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Analog Devices Inc. LTC1629CG#PBF
- Part No.:
- LTC1629CG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1629CG#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:141
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Product details
Overview
LTC1629CG#PBF from Analog Devices (formerly Linear Technology) is a dual-phase, synchronous step-down switching regulator controller driving external N-channel MOSFETs in current-mode PolyPhase architecture. It delivers up to 40A output with ±1% voltage accuracy, 150–300kHz phase-lockable switching frequency, and true remote differential sensing for high-current desktop/server power rails.
For engineers reviewing the LTC1629CG#PBF datasheet, LTC1629CG#PBF pinout, LTC1629CG#PBF application, or LTC1629CG#PBF equivalent, this controller enables high-efficiency, low-noise multiphase DC/DC conversion in systems requiring stable 1.6V–5V outputs at >20A, input ripple reduction, and thermal-aware parallel power stage coordination.
Technical Context
The LTC1629CG#PBF implements fixed-frequency current-mode control with two independent PWM channels operating 180° out of phase. Its OPTI-LOOP™ compensation supports wide output capacitance/ESR ranges, while the internal differential amplifier provides true remote sensing across both VOUT+ and VOUT− terminals with 0.995–1.005 gain and 46–55dB CMRR.
Phase synchronization is achieved via PLLIN input and programmable PHASMD pin, enabling expansion to 12-phase systems using CLKOUT daisy-chaining. The RUN/SS pin integrates soft-start ramping (1.2µA current source), short-circuit timeout, and micropower shutdown - all without external logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Dual-phase synchronous buck controller - drives external high-side and low-side N-MOSFETs per channel |
| Switching Frequency Range | 150–300kHz (phase-lockable); effective 1.8MHz ripple cancellation with 2-phase operation |
| Output Voltage Accuracy | ±1% over line/load/temperature - ensures tight regulation for CPU/GPU core rails |
| Input Voltage Range | 4V to 36V - supports 5V, 12V, and 24V intermediate bus architectures |
| Duty Cycle Capability | Up to 99% - enables very low dropout operation near VIN ≈ VOUT |
| Current Sense Threshold | 75mV typical - sets peak inductor current with <±10% tolerance for accurate current sharing |
| Remote Sensing Gain | 0.995–1.005 V/V - maintains sub-1mV offset error in high-current PCB traces |
Pinout & Package
Available in 28-lead plastic SSOP (G package), 5.6mm × 10.2mm body, 0.635mm pitch. Thermal pad not present; θJA = 95°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS (Pin 1) | Soft-start & fault timer input | 1.2µA internal current source charges external capacitor; <0.8V forces shutdown; 4.1–4.5V arms short-circuit latchoff |
| SENSE1+/SENSE2+ (Pins 2,14) | Positive current sense inputs | Connect to high-side of RSENSE; referenced to SENSE1−/2− for differential current measurement |
| SENSE1−/SENSE2− (Pins 3,13) | Negative current sense inputs | Return path for sense resistor; enables Kelvin connection to minimize PCB trace resistance error |
| EAIN (Pin 4) | Error amplifier inverting input | Compares feedback voltage to 0.800V internal reference; determines ITH setpoint for current limit |
| PLLFLTR (Pin 5) | PLL loop filter node | DC voltage (0–2.4V) sets oscillator frequency; also accepts AC sync signal on PLLIN (Pin 6) |
| PHASMD (Pin 7) | Phase mode select | GND/Open/INTVCC selects 180°/180°/240° phase shift between controllers and CLKOUT alignment |
| ITH (Pin 8) | Control voltage output | 0–2.4V range modulates current comparator threshold; primary compensation node for loop stability |
| SGND (Pin 9) | Signal ground reference | Must be isolated from PGND; serves as common return for all analog circuitry and sense paths |
| VDIFFOUT (Pin 10) | Differential amplifier output | Drives external resistive divider to set output voltage; referenced to SGND, not PGND |
| VOS+/VOS− (Pins 11,12) | Op-amp inputs | Configurable as unity-gain diff amp (via AMPMD) or uncommitted op-amp; 2MHz GBW, 5V/µs slew rate |
| TG1/TG2 (Pins 16,27) | Top gate drivers | Floating N-MOS drivers with INTVCC-referenced swing; support bootstrap operation up to 42V |
| SW1/SW2 (Pins 17,26) | Switch node connections | Connect to inductor high-side; voltage swings from −0.3V (Schottky drop) to VIN |
| BOOST1/BOOST2 (Pins 18,25) | Bootstrap supplies | Capacitor-connected nodes supplying floating gate drive; swing = INTVCC + SW voltage |
