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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > DC DC Switching Controllers

Analog Devices Inc. LTC1778EGN#PBF

Name: LTC1778EGN#PBF
Brand: Analog Devices Inc.
SKU: LTC1778EGN#PBF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LTC1778EGN#PBF

Manufacturer:: Analog Devices Inc.

Category:: DC DC Switching Controllers

Package:: 16-SSOP (0.154", 3.90mm Width)

Datasheet:: LTC1778EGN#PBF.pdf

Description:: IC REG CTRLR BUCK/BCK-BST 16SSOP

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Product details

Overview

LTC1778EGN#PBF from Analog Devices (formerly Linear Technology) is a wide-input synchronous step-down DC/DC controller optimized for CPU and high-step-down-ratio power supplies. It delivers true valley current mode control without an external sense resistor, supports 4V–36V input and 0.8V–(0.9)VIN output, features ≤100ns minimum on-time, ±1% 0.8V reference, and dual N-channel MOSFET synchronous drive - enabling efficient, fast-transient 10A-class point-of-load regulation in notebook and distributed power systems.

For engineers reviewing the LTC1778EGN#PBF datasheet, LTC1778EGN#PBF pinout, LTC1778EGN#PBF application, or LTC1778EGN#PBF equivalent, key selection criteria include its no-R_SENSE current sensing architecture, programmable soft-start via RUN/SS capacitor, PGOOD output monitoring (±7.5% V_FB window), adjustable switching frequency via ION resistor, and stable ceramic-output-capacitor operation.

Technical Context

The LTC1778EGN#PBF implements valley current mode control using the bottom MOSFET's R_DS(ON) as the current sense element, eliminating external sense resistors. Its one-shot timer sets t_ON proportional to ideal duty cycle, enabling near-constant switching frequency across input voltage variations.

Fault protection includes foldback current limiting, output overvoltage detection (5.5–9.5% threshold), undervoltage lockout (3.4–4.0V), and optional short-circuit shutdown timer. Power sequencing is supported via RUN/SS-controlled soft-start and micropower shutdown (I_Q < 30µA).

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	4V to 36V - supports wide industrial and automotive input rails without external pre-regulation.
Output Voltage Range	0.8V to (0.9)×V_IN - enables low-voltage CPU core and I/O rail generation with tight regulation.
Feedback Reference	0.800V ±1% - provides high-accuracy output setpoint for ±1% load/line regulation performance.
Min On-Time	≤100ns - allows high step-down ratios (e.g., 24V→1.2V at 500kHz) without pulse-skipping instability.
Switching Frequency	Adjustable via external R_ON - enables optimization of efficiency vs. size tradeoffs (e.g., 200–300kHz typical).
PGOOD Threshold	±7.5% V_FB window - ensures reliable power-good assertion for system sequencing and fault reporting.
Shutdown Current	<30µA - enables ultra-low quiescent power in battery-backed or standby modes.

Pinout & Package

Package: 16-lead narrow SSOP (GN), RoHS-compliant, 0.15mm max lead thickness, JEDEC MS-012AC footprint.

