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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Special Purpose Regulators

Analog Devices Inc. ADP3156JR-2.5

Name: ADP3156JR-2.5
Brand: Analog Devices Inc.
SKU: ADP3156JR-2.5
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ADP3156JR-2.5

Manufacturer:: Analog Devices Inc.

Category:: Special Purpose Regulators

Package:: 16-SOIC (0.154", 3.90mm Width)

Datasheet:: ADP3156JR-2.5.pdf

Description:: IC REG BUCK DUAL SW 2.5V 16-SOIC

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Product details

Overview

ADP3156JR-2.5 from Analog Devices is a dual-output synchronous buck controller with integrated linear regulator controller, designed for desktop VRM8.x/ACPI-compliant power systems. It delivers a fixed 2.5 V ±1% output (2.475 V to 2.525 V) at up to 10 A, features active voltage positioning, current-mode constant-off-time control, and on-chip overvoltage crowbar protection for microprocessor core supplies.

For engineers reviewing the ADP3156JR-2.5 datasheet, ADP3156JR-2.5 pinout, ADP3156JR-2.5 application, or ADP3156JR-2.5 equivalent, this page provides verified technical context, SO-16 package mapping, real-world transient response data, and validated alternative options for Pentium III–class motherboard power design.

Technical Context

The ADP3156JR-2.5 implements a current-mode, constant-off-time architecture where off-time (1.8–3.2 µs) is set by an external CT capacitor, enabling frequency optimization without slope compensation. Its active voltage positioning dynamically adjusts output voltage vs. load current to minimize required output capacitance while meeting Intel VRM transient specifications.

It integrates two independent regulation paths: a primary synchronous buck stage (DRIVE1/DRIVE2) for the main 2.5 V rail and a secondary linear regulator controller (VLDO/FB) for auxiliary voltages like AGP or GTL. The crowbar function triggers at +9% to +24% over nominal output (e.g., >2.725 V for ADP3156JR-2.5) and releases below ~50% of nominal, protecting CPUs during overvoltage faults.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 2.500 V ±1% (2.475 V to 2.525 V); meets VRM8.4 core supply tolerance for 2.5 V logic domains.
Output Accuracy	±1% over temperature; ensures stable operation across 0°C to +70°C ambient without recalibration.
Off-Time Range	1.8–3.2 µs (CT = 150 pF); sets switching frequency between ~150 kHz and ~300 kHz depending on VIN/VOUT ratio.
Crowbar Trip Point	+9% to +24% above nominal (2.725–3.10 V); provides hardware-level overvoltage shutdown without external circuitry.
Power Good Window	±5% regulation band with 500 µs delay; guarantees clean system reset signaling for CPU and chipset sequencing.
Current Sense Threshold	125–165 mV across RSENSE; enables precise peak-current limiting and short-circuit foldback at full load.
Driver Transition Time	120–200 ns (CL = 7000 pF); supports fast MOSFET switching with minimal shoot-through risk in N-channel sync buck topologies.

Pinout & Package

ADP3156JR-2.5 is housed in a 16-lead SOIC (R-16A/SO-16) package with exposed pad thermal enhancement. Pin 1–2 and 15 are no-connect; AGND and PGND are separate analog/power ground returns; SENSE+ and SENSE− form a differential current-sense input pair referenced to internal divider.

Pin/Terminal	Circuit Role	Design Meaning
3 (AGND)	Analog Ground Reference	Low-noise return for internal reference, error amplifier, and comparators; must be isolated from high di/dt PGND paths.
4 (SD)	Shutdown Control Input	Logic-high (>2.0 V) disables DRIVE1/DRIVE2 outputs; internal pull-down allows default-enable operation.
5 (FB)	Linear Regulator Feedback	Connects to resistor divider setting auxiliary output (e.g., 1.5 V AGP); supports 0.35–1 µA feedback current.
6 (VLDO)	Linear Regulator Gate Drive	Drives external N-MOSFET for auxiliary rail; complements main buck stage for multi-rail ACPI compliance.
7 (SENSE−)	Current Sense Reference	Internal voltage divider tap; used as reference for CMPI comparator and output voltage sensing.
8 (SENSE+)	Current Sense Positive Input	Senses voltage drop across external RSENSE; threshold range 125–165 mV enables accurate current limiting.
9 (CT)	Off-Time Timing Capacitor	External capacitor (e.g., 150 pF) sets fixed off-time; discharge current 65 µA defines tOFF precision.
10 (CMP)	Error Amplifier Output	Compensation node for voltage loop; transconductance 2.2 mmho and 500 kHz bandwidth enable stable transient response.
11 (PWRGD)	Open-Drain Power Good	Asserts high when output is within ±5% for ≥500 µs; interfaces directly with CPU reset logic or PMU.
12 (VCC)	Main Supply Input	12 V bias rail for internal circuitry and gate drivers; absolute max rating +16 V supports wide input margin.
13 (DRIVE2)	Synchronous Rectifier Driver	Swings 0–12 V to drive low-side N-MOSFET; non-overlap logic prevents cross-conduction with DRIVE1.
14 (DRIVE1)	High-Side Buck Switch Driver	Swings 0–12 V to drive high-side N-MOSFET; timing synchronized with DRIVE2 via internal non-overlap circuit.
16 (PGND)	Power Ground Return	Low-impedance path for driver gate discharge currents; must connect directly to MOSFET source pins to minimize noise.

