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Analog Devices Inc./Maxim Integrated DS1877T+
- Part No.:
- DS1877T+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Sensor and Detector Interfaces
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
DS1877T+.pdf
- Description:
- IC CTLR/MON SFP 1-2CH 28TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,429
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Product details
Overview
DS1877T+ from Maxim Integrated is a dual-receiver SFP/SFP+ controller IC that implements full SFF-8472 compliance for optical transceiver modules. It integrates four ADC channels (temperature, VCC, RSSI1, RSSI2), two 10-bit delta-sigma DACs with 72-entry temperature-indexed LUTs, and comprehensive LOS detection for two independent Rx paths. It operates from +2.85V to +3.9V across –40°C to +95°C and is deployed in dual-Rx video SFPs and telecom/datacom pluggable modules.
For engineers reviewing the DS1877T+ datasheet, DS1877T+ pinout, DS1877T+ application, or DS1877T+ equivalent, key selection criteria include its dual-channel RSSI monitoring with differential inputs, I²C-compatible interface at up to 400kHz, 28-pin TQFN-EP package, factory-programmable alarm thresholds, and support for SFF-8472 register map addressing at A0h, A2h, and B2h slave addresses.
Technical Context
The DS1877T+ employs a shared 13-bit ADC with round-robin sampling across four analog inputs (internal temp sensor, VCC, RSSI1, RSSI2), achieving 45–75ms full-cycle update rate. Its dual quick-trip comparators monitor RSSI1_ and RSSI2_ against programmable thresholds to drive LOSOUT and FAULT outputs with 25.6μs response latency.
Two independent 10-bit delta-sigma DACs (DAC1/DAC2) accept temperature-indexed LUT values via EEPROM and output filtered analog control signals referenced to REFIN (0.1×VCC to VCC). The device uses a single I²C interface (SCL/SDA) supporting fast-mode (400kHz) timing and multi-address memory mapping: main device at A2h/B2h, auxiliary EEPROM at A0h.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | +2.85V to +3.9V - supports wide-input industrial SFP module rails without external regulators |
| Operating Temp | –40°C to +95°C - qualified for extended-temperature optical module environments |
| ADC Resolution | 13 bits - provides high-resolution RSSI and VCC monitoring with ±2%FS accuracy |
| DAC Output | 10-bit delta-sigma - enables precise analog bias control of TIA/APD with temperature compensation |
| I²C Interface | Up to 400kHz - meets SFF-8472 fast-mode timing for real-time host communication |
| Package | 28-pin TQFN-EP (5mm × 5mm × 0.75mm) - compact footprint with exposed pad for thermal management in dense SFP PCB layouts |
| Memory Map | A0h (256B EEPROM), A2h (Rx1), B2h (Rx2) - enables independent configuration and monitoring of dual receivers |
Pinout & Package
DS1877T+ is housed in a 28-pin thin quad flat no-lead (TQFN) package with exposed thermal pad (5mm × 5mm × 0.75mm), RoHS-compliant and lead-free.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RSELOUT (Pin 1) | Rate-select output | Drives external rate-select logic; open-drain, compatible with SFF-8431 RS1 signaling |
| SCL (Pin 2) | I²C clock input | Accepts standard-mode (100kHz) or fast-mode (400kHz) clock; internal pull-up not provided |
| SDA (Pin 3) | I²C data I/O | Open-drain bidirectional bus line; requires external pull-up per I²C spec |
| FAULT (Pin 4) | Transmit fault I/O | Open-drain output asserted on any unmasked alarm; also accepts external TX_FAULT input |
| LOS1 / LOS2 (Pins 5, 7) | Loss-of-signal inputs | Dedicated digital inputs for Rx1/Rx2 LOS status; sampled by internal quick-trip comparators |
| RSEL (Pin 9) | Rate-select input | Configures operating mode (e.g., 1G/10G); referenced to GND/VCC logic levels |
| RSSI1P/N, RSSI2P/N (Pins 12–14, 17) | Differential monitor inputs | High-impedance (35–65kΩ), rail-to-rail common-mode inputs for RSSI voltage sensing |
| DAC1 / DAC2 (Pins 19, 20) | Delta-sigma analog outputs | Current-output DACs requiring external RC filter (per Figure 8) for stable analog control |
| REFIN (Pin 22) | DAC reference input | Accepts 0.1×VCC to VCC reference voltage; sets full-scale output range for both DACs |
| LOSOUT (Pin 27) | Receive LOS output | Open-drain output asserted when either LOS1 or LOS2 is active; directly drives SFP LOS indicator |
| OUTX (Pin 28) | General-purpose output | Open-drain digital output usable as AS1 output (SFF-8079) or RS1 output (SFF-8431) |
