Analog Devices Inc./Maxim Integrated MAX1541ETL

Overview

The MAX1541ETL from Maxim Integrated is a dual step-down PWM controller IC designed for notebook computer power management, delivering two independent regulated outputs (0.7V–5.5V and 2.5V/1.8V fixed or adjustable) with inductor-saturation protection, 1% output accuracy over line/load, 2V–28V input range, and ultra-fast 100ns load-step response. It integrates a 5V/100mA adjustable LDO, external reference input (REFIN1), and dynamic voltage scaling for CPU/chipset/GPU core supplies.

For engineers reviewing the MAX1541ETL datasheet, MAX1541ETL pinout, MAX1541ETL application, or MAX1541ETL equivalent, this page provides verified technical context, validated pin functions, confirmed application roles in DDR termination and active bus termination, and real-world selection guidance against comparable dual-buck controllers with saturation protection and dynamic output capability.

Technical Context

The MAX1541ETL implements Maxim's proprietary Quick-PWM™ architecture - a free-running, constant on-time control scheme with input feed-forward - enabling wide VIN–VOUT differential operation (2V to 28V input, down to 0.7V output), tight load regulation (<0.1%), and sub-100ns transient recovery. Its dual-channel design supports independent feedback loops with separate PGOOD comparators and fault-blanking options during transitions.

It features dual valley-current sensing via CSP/CSN inputs, selectable switching frequency (170kHz–620kHz via TON pin), programmable current-limit thresholds (0.25V–2.0V), and integrated gate drivers capable of driving large synchronous FETs (RDH ≤ 5Ω, RDL ≤ 3Ω). The LDO section offers fixed 5V or adjustable 1.175V–24V output with 500mV dropout at 50mA.

Key Specifications

Pinout & Package

MAX1541ETL is housed in a 40-pin Thin QFN package (6mm × 6mm, T4066-5), thermally enhanced with exposed pad for high-power DC-DC operation in space-constrained notebook PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ISL95210IRZ-T and TPS51220RGER, the MAX1541ETL uniquely combines external reference-driven dynamic output, hardware-based inductor saturation protection, and sub-100ns transient response - making it the only option among the three qualified for high-reliability mobile CPU core supplies with adaptive voltage positioning.

Availability

MAX1541ETL is available at Aetrix Electronics and suitable for notebook computer power systems, DDR memory termination networks, and active bus termination designs requiring stable component supply, long-lifecycle availability, and automotive-grade reliability validation.

Supply support for MAX1541ETL 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 semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for computing, communications, and industrial applications.

The MAX1541ETL belongs to Maxim's notebook power management product line, engineered specifically for multi-rail, high-efficiency DC-DC conversion in space- and thermal-constrained mobile platforms with dynamic voltage scaling requirements.

FAQ

What is the function of the REFIN1 pin on the MAX1541ETL?

The REFIN1 pin on the MAX1541ETL accepts an external reference voltage (0.7V to 2.0V) to dynamically set the OUT1 output voltage in real time. When REFIN1 = 0.35 × VREF (≈0.7V), OUT1 regulates to 0.7V; scaling REFIN1 linearly adjusts OUT1 up to 5.5V. This enables adaptive voltage positioning (AVP) for CPU/GPU cores and eliminates need for DACs or digital interfaces in analog-controlled systems. The MAX1541ETL uses this pin to achieve true dynamic output scaling without firmware intervention.

How does the MAX1541ETL implement inductor-saturation protection?

The MAX1541ETL implements hardware-based inductor-saturation protection using the LSAT pin and CSP/CSN differential inputs. When LSAT is enabled, the controller monitors the valley current sense signal and triggers a fault if the sensed voltage exceeds a threshold set relative to the programmed current limit (135–220% of VLIM_VAL). Upon detection, it disables the affected channel's high-side driver and asserts PGOOD low. This occurs within microseconds and is independent of software or external ICs - a key safety feature confirmed in MAX1541ETL's electrical characteristics table (tFBLANK = 35–320µs, ILIM_ sink current = 4–8µA).

Can the MAX1541ETL operate with only one output enabled?

Yes, the MAX1541ETL supports independent enable/disable control of each output via ON1 and ON2 pins. Driving ON1 = GND disables OUT1 while preserving OUT2 operation, and vice versa. Both channels retain full regulation, current limiting, and fault reporting capability when active. The datasheet confirms standby supply current drops to <1µA per enabled supply rail when the other is disabled - confirming true single-channel operation without cross-talk or performance degradation. This makes the MAX1541ETL suitable for flexible power tree designs where rail sequencing or partial operation is required.

What is the purpose of the TON pin on the MAX1541ETL?

The TON pin on the MAX1541ETL selects the switching frequency for both buck channels by setting the on-time duration: GND = 620kHz, REF = 485kHz, open = 345kHz, and VCC = 235kHz (for OUT1) or 170kHz (for OUT2). This four-level logic interface allows frequency optimization without resistors or external components. The selected frequency directly determines minimum off-time (tOFF(MIN) = 500ns) and impacts efficiency vs. size trade-offs - e.g., 620kHz enables smaller inductors for thin-profile notebooks, while 170kHz improves light-load efficiency in always-on subsystems. All values are measured and guaranteed in the MAX1541ETL datasheet.

Does the MAX1541ETL include an integrated linear regulator, and what are its capabilities?

Yes, the MAX1541ETL integrates a configurable 100mA linear regulator with two operating modes: fixed 5V output (when FBLDO = GND) or adjustable 1.175V–24V output (when FBLDO = LDOOUT). Its accuracy is ±1.25% (1.175V–1.275V) for adjustable mode and ±4.7% to ±5.1% (4.7V–5.1V) for fixed mode at 100mA load. Dropout is 500mV at 50mA, and short-circuit current is 130mA. This LDO powers auxiliary circuitry such as clock generators or sensor interfaces, eliminating need for a second discrete regulator - a capability explicitly documented in the MAX1541ETL's "Linear Regulator (LDO)" electrical characteristics section.