Datasheet N2576S, N2576S-3.3, N2576S-5, N2576T, N2576T-3.3 Datasheet (NIKO)

NIKO-SEM

5 Bit Programmable Synchronous

Buck Converter with Dual LDOs

GENERAL DESCRIPTION

FEATURES

N3004

The N3004 is a 5 bit TTL-compatible input, digital-to-analog (DAC) programmable, synchronous buck converter with dual LDOs controller designed specifically to power the Pentium ® II as well as the next generation of P6 family or other high performance core logic in desktop personal computer and file servers CPU applications. The N3004 switching section provides programmability of output voltage from 1.3V to

2.05V in 50mV steps and 2.0V to 3.5V in 100 mV increments and the linear sections use external N-Channel power MOSFETs to provide fixed output voltages of 1.5V for GTL bus and 2.5V for clock. The N3004 monitors all the output voltages. A signal Power-Good signal is issued when the core is within ±15% of the DAC setting. Additional features are built-in over-voltage, over-current protections for the core output and logic compatible shutdown.

z Synchronous operation with high efficiency z TTL-compatible 5 bit DAC, output voltage

selection from 1.3V to 3.5V programmable

z Fast transient response z Provides 2 regulated voltages, 1.5V and

2.5V for linear section

z Power-Good output voltage monitor z Over-Voltage and Over-Current protection z Logic level enable input z High performance and low cost solution

APPLICATIONS

z Powering Pentium, ® II, III or Deschutes, K6 and other advanced processor z High power DC to DC controller with triple output supplies

TYPICAL APPLICATION

ENABLE

VID 0~4

POWER-GOOD

12V

+

LINEAR

SECTION

SWITCHING

SECTION

3.3V

5V

+

VCORE

+

1.5V GTC

+

BUS

2.5V CLOCK

N3004, Motherboard Power Regulation for Computers

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5 Bit Programmable Synchronous

N3004

Buck Converter with Dual LDOs

ABSOLUTE MAXIMUM RATINGS

PARAMETER VALUE

Supply Voltage (V5 to GND) 10V Supply Voltage (V12 to GND) 20V Thermal Resistance Junction to Case, θJC Thermal Resistance Junction to Ambient, θJA

25°C/W

85°C/W Operating Temperature Range 0 to 70°C Storage Temperature Range -65 to +150°C Junction Operating Temperature 0 to +125°C Lead Temperature (Soldering, 10 Seconds) 300°C

ELECTRICAL SPECIFICATIONS

PARAMETER CONDITIONS MIN TYP MAX UNITS

SWITCHING SECTION

DAC Output Voltage (Note 1) 0.99Vs Vs 1.01Vs V DAC Output Line Regulation 0.1 % DAC Output Temp. Variation 0.5 % VID Input LO 0.4 V VID Input HI 2 V VID Input Internal Pull-Up

Resistor to V5

27

KΩ

POWER GOOD SECTION

Power Good Threshold Voltage

85 115 %

Power Good Output LO IL = 3mA 0.4 V Power Good Output HI

RL = 5KΩ pull up to 5V

4.8 V

SOFT START SECTION

Soft Star Current CS+ =0V, CS- =5V 10

μA

UVLO SECTION

UVLO Threshold for V12 Supply ramping up 9.2 10 10.8 V UVLO Hysterises for V12 0.3 0.4 .05 V UVLO Threshold for V5 Supply ramping up 4.1 4.3 4.5 V UVLO Hysterises for V5 0.2 0.3 0.4 V

ERROR COMPARATOR SECTION

Input Bias Current 2

μA

Input Offset Voltage -2 +2 mV Delay to Output V

= 10mV 100 nS

DIFF

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5 Bit Programmable Synchronous

N3004

Buck Converter with Dual LDOs

PARAMETER CONDITIONS MIN TYP MAX UNITS

CURRENT LIMIT SECTION

C.S Threshold Set Current 160 200 240

μA

C.S Comparator Offset Voltage -5 +5 mV Hiccup Duty Cycle

Css = 0.1μF

2 %

SUPPLY CURRENT

Operating Supply Current CL=3000 pF V5 20 V12 14 mA

OUTPUT DRIVERS SECTION

Rise Time CL = 3,000pF 60 100 nS Fall Time CL = 3,000pF 60 130 nS Dead Band Time CL = 3,000pF 100 200 300 nS

OSCILLATOR SECTION

Oscillator Frequency CL = 150pF 220 KHz Oscillator Valley 0.2 V Oscillator Peak V5 V

LINEAR SECTIONS

V

& V

FB1

Input Bias Current 2

I

DRIVER1

Note 1: Vs refers to the set point voltage given in Table 1.

1.40 1.50 1.60 V

FB2

or I

DRIVER2

50 mA

μA

PIN CONFIGURATIONS

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5 Bit Programmable Synchronous

Buck Converter with Dual LDOs

PIN DEFINITIONS

Pin # Pin Name Pin Function Description

N3004

1 CT

2 L 3 V 4 V

IN1

FB1

FB2

The oscillator frequency is programmed by connecting an external capacitor from this pin to GND. Operation in range of 50 KHz to 500 KHz.

