STEVAL-ISA051V1 STMicroelectronics, STEVAL-ISA051V1 Datasheet - Page 40

• 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
40/54
where
Equation 27a
Equation 27b
Referring to the typical application schematic (figure in cover page and
expression is then:
Equation 28
The switching frequency directly affects two parameters:
●
●
Even if the switching frequency is theoretically independent from battery and output
voltages, parasitic parameters involved in power path (like MOSFETs on-resistance and
inductor DCR) introduce voltage drops responsible for a slight dependence on load current.
In addition, the internal delay is due to a light dependence on input voltage.
Table 12.
Inductor size: greater frequencies mean smaller inductances. In notebook applications,
real estate solutions (i.e. low-profile power inductors) are mandatory also with high
saturation and r.m.s. currents.
Efficiency: switching losses are proportional to the frequency. Generally, higher
frequencies imply lower efficiency.
R1 (kΩ)
330
330
330
330
330
330
Typical values for switching frequency selection
Doc ID 14432 Rev 4
f
SW
=
R2 (kΩ)
K
α
11
13
15
18
20
22
α
OSC
OSC
α
OSC
OUT
=
=
=
R
V
V
1
V
R
V
OSC
SNS
OUT
+
IN
2
R
2
⋅
K
Approx switching frequency (kHz)
OSC
1
250
300
350
400
450
500
Figure 29
), the final
PM6670S