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Analog Devices Inc. LTC1778IGN#TRPBF
- Part No.:
- LTC1778IGN#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC1778IGN#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK/BCK-BST 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,170
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Product details
Overview
LTC1778IGN#TRPBF from Analog Devices (formerly Linear Technology) is a wide-input synchronous step-down controller optimized for CPU and high-step-down-ratio DC/DC conversion. It delivers true valley current mode control without an external sense resistor, supports 4V–36V input, 0.8V–(0.9)×VIN output, ≤100ns minimum on-time, and stable ceramic output capacitor operation.
For engineers reviewing the LTC1778IGN#TRPBF datasheet, LTC1778IGN#TRPBF pinout, LTC1778IGN#TRPBF application, or LTC1778IGN#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed thermal and electrical specifications across –40°C to 125°C, and real-world alternative selection guidance for high-efficiency buck controller design.
Technical Context
The LTC1778IGN#TRPBF implements valley current mode control using the bottom MOSFET's RDS(ON) as the current sense element-eliminating RSENSE while maintaining fast transient response. Its one-shot timer sets tON via ION pin current and defaults to 0.7V VON reference (LTC1778 variant), enabling frequency stabilization across VIN variations.
Fault protection includes foldback current limiting, ±7.5% output overvoltage/undervoltage detection with PGOOD assertion, optional short-circuit shutdown timer, and micropower shutdown (IQ < 30µA). Discontinuous mode operation at light loads improves efficiency, and forced continuous mode is selectable via FCB pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 36V - supports industrial, automotive, and distributed power rails without pre-regulation. |
| Output Voltage Range | 0.8V to (0.9)×VIN - enables direct CPU core voltage regulation down to sub-1V levels. |
| Reference Accuracy | ±1% at 0.8V - ensures tight output regulation under line/load/temperature variation. |
| tON(MIN) | ≤100ns - enables high step-down ratios (e.g., 24V→1.2V at ~500kHz) without pulse-skipping instability. |
| Shutdown Current | <30µA - meets ultra-low-power system standby requirements. |
| Operating Temp Range | –40°C to +125°C - qualified for extended-temperature industrial and embedded applications. |
| Package | 16-pin narrow SSOP - surface-mount compatible with standard reflow profiles and PCB layout constraints. |
Pinout & Package
Package: 16-lead plastic narrow SSOP (GN), JEDEC MS-013AC, 0.150" body width, 0.025" lead pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS (Pin 1) | Run enable & soft-start control | Pull below 0.8V to shut down; external capacitor sets soft-start ramp time (~3s/µF) and overcurrent latchoff delay. |
| PGOOD (Pin 2) | Open-drain power-good monitor | Pulled low when VFB exits ±7.5% regulation window - used for system sequencing and fault signaling. |
| VRNG (Pin 3) | Sense voltage range programming | Sets nominal current sense threshold (50mV–200mV) via resistive divider from INTVCC; determines max inductor valley current. |
| FCB (Pin 4) | Forced continuous mode control | Tie to GND for continuous conduction at light load; tie to INTVCC to enable discontinuous mode for higher light-load efficiency. |
| ITH (Pin 5) | Error amplifier output & current limit threshold | Voltage (0–2.4V) sets valley current comparator threshold; also serves as compensation node for loop stability. |
| SGND (Pin 6) | Signal ground reference | Return for all small-signal components (feedback, compensation, soft-start); must connect to PGND at single point to avoid noise coupling. |
| ION (Pin 7) | On-time timing current input | Current sourced from VIN through external RON sets tON; enables frequency adjustment and VIN-compensated constant-frequency operation. |
| VFB (Pin 8) | Feedback input | Connects to resistive divider from VOUT; compared against 0.8V internal reference to regulate output voltage. |
| EXTVCC (Pin 9) | External bias supply input | Accepts 4.5–7V supply to power INTVCC directly - bypasses internal LDO for higher efficiency and stronger gate drive. |
| VIN (Pin 10) | Main input supply | Primary power input (4–36V); requires RC filter (1Ω + 0.1µF) to PGND for noise suppression. |
| INTVCC (Pin 11) | Internal 5V regulator output | Supplies gate drivers and control circuitry; requires ≥4.7µF low-ESR tantalum capacitor to PGND. |