Gate drive output regulator, Linear 1 for GTL+ or Clock supply.

Feedback input for L Feedback input for L

IN1

IN2

.

. 5 V5 5V supply voltage. 6 PGD* Open collector logic output, high if VO within 10% of set point.

7 CS-

8

CS+

Current sense input (Negative), connected to the Source of the power MOSFET for the core supply. Current sense input (Positive), connected to the Drain of the power MOSFET for the core supply. An external resistor programs the C.S threshold depending on the R

of the power MOSFET. An external capacitor is

DS(ON)

placed in parallel with the programming resistor to provide high frequency noise filtering.

9 H

10

High side driver output.

DRV

GND

This pin serves as the ground pin and must be connected directly to the ground plane. A high frequency capacitor (0.1 to 1μF) must be connected

directly from V5 and V12 pins to this pin for noise free operation.

11 L

12

Low side driver output.

DRV

V12

12V supply voltage for LINEAR section. A high frequency capacitor (0.1 to 1μF) must be connected directly from this pin to GND pin in order to

supply the peak current to the power MOSFET during the transients.

13

SS

This pin provides the soft start for the switching regulator. An internal current source charges an external capacitor that is connected from this pin to the GND which ramps up the outputs of the switching regulator, preventing the outputs from overshooting as well as limiting the input current. The second function of the soft start cap is to provide long off time (HICCUP) for the synchronous MOSFET during current limiting.

14 V

Feedback input for V

FB3

CORE

. 15 VID4* Programming input (MSB). 16 VID3* Programming input. 17 VID2* Programming input. 18 VID1* Programming input. 19 VID0* Programming input (LSB). 20 L

* : All logic level inputs and outputs are open collector TTL compatible.

Gate drive output regulator, Linear 2 for GTL+ or Clock supply.

IN2

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5 Bit Programmable Synchronous

Buck Converter with Dual LDOs

OUTPUT SET POINT VOLTAGE vs VID CODES

− Table 1 −

Vs VID4 VID3 VID2 VID1 VID0

1.30 0 1 1 1 1

1.35 0 1 1 1 0

1.40 0 1 1 0 1

1.45 0 1 1 0 0

1.50 0 1 0 1 1

1.55 0 1 0 1 0

1.60 0 1 0 0 1

1.65 0 1 0 0 0

1.70 0 0 1 1 1

1.75 0 0 1 1 0

1.80 0 0 1 0 1

1.85 0 0 1 0 0

1.90 0 0 0 1 1

1.95 0 0 0 1 0

2.00 0 0 0 0 1

2.05 0 0 0 0 0

2.00 1 1 1 1 1

2.10 1 1 1 1 0

2.20 1 1 1 0 1

2.30 1 1 1 0 0

2.40 1 1 0 1 1

2.50 1 1 0 1 0

2.60 1 1 0 0 1

2.70 1 1 0 0 0

2.80 1 0 1 1 1

2.90 1 0 1 1 0

3.00 1 0 1 0 1

3.10 1 0 1 0 0

3.20 1 0 0 1 1

3.30 1 0 0 1 0

3.40 1 0 0 0 1

3.50 1 0 0 0 0

N3004

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5 Bit Programmable Synchronous

Buck Converter with Dual LDOs

APPLICATION CIRCUIT

N3004

5V

VID 0

VID 1

VID 2

VID 3

VID 4

12V

P.G

1000uF

+

3.3V

1uF

10K

1uF

+

0.1uF

1uF

+

150pF

0.1uF

2 uH

VCC

VID 0

VID 1

VID 2

VID 3

VID 4

V12

SS

CT

PGD

N3004

1000uF x 2

CS+

HDRV

CS-

LDRV

VFB3

LIN1

LIN2

VFB2

VFB1

GND

+

2.21K

MOSFET

P50N02L x 2

10

220pF

1K

470pF

10

Short or 5 OHM

1K

10K

150

100

2.5uH

SBD

1A/30V

100

1500uF x 5

3.3V

+

680uF

0.01uF

++ ++ + +

P3055LD x 2

0.1uF

+

10K

MOSFET

0.01uF

100

VCORE

1.5V GTC BUS

+

680uF

2.5V CLOCK

+

220uF

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Dimension

A 12.6 13.0 H 0.4 1.27

B 7.3 7.7 I 0.23 0.32

C 10 10.65 J 0.25 0.74

D 0.33 0.51 K

E 1.27 L

F 2.1 2.3 2.5 M

G 0.1 0.3 N

5 Bit Programmable Synchronous

Buck Converter with Dual LDOs

SOIC-20 (DW) MECHANICAL DATA

mm mm

Dimension

Min. Typ. Max.

N3004

Min. Typ. Max.

0°

8°

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