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Analog Devices Inc. ADP3155JRU-REEL7
- Part No.:
- ADP3155JRU-REEL7
- Manufacturer:
- Analog Devices Inc.
- Category:
- Special Purpose Regulators
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
ADP3155JRU-REEL7.pdf
- Description:
- POWER CONTROLLER FOR PENTIUM III
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
ADP3155JRU-REEL7 from Analog Devices is a 5-bit programmable triple power supply controller optimized for Pentium III and AMD-K6 processor core voltage regulation. It implements active voltage positioning with gain/offset adjustment, delivers 1.3 V to 3.5 V output via internal DAC, supports VRM 8.2/8.3/8.4 compliance, and integrates dual N-channel synchronous drivers plus two linear regulator controllers in a TSSOP-20 package.
For engineers reviewing the ADP3155JRU-REEL7 datasheet, ADP3155JRU-REEL7 pinout, ADP3155JRU-REEL7 application, or ADP3155JRU-REEL7 equivalent, this page provides verified technical context, confirmed pin functions, real-world transient response data (±130 mV at 30 A/µs), crowbar overvoltage protection (9–24% trip), and validated alternatives for VRM-compliant motherboard designs.
Technical Context
The ADP3155JRU-REEL7 uses a current-mode, constant-off-time architecture with CT-pin-programmable off-time (1.8–3.2 µs), enabling frequency optimization without slope compensation. Its internal 5-bit DAC reads VID0–VID4 to set output voltage between 1.3 V and 3.5 V with ±1% accuracy over temperature.
Active voltage positioning dynamically adjusts output voltage vs. load current to meet Intel VRM transient specs (e.g., 130 mV deviation at 30 A/µs), while integrated crowbar protection triggers at +9% to +24% overvoltage and releases at ~50% nominal voltage. Dual linear regulator controllers drive external N-MOSFETs for AGP/GTL auxiliary rails with 3.24–3.38 V output at 1 A.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage Range | 1.3 V to 3.5 V, digitally programmed via 5-bit VID code per Intel VRM 8.2/8.3/8.4 spec |
| Output Accuracy | ±1% over 0°C to +70°C ambient, enabling tight core voltage tolerance for Pentium III processors |
| Switching Architecture | Current-mode constant-off-time control with CT-pin timing capacitor, eliminating need for slope compensation |
| Crowbar Trip Threshold | +9% to +24% above nominal output voltage, protecting microprocessor from overvoltage damage |
| Power Good Window | ±5% regulation band with 500 µs delay, ensuring stable CPU power-up before system release |
| Linear Regulator Outputs | Two independent controllers (VLDO1/VLDO2) supporting 3.24–3.38 V at 1 A for AGP/GTL rails |
| Package | TSSOP-20 (RU-20), surface-mount compatible with high-density motherboard layouts |
Pinout & Package
TSSOP-20 (RU-20) package with 0.65 mm pitch, thermally enhanced for high-current VRM applications; PGND and AGND pins separated for noise isolation between power and analog sections.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VID0–VID4 (Pins 1–4, 20) | Voltage identification inputs | 5-bit DAC code interface; open-circuit = logic high; all open = shutdown mode |
| SENSE– (Pin 9) | Output voltage feedback reference | Connects to resistor divider midpoint; sets regulation point for buck converter |
| SENSE+ (Pin 10) | Current-sense comparator input | Detects inductor current via voltage drop across RSENSE; enables cycle-by-cycle current limiting |
| DRIVE1 (Pin 18) | High-side N-MOSFET gate driver | Swings 0 V to VCC (12 V); drives buck switch with 120–200 ns transition time |
| DRIVE2 (Pin 17) | Low-side N-MOSFET gate driver | Swings 0 V to VCC; enables synchronous rectification and crowbar activation |
| PWRGD (Pin 15) | Open-drain power-good indicator | Asserts high only when output is within ±5% of target for >500 µs |
| VLDO1 / VLDO2 (Pins 8, 13) | Linear regulator gate drivers | Drive external N-MOSFETs for auxiliary voltages (e.g., AGP 3.3 V, GTL 1.5 V) |
| CT (Pin 11) | Off-time timing capacitor connection | 150 pF sets 1.8–3.2 µs off-time; determines switching frequency per VIN/VOUT ratio |
