MC34717EP Freescale Semiconductor, MC34717EP Datasheet - Page 22

• Manufacturer Part Number: MC34717EP
• Description: IC CONVERTER DDR 26QFN
• Manufacturer: Freescale Semiconductor

Specifications of MC34717EP

• Applications: Converter, DDR
• Voltage - Input: 3 ~ 6 V
• Number Of Outputs: 2
• Voltage - Output: 0.7 ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 26-QFN
• Output Voltage: 0.7 V to 3.6 V
• Output Current: 5 A
• Input Voltage: 3 V to 6 V
• Switching Frequency: 1 MHz
• Operating Temperature Range: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• No. Of Outputs: 2
• Power Dissipation Pd: 2.03W
• No. Of Pins: 26
• Filter Terminals: SMD
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

22
34717
TYPICAL APPLICATIONS
F
1. Choose a value for R1
2. Consider a Crossover frequency of one tenth of the
3. Knowing the LC frequency, the Frequency of Zero 1
4. Calculate R
This gives the result
R
Z
COMP
1
F
VOUT
switching frequency, set the Zero pole frequency to
Fcross/10
and Zero 2 in the compensation network are equal to
F
frequency
=
LC
=
INV
SW
F
Figure 9. Type III compensation network
2
2
P
π
x
x
x
x
1
π
F
F
=
*
F
LC
*
P
1
R
ESR
2
0
C
1
π
F
=
S
=
F
C
C
*
R
C
=
by placing the first pole at the ESR zero
F
2
Xx
10
C
F
Sx
Sx
1
1
π
R
Z
L
2
F
1
x
S
π
F
C
=
L
CROSS
*
S
R
C
1
X
2
Co
Fx
Fx
Co
π
1
*
X
R1
=
X
1
R
*
x
1
2
ESR
=
R
F
π
C
S
PO
F
R2
F
S
*
Z
Z
=
x
1
2
1
=
R
=
2
=
=
1
C
π
2
F
C
F
π
2
Ox
F
P
*
π
Z
1
*
2
1
F
*
1
R
P
1
R
1
1
C
1
F
C
S
Z
S
2
TRACKING CONFIGURATIONS.
and Co-incidental Tracking.
RATIOMETRIC TRACKING CIRCUIT
CONFIGURATION
used in place of R
output is connected through its own feedback resistor divider
network to the INV- terminal, resistors R
5. Equating pole 2 to 5 times the Crossover Frequency
This device allows two tracking configurations: Ratiometric
The master voltage feedback resistor divider network is
5
achieves a faster response and a proper phase margin
•
F
CROSS
C
Figure 11. Co-incidental Tracking
Figure 10. Ratiometric Tracking
X
=
=
3
2
and R
F P2
π
Analog Integrated Circuit Device Data
*
Same Slope
=
R
4
Different Slope
F
Slave Regulation Point
as shown in
C
--------------------------------------- -
2π R
C
Vmaster
Vslave
F
Vslave
F
•
Vmaster
F
P
F
Freescale Semiconductor
1
------------------- -
C
2
C
F
−
F
+
C
1
Figure
1
C
X
and R
x
12. The slave
2
. All four