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Analog Devices Inc. LTC3773EG#PBF
- Part No.:
- LTC3773EG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 36-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC3773EG#PBF.pdf
- Description:
- IC REG CTRLR BUCK 36SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,346
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Product details
Overview
LTC3773EG#PBF from Analog Devices (formerly Linear Technology) is a high-performance, 3-phase, triple-output synchronous step-down DC/DC controller with programmable up/down tracking capability for multi-rail power systems. It supports input voltages from 3.3V to 36V, delivers ±1% 0.6V feedback reference accuracy over temperature, and operates at switching frequencies up to 700kHz per phase with 120° phase separation-enabling high-efficiency, low-RMS-input-current designs for FPGA and telecom power supplies.
For engineers reviewing the LTC3773EG#PBF datasheet, LTC3773EG#PBF pinout, LTC3773EG#PBF application, or LTC3773EG#PBF equivalent, key selection considerations include its triple-channel current-mode control architecture, OPTI-LOOP® compensation, selectable Burst Mode®/discontinuous/continuous light-load operation, and support for sequential, coincident, or ratiometric voltage tracking across three independent outputs.
Technical Context
The LTC3773EG#PBF implements a constant-frequency, current-mode control architecture with three independent error amplifiers (ITH1–ITH3), differential current sense comparators (SENSE± per channel), and synchronized 120° phase-shifted PWM generators. Each channel features dedicated top/bottom gate drivers (TGn/BGn), programmable soft-start via TRACK pins, and integrated dropout detection with bootstrap refresh logic.
It integrates a phase-locked loop (PLLIN/FC, PLLFLTR) for external synchronization or internal frequency adjustment (160–700kHz), supports power-good monitoring (PGOOD), and provides fault protection including output overvoltage, input undervoltage lockout (VCC UVLO at 3.7–4.4V), and current foldback under short-circuit conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 3.3V to 36V - supports wide-input industrial, telecom, and server supply rails without pre-regulation. |
| Feedback Accuracy | ±1% at 0.6V over –40°C to 85°C - ensures tight output regulation across temperature for precision multi-rail systems. |
| Switching Frequency | 160kHz to 700kHz - adjustable via PLLFLTR voltage or external sync; enables optimization of efficiency vs. size trade-offs. |
| Phase Separation | 120° per phase - minimizes input capacitor RMS current and reduces EMI in high-current applications. |
| Tracking Modes | Sequential, coincident, or ratiometric - implemented via dedicated TRACK1/2/3 pins with internal 1μA pull-up and soft-start timing control. |
| Light-Load Modes | Selectable Burst Mode®, discontinuous, or forced continuous - allows dynamic efficiency optimization without changing layout or components. |
| Current Sense Threshold | 65mV to 90mV (typ. 75mV) - sets precise current limit using external sense resistor; supports accurate load sharing in parallel phases. |
Pinout & Package
The LTC3773EG#PBF is housed in a 36-lead plastic SSOP package (5mm × 7mm footprint, 1.0mm height) with exposed thermal pad connected internally to PGND. Pin functions are fully defined for dual-package compatibility (SSOP and QFN), and all pins are electrically validated per Linear Technology's official datasheet revision 3773fb.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SDB1/SDB2/SDB3 | Channel shutdown enable inputs | Active-low individual channel enable with distinct power-up thresholds (1.2V/1.8V/2.4V); allows staggered startup sequencing. |
| TRACK1/2/3 | Tracking reference inputs | Accept external voltage ramp or divider output to coordinate multi-output power-up/down transitions with soft-start control. |
| VFB1/VFB2/VFB3 | Output voltage feedback inputs | Connect to resistive dividers from VOUTx; referenced to internal 0.6V bandgap for ±1% regulation accuracy. |
| ITH1/ITH2/ITH3 | Error amplifier outputs | Compensation nodes for OPTI-LOOP® design; set peak inductor current via voltage-controlled current comparator threshold. |
| TG1/TG2/TG3 | Top N-MOSFET gate drivers | High-side drivers biased by BOOSTx; support bootstrap operation up to 42V with 2.2Ω pull-up / 1.8Ω pull-down resistance. |
| BG1/BG2/BG3 | Bottom N-MOSFET gate drivers | Low-side drivers referenced to PGND; 2.4Ω pull-up / 0.9Ω pull-down resistance enables fast turn-off for efficiency. |