Pin/Terminal	Circuit Role	Design Meaning
RUN/SS (1)	Run enable & soft-start ramp input	Capacitor-to-ground sets soft-start time (~3s/µF) and overcurrent latchoff delay; <0.8V forces shutdown.
PGOOD (2)	Open-drain power-good monitor	Pulled low when V_FB deviates >±7.5% from 0.8V - used for system reset or enable sequencing.
VRNG (3)	Sense voltage range configuration	Sets nominal current-sense threshold (50–200mV) via resistive divider from INTVCC; defaults to 70mV if grounded.
FCB (4)	Forced continuous mode control	Tie to GND for forced CCM at light load; to INTVCC for DCM; or to secondary winding for multi-output regulation.
ITH (5)	Error amplifier output & current limit threshold	Voltage (0–2.4V) sets valley current limit; clamped during soft-start and overcurrent foldback.
SGND (6)	Signal ground reference	Reference node for all small-signal circuitry; must connect to PGND at single point to avoid noise coupling.
ION (7)	On-time current programming	Resistor from VIN sets one-shot current → determines t_ON and thus switching frequency.
VFB (8)	Feedback input	Connects to resistive divider from V_OUT; error amplifier compares to 0.8V internal reference.
EXTVCC (9)	External bias supply input	Accepts 4.5–7V to bypass internal 5V LDO; reduces power loss and improves efficiency when secondary rail available.
VIN (10)	Main input supply	4–36V input; requires RC filter (1Ω + 0.1µF) to PGND for EMI suppression and gate driver stability.
INTVCC (11)	Internal 5V regulator output	Powers control logic and gate drivers; requires ≥4.7µF low-ESR tantalum capacitor to PGND.
BG (12)	Bottom gate driver output	Drives N-MOSFET source-to-ground; 1–2Ω pull-down/pull-up resistance enables fast turn-on/turn-off.
PGND (13)	Power ground return	Low-impedance return for C_IN, CVCC, and bottom MOSFET source - critical for current-sense accuracy.
SW (14)	Switch node	Connects to inductor and bootstrap capacitor negative terminal; swings from ~–0.5V to V_IN.
TG (15)	Top gate driver output	Drives N-MOSFET gate with swing = INTVCC superimposed on SW node - requires bootstrap capacitor.
BOOST (16)	Bootstrap capacitor positive terminal	Swings from ~INTVCC–0.5V to V_IN+INTVCC; connects to (+) of CB for high-side gate drive.

Key Features

Feature	Design Value
No external sense resistor	Uses bottom MOSFET R_DS(ON) for current sensing - eliminates power loss, board space, and cost of discrete sense resistor.
Valley current mode control	Enables stable operation at very low duty cycles (<5%) and delivers superior transient response vs. voltage-mode controllers.
Ceramic-output-capacitor compatible	Stable with low-ESR ceramic capacitors - reduces output ripple, improves reliability, and avoids electrolytic aging issues.
Programmable soft-start	External capacitor on RUN/SS pin controls ramp rate and prevents inrush current - essential for multi-rail sequencing.
Discontinuous/continuous mode selection	FCB pin enables user-selectable DCM (efficiency at light load) or forced CCM (low-noise, predictable frequency).
Output overvoltage protection	Hardware comparator shuts off top MOSFET and latches bottom MOSFET on - protects downstream loads during feedback failure.

Applications

Notebook CPU Core Supply	Distributed Telecom Power
Use Scenario: Regulating 1.2V/10A core voltage from 12V or 19V adapter in thin-and-light notebooks. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing dynamic load steps up to 8A/µs while maintaining <±1% regulation. Use Value: Eliminates sense resistor loss (≥0.5W saved), enables 100ns min-on-time for 12V→1.2V conversion, and supports ceramic output caps for compact layout.	Use Scenario: Generating isolated 3.3V/5A auxiliary rail from 48V backplane in telecom line cards. IC Role / Device Role / Timing Role: High-input-voltage step-down controller with UVLO (3.4V) and OVP (±7.5%) for robust field deployment. Use Value: Wide 4V–36V input accommodates brownout conditions; PGOOD output interfaces directly with FPGA management logic for fault logging.
Industrial PLC I/O Module	Automotive Infotainment SoC Supply
Use Scenario: Providing clean, sequenced 1.8V/3A supply for FPGA and ADCs in harsh industrial environments. IC Role / Device Role / Timing Role: Controller with –40°C to 85°C operating range, micropower shutdown, and programmable soft-start for cold-start reliability. Use Value: 30µA shutdown current extends backup battery life; EXTVCC pin allows local 5V rail to power gate drivers - reducing thermal stress.	Use Scenario: Powering 1.0V/6A application processor in automotive infotainment head unit with 9–16V battery input. IC Role / Device Role / Timing Role: Synchronous buck controller with fast transient response and integrated overvoltage/undervoltage protection per AEC-Q100 functional safety needs. Use Value: Valley current mode delivers sub-50µs recovery from 5A load steps; ±1% reference ensures SoC timing margin compliance.

