ADI Power Management ICs for Optical Modules and Instrument Boards
Product Specifications
Product Overview
An optical module has a harder power problem than its size suggests. It draws 3.3 V from the host connector and has to turn that into a quiet rail for the laser driver and the receive chain, a stable rail for the control and diagnostics circuits, and often a separate supply for the monitoring front end. The receive path works down from a few microamps of photocurrent, so switching ripple that reaches the transimpedance stage turns directly into jitter on the recovered eye, and a rail that sags during a burst turns into a bias settling error.
The usual answer is two stages: a synchronous buck that steps the rail down efficiently, followed by a low dropout regulator that removes the switching residue. Splitting those stages across two packages costs board area, extra passives and a headroom budget that somebody has to design. The parts on this page cover both styles, including a micro PMU that puts a 3 A buck and a 3 A ultralow noise LDO in one 5 mm by 5 mm package, with an adaptive headroom mode that moves the buck output in step with the LDO load current so dissipation stays low while rejection stays high.
For instrument and test boards the requirements move in the other direction. Rails of 12 V and 15 V have to be regulated down without injecting noise into an ADC or a clock, which is what the 20 V low noise LDOs are for, while a handheld instrument that runs from USB or a wall adapter and also carries a battery needs a power path manager and a charger rather than a plain regulator.
Every model below is grouped into this single product, so one enquiry can cover a mixed set of rails with the packages, temperature grades and quantities stated per line.
Electrical Specifications
| Parameter | Low noise LDO rails | Synchronous buck rails | Buck plus ultralow noise LDO | USB and battery power path |
|---|---|---|---|---|
| Typical role | Post regulation of a rail that follows a switching stage, or a clean rail straight from the host supply | Point of load step down from 3.3 V or 5 V with sequencing and fault reporting | Two stage supply for noise sensitive loads in one package | Instrument boards that run from USB, a wall adapter or a battery |
| Input voltage range | ADP1754 and ADP1755: 1.6 V to 3.6 V; ADP7102 and ADP7104: 3.3 V to 20 V | ADP2114: 2.75 V to 5.5 V; ADP2118: 2.3 V to 5.5 V | Buck: 4.2 V to 15 V; LDO: 0.65 V to 5 V | USB or adapter input with programmable 100 mA, 500 mA or 1 A input current limit |
| Output current | 1.2 A (ADP1754, ADP1755); 300 mA (ADP7102); 500 mA (ADP7104) | ADP2118: 3 A; ADP2114: dual 2 A, or 3 A plus 1 A, or single 4 A interleaved | 3 A buck plus 3 A LDO | LTC3566: 1 A buck-boost and 1.5 A maximum charge current; LTC3586: two 400 mA bucks, 1 A buck-boost, 800 mA boost |
| Output voltage | ADP1754: seven fixed options from 0.75 V to 2.5 V; ADP1755: 0.75 V to 3.3 V adjustable; ADP7102 and ADP7104: seven fixed options from 1.5 V to 9 V, or adjustable from 1.22 V to VIN minus dropout | ADP2114: fixed 0.8 V, 1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.3 V or adjustable down to 0.6 V; ADP2118: adjustable 0.6 V to VIN with preset 1.2 V and 3.3 V options | Buck: 0.6 V to 5.0 V; LDO: 0.6 V to 3.3 V | Buck-boost adjustable, minimum output 2.75 V; float voltage 4.2 V, or 4.1 V on the LTC3586-1 |
| Noise and rejection | 15 uV rms on the fixed 20 V parts; 23 uV rms at 0.75 V on the low Vin parts; PSRR of 60 dB at 10 kHz | Switching ripple removed by the following LDO, or by the remote sense and output capacitors | 3 uV rms LDO output noise, PSRR above 50 dB to 100 kHz with 400 mV headroom at 3 A | Switching power path with efficiency above 95 percent, so little energy is lost as heat |
| Accuracy and sensing | Initial accuracy plus or minus 1 percent on the low Vin parts, plus or minus 0.8 percent on the 20 V parts, with power good output | Plus or minus 1.5 percent reference accuracy, independent enable inputs and power good outputs | Differential remote sense at the point of load to compensate PCB trace impedance at 3 A | Charge current programmable up to 1.5 A, with an internal 180 milliohm ideal diode |
| Switching frequency | Not applicable | ADP2114: 300 kHz, 600 kHz or 1.2 MHz, synchronisable from 200 kHz to 2 MHz; ADP2118: 600 kHz or 1.2 MHz | 0.3 MHz to 2.5 MHz internal oscillator or external synchronisation | 2.25 MHz constant frequency buck-boost |
| Quiescent and shutdown | Shutdown current under 2 uA on the low Vin parts; under 40 uA at 12 V input on the 500 mA 20 V part | ADP2118 draws under 3 uA from the input when disabled | Precision enable input on each regulator, power good output | No load quiescent current under 30 uA when powered from the battery |
| Package | 16-lead 4 mm by 4 mm LFCSP (ADP1754, ADP1755); 8-lead 3 mm by 3 mm LFCSP or 8-lead SOIC (ADP7102, ADP7104) | 32-lead 5 mm by 5 mm LFCSP (ADP2114); 16-lead 4 mm by 4 mm LFCSP (ADP2118) | 32-lead 5 mm by 5 mm LFCSP | 24-lead 4 mm by 4 mm QFN (LTC3566); 38-pin 4 mm by 6 mm QFN (LTC3586) |
Included Models and Order Codes
The table lists the parts selected most often for optical module and instrument rails. Order codes include a fixed voltage suffix, a temperature grade and a reel option, so send the exact order string and the quantity and we will confirm against that string rather than against the base model.
