STEVAL-ISA051V1 STMicroelectronics, STEVAL-ISA051V1 Datasheet - Page 50

• Manufacturer Part Number: STEVAL-ISA051V1
• Description: BOARD EVAL PM6670S DDR2/3
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of STEVAL-ISA051V1

• Design Resources: STEVAL-ISA051V1 Gerber Files STEVAL-ISA051V1 Schematic STEVAL-ISA051V1 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 ~ 28V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: PM6670
• Input Voltage: 4.5 V to 28 V
• Output Voltage: 1.8 V, 1.5 V
• Product: Power Management Modules
• Silicon Manufacturer: ST Micro
• Silicon Core Number: PM6670S
• 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: PM6670S
• Other names: 497-8411

Application information
50/54
Select C as shown:
Equation 52
Then calculate R in order to have enough ripple voltage on the integrator input:
Equation 53
Where R
equivalent ESR of 30-50 mΩ, even though the choice depends on inductor current ripple.
Then choose R1 as follows:
Equation 54
VESR
is the new virtual output capacitor ESR. A good trade-off is to consider an
Doc ID 14432 Rev 4
R
R
1
C
=
=
>
R
R
R
5
VESR
⋅
−
⎛
⎜ ⎜
⎝
⋅
C
L
C
C
INT
π
1
π
1
⋅
f
f
Z
C
Z
⎞
⎟ ⎟
⎠
PM6670S