 38V - supports wide-input industrial and telecom supplies without pre-regulation. |
| Feedback Reference | 0.8V ±1% - enables precise low-voltage regulation down to 0.8V with minimal divider error. |
| Min On-Time (tON(MIN)) | 43ns - allows stable operation at high step-down ratios (e.g., 28V→1.2V) with >90% duty cycle headroom. |
| Switching Frequency | Adjustable via external RON; typical 400kHz at VIN=12V/VOUT=1.2V - balances efficiency and component size. |
| Current Sense Method | No-RSENSE valley sensing using bottom MOSFET VDS - eliminates power loss and PCB area of external resistor. |
| Package | 16-pin narrow SSOP (GN) - 5.3mm × 6.2mm footprint compatible with standard reflow processes. |
| Thermal Performance | θJA = 110°C/W - requires minimal copper pour for thermal management at full load. |
Pinout & Package
Package: 16-lead plastic narrow SSOP (GN), RoHS-compliant, moisture sensitivity level 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS (1) | Run enable & soft-start timing input | Internal 1.2µA current source charges external capacitor; device enters micropower shutdown below 0.7V. |
| PGOOD (2) | Open-drain power-good monitor | Asserts low when VOUT deviates >±7.5% from regulation - enables system sequencing and fault detection. |
| VRNG (3) | VDS sense voltage range selector | Sets max valley current threshold: 93mV (SGND) to 186mV (INTVCC) - adapts to MOSFET RDS(ON) variation. |
| FCB (4) | Forced continuous mode control | Tie to SGND to disable discontinuous mode - reduces light-load noise and improves regulation stability. |
| ITH (5) | Error amplifier output & current limit threshold | Voltage (0–2.4V) sets valley current comparator trip point - directly links feedback error to inductor current. |
| SGND (6) | Signal ground reference | Must be star-connected to PGND at single point to avoid noise coupling into feedback and current sense paths. |
| ION (7) | On-time current programming input | Resistor from VIN sets tON; enables VIN-compensated frequency stability across wide input range. |
| VFB (8) | Feedback voltage input | Connects to resistive divider from VOUT; internal 0.8V reference enables accurate output voltage setting. |
| NC (9) | No connect | Factory test pin - must remain unconnected or tied ≤ INTVCC; no circuit function in normal operation. |
| VIN (10) | Main input supply | Accepts 4V–38V; requires local RC filter to PGND for EMI suppression and noise immunity. |
| INTVCC (11) | Internal 5.3V LDO output | Powers gate drivers and control logic; requires ≥1µF X5R/X7R ceramic decoupling to PGND. |
| BG (12) | Bottom gate driver output | Drives synchronous N-MOSFET source-to-PGND; 0.7Ω pull-down ensures fast turn-off and prevents shoot-through. |
| PGND (13) | Power ground return | Low-impedance connection point for bottom MOSFET source, CINTVCC(–), and CVIN(–). |
| SW (14) | Switch node | Connects to inductor, bottom MOSFET drain, and bootstrap capacitor (–); swings from –0.3V to VIN. |
| TG (15) | Top gate driver output | Drives top N-MOSFET gate between SW and BOOST; 1.2Ω pull-down minimizes dead time and conduction loss. |
| BOOST (16) | Bootstrap floating supply | Connects to (+) of bootstrap capacitor; floats with SW to provide >VIN gate drive for top MOSFET. |
Key Features
| Feature | Design Value |
|---|---|
| No-RSENSE valley current sensing | Eliminates external sense resistor and associated power loss, PCB area, and thermal drift - improves efficiency by up to 1.6% vs LTC1778. |
| Programmable current limit with foldback | Protects against short-circuits by reducing current setpoint when VOUT drops below 50% regulation - prevents thermal runaway during faults. |
| Stable with low-ESR ceramic output capacitors | Supports multilayer ceramic capacitors (MLCCs) without external compensation - simplifies layout and reduces output ripple. |
| Smooth start-up into pre-biased output | Enables hot-swap and rail sequencing in multi-rail systems without output voltage overshoot or reverse current flow. |
| Pin-compatible with LTC1778 (no EXTVCC) | Direct replacement in legacy designs omitting EXTVCC pin - retains identical pinout except NC instead of EXTVCC at Pin 9. |
Applications
| Telecom Power Supply | Server VRM Core |
|---|---|
|
Use Scenario: 48V intermediate bus conversion to 1.2V/15A for ASIC/FPGA core rails in 5G baseband units. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-current, fast-transient loads with <50µs recovery from 0→10A steps. Use Value: 43ns tON(MIN) enables stable 28:1 step-down ratio; no-RSENSE sensing avoids 2W+ resistor loss at full load. |
Use Scenario: Point-of-load (POL) regulator on motherboard delivering 1.2V to CPU cores with strict ±1% tolerance and <10mV ripple. IC Role / Device Role / Timing Role: Valley current mode controller providing precise output regulation and seamless transition between continuous/discontinuous modes. Use Value: ±1% 0.8V reference and 0.002%/V line regulation ensure tight output accuracy across 4V–38V input variation. |
| Industrial PLC I/O Module | Optical Transceiver Power |
|
Use Scenario: Wide-input (12–36V) DC/DC stage powering isolated analog front-ends and digital logic in factory automation controllers. IC Role / Device Role / Timing Role: High-reliability step-down controller supporting extended temperature range (–40°C to 85°C) and robust overvoltage protection. Use Value: Output overvoltage protection triggers at ±7.5% deviation; PGOOD flag enables system-level fault isolation and safe shutdown. |
Use Scenario: Compact 3.3V→1.2V converter for SFP+ transceivers requiring low EMI, fast load transient response, and small form factor. IC Role / Device Role / Timing Role: Low-noise synchronous controller with forced continuous mode (FCB=SGND) to suppress RF interference in signal integrity-critical links. Use Value: 20ns TG/BG rise/fall times and 15ns synchronous switch delay minimize switching noise; 16-pin SSOP fits tight board space. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3878IGN#TRPBF | Same die, –40°C to 85°C guaranteed spec grade (vs E-grade characterized only); identical pinout and electrical specs. | Required for industrial deployments demanding full temp-range validation; higher screening cost but no design change. | Select when BOM requires guaranteed performance across full –40°C to 85°C range per datasheet Note 4. |
| LTC3892-2#TRPBF | Includes integrated 5V bias supply, dual output capability, and enhanced PMBus telemetry; larger 28-pin QFN package. | Used in multi-rail systems needing coordinated sequencing and telemetry; not drop-in due to pin count and feature set mismatch. | Choose when adding monitoring, dual outputs, or self-powered operation justifies redesign and larger footprint. |
Compared with LTC3878EGN#TRPBF, the LTC3878IGN#TRPBF offers identical functionality with guaranteed specifications across –40°C to 85°C, while the LTC3892-2#TRPBF adds telemetry and dual outputs at the cost of pin compatibility and increased complexity - making the E-grade optimal for cost-sensitive, single-output telecom and computing applications where characterization assurance suffices.