Notebook CPU Core Supply

Distributed Telecom Power

Use Scenario: Regulating 1.2V/10A core voltage from 12V or 19V adapter in thin-and-light notebooks.

IC Role / Device Role / Timing Role: Primary synchronous buck controller managing dynamic load steps up to 8A/µs while maintaining <±1% regulation.

Use Value: Eliminates sense resistor loss (≥0.5W saved), enables 100ns min-on-time for 12V→1.2V conversion, and supports ceramic output caps for compact layout.

Use Scenario: Generating isolated 3.3V/5A auxiliary rail from 48V backplane in telecom line cards.

IC Role / Device Role / Timing Role: High-input-voltage step-down controller with UVLO (3.4V) and OVP (±7.5%) for robust field deployment.

Use Value: Wide 4V–36V input accommodates brownout conditions; PGOOD output interfaces directly with FPGA management logic for fault logging.

Industrial PLC I/O Module

Automotive Infotainment SoC Supply

Use Scenario: Providing clean, sequenced 1.8V/3A supply for FPGA and ADCs in harsh industrial environments.

IC Role / Device Role / Timing Role: Controller with –40°C to 85°C operating range, micropower shutdown, and programmable soft-start for cold-start reliability.

Use Value: 30µA shutdown current extends backup battery life; EXTVCC pin allows local 5V rail to power gate drivers - reducing thermal stress.

Use Scenario: Powering 1.0V/6A application processor in automotive infotainment head unit with 9–16V battery input.

IC Role / Device Role / Timing Role: Synchronous buck controller with fast transient response and integrated overvoltage/undervoltage protection per AEC-Q100 functional safety needs.

Use Value: Valley current mode delivers sub-50µs recovery from 5A load steps; ±1% reference ensures SoC timing margin compliance.

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP2451DT-LF-Z	Fixed 500kHz frequency, integrated MOSFETs, 4.5–28V input, no PGOOD, no VRNG/FCB flexibility	Lower BOM count but limited adjustability; unsuitable for >28V input or precision current threshold tuning	Select MP2451DT-LF-Z only for cost-sensitive, fixed-frequency, medium-current (≤2A) applications where layout simplicity outweighs configurability.
LTC3850EGN#PBF	Higher integration (dual-phase capable), 4–38V input, 0.6V reference, no PGOOD, different pinout and compensation scheme	Targeted at higher-current (>20A), multi-phase CPU VRMs; lacks PGOOD and VRNG-based current-sense scaling	Choose LTC3850EGN#PBF for scalable multi-phase designs requiring tighter current sharing, not for single-phase PGOOD-dependent systems.

Compared with MP2451DT-LF-Z and LTC3850EGN#PBF, the LTC1778EGN#PBF uniquely combines no-R_SENSE valley current control, PGOOD output, VRNG-configurable current sensing, and 4–36V input in a 16-pin SSOP - making it optimal for single-phase, high-reliability, mid-power CPU and FPGA supplies requiring precise sequencing and fault reporting.

Availability

LTC1778EGN#PBF is available at Aetrix Electronics and suitable for notebook computing, distributed telecom power, industrial PLC I/O modules, and automotive infotainment SoC supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC1778EGN#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) is a global leader in high-performance analog, mixed-signal, and power management ICs, serving industrial, automotive, communications, and computing markets.

The LTC1778EGN#PBF belongs to Linear's legacy high-efficiency DC/DC controller product line, designed specifically for CPU and FPGA point-of-load applications demanding no-R_SENSE operation, fast transient response, and robust fault protection in space-constrained systems.

FAQ

What is the function of the VRNG pin on the LTC1778EGN#PBF?