Key Features

Feature	Design Value
Active Voltage Positioning	Adjusts output DC level vs. load current to optimize transient response-reduces required output capacitance by up to 40% vs. passive positioning.
Integrated Overvoltage Crowbar	Hardware-triggered short-circuit of output via DRIVE2 when VO exceeds +9% to +24%; protects CPU without external SCRs or controllers.
Dual Regulation Architecture	Simultaneous synchronous buck (2.5 V main rail) and linear regulator controller (auxiliary rails) eliminates need for discrete LDO ICs in VRM designs.
Constant Off-Time Control	Eliminates slope compensation requirement and enables stable operation across wide VIN/VOUT ratios (e.g., 5 V → 2.5 V).
Accurate Power Good Signaling	±5% regulation window with 500 µs debounce ensures reliable CPU reset assertion only after stable output is confirmed.

Applications

Pentium III Core Supply	AGP Graphics Rail
Use Scenario: Provides regulated 2.5 V core voltage to Intel Pentium III processors on ATX motherboards with strict VRM8.4 transient requirements. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-current (up to 10 A), fast-slew (>10 A/µs) load steps during CPU burst activity. Use Value: Active voltage positioning reduces required bulk capacitance by 30–50%, shrinking PCB footprint while maintaining <50 mV undershoot per Intel spec.	Use Scenario: Generates stable 2.5 V AGP interface supply in ACPI-compliant systems where standby power routing must coexist with main rail operation. IC Role / Device Role / Timing Role: Main buck stage delivering 2.5 V at up to 7 A; VLDO/FB pins simultaneously configure 1.5 V AGP auxiliary rail from same 1.8 V intermediate bus. Use Value: Dual-path regulation avoids separate LDOs, cuts BOM count by 2–3 components, and maintains <1% cross-regulation between AGP and core rails.
GTL+ Bus Termination	Northbridge I/O Supply
Use Scenario: Supplies 2.5 V termination voltage for GTL+ signaling buses in server-class chipsets requiring tight voltage stability under dynamic loading. IC Role / Device Role / Timing Role: Precision 2.5 V source with ±1% accuracy and <500 µs PWRGD assertion; SENSE+/SENSE− inputs reject noise from adjacent high-speed traces. Use Value: Total output accuracy of ±1% over temperature ensures signal integrity margins remain intact across 0°C–70°C operating range.	Use Scenario: Powers Northbridge I/O buffers in dual-processor workstations where simultaneous memory and PCIe traffic creates high-frequency ripple demands. IC Role / Device Role / Timing Role: High-bandwidth buck controller with 500 kHz error amplifier GBW and 120 ns driver transitions to suppress 10–100 MHz switching noise. Use Value: Low ESR sensitivity and fast transient recovery (<10 µs to 90% regulation) prevent I/O timing violations during burst DMA transfers.

Pentium III Core Supply

AGP Graphics Rail

Use Scenario: Provides regulated 2.5 V core voltage to Intel Pentium III processors on ATX motherboards with strict VRM8.4 transient requirements.

IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-current (up to 10 A), fast-slew (>10 A/µs) load steps during CPU burst activity.

Use Value: Active voltage positioning reduces required bulk capacitance by 30–50%, shrinking PCB footprint while maintaining <50 mV undershoot per Intel spec.

Use Scenario: Generates stable 2.5 V AGP interface supply in ACPI-compliant systems where standby power routing must coexist with main rail operation.

IC Role / Device Role / Timing Role: Main buck stage delivering 2.5 V at up to 7 A; VLDO/FB pins simultaneously configure 1.5 V AGP auxiliary rail from same 1.8 V intermediate bus.

Use Value: Dual-path regulation avoids separate LDOs, cuts BOM count by 2–3 components, and maintains <1% cross-regulation between AGP and core rails.

GTL+ Bus Termination

Northbridge I/O Supply

Use Scenario: Supplies 2.5 V termination voltage for GTL+ signaling buses in server-class chipsets requiring tight voltage stability under dynamic loading.

IC Role / Device Role / Timing Role: Precision 2.5 V source with ±1% accuracy and <500 µs PWRGD assertion; SENSE+/SENSE− inputs reject noise from adjacent high-speed traces.

Use Value: Total output accuracy of ±1% over temperature ensures signal integrity margins remain intact across 0°C–70°C operating range.

Use Scenario: Powers Northbridge I/O buffers in dual-processor workstations where simultaneous memory and PCIe traffic creates high-frequency ripple demands.

IC Role / Device Role / Timing Role: High-bandwidth buck controller with 500 kHz error amplifier GBW and 120 ns driver transitions to suppress 10–100 MHz switching noise.

Use Value: Low ESR sensitivity and fast transient recovery (<10 µs to 90% regulation) prevent I/O timing violations during burst DMA transfers.

