Analog Devices Inc./Maxim Integrated MAX1718EEI

Overview

MAX1718EEI from Maxim Integrated is a notebook CPU step-down controller designed for Intel Mobile Voltage Positioning (IMVP-II) core power supplies. It delivers dynamically adjustable 0.6V–1.75V output, ±1% DC accuracy, ultra-fast 100ns load transient response via Quick-PWM™ constant-on-time control, and supports 2V–28V battery input for single-stage buck conversion in high-efficiency laptop CPU VRMs.

For engineers reviewing the MAX1718EEI datasheet, MAX1718EEI pinout, MAX1718EEI application, or MAX1718EEI equivalent, this controller is selected for IMVP-II-compliant CPU core regulation requiring voltage positioning, precision VID DAC slew control, dual-mode (PWM/skip) operation, and integrated offset compensation for IR-drop correction in compact notebook power designs.

Technical Context

The MAX1718EEI implements a feed-forward, constant-on-time PWM architecture where DH on-time is inversely proportional to V+ and directly proportional to VOUT, enabling near-constant switching frequency (200/300/550/1000kHz) across wide input ranges. Its internal 5-bit VID DAC accepts three independent mode codes-Performance, Battery, and Suspend-via ZMODE/SUS-controlled multiplexing.

It integrates precision offset control using POS/NEG differential inputs with DAC-dependent scale factor (0.81–0.91 V/V), enabling voltage positioning to reduce output capacitance and system power loss. The controller drives large synchronous FETs with 1.6A DH source/sink and 4A DL sink capability, while VGATE blanking during transitions prevents shoot-through.

Key Specifications

Pinout & Package

The MAX1718EEI is housed in a 28-pin QSOP package with exposed pad (thermal enhancement). Pin functions are validated per Maxim's official datasheet Rev 4 (8/05).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down controller applications.

Compared with MAX1999EEI and RT8802AGQW, the MAX1718EEI uniquely supports IMVP-II-specific analog VID multiplexing, hardware-based voltage positioning via POS/NEG, and 2V–28V direct battery input-making it irreplaceable in legacy notebook platforms where compatibility, analog control, and wide input range are mandatory.

Availability

MAX1718EEI is available at Aetrix Electronics and suitable for notebook CPU core supplies, IMVP-II-compliant laptop VRMs, and high-efficiency single-stage buck converters requiring stable component supply and long-term lifecycle support.

Supply support for MAX1718EEI 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

Maxim Integrated (now part of Analog Devices) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for computing, industrial, and automotive markets.

The MAX1718EEI belongs to Maxim's notebook power management product line, engineered specifically for Intel IMVP-II CPU core regulation with emphasis on voltage positioning, fast transient response, and analog VID flexibility in space-constrained mobile platforms.

FAQ

What is the primary function of the MAX1718EEI in a notebook power system?

The MAX1718EEI serves as the core step-down controller for Intel IMVP-II-compliant CPU voltage regulation modules. It generates dynamically adjustable 0.6V–1.75V output using a 5-bit VID DAC, implements voltage positioning via POS/NEG inputs, and delivers ultra-fast transient response via Quick-PWM™ control. The MAX1718EEI manages Performance/Battery/Suspend mode transitions and drives external synchronous FETs to regulate CPU core voltage directly from battery or adapter input.

Does the MAX1718EEI require an external 5V bias supply, and why?

Yes, the MAX1718EEI requires an external 4.5V–5.5V bias supply connected to both VCC (PWM core) and VDD (low-side gate driver). This design improves overall efficiency by avoiding an on-chip linear regulator and allows use of the notebook's existing 5V system rail. The MAX1718EEI draws only 700µA quiescent current from VCC, making it compatible with standard 5V DC-DC converters. Without this external bias, the MAX1718EEI cannot power its control circuitry or gate drivers.

How does the MAX1718EEI implement voltage positioning, and what is its practical benefit?

The MAX1718EEI implements voltage positioning using differential inputs POS and NEG. The output voltage shifts by (POS − NEG) multiplied by a DAC-dependent scale factor (0.81–0.91 V/V), allowing precise IR-drop compensation across PCB traces. This feature reduces required output capacitance by up to 40% and lowers total system power dissipation. In practice, the MAX1718EEI enables tighter load-line control for CPU core supplies, improving stability during rapid load transients without oversized capacitors.

What are the valid switching frequency options for the MAX1718EEI, and how are they selected?

The MAX1718EEI supports four discrete switching frequencies: 200kHz, 300kHz, 550kHz, and 1000kHz. These are selected by strapping the TON pin to specific voltage levels: TON = VCC → 200kHz; TON = open → 300kHz; TON = REF → 550kHz; TON = GND → 1000kHz. The choice balances trade-offs among inductor size (higher f = smaller L), efficiency (mid-range f optimal), and EMI (avoiding sensitive bands like 455kHz IF). The MAX1718EEI maintains near-constant frequency across input voltage changes due to its feed-forward architecture.

Can the MAX1718EEI operate with a 2-cell Li+ battery input, and what is the minimum supported voltage?

Yes, the MAX1718EEI fully supports 2-cell Li+ battery input, with a validated minimum operating voltage of 2V on the V+ pin. Its constant-on-time architecture remains functional down to 2V, enabling reliable startup and regulation even at deep battery discharge. The MAX1718EEI's 2V–28V input range accommodates both 2-cell (6–8.4V nominal) and 4-cell (12–16.8V nominal) configurations, making it suitable for diverse notebook battery architectures without redesign.