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Analog Devices Inc. LTC1929IG-PG#PBF
- Part No.:
- LTC1929IG-PG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1929IG-PG#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,653
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Product details
Overview
LTC1929IG-PG#PBF from Analog Devices (formerly Linear Technology) is a 2-phase, synchronous step-down switching regulator controller designed for high-current DC/DC conversion. It drives external N-channel MOSFETs in phase-opposed operation up to 300 kHz, delivers ±1% output voltage accuracy, supports 4 V to 36 V input, and integrates true remote sensing via differential amplifier and PGOOD monitoring. It is used in desktop computers and network servers requiring stable, low-noise 1.6 V/40 A power rails.
For engineers reviewing the LTC1929IG-PG#PBF datasheet, LTC1929IG-PG#PBF pinout, LTC1929IG-PG#PBF application, or LTC1929IG-PG#PBF equivalent, key selection criteria include its 2-phase current-mode architecture, phase-lockable 150–300 kHz frequency range, integrated differential amplifier with 0.995–1.005 V/V gain, PGOOD output with ±7.5% trip threshold, and 28-lead SSOP package with thermal performance rated at θJA = 95°C/W.
Technical Context
The LTC1929IG-PG#PBF implements a fixed-frequency, current-mode control architecture with two synchronized but 180° out-of-phase channels. Its OPTI-LOOP compensation enables stable transient response across wide output capacitance and ESR variations, while internal foldback current limiting and short-circuit shutdown with defeat option protect external MOSFETs during overloads.
It features dual independent current sense comparators (75 mV threshold), a true remote-sensing differential amplifier (CMRR ≥ 46 dB, gain = 0.995–1.005 V/V), and a dedicated open-drain PGOOD output that asserts low when EAIN deviates >±7.5% from 0.8 V reference. The RUN/SS pin provides soft-start ramping and latched fault shutdown triggered by sustained output collapse below 70% of nominal.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | 2-phase synchronous buck controller - enables interleaved operation to halve input/output RMS ripple and improve thermal distribution. |
| Input Voltage Range | 4 V to 36 V - supports wide industrial and server supply rails without external pre-regulation. |
| Output Voltage Accuracy | ±1% over temperature - ensures tight regulation for CPU/GPU core supplies demanding precise voltage margins. |
| Switching Frequency Range | 150 kHz to 300 kHz (phase-lockable) - balances efficiency (lower f) and component size (higher f); PLLIN allows synchronization to system clock. |
| Current Sense Threshold | 75 mV typical - sets peak inductor current with RSENSE; enables accurate current sharing between phases. |
| PGOOD Trip Threshold | ±7.5% of set output voltage - provides reliable power-good signaling for system sequencing and fault detection. |
| Duty Cycle Capability | Up to 99% - supports very low dropout operation (e.g., 5 V → 4.95 V), critical for post-regulator applications. |
| Operating Temperature | –40°C to +85°C - qualified for industrial and extended-temperature embedded systems. |
Pinout & Package
Package: 28-lead plastic SSOP (G package), exposed pad not specified, θJA = 95°C/W, TJMAX = 125°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS (1) | Soft-start timing & fault latch control | Capacitor-connected pin sets soft-start ramp time; pulls low to shut down both channels; discharges under short-circuit to trigger timed latchoff. |
| SENSE1+/SENSE2+ (2,14) | Positive current sense inputs | Connect to high-side of external RSENSE; referenced to SENSE1–/SENSE2– to generate 75 mV comparator threshold. |
| SENSE1–/SENSE2– (3,13) | Negative current sense inputs | Return path for current sense; common-mode range extends to 1.1×INTVCC - supports high-side sensing configurations. |
| EAIN (4) | Error amplifier inverting input | Receives feedback from VDIFFOUT divider; compared to 0.8 V internal reference to regulate output voltage. |
| PLLFLTR (5) | PLL loop filter / frequency control | DC voltage input (0–2.4 V) sets oscillator frequency from 140–310 kHz; also accepts AC sync signal via PLLIN. |
| ITH (8) | Error amplifier output & compensation node | Drives current comparator thresholds; voltage range 0–2.4 V determines peak inductor current per phase. |
| VDIFFOUT (10) | Differential amplifier output | Provides true remote-sensed output voltage; drives external resistor divider to set regulated output level. |
| VOS+/VOS– (11,12) | Op-amp inputs (unity-gain diff amp mode) | AMPMD = high (default on LTC1929-PG) configures internal 40 kΩ resistors for precision differential sensing. |
