Analog Devices Inc./Maxim Integrated DS3920T-002+

Overview

DS3920T-002+ from Maxim Integrated is a precision fast current mirror IC designed for avalanche photodiode (APD) biasing and monitoring in optical receivers. It delivers a 5:1 mirrored current output, features a 4.4mA typical current clamp, operates from +2.97V to +76V supply, and responds in 30ns rise time. It is used in GPON/EPON ONU/OLT burst-mode front-ends where accurate, high-speed photodiode current replication is required.

For engineers reviewing the DS3920T-002+ datasheet, DS3920T-002+ pinout, DS3920T-002+ application, or DS3920T-002+ equivalent, key selection criteria include its 4.4mA current limit setting, 5:1 mirror ratio accuracy across 250nA–2mA input range, thermal shutdown at +150°C, SOT23-6 package compatibility with MAX4007, and voltage clamp protection via DIODE pin.

Technical Context

The DS3920T-002+ implements a high-bandwidth current mirror with fixed 5:1 ratio (0.200 A/A nominal), enabling precise replication of APD photocurrent for analog-to-digital conversion. Its internal current clamp limits MIROUT to 4.4mA (typ) to protect photodiodes during transient overloads.

Thermal shutdown activates at +150°C with 20°C hysteresis, and an integrated diode between MIR and DIODE pins allows external voltage clamping of the mirror output. The device maintains gain error within ±0.5% over -40°C to +85°C and supports fast startup (<10µs) and transient response suitable for GPON Rx burst-mode timing.

Key Specifications

Pinout & Package

DS3920T-002+ is housed in a RoHS-compliant 6-pin SOT23 package (outline 21-0058, land pattern 90-0175), with pin 5 unconnected and pin 1 dedicated to external voltage clamping.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current mirror applications.

Compared with MAX4007ASA+T and DS3920T-001+, the DS3920T-002+ uniquely balances fast 30ns response, precise 4.4mA clamping for APD safety, and external voltage clamping flexibility-making it optimal for GPON/XG-PON burst-mode ROSAs requiring both speed and protection integrity.

Availability

DS3920T-002+ is available at Aetrix Electronics and suitable for GPON ONU design, 10G-EPON OLT manufacturing, and XG-PON transceiver module production requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for DS3920T-002+ 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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for communications, industrial, and computing markets.

The DS3920 product line was engineered specifically for optical receiver subsystems-delivering integrated current mirroring, clamping, and thermal protection in a single SOT23 package to simplify ROSA design and improve reliability in PON infrastructure.

FAQ

What is the primary function of the DS3920T-002+ in optical receiver designs?

The DS3920T-002+ functions as a precision fast current mirror that replicates photodiode current at a 5:1 ratio while providing built-in 4.4mA current clamping and thermal shutdown. In optical receivers, it enables accurate APD biasing and real-time current monitoring for AGC loops-critical for maintaining signal integrity in GPON and XG-PON burst-mode systems. Its 30ns rise time and SOT23-6 footprint make DS3920T-002+ ideal for space-constrained ROSA modules.

How does the DIODE pin on the DS3920T-002+ affect system-level voltage clamping?

The DIODE pin on the DS3920T-002+ connects internally to the MIR output and allows users to externally set a voltage ceiling on the mirror output by applying a reference voltage minus the diode's forward drop (~0.6V at 100nA). This enables precise control of MIR output swing without adding external components. For example, applying 2.0V to DIODE limits VMIR to ~2.6V, protecting downstream ADC inputs-functionality not available in standard current mirrors like MAX4007ASA+T.

What distinguishes the DS3920T-002+ from the DS3920T-001+ variant?

The DS3920T-002+ and DS3920T-001+ share identical pinout, package, and 5:1 mirror ratio-but differ in current clamp setting: DS3920T-002+ is specified for 4.4mA typical clamp, while DS3920T-001+ uses 20mA typical. This makes DS3920T-002+ safer for low-light APD operation where excessive clamp current could cause thermal runaway, whereas DS3920T-001+ suits higher-current PIN diode monitoring. Both versions include thermal shutdown at +150°C.

Can the DS3920T-002+ be used without connecting the DIODE pin?

Yes, the DIODE pin on the DS3920T-002+ may be left unconnected if external voltage clamping is not required-the device remains fully functional with its internal current clamp and thermal protection active. Leaving DIODE open defaults to internal diode protection only, limiting MIR output to VDIODE + 0.6V. However, for applications demanding tight output voltage control-such as driving low-voltage ADCs-the DIODE pin should be actively biased to achieve predictable clamping behavior.

Is the DS3920T-002+ compatible with existing MAX4007-based PCB layouts?

Yes, the DS3920T-002+ is pin-compatible with the MAX4007ASA+T in the same 6-pin SOT23 package (U6SN+1 outline), sharing identical pin assignments for GND, MIR, MIROUT, MIRIN, N.C., and DIODE (though MAX4007 lacks the DIODE pin function). Layout reuse is possible, but designers must verify that the faster 30ns rise time and lower 4.4mA clamp of DS3920T-002+ meet system timing and protection requirements-no PCB changes are needed, but firmware or AGC loop tuning may require adjustment.