Key Features
| Feature | Design Value |
|---|---|
| Dual RSSI monitoring with differential inputs | Enables simultaneous, high-accuracy optical power measurement for two independent receivers using scalable dynamic range and internal/external calibration |
| Temperature-indexed DAC LUTs | 72-entry lookup tables per DAC allow closed-loop thermal compensation of laser bias or TIA gain without host CPU intervention |
| Four programmable ADC monitor channels | Supports user-defined full-scale ranges and offsets for VCC, temperature, RSSI1, RSSI2 - critical for SFF-8472 compliance and margin testing |
| Multi-address I²C memory map | Separate slave addresses (A2h for Rx1, B2h for Rx2, A0h for auxiliary EEPROM) enable independent configuration and real-time monitoring of dual Rx paths |
| Two-level password protection | 120 bytes protected by Password-1 and 128 bytes by Password-2 prevent unauthorized access to calibration data and critical control registers |
Applications
| Optical Transceiver Modules | Dual-Rx Video SFPs |
|---|---|
Use Scenario: Embedded in SFP+ modules used in 10G Ethernet switches and routers for fiber-optic link management. IC Role / Device Role / Timing Role: Primary SFF-8472 controller handling real-time RSSI monitoring, temperature compensation, and LOS assertion for host system diagnostics. Use Value: Enables full compliance with SFF-8472 register map and alarm reporting, reducing firmware development effort and accelerating qualification. | Use Scenario: Deployed in broadcast video over fiber systems where two independent video streams require synchronized optical signal integrity monitoring. IC Role / Device Role / Timing Role: Dual-channel analog monitor and control hub managing RSSI1/RSSI2, VCC, and temperature while driving LOSOUT and FAULT for fail-safe operation. Use Value: Eliminates need for discrete comparators and microcontrollers, lowering BOM cost and PCB area in space-constrained video SFP housings. |
| Industrial Datacom Links | Optical Network Test Equipment |
Use Scenario: Used in ruggedized SFP modules for factory automation networks operating in extended temperature environments (–40°C to +95°C). IC Role / Device Role / Timing Role: Provides robust analog monitoring and fault signaling under thermal stress, with calibrated ADC offset and full-scale tuning for long-term stability. Use Value: Ensures reliable link health reporting across temperature extremes, reducing field failures and maintenance cycles. | Use Scenario: Integrated into optical test fixtures that validate SFP module performance across RSSI, temperature, and supply voltage sweeps. IC Role / Device Role / Timing Role: Acts as programmable stimulus/response node-reading RSSI/VCC/temperature while adjusting DAC outputs to emulate optical power drift or thermal derating. Use Value: Supports automated calibration and conformance testing per SFF-8472, cutting test setup time and improving repeatability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SFP controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX32664ETK+ | Integrated ARM Cortex-M0+ MCU, 12-bit SAR ADC, no built-in SFF-8472 register map or dual-Rx LOS logic | Requires full firmware implementation of SFF-8472; better suited for custom optical monitoring, not drop-in SFP replacement | Select only if full programmability and sensor fusion (e.g., adding humidity/pressure) are required beyond SFF-8472 compliance |
| DS1878T+ | Single-Rx variant with identical DAC/LUT architecture, same pinout but only one RSSI pair and LOS path | Lacks second RSSI channel and B2h address; cannot monitor dual receivers simultaneously | Choose only for cost-sensitive single-Rx SFP designs where dual monitoring is unnecessary |
Compared with MAX32664ETK+, DS1877T+ delivers immediate SFF-8472 compliance and hardware-accelerated dual-Rx monitoring without firmware development; compared with DS1878T+, it adds full second-channel support including dedicated B2h memory map and independent LOS2 handling-essential for true dual-Rx SFP+ modules.
Availability
DS1877T+ is available at Aetrix Electronics and suitable for optical transceiver modules, industrial datacom links, and broadcast video SFPs requiring stable component supply, extended-temperature operation, and SFF-8472 compliance.
Supply support for DS1877T+ 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, communications, and computing applications.
