ADP2114ACPZ-R7 datasheet(32/40 Pages) AD

32 / 40 page

ADP2114

Rev. 0 | Page 32 of 40

Calculate the feedback loop, compensation component

values by using Equation 15.

H(s)

= gm × GCS ×

OUT

REF

× ZCOMP(s) × ZFILT(s)

In this case, the following values are substituted for the

variables in Equation 18:

gm = 550 μs

GCS = 4

VREF = 0.6 V

VOUT = 1.8 V

COUT = 0.8 × (47+22) μF (capacitance derated by 20% to

account for dc bias).

From Equation 18,

RCOMP = 22 kΩ.

Substituting RCOMP in Equation 19 yields CCOMP = 1100 pF.

SYSTEM CONFIGURATION

Complete the following steps to further configure the ADP2114

for this design example:

Set the switching frequency (fSW) = 600 kHz (see Table 5)

by connecting the FREQ pin through an 8.2 kΩ resistor

to GND.

Tie SCFG to VDD and use the CLKOUT signal to

synchronize other converters on the same board with the

ADP2114.

Tie OPCFG to GND for 2 A/2 A maximum output current

operation and to enable pulse skip mode at light load

conditions (see Table 7).

A schematic of the ADP2114 as configured in the design example

described in this section is shown in Figure 79.

Table 12 provides the recommended inductor, output capacitor,

and compensation component values for a set of popular input

and output voltage combinations.

Table 11. Channel 2 Circuit Settings

Circuit Parameter

Setting

Value

Output Voltage, VOUT

Nominal

1.8 V

Reference Voltage, VREF

Typical

0.6 V

Error Amp Transconductance, gm

Typical

550 μs

Current Sense Gain, CCS

Typical

4 A/V

Switching Frequency, fSW

Step 2

600 kHz

Crossover Frequency, fCROSS

1/12 fSW

50 kHz

Zero Frequency, fZERO

1/8 fCROSS

6.25 kHz

Output Inductor, LOUT

Step 3

3.3 μF

Output Capacitors, COUT

Step 4

47 μF + 22 μF

Compensation Resistor, RCOMP

Equation 18

22 kΩ

Compensation Capacitor, CCOMP

Equation 19

1100 pF

Table 12. Selection Table of L, COUT, and Compensation Values

fSW (kHz)

VIN (V)

VOUT (V)

Maximum Load (A)

L (μH)

COUT (μF)

RCOMP (kΩ)

CCOMP (pF)

300

3.3

2.0

6.8

69 (47 + 22)

2400

300

2.5

2.0

6.8

100

2400

300

1.8

2.0

6.8

147 (100 + 47)

2400

300

1.2

2.0

4.7

200 (2 × 100 )

2400

600

3.3

2.0

3.3

1000

600

2.5

2.0

3.3

57 (47 + 10)

1100

600

1.8

2.0

3.3

69 (47 + 22)

1100

600

1.2

2.0

2.2

100

1200

2.5

2.0

1.8

32 (22 + 10)

470

1200

1.8

2.0

1.8

44 (2 × 22)

470

1200

1.2

2.0

1.2

57 (47 + 10)

510

1200

0.8

2.0

1.0

100

470

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