DocumentationDatasheet
Reliability Data
Press Release
- Dual 3A, 4MHz, Synchronous Step-Down Regulators with DDR Memory Now Offered in High Reliability H Grade & Military MP Grade to +150°C
- General Purpose Dual 3A, 4MHz, Synchronous Step-Down Regulator Also Supports DDR Memory
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Features
- High Efficiency: Up to 94%
- Dual Outputs with 2 × 3A Output Current Capability
- Low Output Ripple Burst Mode® Operation: IQ = 130μA
- 2.25V to 5.5V Input Voltage Range
- ±1% Output Voltage Accuracy
- Output Voltages Down to 0.6V
- Programmable Slew Rate at Switch Pins
- Low Dropout Operation: 100% Duty Cycle
- Shutdown Current ≤1μA
- Adjustable Switching Frequency Up to 4MHz
- Internal or External Compensation
- Selectable Pulse-Skipping/Forced Continuous/ Burst Mode Operation with Adjustable Burst Clamp
- Optional Active Voltage Positioning (AVP) with Internal Compensation
- Selectable 0°/90°/180° (LTC3615) or selectable 140°/180° (LTC3615-1) Phase Shift Between Channels
- Fixed Internal and Programmable External Soft-Start
- Accurate Start-Up Tracking Capability
- DDR Memory Mode IOUT = ±1.5A
- Available in 4mm × 4mm QFN-24 and eTSSOP-24 Packages
Typical Application
Description
The LTC3615/LTC3615-1 are dual 3A synchronous stepdown regulators using a current mode, constant-frequency architecture. The DC supply current is only 130μA (Burst Mode operation at no-load) while maintaining the output voltages, dropping to zero current in shutdown. The 2.25V to 5.5V input supply range makes the parts ideally suited for single Li-Ion applications. 100% duty cycle capability provides low dropout operation, which extends operating time in battery-operated systems.
The operating frequency is externally programmable up to 4MHz, allowing the use of small surface mount inductors. 0°, 90°, or 180° (LTC3615) or 140°/180° (LTC3615-1) of phase shift between the two channels can be selected to minimize input current ripple and output voltage ripple in a dual 3A or single 6A output configuration. Programmable slew rate limiting reduces EMI, and external synchronization can be applied up to 4MHz.
The internal synchronous switches increase efficiency and eliminate the need for external catch diodes, saving external components and board space.
The LTC3615/LTC3615-1 are offered in leadless 24-pin 4mm × 4mm QFN and thermally enhanced 24-pin eTSSOP packages.
4x4 QFN-24,TSSOP-24
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LTC3615EFE#PBF | TSSOP | 24 | E | $5.86 | $4.10 |
| LTC3615EFE#TRPBF | TSSOP | 24 | E | $4.16 | |
| LTC3615EFE-1#PBF | TSSOP | 24 | E | $5.86 | $4.10 |
| LTC3615EFE-1#TRPBF | TSSOP | 24 | E | $4.16 | |
| LTC3615EUF#PBF | QFN | 24 | E | $5.64 | $3.95 |
| LTC3615EUF#TRPBF | QFN | 24 | E | $4.01 | |
| LTC3615EUF-1#PBF | QFN | 24 | E | $5.64 | $3.95 |
| LTC3615EUF-1#TRPBF | QFN | 24 | E | $4.01 | |
| LTC3615HFE#PBF | TSSOP | 24 | H | $7.64 | $5.35 |
| LTC3615HFE#TRPBF | TSSOP | 24 | H | $5.41 | |
| LTC3615HFE-1#PBF | TSSOP | 24 | H | $7.64 | $5.35 |
| LTC3615HFE-1#TRPBF | TSSOP | 24 | H | $5.41 | |
| LTC3615HUF#PBF | QFN | 24 | H | $7.14 | $5.00 |
| LTC3615HUF#TRPBF | QFN | 24 | H | $5.06 | |
| LTC3615HUF-1#PBF | QFN | 24 | H | $7.14 | $5.00 |
| LTC3615HUF-1#TRPBF | QFN | 24 | H | $5.06 | |
| LTC3615IFE#PBF | TSSOP | 24 | I | $6.89 | $4.82 |
| LTC3615IFE#TRPBF | TSSOP | 24 | I | $4.88 | |
| LTC3615IFE-1#PBF | TSSOP | 24 | I | $6.89 | $4.82 |
| LTC3615IFE-1#TRPBF | TSSOP | 24 | I | $4.88 | |
| LTC3615IUF#PBF | QFN | 24 | I | $6.64 | $4.65 |
| LTC3615IUF#TRPBF | QFN | 24 | I | $4.71 | |
| LTC3615IUF-1#PBF | QFN | 24 | I | $6.64 | $4.65 |
| LTC3615IUF-1#TRPBF | QFN | 24 | I | $4.71 | |
| LTC3615MPFE#PBF | TSSOP | 24 | MP | $18.57 | $13.00 |
| LTC3615MPFE#TRPBF | TSSOP | 24 | MP | $13.06 | |
| LTC3615MPFE-1#PBF | TSSOP | 24 | MP | $18.57 | $13.00 |
| LTC3615MPFE-1#TRPBF | TSSOP | 24 | MP | $13.06 | |
| LTC3615MPUF#PBF | QFN | 24 | MP | $17.93 | $12.55 |
| LTC3615MPUF#TRPBF | QFN | 24 | MP | $12.61 | |
| LTC3615MPUF-1#PBF | QFN | 24 | MP | $17.93 | $12.55 |
| LTC3615MPUF-1#TRPBF | QFN | 24 | MP | $12.61 | |
| LTC3615IUF | QFN | 24 | I | $13.28 | $9.30 |
| LTC3615IUF#TR | QFN | 24 | I | $9.42 |
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.
| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC1435A | LTC3615EUF Demo Board (QFN) | 2.25V ≤ VIN ≤ 5.5V, VOUT1 = 1.8V to 3.3V @ 3A, VOUT2 = 1.2V to 1.8V @ 3A | Contact Factory | |
| DC1572A | LTC3615EFE Demo Board (TSSOP)| 2.25V ≤ VIN ≤ 5.5V, VOUT1 = 1.8V to 3.3V @ 3A, VOUT2 = 1.2V to 1.8V @ 3A | Contact Factory |