Analog Devices Inc./Maxim Integrated MAX3806GTC+T

Overview

MAX3806GTC+T from Maxim Integrated is a single-channel, high-gain linear transimpedance preamplifier designed for optical distance measurement systems using AC-coupled photodiodes. It operates from a +5.0V supply, delivers 60kΩ or 30kΩ selectable transimpedance gain, supports input pulses as narrow as 30ns, maintains linearity up to 40μA_P, and withstands overload currents up to 2mA_P - enabling robust laser time-of-flight (ToF) receiver front-ends in portable and industrial LIDAR sensors.

For engineers reviewing the MAX3806GTC+T datasheet, MAX3806GTC+T pinout, MAX3806GTC+T application, or MAX3806GTC+T equivalent, this page provides verified functional context, validated pin roles, confirmed noise performance (1.5pA/√Hz at 60kΩ), real-world settling behavior, and direct alternative options for optical receiver design.

Technical Context

The MAX3806GTC+T integrates three configurable blocks: a CMOS/TTL-controlled transimpedance amplifier with two discrete gain settings (60kΩ or 30kΩ), a 14dB attenuator selected via the ATT pin, and an output driver with high-impedance disable capability controlled by the DIS pin. Its input stage accepts fast, low-amplitude photodiode current pulses without saturation, while its output is strictly AC-coupled to ≥2kΩ loads.

It features internal pull-up (60kΩ on DIS) and pull-down (40kΩ on GAIN/ATT) resistors, operates across –40°C to +105°C, and uses a thermally enhanced 3mm × 3mm 12-pin TQFN-EP package with soldered exposed pad for ground and thermal management. The device does not support DC-coupled output loading - doing so risks permanent damage.

Key Specifications

Pinout & Package

The MAX3806GTC+T is housed in a 3mm × 3mm, 12-pin thin quad flat no-lead package with exposed pad (TQFN-EP), requiring soldering of the EP pad to PCB ground for thermal integrity and electrical reference.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transimpedance amplifier applications.

Compared with MAX3805GTC+, the MAX3806GTC+ adds programmable gain and attenuation for adaptive signal conditioning; compared with LMH6629MA/NOPB, it integrates configuration logic and reduces system-level complexity at the cost of fixed bandwidth limits.

Availability

MAX3806GTC+T is available at Aetrix Electronics and suitable for laser distance meters, industrial LIDAR sensors, and optical safety scanners requiring stable component supply, extended temperature qualification, and RoHS-compliant packaging.

Supply support for MAX3806GTC+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, medical, and communications applications.

The MAX3806GTC+T belongs to Maxim's optical receiver front-end product line, engineered specifically for high-speed, low-noise amplification of photodiode current in time-of-flight distance measurement systems.

FAQ

What is the maximum input pulse width the MAX3806GTC+T can handle linearly?

The MAX3806GTC+T does not specify a maximum pulse width for linear operation - its linearity is defined by input amplitude, not duration. It remains linear for input currents from 42nA_P (SNR = 3) up to 40μA_P, regardless of pulse width, provided the signal stays within its small-signal bandwidth (up to 49MHz at 60kΩ gain). Pulse widths from 30ns to continuous CW are supported within these amplitude limits.

Can the MAX3806GTC+T output be DC-coupled to a 1kΩ load?

No - the MAX3806GTC+T output stage is explicitly designed for AC-coupled operation to loads ≥2kΩ. DC-coupling the output to a 1kΩ or lower impedance load violates the Absolute Maximum Ratings and may permanently damage the output driver. The datasheet warns: "Operating the part with its output DC-coupled to GND through a 2kΩ or less load may damage the output." Always use a series DC-blocking capacitor (e.g., 0.01µF) and verify load impedance.

How does the DIS pin affect settling time in the MAX3806GTC+T?

When the DIS pin is asserted high, the MAX3806GTC+T output enters high-impedance state and settles to steady state within 200ns. When DIS is deasserted (driven low), the output re-enables and settles within 50ns. These values are independent of RC time constants associated with gain or attenuation switching - DIS control provides deterministic, sub-200ns blanking for time-critical optical gating or channel multiplexing.

What is the role of the exposed pad (EP) on the MAX3806GTC+T package?

The exposed pad (EP) on the MAX3806GTC+T serves dual functions: it provides a low-thermal-resistance path for heat dissipation and acts as the internal analog ground connection. Per the datasheet, the EP must be soldered directly to the PCB ground plane to ensure proper thermal performance and electrical reference stability. Failure to do so risks degraded noise performance, bandwidth reduction, and potential thermal shutdown under sustained operation.

Does the MAX3806GTC+T support differential output or require external components for common-mode rejection?

No - the MAX3806GTC+T provides a single-ended output only and does not include differential output capability or built-in common-mode rejection circuitry. Its output is referenced to VCC/2 (e.g., 1.65V common-mode voltage at GAIN=0, ATT=0), and common-mode rejection relies entirely on downstream stages (e.g., ADC input buffer or external differential amplifier). No external components are required for basic operation, but system-level CMRR depends on external design choices.