The VRNG pin on the LTC1778EGN#PBF sets the nominal current-sense voltage threshold by scaling the bottom MOSFET's R_DS(ON)-based sense signal. Applying 0.5V–2V to VRNG yields a nominal sense voltage of 50–200mV (≈0.133×VRNG); grounding VRNG defaults to 70mV. This allows precise adjustment of current-limit thresholds without changing external MOSFETs - a key enabler for no-R_SENSE design in the LTC1778EGN#PBF.

Does the LTC1778EGN#PBF require an external bootstrap diode?

Yes, the LTC1778EGN#PBF requires an external Schottky diode (e.g., CMDSH-3 or B340A) between INTVCC and BOOST to recharge the bootstrap capacitor during each switching cycle. This diode must have low forward voltage (<0.4V) and fast recovery to maintain sufficient gate drive voltage for the top N-MOSFET - a mandatory component in every LTC1778EGN#PBF application circuit.

How does the PGOOD output of the LTC1778EGN#PBF behave during startup and fault conditions?

The PGOOD output of the LTC1778EGN#PBF is an open-drain signal that remains high-impedance until V_FB reaches within ±7.5% of 0.8V and stays there for >10µs. It pulls low during startup ramp, output overvoltage (>0.86V), undervoltage (<0.74V), or shutdown. This behavior enables reliable power sequencing in multi-rail systems - a defined feature of the LTC1778EGN#PBF, not shared by the pin-compatible LTC1778-1 variant.

Can the LTC1778EGN#PBF operate with ceramic output capacitors only?

Yes, the LTC1778EGN#PBF is explicitly designed for stable operation with ceramic output capacitors - confirmed in its datasheet "Stable with Ceramic C_OUT" feature and validated across load/transient conditions. Its Type III compensation architecture and valley current mode control eliminate the need for high-ESR electrolytics, enabling smaller, more reliable, and longer-life power stages - a core design advantage of the LTC1778EGN#PBF.

What is the minimum on-time specification for the LTC1778EGN#PBF, and why does it matter?

The LTC1778EGN#PBF has a guaranteed minimum on-time (t_ON(MIN)) of ≤100ns. This spec enables high step-down ratios - for example, generating 1.2V from 24V at 500kHz requires ~100ns on-time. Without this capability, the controller would skip pulses or lose regulation at light loads or high input voltages. The ≤100ns t_ON(MIN) is a critical parameter distinguishing the LTC1778EGN#PBF from standard controllers and enabling its use in modern low-voltage, high-input applications.

LTC1778EGN#PBF Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc.

Series:: -

Package/Case:: 16-SSOP (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Active

Output Type:: Transistor Driver

Function:: Step-Down, Step-Up/Step-Down

Output Configuration:: Positive or Negative

Topology:: Buck, Buck-Boost

Number of Outputs:: 1

Output Phases:: 1

Voltage - Supply (Vcc/Vdd):: 4V ~ 36V

Frequency - Switching:: -

Duty Cycle (Max):: -

Synchronous Rectifier:: Yes

Clock Sync:: Yes

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

LTC1778EGN#PBF FAQ

1.How can I place an order for LTC1778EGN#PBF through Aetrix?

Please submit a Request for Quotation (RFQ) for LTC1778EGN#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 LTC1778EGN#PBF reliable?

The price and inventory of LTC1778EGN#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1778EGN#PBF is usually 5 days.

3.What payment methods are accepted for LTC1778EGN#PBF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1778EGN#PBF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LTC1778EGN#PBF?

LTC1778EGN#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LTC1778EGN#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 LTC1778EGN#PBF?

For technical support, including LTC1778EGN#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1778EGN#PBF requirements.

6.How does Aetrix verify that LTC1778EGN#PBF is sourced from the original manufacturer or authorized distributors?

All LTC1778EGN#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 LTC1778EGN#PBF meets industry standards.

7.What is the process for return or replacement of LTC1778EGN#PBF?

All LTC1778EGN#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1778EGN#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 LTC1778EGN#PBF part is unused and in its original packaging.

Return procedure for LTC1778EGN#PBF:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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