STEVAL-ISA051V1 STMicroelectronics, STEVAL-ISA051V1 Datasheet - Page 47
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STEVAL-ISA051V1
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
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
STEVAL-ISA051V1
Manufacturer:
STMicroelectronics
Quantity:
1
PM6670S
8.1.6
VDDQ current limit setting
The valley current limit is set by R
current. The valley of the inductor current I
Equation 45
The output current limit depends on the current ripple as shown in
Figure 41. Valley current limit waveforms
As the valley threshold is fixed, the greater the current ripple, the greater the DC output
current will be. If an output current limit greater than I
range is required, the minimum current ripple must be considered in the previous formula.
Then the resistor R
Equation 46
where R
temperature effect and the worst case value in R
The accuracy of the valley current also depends on the offset of the internal comparator
(±6 mV).
The negative valley-current limit (if the device works in forced-PWM mode) is given by:
Equation 47
DSon
is the drain-source on-resistance of the low-side switch. Consider the
MAX LOAD 1
Current
Valley current limit
CSNS
Inductor current
is:
Doc ID 14432 Rev 4
I
CSNS
Lvalley
R
CSNS
I
NEG
and must be chosen to support the maximum load
=
Inductor current
I
=
LOAD
Lvalley
MAX LOAD 2
=
R
DSon
110
R
(max)
100
DSon
DSon
is:
mV
⋅
uA
I
Lvalley
−
LOAD
calculation (typically +0.4 %/°C).
Δ
2
I
L
(max) over all the input voltage
Application information
Figure 41
Time
:
47/54