FAN5018B Просмотр технического описания (PDF) - Fairchild Semiconductor

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FAN5018B

6-Bit VID Controller 2-4 Phase VR10.X Controller

Fairchild Semiconductor 

FAN5018B

Pin Assignments

VID4 1

VID3 2

VID2 3

VID1 4

VID0 5

VID5/SEL 6

FBRTN 7

FB 8

COMP 9

PWRGD 10

EN 11

DELAY 12

RT 13

RAMPADJ 14

FAN5018B

TSSOP-28

28 VCC

27 PWM1

26 PWM2

25 PWM3

24 PWM4

23 SW1

22 SW2

21 SW3

20 SW4

19 GND

18 CSCOMP

17 CSSUM

16 CSREF

15 ILIMIT

PRODUCT SPECIFICATION

Pin Definitions

Pin Number

1–5

6

Pin Name

VID [4:0]

VID5/SEL

Pin Function Description

VID inputs. Determines the output voltage via the internal DAC. These inputs

comply to VRM10/VRD10 specifications for static and dynamic operation. All have

internal pull-ups (1.25V for VRM10 and 2.5V for VRM9) so leaving them open

results in logic high. Leaving VID[4:0] open results in a "No CPU" condition

disabling the PWM outputs.

VID5 Input/DAC Select. Dual function pin that is either the 12.5mV DAC LSB for

VRM10 or selects the VRM9 DAC codes when forced higher than Vtblsel(VRM9)

voltage. The truth table is as follows:

VVID5/SEL held > Vtblsel(VRM9); VRM9 DAC table is selected (See Table 3)

VViD5/SEL < Vtblsel(VRM10); VRM10 DAC table is selected (See Table 2) and

VViD5/SEL pin is used as VID5 input.

7

FBRTN Feedback Return. Error Amp and DAC reference point.

8

FB

Feedback Input. Inverting input for Error Amp this pin is used for external

compensation. This pin can also be used to introduce DC offset voltage to the

output.

9

COMP Error Amp output. This pin is used for external compensation.

10

PWRGD Power Good output. This is an open-drain output that asserts when the output

voltage is within the specified tolerance. It is expected to be pulled up to an external

voltage rail.

11

EN

Enable. Logic signal that enables the controller when logic high.

12

DELAY Soft-start and Current Limit Delay. An external resistor and capacitor sets the

softstart ramp rate and the over-current latch off delay.

13

RT

Switching Frequency Adjust. This pin adjusts the output PWM switching

frequency via an external resistor.

14

RAMPADJ PWM Current Ramp Adjust. An external resistor to Vcc will adjust the amplitude of

the internal PWM ramp.

15

ILIMIT Current Limit Adjust. An external resistor sets the current limit threshold for the

regulator circuit. This pin is internally pulled low when EN is low or the UVLO circuit

is active. It is also used to enable the drivers.

2

REV. 1.0.0 Jul/15/05

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