Availability
LTC3878EGN#TRPBF is available at Aetrix Electronics and suitable for distributed power systems, embedded computing platforms, and communications infrastructure requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for LTC3878EGN#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, industrial, automotive, and communications markets.
The LTC3878EGN#TRPBF belongs to Linear's high-efficiency synchronous buck controller product line, designed specifically for fast-transient, wide-input-range DC/DC conversion in space-constrained and thermally demanding environments.
FAQ
What is the minimum on-time specification for the LTC3878EGN#TRPBF, and why does it matter?
The LTC3878EGN#TRPBF has a guaranteed minimum on-time (tON(MIN)) of 43ns. This parameter determines the lowest achievable output voltage at a given input voltage and switching frequency - critical for high step-down ratio applications like 28V→1.2V conversion. A shorter tON(MIN) preserves regulation margin and prevents dropout during low-duty-cycle operation, directly enabling stable core voltage generation in modern processors and FPGAs.
How does the LTC3878EGN#TRPBF achieve current sensing without an external resistor?
The LTC3878EGN#TRPBF uses the on-resistance (RDS(ON)) of the external bottom N-channel MOSFET as the current sense element. It measures the voltage drop between SW and PGND pins (VDS) during bottom-FET conduction and compares it to a programmable threshold set by the VRNG pin. This No-RSENSE architecture eliminates power loss, board area, and thermal drift associated with discrete sense resistors - improving efficiency and simplifying layout in high-current designs.
Is the LTC3878EGN#TRPBF pin-compatible with the LTC1778, and what are the key differences?
Yes, the LTC3878EGN#TRPBF is pin-compatible with the LTC1778 in applications that do not use the EXTVCC pin (Pin 9 on LTC1778 is NC on LTC3878EGN#TRPBF). Key improvements include reduced gate driver on-resistances (1.2Ω vs 2.5Ω pull-down), lower dead time, and removal of the shutdown latch-off timer. These changes yield higher efficiency and simpler startup behavior - but full compatibility must be verified per application, especially under transient and fault conditions.
What is the role of the VRNG pin on the LTC3878EGN#TRPBF, and how should it be configured?
The VRNG pin on the LTC3878EGN#TRPBF sets the maximum allowable valley current sense threshold by scaling the bottom MOSFET VDS measurement. Applying 0.2V–2V to VRNG adjusts the threshold from ~26.6mV to ~266mV. Tying VRNG to SGND fixes it at 93mV (typ), while connecting to INTVCC sets it to 186mV (typ). Proper configuration ensures accurate current limiting across MOSFET RDS(ON) variation and temperature - critical for reliable foldback protection and load-step response.
Does the LTC3878EGN#TRPBF support operation into a pre-biased output, and how is it implemented?
Yes, the LTC3878EGN#TRPBF supports smooth start-up into a pre-biased output. During soft-start, the controller monitors the VFB pin and only enables gate drive when the feedback voltage rises above the 0.8V reference - preventing reverse current flow through the bottom MOSFET. This behavior is inherent to its valley current mode architecture and requires no external circuitry, making it ideal for hot-swap and multi-rail sequencing applications where downstream rails may already be powered.
LTC3878EGN#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 38V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
LTC3878EGN#TRPBF FAQ
1.How can I place an order for LTC3878EGN#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3878EGN#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 LTC3878EGN#TRPBF reliable?
The price and inventory of LTC3878EGN#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3878EGN#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3878EGN#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3878EGN#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3878EGN#TRPBF?
LTC3878EGN#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3878EGN#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 LTC3878EGN#TRPBF?
For technical support, including LTC3878EGN#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3878EGN#TRPBF requirements.
6.How does Aetrix verify that LTC3878EGN#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3878EGN#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 LTC3878EGN#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3878EGN#TRPBF?
All LTC3878EGN#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3878EGN#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 LTC3878EGN#TRPBF part is unused and in its original packaging.
Return procedure for LTC3878EGN#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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