The DS1877T+ belongs to Maxim's SFP/SFP+ controller product line, engineered specifically to offload SFF-8472 monitoring, calibration, and alarm management from host processors in pluggable optical modules.
FAQ
What is the primary function of the DS1877T+ in an SFP module?
The DS1877T+ serves as the dedicated SFF-8472-compliant controller for dual-receiver SFP/SFP+ modules. It continuously monitors temperature, supply voltage (VCC), and two differential RSSI inputs (RSSI1, RSSI2), manages loss-of-signal detection for both receivers, and provides two temperature-compensated DAC outputs for analog control. Its integrated I²C interface and multi-address memory map (A2h, B2h, A0h) enable full compliance with SFF-8472 register definitions without host processor overhead. DS1877T+ eliminates the need for external microcontrollers in standard optical modules.
Does the DS1877T+ support SFF-8472 register compatibility out of the box?
Yes, the DS1877T+ implements the complete SFF-8472 register map natively. Receiver 1 is accessed at slave address A2h, Receiver 2 at B2h, and auxiliary EEPROM at A0h-matching the standard SFP memory layout. All required alarm/warning flags, calibration coefficients, and monitoring registers are pre-mapped and user-programmable via I²C. No firmware translation layer is needed; host systems read and write registers directly per SFF-8472 specification. DS1877T+ also supports the two-level password scheme defined in the standard for secure access.
How does the DS1877T+ handle temperature compensation for its DAC outputs?
The DS1877T+ uses two independent 72-entry temperature-indexed lookup tables (LUTs) - one for DAC1 and one for DAC2 - to provide hardware-based temperature compensation. Each LUT entry corresponds to a specific temperature bin measured by the internal 13-bit digital thermometer (±3°C accuracy). During operation, the device automatically selects the appropriate DAC code based on real-time temperature, enabling closed-loop bias control of TIAs or APDs without host intervention. DS1877T+ stores LUT data in nonvolatile memory, retaining calibration across power cycles.
What are the key electrical characteristics of the RSSI inputs on the DS1877T+?
The DS1877T+ features two differential RSSI inputs (RSSI1P/N and RSSI2P/N) with rail-to-rail common-mode range (GND to VCC), 35–65kΩ input resistance, and 8-bit resolution with ±2%FS accuracy at +25°C. Each channel supports internal and external calibration, right-shifting up to 7 bits for fine-grained small-signal measurement, and programmable full-scale ranges (e.g., 2.5V factory default). The inputs are optimized for direct connection to transimpedance amplifier outputs in ROSA assemblies. DS1877T+ also provides dedicated quick-trip comparators for low-latency LOS assertion.
Can the DS1877T+ operate reliably across the full industrial temperature range?
Yes, the DS1877T+ is fully specified and tested for continuous operation from –40°C to +95°C. Its ADC accuracy (±0.5%FS), DAC linearity (±1 LSB INL/DNL), digital thermometer error (±3°C), and I²C timing (400kHz fast-mode) are all guaranteed across this range. The 28-pin TQFN-EP package includes an exposed thermal pad for efficient heat dissipation, and internal power-on reset circuitry (POA = 2.0–2.75V) ensures robust startup under varying thermal and supply conditions. DS1877T+ meets the environmental requirements of commercial and industrial-grade SFP modules.
DS1877T+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- 28-WFQFN Exposed Pad
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- SFP+ Controller
- Input Type:
- Logic
- Output Type:
- Logic
- Current - Supply:
- 2.5 mA
- Operating Temperature:
- -40°C ~ 95°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TQFN (5x5)
DS1877T+ FAQ
1.How can I place an order for DS1877T+ through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1877T+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for DS1877T+ reliable?
The price and inventory of DS1877T+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1877T+ is usually 5 days.
3.What payment methods are accepted for DS1877T+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1877T+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1877T+?
DS1877T+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1877T+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for DS1877T+?
For technical support, including DS1877T+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1877T+ requirements.
6.How does Aetrix verify that DS1877T+ is sourced from the original manufacturer or authorized distributors?
All DS1877T+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that DS1877T+ meets industry standards.
7.What is the process for return or replacement of DS1877T+?
All DS1877T+ units undergo pre-shipment inspection (PSI). If there is an issue with DS1877T+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The DS1877T+ part is unused and in its original packaging.
Return procedure for DS1877T+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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