Analog Devices Inc./Maxim Integrated MAX6834HXRD3+T

Overview

MAX6834HXRD3+T from Maxim Integrated is an ultra-low-voltage, open-drain active-low microprocessor reset circuit in a 3-pin SC70 package, designed to monitor +1.313V supply rails with ±2.5% threshold accuracy over temperature and assert reset for 210ms after VCC recovery or manual reset release. It operates down to VCC = 0.55V, consumes only 9µA typical at 1.8V, and supports bidirectional µP reset I/O via its open-drain output - used in portable battery-powered systems requiring reliable brownout protection.

For engineers reviewing the MAX6834HXRD3+T datasheet, MAX6834HXRD3+T pinout, MAX6834HXRD3+T application, or MAX6834HXRD3+T equivalent, key selection criteria include its H-suffix 1.313V reset threshold, D3-suffix 210ms timeout, SC70-3 open-drain configuration, guaranteed reset validity to 0.55V, and compatibility with multi-supply level-shifting reset networks.

Technical Context

The MAX6834HXRD3+T implements a precision bandgap-based voltage comparator with 444mV internal reference, comparing VCC directly against a factory-trimmed 1.313V threshold (H suffix). Its reset assertion logic is triggered solely by VCC falling below threshold - unlike RESET-IN variants, it does not support external threshold adjustment.

It features a fixed 210ms (D3) timeout period after VCC rises above threshold, with no manual reset (MR) input - confirmed by pin configuration (GND, RESET, VCC only) and absence of MR functionality in MAX6834 series. The open-drain RESET output requires an external pullup and remains functional down to VCC = 0.55V, sinking 200µA at 0.2V VOL.

Key Specifications

Pinout & Package

MAX6834HXRD3+T is housed in a 3-pin SC70-3 package (1.25mm × 0.8mm, 0.65mm pitch), with GND on pin 1, RESET (open-drain active-low) on pin 2, and VCC on pin 3 - no MR or RESET-IN pins present.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervisor applications.

Compared with MAX6834HXRD3+T, MAX809HTR eliminates the need for a pullup but forfeits multi-supply flexibility, while TPS3123HDBVR reduces current draw by >60% but introduces timing and packaging mismatches requiring layout revision.

Availability

MAX6834HXRD3+T is available at Aetrix Electronics and suitable for portable medical devices, industrial wireless sensors, and smart energy metering systems requiring stable component supply with guaranteed long-term availability and RoHS-compliant lead-free packaging.

Supply support for MAX6834HXRD3+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 demanding industrial, automotive, and computing applications.

The MAX6832–MAX6840 family was engineered specifically for ultra-low-voltage microprocessor supervision in battery-constrained systems, emphasizing sub-1µA quiescent current, SC70 miniaturization, and robust transient immunity.

FAQ

What is the exact reset threshold voltage of the MAX6834HXRD3+T?

The MAX6834HXRD3+T has a factory-trimmed reset threshold of 1.313V, specified with ±2.5% accuracy over the full operating temperature range (-40°C to +85°C). This value is fixed and unadjustable, corresponding to the 'H' suffix in the part number. The threshold is referenced directly to the VCC pin and does not require external components. This makes MAX6834HXRD3+T suitable for monitoring 1.3V logic or core supplies where precise undervoltage detection is required.

Does the MAX6834HXRD3+T include a manual reset (MR) input?

No, the MAX6834HXRD3+T does not include a manual reset (MR) input. It is a 3-pin device (GND, RESET, VCC) with no provision for external reset assertion. This distinguishes it from 4-pin variants like MAX6835/MAX6836/MAX6837, which integrate debounced MR inputs. The MAX6834HXRD3+T relies solely on VCC monitoring for reset generation - confirming its role as a minimal-footprint, single-function voltage detector optimized for space- and cost-sensitive designs.

What is the function of the RESET pin on the MAX6834HXRD3+T?

The RESET pin on the MAX6834HXRD3+T is an open-drain, active-low output. When asserted (i.e., during reset), it sinks current to pull the line low; when deasserted, it presents high impedance, requiring an external pullup resistor to establish a logic-high state. This configuration enables wired-OR reset buses and level-shifting - for example, pulling RESET up to 3.3V while monitoring a 1.3V VCC rail. The MAX6834HXRD3+T's RESET pin remains functional down to VCC = 0.55V, with VOL ≤ 0.2V at 200µA sink current.

Can the MAX6834HXRD3+T be used to monitor supplies below 1.3V?

No - the MAX6834HXRD3+T is factory-configured for a fixed 1.313V reset threshold and cannot monitor supplies below that level. For adjustable or lower thresholds (e.g., 0.44V), Maxim offers the MAX6838/MAX6839/MAX6840 series with RESET-IN inputs. The MAX6834HXRD3+T compares VCC directly to its internal trimmed reference; it lacks RESET-IN capability. Attempting to use it for sub-1.3V monitoring would result in permanent reset assertion, as VCC would always remain below threshold.

What timeout period is implemented in the MAX6834HXRD3+T?

The MAX6834HXRD3+T implements a fixed 210ms reset active timeout period, indicated by the 'D3' suffix in the part number. After VCC rises above the 1.313V threshold, RESET remains low for exactly 210ms before going high-impedance (deasserting). This timeout is internally generated and temperature-stable, meeting common µP reset timing requirements such as those specified in ARM CoreBoot or Intel PCH specifications. It is not user-adjustable and does not depend on external components.