Part A
LNK304DN
包爾英特
- Lifecycle
- Active
- Stock
- 5367 件
- Package
- SO-8C
- Series
- PMIC-AC-DC轉換器、離線開關
Replacement verdict
Compatible functional replacement candidate
The LNK302DG can serve as a functional replacement candidate for the LNK304DN in low-power offline switching applications, provided the reduced current capability and thermal margins are validated in the target design. Both devices share the same LinkSwitch-TN family architecture, package footprint, and control scheme, but the LNK304DN offers higher output current and power handling, making direct substitution feasible only where the load demand remains within the LNK302DG limits.
Output Power Rating
Validation required
Package Type
High match
Control Scheme
High match
Current Rating
Validation required
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | LNK304DN | LNK302DG | Why it matters |
|---|---|---|---|
| Output Current (Max) | 170 mA | 80 mA | Determines the maximum load current the device can supply; a lower-rated part cannot directly replace a higher-rated one in the same design. |
| RDS(on) at 100 mA | 12 Ω | 24 Ω | Higher on-resistance increases conduction losses and reduces efficiency, affecting thermal performance and usable output power. |
| Breakdown Voltage | 700 V | 700 V | Sets the maximum drain voltage the internal MOSFET can withstand, critical for offline AC-DC applications. |
| Switching Frequency | 66 kHz | 66 kHz | Affects the size of the inductor and output capacitor; matching frequency allows reuse of the same magnetics and filter design. |
| Package / Mounting | SO-8C (Surface Mount) | SO-8C (Surface Mount) | Physical footprint and mounting style must match for a drop-in replacement on an existing PCB. |
| Internal MOSFET Current Limit | 250 mA | 120 mA | Defines the peak current the device can deliver; a lower limit restricts the maximum output power achievable. |
| Operating Junction Temperature (Max) | 150 °C | 150 °C | Thermal limit that constrains power dissipation and reliability under worst-case ambient conditions. |
| Typical Output Power (Universal Input) | ~2.4 W (adapter) | ~1.2 W (adapter) | Indicates the practical power delivery capability; substituting a lower-power device may cause thermal or current-limit issues. |
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Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | LNK304DN | LNK302DG |
|---|---|---|
| Series | LinkSwitch®-TN | LinkSwitch®-TN |
| Part Status | Discontinued at Digi-Key | Discontinued at Digi-Key |
| Output Isolation | Non-Isolated | Non-Isolated |
| Internal Switch(s) | Yes | Yes |
| Voltage - Breakdown | 700V | 700V |
| Topology | Buck, Buck-Boost, Flyback | Buck, Buck-Boost, Flyback |
| Duty Cycle | 69% | 69% |
| Frequency - Switching | 66kHz | 66kHz |
| Fault Protection | Current Limiting, Open Loop, Over Temperature, Short Circuit | Current Limiting, Open Loop, Over Temperature, Short Circuit |
| Operating Temperature | -40°C ~ 150°C (TJ) | -40°C ~ 150°C (TJ) |
Frequently asked questions
What are the primary differences between the LNK304DN and LNK302DG?
The LNK304DN is a LinkSwitch-TN family device rated for a higher output current (up to 170 mA in buck-boost topology) and delivers approximately 3 W maximum output power, while the LNK302DG is rated for lower output current (up to 80 mA) and approximately 1 W maximum output power. Both are monolithic off-line switching power supply ICs in SO-8 packages, but the LNK304DN provides greater power capability.
Are the LNK304DN and LNK302DG pin-compatible?
Yes. Both devices are offered in the same SO-8 (D package) footprint with identical pin functions: DRAIN, SOURCE, BYPASS, and FEEDBACK pins. This allows a common PCB layout to accommodate either device, though external component values may need adjustment for the different power levels.
Can the LNK304DN directly replace the LNK302DG in an existing design?
Pin compatibility allows a physical swap, but the designer must verify that the higher current capability of the LNK304DN does not exceed the ratings of external components such as the inductor, output diode, and output capacitor. The feedback and bypass capacitor values may also require review per the respective datasheets.
What is the maximum output current for each device?
Per Power Integrations datasheets, the LNK304DN supports up to 170 mA in a buck-boost configuration, while the LNK302DG supports up to 80 mA in the same topology. Actual achievable current depends on input voltage range, inductor value, and thermal conditions.
Do both devices operate from a universal AC input?
Yes. Both the LNK304DN and LNK302DG are designed for off-line power supplies and can operate from a universal AC input range (typically 85 VAC to 265 VAC) when used with appropriate external rectification and filtering components, as specified in the Power Integrations LinkSwitch-TN datasheet.
What switching frequency do the LNK304DN and LNK302DG use?
Both devices operate at a fixed switching frequency of 66 kHz, as stated in the LinkSwitch-TN family datasheet. This frequency is internally set and does not require external timing components.
What are the typical applications for each device?
The LNK302DG is typically used in low-power applications such as standby supplies, small appliance controls, and low-current bias supplies up to approximately 1 W. The LNK304DN is used in slightly higher-power applications such as AC adapter replacements, LED drivers, and small motor controls up to approximately 3 W.
Do both devices include built-in protection features?
Yes. Both the LNK304DN and LNK302DG integrate auto-restart protection for output short-circuit and open-loop conditions, thermal shutdown, and cycle-by-cycle current limiting, as documented in the LinkSwitch-TN family datasheet. These features reduce external component count and improve system reliability.