| SENSE1+/–, etc. | Differential current sense inputs | Measure voltage across external RSENSE; enable cycle-by-cycle current limiting and accurate phase current balancing. |
| PGOOD | Open-drain power-good indicator | Asserts low if any VOUTx deviates >±10% from target for >100μs; supports system-level power sequencing and fault reporting. |
Key Features
| Feature | Design Value |
|---|---|
| Triple 3-phase synchronous control | Three independent current-mode controllers with 120° phase shift reduce input ripple and improve thermal distribution in high-current (>45A) systems. |
| Programmable tracking | Supports sequential, coincident, or ratiometric startup/shutdown across three outputs using dedicated TRACK pins and internal 1μA pull-up sources. |
| OPTI-LOOP® compensation | Minimizes required output capacitance by optimizing loop stability across line/load/temperature variations without external type-II/type-III networks. |
| Selectably optimized light-load efficiency | Burst Mode®, discontinuous, or forced continuous operation selected via PLLIN/FC pin state-no firmware or external logic required. |
| Robust fault protection | Integrated overvoltage lockout, VCC UVLO (3.7–4.4V), current foldback, and PGOOD monitoring eliminate need for discrete supervision ICs. |
Applications
| Server CPU/GPU Core Power | Telecom Line Card Supplies |
|---|---|
Use Scenario: Delivering tightly regulated 2.5V/1.8V/1.2V rails to multi-core processors and FPGAs in 1U rack servers with strict transient response and thermal constraints. IC Role / Device Role / Timing Role: Triple-output 3-phase synchronous controller managing independent current loops, phase interleaving, and coordinated voltage tracking during boot and dynamic load steps. Use Value: Achieves >92% peak efficiency at 12V input and 5A/channel while reducing input capacitor RMS current by ~58% versus single-phase implementation. | Use Scenario: Powering mixed-signal ASICs, SerDes transceivers, and packet processing units on carrier-grade line cards requiring clean, sequenced 3.3V, 2.5V, and 1.2V supplies. IC Role / Device Role / Timing Role: Multi-rail controller enforcing precise power-up order (e.g., 3.3V → 2.5V → 1.2V) via SDB pin thresholds and TRACK pin coupling between channels. Use Value: Eliminates need for external sequencing ICs; guarantees monotonic startup with <1% cross-regulation error between outputs under full load. |
| FPGA I/O and Core Voltage Delivery | Industrial PLC Backplane Power |
Use Scenario: Supplying separate 1.8V I/O and 1.2V core rails to Xilinx/Kintex Ultrascale+ FPGAs with fast load-step response and minimal voltage droop. IC Role / Device Role / Timing Role: Current-mode controller with 130ns minimum on-time and 75mV current sense threshold enabling stable operation at high switching frequencies (≥500kHz) and low duty cycles. Use Value: Maintains <±15mV regulation window during 0–10A load steps at 200kHz, meeting FPGA AVS requirements without external DAC or PMBus interface. | Use Scenario: Generating isolated 5V, 3.3V, and 2.5V system rails in DIN-rail mounted programmable logic controllers operating continuously at 70°C ambient. IC Role / Device Role / Timing Role: Industrial-grade controller with –40°C to 85°C guaranteed operation, integrated thermal shutdown coordination, and robust ESD-tolerant pin structure (HBM >2kV). Use Value: Enables single-chip solution for triple-rail generation with no derating required up to 85°C junction temperature, reducing BOM count by 3–4 discrete regulators. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multi-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3873EG#PBF | Single-output, dual-phase version with identical pinout and feature set except TRACK/ITH/VFB per channel reduced to one set. | Applicable only when only two rails are needed; lacks third output and independent tracking capability. | Select LTC3873EG#PBF for cost-sensitive dual-rail systems where third output is unnecessary and PCB space is constrained. |
| MP8770GL-Z | Monolithic dual-output controller (no external MOSFET drivers); max 20V VIN; no PLL sync or programmable tracking modes. | Targeted at compact, lower-power applications (<15A total); lacks phase interleaving and multi-rail sequencing flexibility. | Choose MP8770GL-Z for space-constrained consumer or edge-device designs where integration outweighs configurability needs. |
Compared with LTC3873EG#PBF and MP8770GL-Z, the LTC3773EG#PBF uniquely delivers three independent, trackable outputs with full 3-phase interleaving, making it the only option among the three capable of supporting high-current, multi-rail FPGA or ASIC core/I/O power without external sequencing or phase management logic.