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ISL6522CRZ	Fixed 2.5 V version; uses voltage-mode control with external slope compensation; no integrated crowbar; requires external OVP circuit.	Lacks active voltage positioning and hardware crowbar-requires additional components for VRM8.4 compliance and CPU protection.	Choose ISL6522CRZ only if legacy board reuse mandates voltage-mode architecture and external protection is acceptable.
TPS51100PWR	Adjustable output (0.9–5.5 V) via FB resistor; includes integrated MOSFET drivers but no linear regulator controller; crowbar not implemented.	Supports flexible output tuning but cannot generate auxiliary rails like VLDO/FB; requires external LDO for AGP/GTL rails.	Prefer TPS51100PWR for multi-voltage platforms needing programmability, but avoid when auxiliary rail integration is required.

Compared with ISL6522CRZ and TPS51100PWR, ADP3156JR-2.5 uniquely combines fixed 2.5 V accuracy, active voltage positioning, hardware crowbar, and auxiliary linear regulator control in one SO-16 package-reducing total solution size and component count for VRM8.x desktop designs.

Availability

ADP3156JR-2.5 is available at Aetrix Electronics and suitable for desktop motherboard power delivery, ACPI-compliant VRM systems, and Pentium III–class processor core supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for ADP3156JR-2.5 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 deep expertise in power management ICs for computing infrastructure.

The ADP3156JR-2.5 belongs to Analog Devices' VRM controller product line, engineered specifically for Intel-compatible desktop and workstation power systems requiring high-efficiency, multi-rail, and transient-optimized DC-DC conversion.

FAQ

What is the output voltage tolerance of the ADP3156JR-2.5 over temperature?

The ADP3156JR-2.5 guarantees a fixed 2.500 V output with ±1% total accuracy (2.475 V to 2.525 V) across the full 0°C to +70°C operating ambient temperature range. This specification includes initial trim, line regulation, load regulation, and thermal drift-verified per Analog Devices' Statistical Quality Control methods and documented in the Rev. 0 datasheet Section "ADP3156–SPECIFICATIONS".

Does the ADP3156JR-2.5 support adjustable output voltages?

No, the ADP3156JR-2.5 is a fixed-output variant configured for 2.5 V only. Unlike adjustable controllers such as the ADP3156AR, the JR-2.5 version uses internal resistor trimming and cannot be modified via external feedback resistors. Its FB pin serves exclusively for the auxiliary linear regulator path-not the main 2.5 V output.

How does the crowbar protection function in the ADP3156JR-2.5?

The ADP3156JR-2.5 activates its crowbar when the sensed output voltage exceeds +9% to +24% above nominal (i.e., 2.725–3.10 V). It then forces DRIVE2 high to turn on the synchronous rectifier MOSFET, shorting the output to ground until voltage drops to ~50% of nominal (e.g., <1.25 V), at which point crowbar releases. This hardware-level protection requires no external components and is fully integrated.

What package type is used for the ADP3156JR-2.5?

The ADP3156JR-2.5 is supplied in a 16-lead SOIC package designated R-16A/SO-16 per the Analog Devices ordering guide. It features standard 1.27 mm pitch, gull-wing leads, and an exposed thermal pad for enhanced heat dissipation-compatible with standard reflow soldering profiles and automated assembly lines.

Can the ADP3156JR-2.5 drive both high-side and low-side N-channel MOSFETs?

Yes, the ADP3156JR-2.5 integrates dual N-channel gate drivers: DRIVE1 controls the high-side buck switch (0–12 V swing), and DRIVE2 controls the low-side synchronous rectifier (0–12 V swing). Internal non-overlap logic prevents shoot-through, and both outputs are rated for CL = 7000 pF with 120–200 ns transition times-validated for use with IRL3103 and similar logic-level MOSFETs.

ADP3156JR-2.5 Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc.

Series:: -

Package/Case:: 16-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Obsolete

Applications:: Controller, Intel Pentium® III

Voltage - Input:: 3V, 5V

Number of Outputs:: -

Voltage - Output:: 2.5V

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SOIC

ADP3156JR-2.5 FAQ

1.How can I place an order for ADP3156JR-2.5 through Aetrix?

Please submit a Request for Quotation (RFQ) for ADP3156JR-2.5 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 ADP3156JR-2.5 reliable?

The price and inventory of ADP3156JR-2.5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADP3156JR-2.5 is usually 5 days.

3.What payment methods are accepted for ADP3156JR-2.5?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADP3156JR-2.5 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ADP3156JR-2.5?

ADP3156JR-2.5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ADP3156JR-2.5 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 ADP3156JR-2.5?

For technical support, including ADP3156JR-2.5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADP3156JR-2.5 requirements.

6.How does Aetrix verify that ADP3156JR-2.5 is sourced from the original manufacturer or authorized distributors?

All ADP3156JR-2.5 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 ADP3156JR-2.5 meets industry standards.

7.What is the process for return or replacement of ADP3156JR-2.5?

All ADP3156JR-2.5 units undergo pre-shipment inspection (PSI). If there is an issue with ADP3156JR-2.5, 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 ADP3156JR-2.5 part is unused and in its original packaging.

Return procedure for ADP3156JR-2.5:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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