Datasheet

Analog Integrated Circuit Device Data
Freescale Semiconductor 60
MC34708
Functional Block Description
7.5.4.7 SW5
SW5 is fully integrated synchronous Buck PWM voltage mode control DC/DC regulator.
Figure 15. SW5 Block Diagram
The peak current is sensed internally for over-current protection purposes. If an over-current condition is detected the regulator
will limit the current through cycle by cycle operation and alert the system through the SW5FAULT SPI bit and issue an SCPI
interrupt via the INT pin.
SW5 can be programmed in step sizes of 25 mV as shown in Table 47. If the software wants to change the output voltage, after
power up the regulator should be forced into PWM mode to change the voltage.
Table 47. SW5 Output Voltage Programmability
Set Point SW5[4:0]
SW5
Output (V)
Set Point SW5[4:0]
SW5
Output (V)
0 00000 1.2000 16 10000 1.6000
1 00001 1.2250 17 10001 1.6250
2 00010 1.2500 18 10010 1.6500
3 00011 1.2750 19 10011 1.6750
4 00100 1.3000 20 10100 1.7000
5 00101 1.3250 21 10101 1.7250
6 00110 1.3500 22 10110 1.7500
7 00111 1.3750 23 10111 1.7750
8 01000 1.4000 24 11000 1.8000
9 01001 1.4250 25 11001 1.8250
10 01010 1.4500 26 11010 1.8500
11 01011 1.4750 - - -
12 01100 1.5000 - - -
13 01101 1.5250 - - -
14 01110 1.5500 - - -
15 01111 1.5750 - - -
Driver
Controller
EA
Z1
Z2
Internal
Compensation
SW5IN
SW5LX
SW5FB
I
SENSE
C
OSW5
C
INSW5
L
SW5
SPI
Interface
GNDSW5
SW5
SW5MODE
SW5FAULT
V
REF
DAC
SPI
BP
D
SW5