| Model | Function | Input Range | Output Current | Output Voltage | Package |
|---|---|---|---|---|---|
| ADP1754 | Low Vin low dropout regulator, fixed output, external soft start, power good | 1.6 V to 3.6 V | 1.2 A | Seven fixed options from 0.75 V to 2.5 V | 16-lead 4 mm by 4 mm LFCSP |
| ADP1755 | Low Vin low dropout regulator, adjustable output, external soft start, power good | 1.6 V to 3.6 V | 1.2 A | 0.75 V to 3.3 V adjustable through an external divider | 16-lead 4 mm by 4 mm LFCSP |
| ADP7102 | 20 V low noise LDO, reverse current protection, programmable UVLO, power good | 3.3 V to 20 V | 300 mA | Seven fixed options or adjustable from 1.22 V, dropout 200 mV at 300 mA | 8-lead 3 mm by 3 mm LFCSP or 8-lead SOIC |
| ADP7104 | 20 V low noise LDO, foldback current limit, thermal overload protection, power good | 3.3 V to 20 V | 500 mA | Seven fixed options or adjustable, dropout 350 mV at 500 mA | 8-lead 3 mm by 3 mm LFCSP or 8-lead SOIC |
| ADP5003 | Buck regulator plus ultralow noise LDO in one package, adaptive headroom or independent mode | Buck 4.2 V to 15 V, LDO 0.65 V to 5 V | 3 A buck plus 3 A LDO | Buck 0.6 V to 5.0 V, LDO 0.6 V to 3.3 V | 32-lead 5 mm by 5 mm LFCSP |
| ADP2114 | Configurable synchronous step-down, dual phase 180 degree shifted channels, external sync | 2.75 V to 5.5 V | Dual 2 A, or 3 A plus 1 A, or single 4 A | Fixed 0.8 V to 3.3 V options or adjustable down to 0.6 V | 32-lead 5 mm by 5 mm LFCSP |
| ADP2118 | 3 A synchronous step-down with internal compensation, PWM or PFM at light load | 2.3 V to 5.5 V | 3 A | Adjustable 0.6 V to VIN, preset 1.2 V and 3.3 V options | 16-lead 4 mm by 4 mm LFCSP |
| LTC3566 | USB power manager with Li-Ion charger, ideal diode and 1 A buck-boost | USB or wall adapter, programmable input limit | 1 A buck-boost, 1.5 A maximum charge current | Buck-boost adjustable, minimum output 2.75 V | 24-lead 4 mm by 4 mm QFN |
| LTC3586 | USB power manager with Li-Ion charger, boost, buck-boost and two buck regulators | USB or wall adapter, programmable input limit | Two 400 mA bucks, 1 A buck-boost, 800 mA boost | Float voltage 4.2 V, or 4.1 V on the LTC3586-1 | 38-pin 4 mm by 6 mm QFN |
Key Features
Low Noise Rails After A Switching Stage – 15 uV rms output noise on the fixed 20 V parts and 23 uV rms at 0.75 V on the low Vin family, with PSRR of 60 dB at 10 kHz, so the residue of a 600 kHz to 1.2 MHz buck is attenuated before it reaches the analog rail.
Buck And LDO In One Package – The ADP5003 carries a 3 A buck and a 3 A ultralow noise LDO in a 5 mm by 5 mm package, with 3 uV rms LDO noise and PSRR above 50 dB to 100 kHz at 400 mV headroom, which removes the layout work of building the two stages from separate parts.
