MAX15066EWE+T Maxim Integrated Products, MAX15066EWE+T Datasheet - Page 17

• Manufacturer Part Number: MAX15066EWE+T
• Description: DC/DC Switching Controllers 4A 12V 500kHz w/Integrated Switch
• Manufacturer: Maxim Integrated Products

Specifications of MAX15066EWE+T

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Figure 4. Asymptotic Loop Response of Peak Current-Mode Regulator
Figure 4 shows a graphical representation of the asymp-
totic system closed-loop response, including dominant
pole and zero locations.
The loop response’s fourth asymptote (in bold, Figure 4)
is the one of interest in establishing the desired cross-
over frequency (and determining the compensation
component values). A lower crossover frequency pro-
vides for stable closed-loop operation at the expense of
a slower load and line transient response. Increasing the
crossover frequency improves the transient response at
UNITY
GAIN
[2 G C
NOTE:
R
f
WHICH FOR
ESR << {R
BECOMES
f
f
PMOD
PMOD
PMOD
OUT
C
1ST POLE
x g
(10
= 10
= [2 G C
= [2 G C
= (2 G C
MV
AVEA(dB)/20
-1
AVEA(dB)/20
LOAD
)]
-1
OUT
OUT
OUT
-1
______________________________________________________________________________________
+ [K
x (ESR + {R
x {R
x R
Regulator with Internal Power Switches
S
LOAD
x g
LOAD
(1 – D) – 0.5] x (L x f
2ND POLE
f
MV
PMOD
)
-1
-1
1ST ASYMPTOTE
R2 x (R1 + R2)
-1
+ [K
+ [K
LOAD
High-Efficiency, 4A, Step-Down DC-DC
*
1ST ZERO
(2 G C
S
S
(1 – D) – 0.5] x (2 G C
-1
(1 – D) – 0.5] x (L x f
+ [K
2ND ASYMPTOTE
R2 x (R1 + R2)
C
R
C
S
)
-1
(1 – D) – 0.5] x (L x f
-1
SW
x 10
)
-1
f
AVEA(dB)/20
CO
}
-1
-1
3RD ASYMPTOTE
R2 x (R1 + R2)
x (2 G C
x g
OUT
SW
MV
)
OUT
-1
x L x f
x g
x (2 G C
}
-1
4TH ASYMPTOTE
R2 x (R1 + R2)
x (2 G C
SW
MC
3RD POLE
]
x {R
0.5 x f
-1
SW
)
x R
-1
-1
C
LOAD -1
}
)
)
-1
-1
-1
x g
OUT
SW
LOAD
)]
x g
-1
MV
x {R
MC
+ [K
x {1 + R
(2 G C
x (2 G C
2ND ZERO
x R
LOAD -1
S
-1
(1 – D) – 0.5] x (L x f
OUT
LOAD
x g
C
LOAD
)
ESR)
-1
MV
+ [K
x {1 + R
x g
x [K
x R
-1
5TH ASYMPTOTE
R2 x (R1 + R2)
x [(2 G C
MC
S
S
C
(1 – D) – 0.5] x (L x f
x R
x (1 – D) – 0.5] x (L x f
x g
LOAD
the (potential) cost of system instability. A standard rule
of thumb sets the crossover frequency P 1/5 to 1/10 of
the switching frequency.
First, select the passive power components that meet
the application’s requirements. Then, choose the small-
signal compensation components to achieve the desired
closed-loop frequency response and phase margin
as outlined in the Closing the Loop: Designing the
Compensation Circuitry section.
OUT
LOAD
MC
6TH ASYMPTOTE
R2 x (R1 + R2)
x ESR x {R
x [K
SW
x {R
x R
x {1 + R
-1
S
)
-1
LOAD -1
LOAD
x (1 – D) – 0.5] x (L x f
x g
}
-1
MV
)
LOAD -1
LOAD
-1
x {1 + R
+ [K
x R
-1
x [K
C
x g
SW
S
SW
+ [K
x g
(1 – D) – 0.5] x (L x f
MV
)
S
)
LOAD
-1
-1
MC
S
x (1 – D) – 0.5] x (L x f
(1 – D) – 0.5] x (L x f
}
x R
}
-1
-1
x R
)
C
x [K
-1
LOAD
x g
SW
MC
S
)
-1
x (1 – D) – 0.5] x (L x f
x {1 + R
}
x R
-1
LOAD
SW
LOAD
)
-1
x {1 + R
SW
SW
}
-1
)
x [K
-1
)
)
-1
-1
}
}
-1
S
x (0.5 x f
-1
LOAD
x (1 – D) – 0.5] x (L x f
x (0.5 f
x [K
SW
SW
SW
S
)
)2 x (2 G f)
x (1 – D) – 0.5] x (L x f
)
-1
2
x (2 G f)
}
-1
-2
-2
FREQUENCY
SW
)
-1
}
-1
SW
)
-1
}
-1
17