| BG1/BG2 (Pins 19,23) | Bottom gate drivers | Ground-referenced N-MOS drivers; 0–5V swing, 30–90ns transition times |
| PGND (Pin 20) | Power ground | Return for bottom MOSFET sources and CIN negative terminals; separate from SGND |
| INTVCC (Pin 21) | Internal 5V LDO output | Powers drivers and control logic; bypassed with 1µF ceramic + ≥4.7µF tantalum |
| EXTVCC (Pin 22) | External bias input | ≥4.7V bypasses internal LDO; reduces power loss when VOUT used as supply |
| VIN (Pin 24) | Main input supply | 4–36V input; decoupled directly to SGND with low-ESR capacitors |
| CLKOUT (Pin 28) | Phase-synchronized clock output | Drives PLLIN of additional LTC1629 devices for seamless 3–12 phase expansion |
Key Features
| Feature | Design Value |
|---|---|
| PolyPhase™ phase interleaving | Two 180°-out-of-phase channels reduce input/output RMS ripple by √2, cutting required capacitor size and ESR by >50% |
| True remote differential sensing | Internal differential amplifier (ADA = 0.995–1.005 V/V, CMRR = 46–55dB) compensates for PCB IR drop in >20A rails |
| OPTI-LOOP™ compensation | Supports 10µF–10000µF output capacitance with varying ESR - eliminates need for custom compensation per design |
| Phase-lockable architecture | PLLIN input and CLKOUT output enable deterministic multi-controller synchronization without jitter accumulation |
| 99% duty cycle capability | Enables ultra-low dropout operation (e.g., 5V→4.95V) while maintaining bootstrap capacitor recharge via forced off-time pulses |
| Integrated short-circuit protection | RUN/SS pin combines soft-start ramp, timed shutdown, and foldback current limiting - no external fault logic required |
Applications
| Desktop CPU Core Power | Internet Server VRM |
|---|---|
Use Scenario: High-current, low-voltage power delivery to Intel/AMD processors with dynamic load steps up to 30A/µs. IC Role / Device Role / Timing Role: Dual-phase controller coordinating two synchronous buck stages with interleaved timing to suppress input ripple and improve transient response. Use Value: 1.8MHz effective ripple cancellation reduces 12V input capacitor RMS current by 75%, enabling smaller, cooler 1206 MLCC arrays. |
Use Scenario: Redundant, scalable 12V-to-1.8V conversion for multi-socket server motherboards with >40A total load. IC Role / Device Role / Timing Role: Master controller in daisy-chained PolyPhase system; CLKOUT synchronizes up to 11 additional LTC1629 units for 12-phase operation. Use Value: Phase alignment ensures balanced current sharing across all MOSFETs, reducing thermal hotspots and extending FET lifetime under sustained 100% load. |
| Large Memory Array Supply | DC Power Distribution System |
Use Scenario: Stable 1.2V/25A supply for DDR4/DDR5 memory modules with strict ±1% regulation and fast load-step recovery. IC Role / Device Role / Timing Role: Dual-phase buck controller with true remote sensing across memory module VDD/VSS pins to reject board-level IR drop. Use Value: Differential amplifier gain tolerance (±0.5%) maintains <12mV total output error despite 50mΩ PCB trace resistance, meeting JEDEC spec. |
Use Scenario: Modular 48V-to-12V intermediate bus converter feeding multiple downstream point-of-load regulators. IC Role / Device Role / Timing Role: High-efficiency PolyPhase controller operating at 250kHz with EXTVCC powered from 12V output to minimize driver losses. Use Value: 99% duty cycle operation allows 48V→47.5V conversion during brownout, sustaining downstream PoL operation without interruption. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3838EG#PBF | Single-phase, higher max frequency (850kHz), integrated MOSFET drivers only - no external FET support | Suitable for lower-current (<15A), space-constrained designs; lacks PolyPhase expansion and remote sensing | Select when board area is critical and phase count ≤1; avoid for >20A or multi-rail synchronization needs |
| MP8765GL-Z | Monolithic dual-phase controller (integrated FETs), 4.5–16V VIN, no PLLIN/CLKOUT, no remote sensing | Targeted at cost-sensitive consumer power supplies; limited to mid-range input voltages and fixed topology | Choose for simplified BOM and layout in ≤12V systems where PolyPhase scalability and precision sensing are unnecessary |
Compared with LTC3838EG#PBF and MP8765GL-Z, the LTC1629CG#PBF uniquely supports external N-MOSFETs, true Kelvin sensing, and deterministic multi-phase expansion - making it the only option for high-current, high-accuracy, field-upgradeable server/desktop VRMs.
