Analog Devices Inc. ADL5308ACCZ

Overview

ADL5308ACCZ from Analog Devices is a fast-response logarithmic transimpedance amplifier optimized for optical power monitoring in fiber-optic systems. It delivers 188 dB dynamic range (10 pA to 25 mA), 200 mV/dec logarithmic slope, ±0.2 dB conformance error (10 nA–1 mA), and <3.5 µs 2 dB settling time. It serves as the core signal-conditioning IC in EDFA gain control loops.

For engineers reviewing the ADL5308ACCZ datasheet, ADL5308ACCZ pinout, ADL5308ACCZ application, or ADL5308ACCZ equivalent, key selection criteria include its adaptive photodiode bias (PDB), I²C-programmable comparator hysteresis, ratio-input capability for optical gain measurement, and guaranteed operation from −40°C to +105°C in a 2 mm × 3 mm LGA package.

Technical Context

The ADL5308ACCZ implements a factory-trimmed logarithmic transfer function VLOG = SLOPE × log₁₀(IINP/IZ), with nominal slope 200 mV/dec and intercept 10 pA. Its transimpedance architecture uses bipolar junction elements for temperature-stable compression across 188 dB input current range.

It integrates three co-located functional blocks: a logarithmic TIA with feedback-controlled VLOG output, an I²C-configurable comparator with adjustable hysteresis and latch enable via HYST pin, and an adaptive PDB driver that scales reverse bias voltage linearly above 160 µA to mitigate dark current and series resistance errors.

Key Specifications

Pinout & Package

The ADL5308ACCZ is housed in a 2 mm × 3 mm, 14-terminal Land Grid Array (LGA) package with exposed thermal pads (SUM and GND) on the underside. The package supports high-density PCB layout and efficient heat dissipation in compact optical modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX4007AEEE+ and LT6553IMS8#PBF, the ADL5308ACCZ uniquely combines ultra-wide 188 dB range, on-chip I²C-configurable comparator with latch, and adaptive PDB-making it the only single-chip solution qualified for uncooled EDFA gain control and optical safety interlock in telecom infrastructure.

Availability

ADL5308ACCZ is available at Aetrix Electronics and suitable for optical power monitoring, EDFA gain control, and fiber link loss detection requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for ADL5308ACCZ 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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and industrial markets since 1965.

The ADL5308ACCZ belongs to Analog Devices' RF and microwave logarithmic amplifier product line, designed specifically for wide-dynamic-range optical and current sensing in fiber-optic infrastructure and test equipment.

FAQ

What is the guaranteed operating temperature range for the ADL5308ACCZ?

The ADL5308ACCZ is fully specified and tested from −40°C to +105°C ambient temperature. This extended range enables direct mounting on optical line cards without heatsinking and supports deployment in uncontrolled environments such as outdoor fiber cabinets and base station enclosures. All key specifications-including logarithmic conformance error, bandwidth, and comparator performance-are validated across this full range.

Does the ADL5308ACCZ require external components to achieve its specified 188 dB dynamic range?

No. The ADL5308ACCZ achieves its full 10 pA to 25 mA input range with only standard power supply decoupling: a 1 nF ceramic capacitor and a 4.7 µF bulk capacitor at the VCC pin. No external resistors, op-amps, or trimming components are required for basic logarithmic conversion, ratio measurement, or comparator operation-reducing bill-of-materials cost and PCB area.

How does the adaptive photodiode bias (PDB) function improve measurement accuracy in the ADL5308ACCZ?

The ADL5308ACCZ's PDB pin dynamically adjusts reverse bias voltage from ~1.5 V at low photocurrents (minimizing dark current) to up to 5 V at high currents (preventing photodiode saturation). This dual-regime biasing-configurable via I²C registers-reduces measurement nonlinearity caused by either dark current drift or series resistance drop, directly improving optical power accuracy across the full 188 dB range.

Can the ADL5308ACCZ perform optical gain measurements without external circuitry?

Yes. By connecting a second photodiode to the IREF pin while the primary photodiode connects to INP, the ADL5308ACCZ performs true log-ratio detection. Its internal architecture computes VLOG ∝ log₁₀(IINP/IREF), yielding optical gain in dB directly at the VLOG pin-eliminating the need for external ADCs, microcontrollers, or analog subtractors to derive gain values.

What is the maximum I²C clock frequency supported by the ADL5308ACCZ?

The ADL5308ACCZ supports standard-mode I²C operation up to 400 kHz (fSCL(MAX)), as confirmed in Table 2 of the Rev. A datasheet. This allows rapid configuration of comparator hysteresis, PDB parameters, and DAC references during system startup or runtime recalibration-without requiring custom timing firmware or bit-banging interfaces.