Key Features
| Feature | Design Value |
|---|---|
| Active voltage positioning | Adjusts output voltage dynamically with load current to minimize required output capacitance and optimize transient response |
| Integrated crowbar protection | Triggers low-side MOSFET during overvoltage (>9% above nominal), eliminating need for external protection circuitry |
| VRM 8.2/8.3/8.4 compliance | Fully meets Intel's desktop PC power supply specifications for Pentium II/III and AMD-K6 processors |
| Dual linear regulator controllers | Support independent AGP and GTL rail generation with fast load-transient response and external MOSFET flexibility |
| Current-mode constant-off-time control | Enables stable operation without slope compensation and simplifies loop compensation design |
Applications
| Desktop PC Motherboard Core VRM | AGP Graphics Power Supply |
|---|---|
Use Scenario: Regulating Pentium III processor core voltage (1.3–3.5 V) from 5 V main rail in ATX power systems. IC Role / Device Role / Timing Role: Primary VRM controller implementing VID decoding, synchronous buck conversion, and active voltage positioning. Use Value: Achieves ±130 mV transient tolerance at 30 A/µs di/dt while minimizing output capacitor count per VRM 8.4 spec. |
Use Scenario: Generating stable 3.3 V AGP interface supply from 5 V or 12 V rails in graphics subsystems. IC Role / Device Role / Timing Role: Linear regulator controller driving external N-MOSFET with 3.24–3.38 V output at 1 A. Use Value: Delivers high-bandwidth load transient response for AGP bus signaling without requiring separate LDO IC. |
| GTL Bus Termination Supply | ACPI-Compliant Standby Power Management |
Use Scenario: Providing 1.5 V or 1.8 V termination voltage for GTL+ bus interfaces on chipsets. IC Role / Device Role / Timing Role: Secondary linear regulator channel (VLDO2) with adjustable feedback resistors. Use Value: Enables precise GTL voltage setting (±0.06 V) and fast transient recovery for signal integrity. |
Use Scenario: Maintaining auxiliary rail operation during ACPI S3/S4 standby states using charge-pump boosted 5VSB. IC Role / Device Role / Timing Role: Dual linear regulators powered from ORed 9 V supply when main 5 V rail collapses. Use Value: Supports seamless transition between active and standby modes without external sequencing logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar VRM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADP3165JRU-REEL7 | Supports VRM 8.5/9.0, adds 6-bit VID, higher efficiency at light load, same TSSOP-20 package | Required for newer Pentium 4 platforms; not backward-compatible with VRM 8.2/8.3 timing requirements | Select when upgrading to VRM 8.5+ compliance or needing extended VID resolution beyond 5 bits |
| ISL6522CBZ-T | Intersil VRM 8.4 controller with integrated MOSFET drivers, 1.25–2.0 V range, no linear regulator controllers | Lacks dual linear regulator outputs; requires external LDOs for AGP/GTL rails | Choose when prioritizing integrated driver strength over auxiliary rail integration |
Compared with ADP3155JRU-REEL7, ADP3165JRU-REEL7 extends VRM support and VID resolution but increases BOM count for legacy designs, while ISL6522CBZ-T reduces component count for the main VRM but necessitates additional regulators for auxiliary voltages.
Availability
ADP3155JRU-REEL7 is available at Aetrix Electronics and suitable for desktop motherboard VRM modules, Pentium III processor power supplies, and AMD-K6 chipset reference designs requiring stable component supply and long-term industrial availability.
Supply support for ADP3155JRU-REEL7 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with design centers worldwide.
The ADP3155JRU-REEL7 belongs to Analog Devices' VRM-compliant power management IC product line, engineered specifically for high-efficiency, multi-rail voltage regulation in x86 desktop platforms requiring strict Intel VRM compliance and active transient response.
FAQ
What is the primary function of the ADP3155JRU-REEL7 in a Pentium III motherboard?
