Analog Integrated Circuit Device Data

Freescale Semiconductor

3

34670

PIN CONNECTIONS

PIN CONNECTIONS

Figure 3. 34670 Pin Connections

Table 1. 34670 Pin Definitions

Pin Number

Pin Name

Formal Name

Definition

1, 2

VPWR

Positive Supply

Voltage Input

This is the most positive power supply input. The load connects between this pin

3

RCLA

Classification Resistor

4

UVLO

Undervoltage Lookout

the default threshold voltage.

5

TEST1

Test pins

6

TEST2

7

FREQ

Frequency Adjustment

Adjusts the internal oscillator frequency by connecting a resistor between FREQ

8

ILIM

Inrush Current Limit

Used to adjust the inrush current limit of the isolation switch, add a resistor

9

VIN

Negative Supply Voltage

This is the most negative power supply input.

10

VIN

11, 12

VOUT

Output Voltage

This pin is the drain of the internal Power MOSFET (high current path).

13

VOUT

Output Voltage

This pin is the drain of the internal Power MOSFET (low current path).

14

RESET

RESET Output

(active low)

15

SS

Soft Start Input

Connect an external capacitor to SS. The internal current source charges the

capacitor and generates a soft-start ramp.

16

COMP

Compensation Pin

COMP is the output of the error amplifier and is available for feedback

compensation. COMP is pulled-up by an internal 5.0 k

Ω resistor to 5.0 V.

17

FB

Feedback Input

This is the inverting input of the error amplifier. In non-isolated applications it’s

connected to the secondary output through a resistor divider.

18

CS

Current Sense

The current sense pin CS senses a voltage that is proportional to the current

through the sense resistor.

19

GATE

Gate Driver Output

GATE drives the gate of the external power MOSFET. GATE sources and sinks

up to 1.0 A.

20

VDD

1

2

3

5

4

6

7

8

9

10

20

11

12

13

14

15

16

17

18

19

VPWR

VPWR

RCLA

UVLO

TEST1

TEST2

FREQ

ILIM

VIN

VIN

VDD

GATE

CS

FB

COMP

SS

RESET

VOUT

VOUT

VOUT