PIN CONNECTIONS

FUNCTIONAL PIN DESCRIPTIONS

Analog Integrated Circuit Device Data

8

Freescale Semiconductor

34700

PIN CONNECTIONS

FUNCTIONAL PIN DESCRIPTIONS

Table 3. 34700 Pin Definitions

Pin

Name

Pin Description

1,32

VIN1

Buck regulator #1’s power input voltage. VIN1 is connected to the drain of the DC/DC #1’s high side MOSFET. Local

bypass capacitors are recommended.

2,3

SW1

Buck regulator #1’s switching node. SW1 is connected to the source of the high side MOSFET. Connect this pin to the

cathode of the catch diode and the output inductor.

4

BST1

Buck regulator #1’s bootstrap capacitor input. Connect a capacitor between the BST1 and SW1 pin of DC/DC #1 to

enhance the gate of the high side MOSFET during switching.

5

GND2

Buck regulator #2’s power ground. GND2 is connected to the source of DC/DC #2’s low side MOSFET. Connect this pin

to the DC/DC #2’s power return path.

6

SW2

Buck regulator #2’s switching node. SW2 is connected to source of the high side and the drain of the low side MOSFET.

Connect this pin to the output inductor.

7

VIN2

Buck regulator #2’s power input voltage. VIN2 is connected to the drain of the DC/DC #2’s high side MOSFET. Local

bypass capacitors are recommended.

8

BST2

Buck regulator #2’s bootstrap capacitor input. Connect a capacitor between the BST2 and SW2 pin of DC/DC #2 to

enhance the gate of the high side MOSFET during switching.

9

COMP2

Buck regulator #2’s compensation output. COMP2 is connected to DC/DC #2’s error amplifier’s output. Connect the

required external compensation network between the COMP2 pin and the FB2 pin.

10

FB2

DC/DC #2’s error amplifier inverting input. Connect the required compensation network and feedback network to this

terminal as appropriate.

11

EN1

This input enables buck regulator #1. Asserting EN1 high turns on DC/DC #1. The internal control logic remains active

as long as VIN is present.

12

EN2

This input enables buck regulator #2. Asserting EN2 high turns on DC/DC #2. The internal control logic remains active

as long as VIN is present.

VIN1

SW1

SW1

BST1

GND2

SW2

VIN2

BST2

BST3

VIN3

SW3

LDO_FB

LDO

LDO_VIN

VIN

GND3

TRANSPARENT

TOP VIEW

1

2

3

4

5

6

7

8

9

10

11 12

13

14 15 16

17

18

27

19

20

21

22

23

24

25

26

28

29

30

31

32

PIN 33

Figure 3. 34700 Pin Connections