STEVAL-PSQ001V1 STMicroelectronics, STEVAL-PSQ001V1 Datasheet - Page 19

BOARD EVAL BASED ON PM6680A

STEVAL-PSQ001V1

Manufacturer Part Number
STEVAL-PSQ001V1
Description
BOARD EVAL BASED ON PM6680A
Manufacturer
STMicroelectronics
Type
Other Power Managementr
Datasheets

Specifications of STEVAL-PSQ001V1

Design Resources
STEVAL-PSQ001V1 Gerber Files STEVAL-PSQ001V1 Schematic STEVAL-PSQ001V1 Bill of Material
Main Purpose
DC/DC, Step Down with LDO
Outputs And Type
6, Non-Isolated
Voltage - Output
0.9 ~ 2.5 V, 1 ~ 3.3 V, 2x 3.3 V, 2.5 V, 5 V
Current - Output
4A, 2A, 800mA, 400mA, 400mA, 150mA
Voltage - Input
5 ~ 36V
Regulator Topology
Buck
Frequency - Switching
200kHz, 300kHz
Board Type
Fully Populated
Utilized Ic / Part
PM6680A
Input Voltage
5 V to 36 V
Output Voltage
1 V to 3.3 V
Product
Power Management Modules
Silicon Manufacturer
ST Micro
Silicon Core Number
PM6680A
Kit Application Type
Power Management
Application Sub Type
Power Supply
Kit Contents
Board
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
For Use With/related Products
PM6680A
Other names
497-6425
STEVAL-PSQ001V1
PM6680A
Figure 28. Constant ON time PWM control
The duty cycle of the buck converter in steady state is:
Equation 2
The PWM control works at a nearly fixed frequency f
Equation 3
As mentioned the steady state switching frequency is theoretically independent from input
voltage and from output voltage.
Actually the frequency depends on parasitic voltage drops that are present during the
charging path(high side switch resistance, inductor resistance(DCR)) and discharging
path(low side switch resistance, DCR).
As a result the switching frequency increases as a function of the load current.
Standard switching frequency values can be selected for both sections by pin FSEL as
shown in the following table:
Table 6.
FSEL = VREF
FSEL = LDO5
FSEL = GND
FSEL pin selection: typical switching frequency
Fsw@OUT1 = 3.3 V (kHz)
f
SW
195
295
390
=
------------------------------ -
K
on
D
V
--------------
=
V
×
OUT
IN
V
--------------
V
--------------
V
V
OUT
OUT
IN
IN
=
1 K
SW
:
on
Fsw@OUT2 = 1.8 V (kHz)
Device description
335
440
600
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