ADP2114ACPZ-R7 datasheet(24/40 Pages) AD

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ADP2114

Rev. 0 | Page 24 of 40

CONVERTER CONFIGURATION

SELECTING THE OUTPUT VOLTAGE

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

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

(V2SET) pin to GND through an appropriate value resistor (see

Figure 70). V1SET and V2SET set the voltage output levels for

Channel 1 and Channel 2, respectively. The feedback pin FB1

(FB2) should be directly connected to VOUT1 (VOUT2).

Table 4. Output Voltage Programming

RV1SET (Ω) ± 5%

VOUT1 (V)

RV2SET (Ω) ± 5%

VOUT2 (V)

0 to GND

0.8

0 to GND

0.8

4.7 k to GND

1.2

4.7 k to GND

1.2

8.2 k to GND

1.5

8.2 k to GND

1.5

15 k to GND

1.8

15 k to GND

1.8

27 k to GND

2.5

27 k to GND

2.5

47 k to GND

3.3

47 k to GND

3.3

82 k to GND

0.6 to <1.6

(adjustable)

82 k to GND

0.6 to <1.6

(adjustable)

0 to VDD

1.6 to 3.3

(adjustable)

0 to VDD

1.6 to 3.3

(adjustable)

If the required output voltage VOUT1 (VOUT2) is in the adjustable

range, from 0.6 V to less than 1.6 V, connect V1SET (V2SET)

through an 82 kΩ resistor to GND. For the adjustable output

voltage range of 1.6 V to 3.3 V, tie V1SET (V2SET) to VDD (see

Table 4). The adjustable output voltage of ADP2114 is externally

set by a resistive voltage divider from the output voltage to the

feedback pin (see Figure 71). The ratio of the resistive voltage

divider sets the output voltage, while 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

should be taken into account when calculating the resistor

values. The FB 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 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, R1, by

R1 = VREF/ISTRING

(2)

where:

VREF is 0.6 V, the internal reference.

ISTRING is the resistor divider string current.

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

R2, by

⎥

⎦

⎤

⎢

⎣

⎡

−

REF

OUT

(3)

VOUT1/VOUT2

RV1SET/

RV2SET

VIN

RFREQ

GND

V1SET/

V2SET

VINx

SWx

FB1/FB2

PGNDx

COMP1/

COMP2

ADP2114

Figure 70. Configuration for Fixed Outputs

VOUT1/VOUT2

RV1SET/

RV2SET

VIN

RFREQ

GND

V1SET/

V2SET

VINx

SWx

FB1/FB2

PGNDx

COMP1/

COMP2

ADP2114

Figure 71. Configuration for Adjustable Outputs

ADP2114ACPZ-R7 Datasheet(PDF) 24 Page - Analog Devices

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