E-L6911C STMicroelectronics, E-L6911C Datasheet - Page 12
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E-L6911C
Manufacturer Part Number
E-L6911C
Description
IC CTRLR 5BIT PROGR STPDN 20SOIC
Manufacturer
STMicroelectronics
Type
Step-Down (Buck)r
Datasheet
1.E-L6911C.pdf
(20 pages)
Specifications of E-L6911C
Internal Switch(s)
No
Synchronous Rectifier
Yes
Number Of Outputs
1
Voltage - Output
1.3 ~ 3.5 V
Current - Output
1.3A
Frequency - Switching
200kHz
Voltage - Input
5 ~ 12 V
Operating Temperature
-40°C ~ 150°C
Mounting Type
Surface Mount
Package / Case
20-SOIC (7.5mm Width)
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
L6911C
Where I
Therefore, with the droop function the output voltage decreases as the load current increases, so the DC output
impedance is equal to a resistance R
sient is minimum when the output impedance is constant with frequency.
To choose the other components of the compensation network, the transfer function of the voltage loop is con-
sidered. To simplify the analysis is supposed that R3 << Rd, where Rd = (R8//R9).
Figure 8. Compensation network definition
The transfer function may be evaluated neglecting the connection of R8 to PHASE because, as will see later,
this connection is important only at low frequencies. So R4 is considered connected to VOUT. Under this as-
sumption, the voltage loop has the following transfer function:
12/20
From the above equations, it results:
The component R3 must be chosen in order to obtain R3<<R8//R9 to permit these and successive
simplifications.
ConverterS
MAX
is the maximum output current.
ingularity
|G lo o p |
f
f
f
f
LC
CE
EC
CC
|A v |
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R
G
/ 1
/ 1
/ 1
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2
2
2
2
ESR
Rceramic
ESR
LC
f
D
R9
Cceramic
C
OUT
OUT
Cceramic
=
R8
R8
. It is easy to verify that the output voltage deviation under load tran-
f
f
L C
2
2
=
-------------------------- -
-----------------------
R
doublepole
ESRzero
Introduced
CeramicCap
V
V
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L
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M AX
R 2
by
acitor
-------------------------- -
R
Compensati
------------------------------------ -
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V
L
+
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fc
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R
M AX
V
L
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onNetworkS
DROOP
I
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M AX
E C
;
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ingularity
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(
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