Wide Vin 4.5-26V, 12A, Low Iq, High Current Synchronous Buck Converter with +/-1A LDO and Buffered Reference
The NB685 provides a complete power supply with the highest density for DDR3, DDR3L, LPDDR3, and DDR4 memory. It integrates a high-frequency, synchronous, rectified, step-down, switch-mode converter (VDDQ) with a 1 A sink/source LDO (VTT) and buffered low noise reference (VTTREF).
The NB685 operates at high efficiency over a wide output current load range based on MPS proprietary switching loss reduction technology and internal low Ron power MOSFETs.
Adaptive constant-on-time (COT) control mode provides fast transient response and eases loop stabilization. The DC auto-tune loop provides good load and line regulation.
The VTT LDO provides 1 A sink/source current capability and requires only 22 μF ceramic capacitors. The VTTREF tracks VDDQ/2 with excellent 1% accuracy.
Full protection features include OC limit, OVP, UVP, thermal shutdown, and over-temperature warning (OTW).
The converter requires a minimum number of external components, and it is available in a QFN 3mm x 3mm package.
- Wide 4.5 V to 26 V Operating Input Range
- Compatible for IMVP8
- 135 μA Low Quiescent Current
- 12 A Continuous Output Current
- 13 A Peak Output Current
- Selectable Ultrasonic Mode
- Selectable 500 k/700 k Switching Frequency
- Built-In +/- 1 A VTTLDO
- 1% Buffered VTTREF Output
- Adaptive COT for Fast Transient
- DC Auto-Tune Loop
- Stable with POSCAP and Ceramic Output Capacitors
- Over-Temperature Warning
- Internal Soft Start
- Output Discharge
- OCL, OVP, UVP, and Thermal Shutdown
- Latch-Off Re-set via EN or Power Cycle
- QFN 3mm x 3mm Package
- fsw (max) (kHz)700
- Vin (max) (V)26
- Iout (max) (A)12
- Isw Limit (typ) (A)13
- Vfb (typ) (V)0.6
- Iq (typ) (mA)0.185
- Vout (max) (V)3.3
- Vout (min) (V)0.6
- PackageQFN-16 (3x3)
- Control ModeCOT
- Common FeaturesLight-Load Efficiency, Power Good, Synchronous Rectification
- Special FeaturesProgrammable Frequency, Soft Stop, Ultrasonic Mode