STEVAL-ISA051V1 STMicroelectronics, STEVAL-ISA051V1 Datasheet - Page 31

• 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

PM6670S
7.1.5
VDDQ output voltage can be set in the range of 0.9 V to 2.6 V. Adjustable mode
automatically switches DDRSEL pin to become the power saving algorithm selector: if tied
to +5 V, the forced-PWM (fixed frequency) control is performed. If grounded or connected to
VREF pin (1.237 V reference voltage), the pulse-skip or non-audible pulse-skip modes are
respectively selected.
Table 8.
Current sensing and current limit
The PM6670S switching controller uses a valley current sensing algorithm to properly
handle the current limit protection and the inductor current zero-crossing information. The
current is sensed during the conduction time of the low-side MOSFET. The current sensing
element is the on-resistance of the low-side switch. The sensing scheme is visible in
Figure 36
Figure 36. Current sensing scheme
An internal 120 μA current source is connected to C
input of the positive current limit comparator. When the voltage drop developed across the
sensing parameter equals the voltage drop across the programming resistor R
controller skips subsequent cycles until the overcurrent condition is detected or the output
UV protection latches off the device (see
protections on page 36
V
V
MODE
MODE
Mode
.
> 4.3 V
< 3.7 V
Mode-of-operation settings summary
1V < V
1V < V
).
PM6670S
PM6670
PM6670
V
V
V
PGND
PGND
DDRSEL
DDRSEL
DDRSEL
DDRSEL
DDRSEL
DDRSEL
<0.5 V
Doc ID 14432 Rev 4
HGATE
HGATE
PHASE
PHASE
LGATE
LGATE
CSNS
CSNS
> 4.2 V
> 4.2 V
< 0.5 V
< 3.5 V
< 3.5 V
100µA·
100µA·
Section 7.1.11: Over voltage and under voltage
R
R
ILIM
ILIM
VDDQ
1.8 V
1.5 V
V
V
ADJ
IN
IN
I
I
VALLEY
VALLEY
SNS
·
·
R
R
pin that is also the non-inverting
DSon
DSon
V
V
OUT
OUT
Non-audible pulse-skip
Operating mode
Forced-PWM
Pulse-skip
Pulse-skip
Device description
ILIM
, the
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