HIP6014

FN4420 Rev.2.00

Page 4 of 12

March 2000

Functional Pin Description

VSEN (Pin 1)

This pin is connected to the converters output voltage. The

PGOOD and OVP comparator circuits use this signal to report

output voltage status and for overvoltage protection.

OCSET (Pin 2)

Connect a resistor (ROCSET) from this pin to the drain of the

upper MOSFET. ROCSET, an internal 200A current source

(IOCS), and the upper MOSFET on-resistance (rDS(ON)) set

the converter over-current (OC) trip point according to the

following equation:

An over-current trip cycles the soft-start function.

SS (Pin 3)

Connect a capacitor from this pin to ground. This capacitor,

along with an internal 10

A current source, sets the soft-start

interval of the converter.

VID0-4 (Pins 4-8)

VID0-4 are the input pins to the 5-bit DAC. The states of these

five pins program the internal voltage reference (DACOUT).

The level of DACOUT sets the converter output voltage. It also

sets the PGOOD and OVP thresholds. Table 1 specifies

DACOUT for the 32 combinations of DAC inputs.

COMP (Pin 9) and FB (Pin 10)

COMP and FB are the available external pins of the error

amplifier. The FB pin is the inverting input of the error amplifier

and the COMP pin is the error amplifier output. These pins are

used to compensate the voltage-control feedback loop of the

converter.

GND (Pin 11)

Signal ground for the IC. All voltage levels are measured with

respect to this pin

PGOOD (Pin 12)

PGOOD is an open collector output used to indicate the status

of the converter output voltage. This pin is pulled low when the

converter output is not within

10%of the DACOUT reference

voltage. Exception to this behavior are the cases where the

VID pins combination yield a 0V converter output; in these

cases PGOOD asserts a high level.

PHASE (Pin 13)

Connect the PHASE pin to the upper MOSFET source. This

pin is used to monitor the voltage drop across the MOSFET for

over-current protection. This pin also provides the return path

for the upper gate drive.

UGATE (Pin 14)

Connect UGATE to the upper MOSFET gate. This pin provides

the gate drive for the upper MOSFET.

Typical Performance Curves

FIGURE 1. RT RESISTANCE vs FREQUENCY

FIGURE 2. BIAS SUPPLY CURRENT vs FREQUENCY

10

100

1000

SWITCHING FREQUENCY (kHz)

10

100

1000

RT PULLUP

TO +12V

RT PULLDOWN TO VSS

100

200

300

400

500

600

700

800

900

1000

SWITCHING FREQUENCY (kHz)

CGATE = 3300pF

CGATE = 1000pF

CGATE = 10pF

CUPPER = CLOWER = CGATE

80

70

60

50

40

30

20

10

0

11

12

13

14

15

16

17

18

20

19

10

9

8

7

6

5

4

3

2

1

VSEN

OCSET

SS

VID0

VID1

VID2

VID4

VID3

COMP

FB

RT

VCC

LGATE

PGND

OVP

BOOT

UGATE

PHASE

PGOOD

GND

IPEAK

IOCS ROCSET



rDS ON



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