| BG (Pin 12) | Bottom gate driver output | Drives gate of synchronous N-MOSFET between PGND and INTVCC; 1–2Ω pull-down/pull-up resistance. |
| PGND (Pin 13) | Power ground | High-current return for bottom MOSFET source, CIN (–), CVCC (–); must be connected near MOSFET source with low-inductance path. |
| SW (Pin 14) | Switch node | Connects to drain of top MOSFET and (–) terminal of bootstrap capacitor CB; swings from ~–0.5V to VIN. |
| TG (Pin 15) | Top gate driver output | Drives gate of high-side N-MOSFET with swing equal to INTVCC superimposed on SW node voltage. |
| BOOST (Pin 16) | Bootstrap capacitor positive terminal | Connects to (+) terminal of CB; floats up to VIN + INTVCC during top switch conduction. |
Key Features
| Feature | Design Value |
|---|---|
| No external sense resistor | Uses bottom MOSFET RDS(ON) for current sensing - eliminates component count, board space, and power loss of discrete RSENSE. |
| Valley current mode control | Enables stable operation at very low duty cycles (<5%) and fast load transient recovery without slope compensation. |
| Programmable minimum on-time | Configurable tON via ION pin current - supports high-frequency, high-step-down designs (e.g., 24V→1.2V @ 1MHz). |
| Discontinuous/continuous mode selection | FCB pin allows dynamic switching between DCM (high light-load efficiency) and CCM (low EMI, better secondary regulation). |
| Integrated PGOOD monitoring | Dedicated open-drain output asserts fault when output deviates >±7.5% - simplifies system power sequencing and health monitoring. |
| Micropower shutdown | IQ < 30µA in shutdown - meets stringent energy-saving requirements for battery-backed or always-on systems. |
Applications
| Server CPU Core Power | Industrial Distributed Power |
|---|---|
Use Scenario: Regulating 1.2V/10A core voltage for x86 or ARM processors in rack-mounted servers with 12V or 48V intermediate bus. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-current, low-voltage conversion with fast transient response to CPU load steps. Use Value: Eliminates sense resistor losses, achieves <90% efficiency at full load, and maintains ±1% output accuracy across temperature and line variation. | Use Scenario: Generating 3.3V/5A auxiliary rail from 24V factory automation PLC backplane with strict EMI and thermal constraints. IC Role / Device Role / Timing Role: High-reliability step-down controller supporting wide input range and extended temperature operation in harsh environments. Use Value: Stable ceramic-capacitor-based output filtering, programmable soft-start prevents inrush, and –40°C to +125°C rating ensures uptime in uncontrolled enclosures. |
| Telecom Base Station RF Power | Medical Imaging Subsystem |
Use Scenario: Supplying 2.5V/8A power to GaN PA bias circuits in 5G macro base stations where input varies from 28V to 36V. IC Role / Device Role / Timing Role: High-input-voltage buck controller delivering tightly regulated, low-noise bias with fast transient immunity to RF burst loading. Use Value: ≤100ns tON(MIN) enables stable 28V→2.5V conversion at 500kHz; PGOOD interface coordinates with FPGA supervisory logic. | Use Scenario: Providing isolated 1.8V/3A digital supply for FPGA-based image reconstruction engines in MRI/PET scanners requiring low EMI and zero failure risk. IC Role / Device Role / Timing Role: Safety-critical power controller with overvoltage/undervoltage lockout, foldback current limiting, and latchoff timer for fault containment. Use Value: Output OVP shuts down top MOSFET and holds bottom MOSFET on to clamp VOUT; shutdown IQ < 30µA supports battery backup modes. |
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, no PGOOD, lower VIN max (36V same), no VRNG/FCB programmability | Lacks adjustable current sense range and forced continuous mode - less flexible for high-precision or variable-load systems | Select when cost sensitivity outweighs need for programmable light-load behavior or precision current limiting. |
| TPS54620RGYR | Integrated FETs (not controller), 4.5–17V VIN, 0.6V ref, no PGOOD, different package (VQFN) | Monolithic solution - eliminates external MOSFETs but limits max current and input voltage range vs. LTC1778IGN#TRPBF | Select for compact, medium-power (≤6A) designs where board space is critical and 36V input not required. |
Compared with MP2451DT-LF-Z and TPS54620RGYR, the LTC1778IGN#TRPBF offers superior flexibility in current sensing, light-load mode control, and high-input-voltage capability - making it preferred for demanding CPU, telecom, and industrial applications where performance and configurability are prioritized over integration or lowest BOM cost.
