ADP2116ACPZ-R7 datasheet(23/36 Pages) AD

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ADP2116

Rev. 0 | Page 23 of 36

CONVERTER CONFIGURATION

SELECTING THE OUTPUT VOLTAGE

To set the output voltage, VOUT1 or VOUT2, select one of the six

fixed voltages, as shown in Table 4, by connecting the V1SET or

V2SET pin to GND through a resistor of an appropriate value

(see Figure 62). V1SET and V2SET set the voltage output levels

for Channel 1 and Channel 2, respectively. The feedback pin,

FB1 or FB2, should be directly connected to VOUT1 or VOUT2.

Table 4. Output Voltage Programming

RV1SET ± 5%

VOUT1 (V)

RV2SET ± 5%

VOUT2 (V)

0 Ω to GND

0.8

0 Ω to GND

0.8

4.7 kΩ to GND

1.2

4.7 kΩ to GND

1.2

8.2 kΩ to GND

1.5

8.2 kΩ to GND

1.5

15 kΩ to GND

1.8

15 kΩ to GND

1.8

27 kΩ to GND

2.5

27 kΩ to GND

2.5

47 kΩ to GND

3.3

47 kΩ to GND

3.3

82 kΩ to GND

0.6 to <1.6

(adjustable)

82 kΩ to GND

0.6 to <1.6

(adjustable)

0 Ω to VDD

1.6 to 3.3

(adjustable)

0 Ω to VDD

1.6 to 3.3

(adjustable)

If the required output voltage, VOUT1 or VOUT2, is in the adjustable

range, from 0.6 V to <1.6 V, connect V1SET or V2SET through

an 82 kΩ resistor to GND. For the adjustable output voltage range

of 1.6 V to 3.3 V, tie V1SET or V2SET to VDD (see Table 4). The

adjustable output voltage of the ADP2116 is externally set by a

resistive voltage divider from the output voltage to the feedback

pin (see Figure 63). The ratio of the resistive voltage divider sets

the output voltage, whereas the absolute value of these resistors

sets the divider string current. For lower divider string currents,

the small 10 nA (100 nA maximum) feedback bias current should

be taken into account when calculating the resistor values. The

feedback bias current can be ignored for a higher divider string

current; however, this degrades efficiency at very light loads.

To limit output voltage accuracy degradation due to feedback

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, R1, using the following equation:

R1 = VREF/ISTRING

(2)

where:

VREF is the internal reference voltage, 0.6 V.

ISTRING is the resistor divider string current.

When R1 is determined, calculate the value of the top resistor, R2,

using the following equation:

⎥

⎦

⎤

⎢

⎣

⎡

−

REF

OUT

(3)

VOUT1/VOUT2

RV1SET/

RV2SET

VIN

RFREQ

GND

V1SET/

V2SET

VINx

SWx

FB1/FB2

PGNDx

COMP1/

COMP2

ADP2116

Figure 62. Configuration for Fixed Outputs

VOUT1/VOUT2

RV1SET/

RV2SET

VIN

RFREQ

GND

V1SET/

V2SET

VINx

SWx

FB1/FB2

PGNDx

COMP1/

COMP2

ADP2116

Figure 63. Configuration for Adjustable Outputs

ADP2116ACPZ-R7 Datasheet(PDF) 23 Page - Analog Devices

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