| PGOOD (15) | Open-drain power-good indicator | Asserts low when EAIN is outside ±7.5% of 0.8 V; <10 µs response; requires external pull-up for logic-level signaling. |
| TG1/TG2 (16,27) | Top gate drivers | Floating N-channel drivers with INTVCC-referenced swing; drive external high-side MOSFET gates via bootstrap capacitors. |
| BG1/BG2 (19,23) | Bottom gate drivers | Ground-referenced N-channel drivers; sink/source capability supports synchronous rectification with low RDS(on) MOSFETs. |
| INTVCC (21) | Internal 5 V LDO output | Powers control circuitry and gate drivers; bypassed with 1 µF ceramic + ≥4.7 µF tantalum; switchover to EXTVCC at 4.7 V. |
Key Features
| Feature | Design Value |
|---|---|
| 2-phase interleaved control | Reduces input/output RMS ripple current by ~70%, enabling smaller bulk capacitors and lower EMI in high-current rails. |
| True remote sensing differential amplifier | Compensates for PCB trace IR drop in high-current paths; achieves ±1% regulation at load point with CMRR ≥ 46 dB. |
| OPTI-LOOP™ compensation | Allows stable loop response across wide range of output capacitor ESR (1–100 mΩ) and capacitance (100 µF–10,000 µF). |
| Phase-lockable oscillator (150–300 kHz) | Enables synchronization to system clock or other converters to eliminate beat frequencies and simplify EMI filtering. |
| Integrated PGOOD with ±7.5% threshold | Provides deterministic power-good assertion for FPGA/CPU reset sequencing without external comparators or dividers. |
| Defeatable short-circuit latchoff | Prevents nuisance shutdowns during transient overloads; disable via >5 µA current injection into RUN/SS pin. |
Applications
| Desktop Computer VRM | Network Server Core Supply |
|---|---|
Use Scenario: Delivering 1.6 V/40 A to dual-core CPU with tight transient response requirements and minimal output voltage droop. IC Role / Device Role / Timing Role: 2-phase synchronous buck controller managing interleaved high-side/low-side MOSFET switching at 200 kHz with phase alignment. Use Value: Achieves <1% output deviation under 20 A/µs load steps and reduces input capacitor RMS current by 75% versus single-phase design. |
Use Scenario: Powering ASIC/FPGA banks in 1U rack-mounted servers where thermal density and board space are constrained. IC Role / Device Role / Timing Role: Dual-channel current-mode controller with remote sensing compensating for 50 mΩ board trace resistance between regulator and load. Use Value: Maintains ±1% regulation at point-of-load despite 150 mV IR drop; PGOOD output coordinates system power-on sequencing. |
| Large Memory Array Power | DC Power Distribution System |
Use Scenario: Supplying 1.2 V/30 A to DDR4 memory modules with strict noise and ripple specifications (<15 mVpp). IC Role / Device Role / Timing Role: Interleaved controller driving parallel inductor stages; uses OPTI-LOOP to stabilize loop with low-ESR polymer capacitors. Use Value: Cuts output ripple by >60% vs single-phase; enables use of smaller, lower-cost 100 µF/2.5 V polymer caps instead of 1000 µF electrolytics. |
Use Scenario: Centralized 12 V-to-3.3 V conversion feeding multiple downstream point-of-load regulators in telecom infrastructure. IC Role / Device Role / Timing Role: High-efficiency 2-phase controller operating at 250 kHz with EXTVCC powered from intermediate rail to minimize driver losses. Use Value: Delivers >92% peak efficiency at 20 A; reduces heat sink requirements by distributing thermal load across two phases. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 2-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3729L-1 | Single-phase controller with external clock sync; no integrated PGOOD; 4–36 V input; 0.6–5 V output. | Lacks 2-phase interleaving and remote sensing amplifier; requires external PGOOD circuit. | Select when only one output stage is needed and board space is limited; not suitable for direct replacement. |
| MP8765GQ | Monolithic 2-phase buck converter (integrated MOSFETs); 4.5–18 V input; 0.6–5.5 V output; no PGOOD or remote sensing. | Higher integration but lower voltage/current capability; no differential sensing or EXTVCC switchover. | Choose for cost-sensitive, lower-power applications (<20 A) where layout simplicity outweighs precision regulation needs. |
Compared with LTC3729L-1 and MP8765GQ, the LTC1929IG-PG#PBF uniquely combines 2-phase interleaving, true remote sensing, PGOOD, and EXTVCC switchover in a controller-only package-enabling high-accuracy, high-current, thermally optimized designs unattainable with single-phase or monolithic alternatives.
