Analog Devices Inc./Maxim Integrated MAX6820UT-T

Overview

The MAX6820UT-T from Maxim Integrated is a dual-supply power sequencer IC designed to control voltage sequencing between primary and secondary rails in multivoltage systems. It monitors a primary supply (VCC1 or VCC2) with an adjustable 0.618V internal reference, enables an external n-channel MOSFET via charge-pumped GATE drive (VCC2 + 5.5V), and provides capacitor-adjustable delay (tDELAY = 2.48×10⁶ × CSET) for precise timing control-used in PowerPC™ and dual-voltage µP boards where VI/O must follow VCORE.

For engineers reviewing the MAX6820UT-T datasheet, MAX6820UT-T pinout, MAX6820UT-T application, or MAX6820UT-T equivalent, this device is selected when system-level sequencing requires programmable delay, immunity to short transients, automotive-grade temperature operation (-40°C to +125°C), and minimal external components in a 6-pin SOT23 package.

Technical Context

The MAX6820UT-T implements a comparator-based monitoring architecture with an internally trimmed 0.618V reference applied to the SETV input, enabling threshold setting for either VCC1 or VCC2 via external resistor dividers. Its charge pump generates a regulated +5.5V gate drive relative to VCC2 to fully enhance external n-channel MOSFETs, ensuring low RDS(ON) and avoiding linear-region operation.

Unlike the MAX6819UT-T, the MAX6820UT-T replaces the logic-driven EN input with a SETD terminal that accepts an external capacitor to set tDELAY (140–280ms typical range), while retaining UVLO protection (1.875V–2.125V), transient immunity, and dual-supply flexibility-either rail may serve as primary if ≥2.125V.

Key Specifications

Pinout & Package

MAX6820UT-T is housed in a 6-pin SOT23-6 package (JEDEC MO-178AA), 2.9mm × 1.6mm × 1.1mm, with gull-wing leads and RoHS-compliant lead-free finish (marked "AARG").

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power-supply sequencing applications.

Compared with MAX6819UT-T and TPS3808G33DBVR, the MAX6820UT-T uniquely delivers capacitor-programmable sequencing delay and integrated charge-pump MOSFET drive in a 6-pin SOT23, making it the only option among the three capable of autonomous, adjustable, two-rail sequencing without external logic or PMIC support.

Availability

MAX6820UT-T is available at Aetrix Electronics and suitable for automotive infotainment head units, industrial PLCs, and PowerPC™-based test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6820UT-T 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) designs precision analog, mixed-signal, and power-management ICs for automotive, industrial, and communications markets.

The MAX6819/MAX6820 product line was engineered specifically for local, autonomous power-supply sequencing in multivoltage embedded systems where centralized PMICs are impractical or cost-prohibitive.

FAQ

What is the function of the SETD pin on the MAX6820UT-T?

The SETD pin on the MAX6820UT-T accepts an external capacitor connected to GND to set the delay time (tDELAY) between SETV crossing its 0.618V threshold and GATE activation. The relationship is tDELAY (seconds) = 2.48 × 10⁶ × CSET (farads). This replaces the fixed-delay EN input found on the MAX6819UT-T, enabling precise, board-specific timing without firmware or logic control. The MAX6820UT-T uses this pin exclusively for analog delay programming.

Can the MAX6820UT-T monitor VCC2 as the primary supply instead of VCC1?

Yes, the MAX6820UT-T supports bidirectional monitoring: either VCC1 or VCC2 can serve as the primary supply being monitored at SETV, provided that at least one supply exceeds the 1.875V UVLO threshold. The device does not assign functional priority to VCC1 or VCC2 - both are electrically symmetric inputs. In practice, users connect the higher-voltage rail (e.g., 3.3V) to SETV via a resistor divider to set the trip point, while the lower rail (e.g., 1.2V) is switched via GATE. This flexibility is confirmed in the Functional Diagram and Pin Description sections of the MAX6820UT-T datasheet.

What is the maximum gate capacitance the MAX6820UT-T can drive reliably?

The MAX6820UT-T's GATE output is characterized with a 1500pF capacitive load, achieving 0.5ms to 10ms turn-on time and 30µs turn-off time. While the datasheet does not specify an absolute maximum, design guidelines indicate reliable operation up to ~2000pF with acceptable timing margins. Larger gate capacitances increase tON and reduce peak dV/dt, potentially extending delay beyond the programmed tDELAY window. For MOSFETs with >2000pF gate charge, parallel driving or gate resistors should be evaluated per the "Gate Drive Characteristics" section of the MAX6820UT-T datasheet.

Does the MAX6820UT-T require external charge-pump capacitors?

No, the MAX6820UT-T integrates a self-contained charge pump circuit that requires no external capacitors. The internal charge pump generates the +5.5V gate drive offset relative to VCC2 directly from the supply rails, eliminating the need for flying capacitors or external timing components beyond the SETD capacitor. This is explicitly stated in the Applications Information section: "The internal charge pump does not require external capacitors." The only external passive required for basic operation is the CSET capacitor on SETD and the resistor divider on SETV.

How does the MAX6820UT-T behave during power-down sequencing?

During power-down, the MAX6820UT-T disables the GATE output immediately when SETV falls below its 0.618V threshold or when either VCC1 or VCC2 drops below the 1.875V UVLO level. There is no intentional power-down delay - turn-off is synchronous with supply collapse. This ensures rapid, safe deactivation of the secondary rail to prevent backfeeding or uncontrolled discharge. The behavior is identical in both power-up and power-down directions, as confirmed by the timing diagram (Figure 3) and "Detailed Description" section of the MAX6820UT-T datasheet.