MC34717EP Freescale Semiconductor, MC34717EP Datasheet - Page 20

• 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

CONFIGURING THE OUTPUT VOLTAGE:
converters. The resistor divider to the INV node is
responsible for setting the output voltage. The equation is:
internal reference selector, thus V
voltage at VREFIN terminal or the internal reference voltage
V
V
V
calculated using the internal reference V
V
SWITCHING FREQUENCY CONFIGURATION
connecting the FREQ terminal to the GND. If the smallest
frequency value of 200 kHz is desired, then connect the
FREQ terminal to VDDI. To program the switching frequency
to another value, an external resistor divider must be
connected to the FREQ terminal to achieve the voltages
given by
20
34717
TYPICAL APPLICATIONS
BG
REF
REF
REF
FREQUENCY
Both channels for the 34717 are general purpose DC-DC
For channel 1: V
For channel 2: The second channel of the 34717 has an
The switching frequency will have a value of 1.0MHz by
. The reference value is given by the following condition:
=VREFIN if VREFIN is less than V
=V
=VREFIN is used for tracking purposes.
200
253
307
360
413
466
520
573
627
BG
Table
. Usually the output regulation voltage is
5.
V
OUT
REF
VOLTAGE APPLIED TO PIN FREQ
=
=V
V
BG
REF
=0.7V.
⎛
⎜
⎝
R
R
2.341 – 2.500
1.717 – 1.872
1.561 – 1.716
2.185 - 2.340
2.029 - 2.184
1.873 - 2.028
1.405 - 1.560
1.249 - 1.404
1.093 - 1.248
REF
1
2
+
can be either the
1
BG
BG
⎞
⎟
⎠
=0.7 V. Otherwise,
, and the condition
Table 5. Frequency Selection Table
SOFT START ADJUSTMENT
ILIM1and ILIM2 pins to get the desired soft start timing.
Table 6. Soft Start Configurations
Figure 8. Resistor Divider for Frequency and Soft Start
Table 6
1000
SOFT START [MS]
680
733
787
840
893
947
C
VDDI
shows the voltage that should be applied to the
3.2
1.6
0.8
0.4
R
R
IH
IL
Analog Integrated Circuit Device Data
Adjustment
R
R
IH
IL
R
R
VOLTAGE APPLIED TO ILIM
FQH
FQL
0.936 - 1.092
0.781 - 0.936
0.625 - 0.780
0.469 - 0.624
0.313 - 0.468
0.157 - 0.312
0.000 - 0.156
Freescale Semiconductor
1.19 - 1.49 V
1.50 - 1.81 V
1.82 - 2.13 V
2.14 - 2.50 V
ILIM1
VDDI
FREQ
GND