Availability
LTC1778IGN#TRPBF is available at Aetrix Electronics and suitable for server CPU power, industrial distributed power, telecom RF bias, and medical imaging subsystems requiring stable component supply, extended temperature support, and long-term lifecycle continuity.
Supply support for LTC1778IGN#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 by the acquisition of Linear Technology in 2017.
The LTC1778IGN#TRPBF belongs to ADI's legacy Linear Technology power controller family, designed specifically for high-efficiency, high-step-down-ratio synchronous buck conversion in computing, communications, and industrial systems where precision, reliability, and thermal robustness are essential.
FAQ
What is the maximum input voltage rating for the LTC1778IGN#TRPBF?
The LTC1778IGN#TRPBF has an absolute maximum input voltage (VIN) rating of 36V. Operation above this level risks permanent damage. The recommended operating range is 4V to 36V, with guaranteed performance across the full –40°C to +125°C junction temperature range. Input transients must be clamped externally if exceeding 36V.
Does the LTC1778IGN#TRPBF require an external current sense resistor?
No, the LTC1778IGN#TRPBF does not require an external current sense resistor. It uses the RDS(ON) of the external bottom N-channel MOSFET as the current sensing element - a key feature enabling higher efficiency and reduced component count. The VRNG pin configures the effective sense voltage range (50mV–200mV) based on the MOSFET's on-resistance.
What is the function of the PGOOD pin on the LTC1778IGN#TRPBF?
The PGOOD pin on the LTC1778IGN#TRPBF is an open-drain output that signals valid regulation: it remains high-impedance when VFB is within ±7.5% of 0.8V, and pulls low when the output voltage deviates beyond that window. This enables precise power sequencing, fault detection, and system-level health monitoring without additional supervision ICs.
How is switching frequency set on the LTC1778IGN#TRPBF?
Switching frequency on the LTC1778IGN#TRPBF is set by the current into the ION pin, determined by an external resistor (RON) from VIN to ION. The default VON reference is 0.7V (LTC1778 variant), yielding tON ≈ (10pF × VON)/IION. Frequency remains approximately constant across VIN changes due to the inverse relationship between IION and VIN.
What package type and temperature grade does the LTC1778IGN#TRPBF use?
The LTC1778IGN#TRPBF uses a 16-lead narrow SSOP (GN) package and is rated for operation from –40°C to +125°C ambient temperature (Grade I). Its part marking "1778I" confirms the industrial temperature grade, and the θJA is specified at 130°C/W - critical for thermal design in enclosed or high-ambient environments.
LTC1778IGN#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, 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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
LTC1778IGN#TRPBF FAQ
1.How can I place an order for LTC1778IGN#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1778IGN#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 LTC1778IGN#TRPBF reliable?
The price and inventory of LTC1778IGN#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1778IGN#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1778IGN#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1778IGN#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1778IGN#TRPBF?
LTC1778IGN#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1778IGN#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 LTC1778IGN#TRPBF?
For technical support, including LTC1778IGN#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1778IGN#TRPBF requirements.
6.How does Aetrix verify that LTC1778IGN#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1778IGN#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 LTC1778IGN#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1778IGN#TRPBF?
All LTC1778IGN#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1778IGN#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 LTC1778IGN#TRPBF part is unused and in its original packaging.
Return procedure for LTC1778IGN#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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