Analog Devices Inc. ADL5308ACCZ-R7

Overview

ADL5308ACCZ-R7 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 Erbium-doped fiber amplifiers (EDFAs) for real-time gain control.

For engineers reviewing the ADL5308ACCZ-R7 datasheet, ADL5308ACCZ-R7 pinout, ADL5308ACCZ-R7 application, or ADL5308ACCZ-R7 equivalent, key selection criteria include its adaptive photodiode bias (PDB), I²C-programmable comparator hysteresis, ratio-input log-ratio detection capability, and guaranteed operation from −40°C to +105°C in a 2 mm × 3 mm LGA package.

Technical Context

The ADL5308ACCZ-R7 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-compensated log response, and includes an integrated I²C interface (400 kHz max) for configuring PDB bias, comparator reference, and hysteresis.

It features dual input paths - INP for photocurrent and IREF for reference current - enabling true log-ratio detection for optical gain measurement. The comparator supports external CREF or internal DAC-based thresholding, with latch enable via HYST pin voltage >1.6 V, and hysteresis adjustable up to 109 mV.

Key Specifications

Pinout & Package

ADL5308ACCZ-R7 is housed in a 2 mm × 3 mm, 14-terminal Land Grid Array (LGA) package (Analog Devices part number CC-14-4), with exposed thermal pads (Pins 15 and 16) internally connected to SUM and GND respectively. All SUM pins must be tied together and left floating for optimal input shielding; GND pins require low-impedance connection to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX40075ATA+T and LT6553IMS8#PBF, the ADL5308ACCZ-R7 uniquely integrates log-ratio detection, adaptive PDB, and I²C-configurable comparator - enabling compact, self-calibrating optical monitoring in space-constrained EDFA and transceiver designs without external support components.

Availability

ADL5308ACCZ-R7 is available at Aetrix Electronics and suitable for optical power monitoring, Erbium-doped fiber amplifiers (EDFA), and fiber optic transceiver modules requiring stable component supply, extended temperature operation, and high dynamic range analog signal conditioning.

Supply support for ADL5308ACCZ-R7 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving communications, industrial, automotive, and healthcare markets.

The ADL5308ACCZ-R7 belongs to Analog Devices' RF and microwave logarithmic amplifier product line, designed specifically for wide-dynamic-range optical and electrical signal level measurement in fiber infrastructure and test equipment.

FAQ

What is the guaranteed operating temperature range for the ADL5308ACCZ-R7?

The ADL5308ACCZ-R7 is fully specified and tested from −40°C to +105°C ambient temperature. This range covers industrial and telecom chassis environments where passive cooling and wide thermal swings occur. All key parameters - including logarithmic conformance error (±0.2 dB), slope (198–202 mV/dec), and comparator hysteresis - are guaranteed across this full range per the Rev. A datasheet.

Does the ADL5308ACCZ-R7 support true log-ratio measurement between two photodiodes?

Yes. The ADL5308ACCZ-R7 supports true log-ratio detection using its dual-input architecture: INP accepts the main photocurrent, while IREF accepts a second photodiode current or precision reference. The output VLOG is proportional to log₁₀(IINP/IREF), enabling direct optical gain calculation without software correction or calibration drift compensation - a core feature confirmed in the General Description and Figure 6 of the datasheet.

How does the adaptive photodiode bias (PDB) function improve measurement accuracy in the ADL5308ACCZ-R7?

The ADL5308ACCZ-R7's PDB pin dynamically adjusts reverse bias voltage applied to the photodiode cathode. At low input currents (<63 µA), it maintains minimal bias to suppress dark current; above threshold, bias scales linearly with current to prevent series resistance-induced saturation. This dual-regime control - configurable via I²C registers REG_14 and REG_15 - improves low-light SNR and high-current linearity, directly validated in Figures 16–21 of the datasheet.

Can the comparator in the ADL5308ACCZ-R7 be configured without external components?

Yes. The ADL5308ACCZ-R7 comparator supports both external CREF voltage and internal I²C-programmable DAC reference (CREF_DAC register). Hysteresis is set by analog voltage on HYST pin (e.g., 109 mV at 1 V), and latch enable is activated when HYST >1.6 V - all without resistors, capacitors, or external comparators. This is documented in Table 5 (Pin Descriptions) and the "Comparator" section of the Electrical Specifications.

What package type and thermal performance does the ADL5308ACCZ-R7 use?

The ADL5308ACCZ-R7 uses a 2 mm × 3 mm, 14-terminal LGA package (CC-14-4) with exposed thermal pads (Pins 15 and 16). Its thermal resistance is θJA = 86°C/W (JEDEC 2S2P board), θJB = 45°C/W, and θJC = 32°C/W. The datasheet mandates connecting all GND pins to a low-impedance ground plane and recommends decoupling VCC with 1 nF + 4.7 µF capacitors - details found in Table 4 and Pin Configuration section.