Availability
LTC1929IG-PG#PBF is available at Aetrix Electronics and suitable for desktop computer VRMs, network server core supplies, and large memory array power delivery requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC1929IG-PG#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 product support, documentation, and manufacturing continuity for legacy Linear parts including the LTC1929 series.
The LTC1929 product line was designed specifically for high-current, high-efficiency, multi-phase DC/DC conversion in computing and communications infrastructure-emphasizing thermal manageability, remote sensing accuracy, and system-level power sequencing.
FAQ
What is the function of the AMPMD pin on the LTC1929IG-PG#PBF?
The AMPMD pin configures the internal op-amp's feedback network: when pulled high (default on LTC1929IG-PG#PBF), it connects precision 40 kΩ resistors to form a unity-gain differential amplifier for remote sensing; when pulled low, it bypasses those resistors to expose raw op-amp inputs. This flexibility allows the same LTC1929IG-PG#PBF die to serve both precision sensing and general-purpose amplifier roles without redesign.
Does the LTC1929IG-PG#PBF support synchronization to an external clock source?
Yes, the LTC1929IG-PG#PBF supports external synchronization via the PLLIN pin (Pin 6), which accepts TTL/CMOS-compatible clock signals. The internal phase-locked loop aligns the rising edge of TG1 to the rising edge of the external clock, enabling deterministic switching and elimination of beat frequencies in multi-rail systems using the LTC1929IG-PG#PBF.
How does the PGOOD feature work on the LTC1929IG-PG#PBF?
The PGOOD pin on the LTC1929IG-PG#PBF is an open-drain output that pulls low when the EAIN voltage deviates more than ±7.5% from the 0.8 V internal reference-indicating the regulated output is out of specification. It releases within 10 µs of recovery and requires an external pull-up resistor; this behavior is intrinsic to the LTC1929IG-PG#PBF and requires no configuration.
What is the maximum duty cycle supported by the LTC1929IG-PG#PBF?
The LTC1929IG-PG#PBF supports up to 99% duty cycle, enabling very low dropout operation (e.g., 5 V input → 4.95 V output). This is achieved via internal dropout detection that forces brief top-FET off-times to recharge bootstrap capacitors-ensuring continuous gate drive even near VIN ≈ VOUT, a key capability of the LTC1929IG-PG#PBF in post-regulator applications.
Can the LTC1929IG-PG#PBF operate with only one phase enabled?
No-the LTC1929IG-PG#PBF is a fixed 2-phase controller and requires both phases to be fully populated and operational. It does not support single-phase mode or channel disable; unused phase components will cause instability or failure to regulate. All applications must implement both TG1/BG1/SW1/SENSE1 and TG2/BG2/SW2/SENSE2 circuits as specified for the LTC1929IG-PG#PBF.
LTC1929IG-PG#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- 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:
- -
- Duty Cycle (Max):
- 99.5%
- 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:
- 28-SSOP
LTC1929IG-PG#PBF FAQ
1.How can I place an order for LTC1929IG-PG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1929IG-PG#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 LTC1929IG-PG#PBF reliable?
The price and inventory of LTC1929IG-PG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1929IG-PG#PBF is usually 5 days.
3.What payment methods are accepted for LTC1929IG-PG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1929IG-PG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1929IG-PG#PBF?
LTC1929IG-PG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1929IG-PG#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 LTC1929IG-PG#PBF?
For technical support, including LTC1929IG-PG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1929IG-PG#PBF requirements.
6.How does Aetrix verify that LTC1929IG-PG#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1929IG-PG#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 LTC1929IG-PG#PBF meets industry standards.
7.What is the process for return or replacement of LTC1929IG-PG#PBF?
All LTC1929IG-PG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1929IG-PG#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 LTC1929IG-PG#PBF part is unused and in its original packaging.
Return procedure for LTC1929IG-PG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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