ADP2105-BL1-EVZ Analog Devices Inc, ADP2105-BL1-EVZ Datasheet - Page 16

• Manufacturer Part Number: ADP2105-BL1-EVZ
• Description: Blank ADISimPower Eval ADP2105
• Manufacturer: Analog Devices Inc

Specifications of ADP2105-BL1-EVZ

• Design Resources: Powering the AD9788 Using ADP2105 for Increased Efficiency (CN0141)
• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Regulator Topology: Buck
• Board Type: Bare (Unpopulated)
• Utilized Ic / Part: ADP2105
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Output: -
• Voltage - Input: -
• Power - Output: -
• Frequency - Switching: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADP2105/ADP2106/ADP2107
APPLICATIONS INFORMATION
EXTERNAL COMPONENT SELECTION
The external component selection for the ADP2105/ADP2106/
ADP2107 application circuits shown in Figure 37 and Figure 38
depend on input voltage, output voltage, and load current
requirements. Additionally, trade-offs between performance
parameters like efficiency and transient response can be made
by varying the choice of external components.
SETTING THE OUTPUT VOLTAGE
The output voltage of ADP2105/ADP2106/ADP2107(ADJ) is
externally set by a resistive voltage divider from the output
voltage to FB. The ratio of the resistive voltage divider sets the
output voltage, and the absolute value of those resistors sets the
divider string current. For lower divider string currents, the
small 10 nA (0.1 μA maximum) FB bias current is to be taken
Figure 38. Typical Applications Circuit for Adjustable Output Voltage Option of ADP2105/ADP2106/ADP2107(ADJ)
Figure 37. Typical Applications Circuit for Fixed Output Voltage Options of ADP2105/ADP2106/ADP2107(x.x V)
OFF
OFF
ON
ON
C
R
1
2
3
4
COMP
COMP
C
R
EN
GND
GND
GND
1
2
3
4
COMP
COMP
COMP
V
EN
GND
GND
GND
FB
OUT
16
COMP
5
FB
FB
16
5
ADP2105/
ADP2106/
ADP2107
SS
15
GND
ADP2105/
ADP2106/
ADP2107
6
GND
C
0.1μF
SS
15
SS
6
C
0.1μF
AGND
SS
14
IN
NC = NO CONNECT
7
AGND
10Ω
IN
14
NC = NO CONNECT
7
PWIN1
10Ω
PWIN2
PGND
NC
13
PWIN1
8
PWIN2
LX2
LX1
PGND
NC
13
Rev. C | Page 16 of 36
8
V
LX2
LX1
IN
12
11
10
V
9
IN
12
11
10
INPUT VOLTAGE = 2.7V TO 5.5V
V
9
IN
INPUT VOLTAGE = 2.7V TO 5.5V
V
C
C
IN
IN2
IN1
C
C
IN2
IN1
into account when calculating resistor values. The FB bias
current can be ignored for a higher divider string current, but
this degrades efficiency at very light loads.
To limit output voltage accuracy degradation due to FB bias
current to less than 0.05% (0.5% maximum), ensure that the
divider string current is greater than 20 μA. To calculate the
desired resistor values, first determine the value of the bottom
divider string resistor (R
where:
V
I
STRING
L
FB
L
OUTPUT VOLTAGE = 1.2V, 1.5V, 1.8V, 3.3V
FB
= 0.8 V, the internal reference.
R
is the resistor divider string current.
BOT
=
R
R
TOP
BOT
I
STRING
V
C
OUT
FB
V
OUTPUT VOLTAGE
= 0.8V TO V
OUT
C
OUT
BOT
LOAD
IN
) using the following equation:
LOAD