STEVAL-ISA053V2 STMicroelectronics, STEVAL-ISA053V2 Datasheet - Page 19
![BOARD EVALUATION FOR PM6680A](/photos/9/13/91332/steval-isa053v2_sml.jpg)
STEVAL-ISA053V2
Manufacturer Part Number
STEVAL-ISA053V2
Description
BOARD EVALUATION FOR PM6680A
Manufacturer
STMicroelectronics
Type
DC/DC Switching Converters, Regulators & Controllersr
Specifications of STEVAL-ISA053V2
Design Resources
STEVAL-ISA053V2 Gerber Files PM6680A Eval Kit Schematic STEVAL-ISA053V2 Bill of Material
Main Purpose
DC/DC, Step Down with LDO
Outputs And Type
3, Non-Isolated
Voltage - Output
1.8V, 3.3V, 5V
Current - Output
2.5A, 2.5A, 100mA
Voltage - Input
6 ~ 28V
Regulator Topology
Buck
Frequency - Switching
200kHz, 300kHz
Board Type
Fully Populated
Utilized Ic / Part
PM6680A
Input Voltage
6 V to 36 V
Output Voltage
5 V
Product
Power Management Modules
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
497-6379
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
STEVAL-ISA053V2
Manufacturer:
STMicroelectronics
Quantity:
1
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
19/48