Adaptive Headroom Control – In adaptive mode the buck output follows the LDO load current, so headroom stays at the minimum needed for high rejection and the loss does not grow with load. In independent mode the two regulators are programmed separately through resistor dividers.
Wide Input Range For Instrument Rails – The 20 V parts regulate from 3.3 V to 20 V at 300 mA or 500 mA, which suits 12 V and 15 V instrument rails that also need a clean analog supply, and both include reverse current protection and a programmable undervoltage lockout for sequencing.
Configurable Output Channels – The ADP2114 can be set to 3 A plus 1 A, 2 A plus 2 A or a single 4 A interleaved output, with the two channels 180 degrees apart to reduce input ripple current and input capacitance, while the ADP2118 gives a single 3 A rail with preset 1.2 V or 3.3 V outputs.
Sequencing, Sensing And Fault Reporting – Precision enable inputs, power good outputs, programmable undervoltage lockout, overcurrent and thermal protection are standard across the family, and the ADP5003 adds differential remote sense at the point of load so the rail is regulated at the load rather than at the regulator.
USB And Battery Power Path For Handheld Instruments – The LTC3566 and LTC3586 manage the input from USB or an adapter with a programmable current limit, charge a Li-Ion cell at up to 1.5 A, and supply the system through an internal ideal diode, with a 1 A buck-boost on the LTC3566 and a boost, buck-boost and two 400 mA bucks on the LTC3586.
Small Footprints For Dense Module Boards – From an 8-lead 3 mm by 3 mm LFCSP up to a 32-lead 5 mm by 5 mm package, the range keeps the power section inside the height and area budget of a pluggable module or a handheld instrument.
Applications
Boards where these parts are specified most often: Module and instrument rails are usually quoted together with the SUPERB PCB and SUPERB PCBA work we support, so the regulators, the passives and the assembly arrive as one line on the order.
Optical Module And Line Card Rails – Laser driver bias, receive chain and control rails inside SFP, SFP+ and QSFP modules and on the line card that hosts them, where a quiet rail is part of the optical budget.
Test And Measurement Instruments – Analog front ends, converters and clock circuits that need a rail with low noise and high rejection rather than raw efficiency.
Handheld And Portable Instruments – Equipment powered from USB or an adapter with a battery inside, where the power path, the charger and the system rails have to be managed together.
RF, Clock And Converter Boards – Boards where a switching stage feeds a sensitive load and the ripple has to be removed with a controlled headroom rather than a large passive filter.
Obsolete and Hard-to-Find Supply
Power parts are the first thing to disappear from a distributor shelf when a module family goes end of life, because the exact package, fixed voltage suffix and temperature grade all have to match. We check the requested order code against available stock and confirm the grade, the packaging and the batch information on the quote, and where the exact part is no longer available we say so before proposing anything else.
Substitution inside this family is not always a drop-in. The fixed voltage suffix and the adjustable version of the same die are different order codes (ADP1754 against ADP1755), the 20 V parts regulate a 12 V rail that the low Vin parts cannot accept, and the buck plus LDO part replaces two components only if the board has been laid out for the combined pinout. We state which of those limits applies to a proposed alternative so your engineer can decide, and we can also quote the replacement together with the matching passive parts and the connector for the same board.
Where the board is built in volume, SUPERB Assembly support covers the SMT build of the power section.
Q: Can you supply power parts for a module that the original maker has discontinued?
A: Yes. Send the order code, the package, the grade and the quantity and the SUPERB Tech sales team will confirm availability, batch information and the nearest option in the same family.
Why Source Power Parts from Superb Automation?
- Optical And Instrument Focus: Parts chosen for module and instrument rails, quoted by people who read the datasheet conditions rather than the headline current rating.
- Hard-To-Find And Obsolete Parts: End of life and last time buy positions are the normal case on this page, and the status of the exact order code is stated on the quote.
- Cross Reference With The Limits Spelled Out: Fixed against adjustable versions, input range and package differences are written down, so a substitute is never presented as a drop-in when it is not.
- Stock, Samples And Build Quantities: Repair quantities and production volumes are both welcome, with the batch information for each line item shown on the quote.
- BOM Kitting For The Same Board: Regulators, inductors, capacitors and the interface parts for one board can be quoted together, which removes a layer of incoming inspection.
- Documents With The Quote: Package drawing, marking and condition (new and sealed, or pulled and tested) are confirmed before the order is placed.
Related Product Families
This page is part of the component range we supply for industrial, telecom, medical and defence builds. Continue with: Power Management ICs, ADI TEC Controller Chips for Optical Modules, Step-Down DC-DC Converter Chips, Components.