STEVAL-ISA051V2 STMicroelectronics, STEVAL-ISA051V2 Datasheet - Page 32

• Manufacturer Part Number: STEVAL-ISA051V2
• Description: BOARD EVAL PM6670AS DDR2/3
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of STEVAL-ISA051V2

• Design Resources: STEVAL-ISA051V2 Gerber Files STEVAL-ISA051V2 Schematic STEVAL-ISA051V2 Bill of Material
• Main Purpose: Special Purpose DC/DC, DDR Memory Supply
• Outputs And Type: 4, Non-Isolated
• Voltage - Output: 1.5V, 1.8V
• Voltage - Input: 4.5 ~ 36V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: PM6670A
• Input Voltage: 4.5 V to 36 V
• Output Voltage: 1.8 V, 1.5 V
• Product: Power Management Modules
• Silicon Manufacturer: ST Micro
• Silicon Core Number: PM6670AS
• Kit Application Type: Power Management
• Application Sub Type: DDR2/3 Memory Power Supply Controller
• Kit Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Power - Output: -
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: PM6670AS
• Other names: 497-8412

Device description
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Figure 36. Soft-start at heavy load (a) and short-circuit (b) conditions, pulse-skip enabled
The soft-start allows a gradual increase of the internal current limit threshold during start-up
reducing the input/output surge currents. At the beginning of start-up, the PM6670AS
current limit is set to 25% of nominal value and the under voltage protection is disabled.
Then, the current limit threshold is sequentially brought to 100% in four steps of
approximately 750 μs (
Figure 35. Soft-start waveforms
After a fixed 3 ms total time, the soft-start finishes and UVP is released: if the output voltage
doesn't reach the Power-Good lower threshold within soft-start duration, the UVP condition
is detected and the device performs a soft end and latches off. Depending on the load
conditions, the inductor current may or may not reach the nominal value of the current limit
during the soft-start (
(a)
Switching output
Figure 36
Figure 35
Current limit threshold
S5
Doc ID 14436 Rev 2
shows two examples).
).
(b)
Time
PM6670AS