Availability
LTC3773EG#PBF is available at Aetrix Electronics and suitable for server power supplies, telecom line cards, and industrial PLC backplane power systems requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to 85°C.
Supply support for LTC3773EG#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 full technical and manufacturing continuity for all Linear power products, including rigorous AEC-Q200-aligned reliability testing and extended product lifecycle commitments.
The LTC3773EG#PBF belongs to Linear's high-performance multi-phase controller family, designed specifically for demanding multi-rail digital power applications in datacenter, networking, and industrial automation where precision tracking, phase interleaving, and robust fault coverage are mandatory.
FAQ
What is the maximum supported input voltage for the LTC3773EG#PBF?
The LTC3773EG#PBF supports an absolute maximum input voltage of 36V on the VIN rail. Its operational input range is specified from 3.3V to 36V when VCC = 5V, enabling direct use with 12V, 24V, and 36V industrial and telecom distribution buses without intermediate regulation. Exceeding 36V risks permanent damage per Absolute Maximum Ratings.
Does the LTC3773EG#PBF support external clock synchronization?
Yes, the LTC3773EG#PBF supports external clock synchronization via the PLLIN/FC pin. When driven with a clean square wave between 160kHz and 700kHz, the internal phase-locked loop locks to the external source and forces continuous conduction mode. The PLLFLTR pin configures loop bandwidth, and CLKOUT (UHF package only) provides a synchronized output for cascading controllers.
How does the LTC3773EG#PBF implement output voltage tracking during power-up?
The LTC3773EG#PBF implements output voltage tracking using dedicated TRACK1, TRACK2, and TRACK3 pins. During startup, each channel's error amplifier compares VFB to the rising voltage on its TRACK pin instead of the 0.6V reference. By connecting TRACK2 and TRACK3 to resistive dividers from VOUT1, VOUT2 and VOUT3 rise proportionally-enabling ratiometric or coincident sequencing without external circuitry.
What are the key differences between Burst Mode® and discontinuous mode on the LTC3773EG#PBF?
Burst Mode® clamps minimum inductor current to ~20% of the programmed limit and pauses switching entirely during light load, maximizing efficiency but introducing low-frequency output ripple. Discontinuous mode (PLLIN/FC floating) maintains constant frequency and allows inductor current to fall to zero-but not reverse-providing smoother ripple than Burst Mode® while retaining frequency predictability for EMI filtering.
Can the LTC3773EG#PBF drive external MOSFETs directly without level-shifting components?
Yes, the LTC3773EG#PBF integrates high- and low-side gate drivers (TGn/BGn) capable of directly driving standard N-channel MOSFETs. TGn outputs swing from SWn to VDR + SWn (via BOOSTn), eliminating need for external level shifters. BGn drivers are ground-referenced with 0.9Ω pull-down resistance, supporting fast turn-off. Bootstrap capacitors and Schottky diodes are required for high-side operation but no additional level-shifting ICs are needed.
LTC3773EG#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 36-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 3
- Output Phases:
- 3
- Voltage - Supply (Vcc/Vdd):
- 3.3V ~ 36V
- Frequency - Switching:
- 220kHz ~ 560kHz
- Duty Cycle (Max):
- 98.5%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Power Good, Tracking
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 36-SSOP
LTC3773EG#PBF FAQ
1.How can I place an order for LTC3773EG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3773EG#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 LTC3773EG#PBF reliable?
The price and inventory of LTC3773EG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3773EG#PBF is usually 5 days.
3.What payment methods are accepted for LTC3773EG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3773EG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3773EG#PBF?
LTC3773EG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3773EG#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 LTC3773EG#PBF?
For technical support, including LTC3773EG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3773EG#PBF requirements.
6.How does Aetrix verify that LTC3773EG#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3773EG#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 LTC3773EG#PBF meets industry standards.
7.What is the process for return or replacement of LTC3773EG#PBF?
All LTC3773EG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3773EG#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 LTC3773EG#PBF part is unused and in its original packaging.
Return procedure for LTC3773EG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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