Part A
LTC3558EUD#TRPBF
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6354 Stückzahl
- Package
- QFN-20
- Series
- PMIC
Replacement verdict
Compatible functional replacement candidate
The LTC3558EUD#TRPBF and LTC3523EUD-2#PBF share a common 3mm x 3mm QFN-16 package and overlapping input voltage ranges, but they are not pin-to-pin equivalent. The LTC3558 integrates a USB power manager with a Li-Ion battery charger and a 200mA buck-boost regulator, while the LTC3523-2 is a dual 600mA synchronous step-up DC-DC converter with independent shutdown and a fixed 1.2MHz switching frequency. Designers may consider the LTC3523EUD-2#PBF as a functional substitute only when battery charging and power-path management are not required and the load can tolerate the higher output current capability and different feedback topology. Careful validation of the feedback network, inductor selection, and PCB layout is mandatory before committing to this substitution.
Function Type
Validation required
Output Current
Validation required
Package Type
High match
Pin Configuration
Not compatible
Parts at a glance
Part B
LTC3523EUD-2#PBF
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2295 Stückzahl
- Package
- QFN-16
- Series
- PMIC Frequenzregler für Spannungsregler und DC DC Schaltregler
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | LTC3558EUD#TRPBF | LTC3523EUD-2#PBF | Why it matters |
|---|---|---|---|
| Function | USB Power Manager with Li-Ion battery charger and dual buck regulators | Dual synchronous step-up DC/DC converter | Defines the core role of the IC; these parts perform fundamentally different power-management functions and are not direct substitutes. |
| Topology | Buck (step-down) regulators plus battery charger | Boost (step-up) regulators | Buck vs boost determines whether the output voltage is below or above the input, which is critical for system rail design. |
| Number of Regulator Channels | 2 buck regulators | 2 boost regulators | Channel count affects how many independent rails can be supplied from a single device. |
| Battery Charger Included | Yes (Li-Ion linear charger with PowerPath) | No | An integrated charger is essential for battery-powered portable designs; its absence requires a separate charging IC. |
| Input Voltage Range | USB/VBUS input with battery operation (approx. 4.35 V to 5.5 V VBUS) | 0.5 V to 5.5 V (start-up from 0.7 V) | Determines compatibility with the available source voltage and whether the part can start from low-voltage sources such as single-cell batteries. |
| Output Voltage Configuration | Adjustable buck outputs | Fixed 3.3 V and adjustable outputs | Fixed vs adjustable outputs affects design flexibility and the number of external components required. |
| Switching Frequency | 2.25 MHz buck switching frequency | 1.2 MHz boost switching frequency | Switching frequency influences inductor and capacitor sizing, efficiency, and EMI performance. |
| Package | 20-Lead QFN (3 mm x 4 mm) | 16-Lead QFN (3 mm x 3 mm) | Package footprint and pin count affect PCB layout, thermal performance, and drop-in compatibility. |
| Typical Application | Portable USB-powered devices with Li-Ion battery | Battery-powered devices needing boosted rails from low input voltage | Application fit determines whether the part meets the system's power architecture requirements. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | LTC3558EUD#TRPBF | LTC3523EUD-2#PBF |
|---|---|---|
| Part Status | Active | Active |
| Function | - | Step-Up, Step-Down |
| Output Configuration | - | Positive |
| Topology | - | Buck, Boost |
| Output Type | - | Adjustable |
| Number of Outputs | - | 2 |
| Voltage - Input (Min) | - | 1.8V |
| Voltage - Input (Max) | - | 5.5V |
| Voltage - Output (Min/Fixed) | - | 0.615V |
| Voltage - Output (Max) | - | 5.5V |
| Current - Output | - | 400mA, 600mA (Switch) |
| Frequency - Switching | - | 2.4MHz |
| Synchronous Rectifier | - | Yes |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C (TA) |
| Mounting Type | Surface Mount | Surface Mount |
| Applications | Handheld/Mobile Devices | - |
| Supply Current | 200µA | - |
| Voltage - Supply | 4.35V ~ 5.5V | - |
Frequently asked questions
What are the main functional differences between the LTC3558EUD#TRPBF and the LTC3523EUD-2#PBF?
The LTC3558EUD#TRPBF is a power management IC combining a USB-compatible Li-Ion battery charger with a synchronous buck-boost DC/DC converter and a low-dropout (LDO) regulator. The LTC3523EUD-2#PBF is a dual-channel synchronous step-up (boost) DC/DC converter with an integrated LDO controller, designed primarily for two-cell alkaline/NiMH or single-cell Li-Ion applications requiring two boosted outputs. They are not functionally equivalent.
Are the LTC3558EUD#TRPBF and LTC3523EUD-2#PBF pin-to-pin compatible?
No. Both devices are offered in a 16-lead 3mm x 3mm QFN package (UFD), but their pin functions and internal topologies differ. The LTC3558 integrates a battery charger, buck-boost converter, and LDO, while the LTC3523-2 integrates dual boost converters and an LDO controller. Pin assignments are not interchangeable, and the PCB land patterns must follow each device's respective datasheet.
Can the LTC3558EUD#TRPBF and LTC3523EUD-2#PBF be used in the same application?
Generally no, because they target different power architectures. The LTC3558 is intended for portable devices with a single-cell Li-Ion battery requiring charging plus a regulated system rail and a low-noise auxiliary rail. The LTC3523-2 is intended for systems needing two independent step-up rails from a low input voltage, such as two-cell alkaline or single-cell Li-Ion powered handhelds. Substitution requires full revalidation of the power tree, input/output voltage ranges, and load conditions.
What are the input voltage ranges for these two devices?
According to Analog Devices (Linear Technology) datasheets, the LTC3558 operates from a USB or adapter input for charging and from a battery input for the buck-boost converter, with the buck-boost capable of operating from input voltages above, below, or equal to the output. The LTC3523EUD-2#PBF operates from an input voltage range suitable for single-cell Li-Ion or dual-cell alkaline/NiMH inputs, typically 0.5V to 5.5V per channel, as specified in its datasheet. Designers must verify exact limits from the official datasheet for the target revision.
Do both devices include an LDO regulator?
The LTC3558EUD#TRPBF includes an integrated low-dropout (LDO) regulator as part of its power management function. The LTC3523EUD-2#PBF includes an LDO controller, which requires an external pass transistor to form a complete LDO regulator. This is a significant difference for board design and external component count.
Which device is better suited for battery charging applications?
The LTC3558EUD#TRPBF is the appropriate choice for battery charging because it integrates a full Li-Ion battery charger with USB compatibility. The LTC3523EUD-2#PBF does not include a battery charger; it is a dual boost converter with an LDO controller. Using the LTC3523-2 in a charging application would require an external charging solution.
What are the package and thermal considerations for these devices?
Both devices are supplied in a 16-lead 3mm x 3mm QFN package (UFD suffix). Thermal performance depends on the PCB layout, copper area, and power dissipation of each application. The LTC3558 may dissipate more power due to its integrated charger and buck-boost converter, while the LTC3523-2 dissipates power in its dual boost channels and external pass transistor. Refer to each datasheet's thermal resistance and layout guidelines for exact values.
Are the LTC3558EUD#TRPBF and LTC3523EUD-2#PBF RoHS compliant?
Both part numbers carry the #PBF suffix, which indicates lead-free (Pb-free) construction and RoHS compliance per Analog Devices' standard nomenclature. Designers should confirm the current compliance status on the official Analog Devices product page or the distributor's environmental documentation, as compliance declarations can be updated.