The ADP3155JRU-REEL7 serves as the core voltage regulator controller, converting 5 V input to a programmable 1.3–3.5 V output for Pentium III processors using synchronous buck topology. It reads VID codes directly, implements active voltage positioning for transient response, and integrates dual linear regulators for AGP/GTL rails - all in a single TSSOP-20 package. The ADP3155JRU-REEL7 replaces discrete solutions with a VRM 8.2/8.3/8.4-compliant integrated controller.
How does the ADP3155JRU-REEL7 implement overvoltage protection?
The ADP3155JRU-REEL7 features an integrated crowbar function that activates the low-side synchronous MOSFET when output voltage exceeds +9% to +24% of the nominal value. This pulls down the output rail, protecting the microprocessor without external components. The crowbar releases automatically when voltage falls below ~50% of nominal (e.g., <1.0 V for a 2.0 V output). The ADP3155JRU-REEL7 specifies VCROWBAR = +9% to +24% with hysteresis built into the release threshold.
Can the ADP3155JRU-REEL7 be used for AMD-K6 processor power supplies?
Yes, the ADP3155JRU-REEL7 is explicitly qualified for AMD-K6 processors per its datasheet Applications section. It supports the required voltage range (1.3–3.5 V), meets AMD's transient response demands via active voltage positioning, and operates within the same VRM 8.2/8.3 framework used by K6 designs. The ADP3155JRU-REEL7's VID decoding, crowbar protection, and dual linear regulator outputs align with K6 platform power architecture requirements.
What is the role of the CT pin on the ADP3155JRU-REEL7?
The CT pin on the ADP3155JRU-REEL7 connects to an external capacitor that sets the constant off-time (1.8–3.2 µs typical), determining switching frequency in conjunction with VIN/VOUT ratio. A 150 pF capacitor yields ~200 kHz at 2.8 V output. Unlike fixed-frequency controllers, the ADP3155JRU-REEL7's CT-based timing enables stable current-mode operation without slope compensation and adapts frequency to input/output conditions - a key feature confirmed in the Functional Block Diagram and Specifications table.
Does the ADP3155JRU-REEL7 support both active and standby power states in ACPI systems?
Yes, the ADP3155JRU-REEL7 supports ACPI-compliant operation: its main buck output collapses when the 5 V rail drops, while its two linear regulator controllers (VLDO1/VLDO2) remain functional using charge-pump-boosted 5VSB (~9 V), enabling continuous AGP/GTL supply during S3/S4 standby. This dual-state capability is documented in the Application Information section and Figure 14 block diagram - a defining feature of the ADP3155JRU-REEL7 for modern power-managed systems.
ADP3155JRU-REEL7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Applications:
- -
- Voltage - Input:
- 12V
- Number of Outputs:
- 5
- Voltage - Output:
- 1.3 ~ 3.5V
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
ADP3155JRU-REEL7 FAQ
1.How can I place an order for ADP3155JRU-REEL7 through Aetrix?
Please submit a Request for Quotation (RFQ) for ADP3155JRU-REEL7 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 ADP3155JRU-REEL7 reliable?
The price and inventory of ADP3155JRU-REEL7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADP3155JRU-REEL7 is usually 5 days.
3.What payment methods are accepted for ADP3155JRU-REEL7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADP3155JRU-REEL7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADP3155JRU-REEL7?
ADP3155JRU-REEL7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADP3155JRU-REEL7 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 ADP3155JRU-REEL7?
For technical support, including ADP3155JRU-REEL7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADP3155JRU-REEL7 requirements.
6.How does Aetrix verify that ADP3155JRU-REEL7 is sourced from the original manufacturer or authorized distributors?
All ADP3155JRU-REEL7 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 ADP3155JRU-REEL7 meets industry standards.
7.What is the process for return or replacement of ADP3155JRU-REEL7?
All ADP3155JRU-REEL7 units undergo pre-shipment inspection (PSI). If there is an issue with ADP3155JRU-REEL7, 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 ADP3155JRU-REEL7 part is unused and in its original packaging.
Return procedure for ADP3155JRU-REEL7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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