Availability
LTC1629CG#PBF is available at Aetrix Electronics and suitable for desktop computing, internet server power management, and large memory array regulation requiring stable component supply across extended production lifecycles.
Supply support for LTC1629CG#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 aerospace, automotive, industrial, and computing markets.
The LTC1629CG#PBF belongs to Linear's PolyPhase® controller family, designed specifically for high-current, low-voltage DC/DC conversion in computing infrastructure where efficiency, thermal management, and precise current sharing are critical.
FAQ
What is the maximum output current supported by the LTC1629CG#PBF?
The LTC1629CG#PBF itself does not deliver current - it controls external N-channel MOSFETs. In a typical dual-phase configuration with appropriate FETs (e.g., IRF7811/IRF7809) and 1µH inductors, the LTC1629CG#PBF enables up to 40A continuous output. Peak current capability depends on RSENSE value (75mV threshold), thermal design, and MOSFET SOA - verified in Figure 1 of the datasheet showing 1.6V/40A operation.
Does the LTC1629CG#PBF include a power good (PGOOD) signal?
No - the LTC1629CG#PBF is the base variant without PGOOD. The LTC1629CG-PG#PBF includes the PGOOD open-drain output that asserts low when EAIN deviates >±7.5% from 0.800V. The LTC1629CG#PBF uses the AMPMD pin instead, which configures the internal op-amp for differential sensing - a functional distinction confirmed in Pin Function Descriptions (Page 8) and Feature Comparison (Page 1).
How does the LTC1629CG#PBF achieve phase interleaving without external clock signals?
The LTC1629CG#PBF uses an internal phase-locked loop with programmable PHASMD pin (Pin 7) to set relative timing: GND or open sets Controller 2 and CLKOUT to 180° out of phase with Controller 1; INTVCC sets them to 240°. No external clock is needed - the architecture inherently generates evenly spaced phases using its master oscillator running at 12× channel frequency, as detailed in Table 1 and Functional Diagram (Page 9).
Can the LTC1629CG#PBF operate with input voltage below 4V?
No - the absolute maximum rating specifies minimum VIN = –0.3V, but operational specification requires VIN ≥ 4V (see Absolute Maximum Ratings, Page 2). Below 4V, UVLO activates (trip point 3.0–4.0V), disabling switching. This is a hard silicon limitation; no workaround exists, and attempting sub-4V operation risks undefined behavior or latchup.
What is the purpose of the VDIFFOUT pin on the LTC1629CG#PBF?
The VDIFFOUT pin (Pin 10) outputs the amplified differential voltage between VOS+ and VOS−, providing true remote sensing of the regulated output. It drives an external resistive divider that sets the final output voltage - decoupling regulation from PCB trace resistance. This function is identical in both LTC1629CG#PBF and LTC1629CG-PG#PBF, as confirmed in the Differential Amplifier section (Page 11) and Functional Diagram (Page 9).
LTC1629CG#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 28-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:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 36V
- Frequency - Switching:
- 220kHz
- Duty Cycle (Max):
- 99.5%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Phase Control, Power Good, Soft Start
- Operating Temperature:
- 0°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SSOP
LTC1629CG#PBF FAQ
1.How can I place an order for LTC1629CG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1629CG#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 LTC1629CG#PBF reliable?
The price and inventory of LTC1629CG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1629CG#PBF is usually 5 days.
3.What payment methods are accepted for LTC1629CG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1629CG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1629CG#PBF?
LTC1629CG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1629CG#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 LTC1629CG#PBF?
For technical support, including LTC1629CG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1629CG#PBF requirements.
6.How does Aetrix verify that LTC1629CG#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1629CG#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 LTC1629CG#PBF meets industry standards.
7.What is the process for return or replacement of LTC1629CG#PBF?
All LTC1629CG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1629CG#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 LTC1629CG#PBF part is unused and in its original packaging.
Return procedure for LTC1629CG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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