Analog Devices Inc./Maxim Integrated MAX1729EUB

Overview

MAX1729EUB from Maxim Integrated is a micropower step-up/step-down DC-DC converter with integrated linear regulator and on-chip temperature sensor, designed specifically for ECB and LCD display bias generation. It delivers 2.5V to 16V output in internal feedback mode, maintains ±11ppm/°C output voltage drift, and operates from +2.7V to +5.5V input - enabling precise color/contrast control in portable displays.

For engineers reviewing the MAX1729EUB datasheet, MAX1729EUB pinout, MAX1729EUB application, or MAX1729EUB equivalent, key selection criteria include its dual-mode feedback architecture, 67µA quiescent current, 10-pin µMAX package (1.09mm max height), and integrated temperature-compensated output voltage control for display bias stability across operating temperature.

Technical Context

The MAX1729EUB integrates a PFM-controlled boost converter followed by a PNP low-dropout linear regulator, reducing output ripple while enabling both step-up and step-down conversion. Its internal feedback loop uses a buffered, digitally adjusted PWM signal applied to COMP, with temperature compensation derived from a 16.5mV/°C TC output.

In external feedback mode, the device accepts programmable resistor networks at FB and sums TC voltage directly into the feedback node for first-order negative temperature compensation. The CTLIN pin supports shutdown activation (>1.24ms low pulse) and dynamic VOUT control via 2kHz–12kHz PWM signals.

Key Specifications

Availability

MAX1729EUB is available at Aetrix Electronics and suitable for portable display biasing, handheld medical instrument displays, and industrial HMI panels requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX1729EUB 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 portable, industrial, and communications applications.

The MAX1729 product line was engineered to solve display bias instability in battery-powered devices, combining high-accuracy voltage regulation, integrated temperature sensing, and ultra-low quiescent current in a space-constrained µMAX package.

FAQ

What is the primary function of the MAX1729EUB?

The MAX1729EUB is a dedicated display bias supply IC that generates highly stable, temperature-compensated output voltages (2.5V–16V) for electrically controlled birefringence (ECB) and liquid-crystal-display (LCD) panels. Its architecture combines a PFM boost converter and a linear regulator to minimize ripple while enabling dynamic contrast/color adjustment via PWM on the CTLIN pin - making MAX1729EUB ideal for portable display systems where battery life and visual consistency are critical.

How does the MAX1729EUB achieve temperature compensation?

The MAX1729EUB achieves temperature compensation through an on-chip temperature sensor delivering a 16.5mV/°C output (TC pin). In internal feedback mode, this voltage is read by an external ADC and used to adjust the CTLIN PWM duty cycle. In external feedback mode, the TC voltage is summed directly into the FB network via R5, providing first-order negative temperature compensation - ensuring MAX1729EUB maintains consistent ECB color or LCD gray-scale contrast across -40°C to +85°C.

What are the key differences between internal and external feedback modes on the MAX1729EUB?

In internal feedback mode, MAX1729EUB sets output voltage using its internal 1.228V reference and CTLIN PWM signal, yielding fixed 2.5V–16V range with ±11ppm/°C drift. External feedback mode replaces the internal reference with a resistor divider at FB, allowing custom output ranges up to +18V and direct TC summation for analog temperature compensation - giving designers flexibility to match specific display requirements without firmware intervention. Both modes retain MAX1729EUB's 67µA quiescent current and shutdown capability.

What is the role of the COMP pin on the MAX1729EUB?

The COMP pin on MAX1729EUB serves dual functions: in internal feedback mode, it outputs an inverted, level-shifted, and filtered version of the CTLIN signal used by the internal feedback network to set VOUT; in external feedback mode, it presents the same buffered CTLIN signal to drive an external RC filter (R3/R4/C6) before summing into the FB node. A 1µF capacitor is required on COMP in internal mode; in external mode, COMP drives the feedback network directly - making COMP essential for dynamic output control in both configurations of MAX1729EUB.

Is there an evaluation kit available for the MAX1729EUB?

Yes, the MAX1729EVKIT evaluation kit is available for MAX1729EUB. It implements the typical operating circuit shown in the MAX1729 datasheet (Figure 2), including all recommended passive components (220µH inductor, 0.068µF C2, 1µF C4/C6), and supports both internal and external feedback configurations. The MAX1729EVKIT allows rapid validation of MAX1729EUB performance in ECB/LCD bias applications, including output voltage accuracy, temperature drift, PWM response, and shutdown behavior - accelerating design-in for portable display systems.