NX2147 - Microsemi Corporation

NX2147

Rev. 1.6

03/09/09

Rev. 1.8

12/28/09

TYPICAL APPLICATION

DESCRIPTION

The NX2147 controller IC is a step down switching con-

troller with ability to dynamically adjust the output volt-

age designed for applications such as Graphic Proces-

sor Core voltage in Notebook PC products. It allows

this by adjusting the reference input of the PWM

comprator as oppose to the traditional method of feed-

back adjustment. This device has three mode of opera-

tions; a) Constant ON Time Synchronous Mode, b) Non

Synchronous PFM mode or c) Ultrasonic PFM mode of

operation. When selected in Non Synchronous mode,

the device automatically disables the synchronous

MOSFET in order to improve efficiency at light load.

This device provides excellent dynamic response and

nearly constant frequency for operation from 4.5V to

24V of input voltage operation. Other features of the

device are; internal logic level signal MOSFETs for out-

put dynamic voltage adjustment, internal boost schotcky

diode, less than 1uA VIN shutdown current, adjustable

current limiting using lower MOSFET Rds-On and feed-

back UVLO followed by latchdown, overvoltage protec-

tion , internal digital soft start and soft stop shutdown

using and internal 20 ohm MOSFET pull down.

nOutput voltage can be dynamically changed

n Internal Boost Schottky Diode

n Ultrasonic mode operation available

nBus voltage operation from 4.5V to 24V

n Less than 1uA VIN shutdown current with Enable

low

nExcellent dynamic response with constant on time

control

n Selectable between Synchronous CCM mode and

diode emulation mode to improve efficiency at

light load

n Programmable switching frequency

nCurrent limit and FB UVLO with latch off

nOver voltage protection with latch off

n Pb-free and RoHS compliant

ORDERING INFORMATION

FEATURES

SINGLE CHANNEL MOBILE PWM CONTROLLER WITH

DYNAMIC VOLTAGE ADJUSTMENT

APPLICATIONS

nNotebook PCs and Desknotes

nTablet PCs/Slates

nOn board DC to DC such as

12V to 3.3V, 2.5V or 1.8V

nHand-held portable instruments

PRODUCTION DATA SHEET

Figure1 - Typical application of NX2147

Device Temperature Package Pb-Free

NX2147CMTR -10oC to 100oC3X3 MLPQ-16L Yes

Pb Free Product

VIN 7V~22V

TON

HDRV

BST

LDRV

VREF_OC

VOUT

ENSW

/MODE

10 VCC

PVCC

Vout (see table above) /12A

AGND

1MEG

10 8

1u 1u

2R5TPE330MC

200k

2x10uF

FDS6294

FDS6676AS

1uH

N X 2 1 4 7

330uF

PGND

GPIO0

GPIO1

10n

0.1u

100k

88.7k

634k

LOAD

2.2

GPIO0 GPIO1 VOUT(V)

1 1 1.17

0 1 1.09

1 0 0.95

0 0 0.9

NX2147

Rev. 1.6

03/09/09

Rev. 1.8

12/28/09

ABSOLUTE MAXIMUM RATINGS

VCC,PVCC to GND & BST to SW voltage ............ -0.3V to 6.5V

VIN,TON to GND .................................................. -0.3V to 28V

HDRV to SW Voltage .......................................... -0.3V to 6.5V

SW to GND ......................................................... -2V to 30V

All other pins ........................................................ VCC+0.3V

Storage Temperature Range ..................................-65oC to 150oC

Operating Junction Temperature Range .................-40oC to 150oC

ESD Susceptibility ............................................... 2kV

CAUTION: Stresses above those listed in "ABSOLUTE MAXIMUM RATINGS", may cause permanent

damage to the device. This is a stress only rating and operation of the device at these or any other conditions

above those indicated in the operational sections of this specification is not implied.

PACKAGE INFORMATION

3x3 16-LEAD PLASTIC MLPQ

ELECTRICAL SPECIFICATIONS

Unless otherwise specified, these specifications apply over Vcc =5V, VIN=15V and TA =25oC, unless otherwise

specified.

θ≈46/

VCC

TON

D1 PVCC

VREF_OC

HDRV

PGND

LDRV

GPIO1

16 15 14 13

GPIO0

VOUT

ENSW/MODE

BST

AGND

17(PAD)

PARAMETER SYM Test Condition Min TYP MAX Units

VIN

Recommended voltage range 4.5 24 V

Shut down current ENSW=GND 1 uA

VCC,PVCC Supply

Input voltage range Vcc 4.5 5.5 V

Operating quiescent current No switching, ENSW=5V 1.6 mA

Shut down current ENSW=GND 1 uA

NX2147

Rev. 1.6

03/09/09

Rev. 1.8

12/28/09

PARAMETER SYM Test Condition Min TYP MAX Units

VCC UVLO

Under-voltage Lockout

threshold VCC_UVLO 4.1 V

Falling VCC threshold 3.9 V

ON and OFF time

TON operating current VIN=15V, Rton=1Mohm 15 uA

ON -time VIN=9V,VP=VOUT=0.75V,Rt

on=499k 390 ns

Minimum off time 380 590 800 ns

VREF_OC voltage

VREF_OC voltage 2.475 2.5 2.525 V

Line regulation VCC from 4 to 5.5 -2 2%

OUTPUT voltage

Output range 05.5 V

VOUT shut down discharge

resistance ENSW/MODE=GND 30 ohm

Soft start time 1.5 ms

GPIO threshold

Output high 2 5V

Output low 00.8 V

DO,D1 internal pull down

MOSFET

impedance

mohm

SW zero cross comparator

Offset voltage

5 mV

High Side Driver

(CL=3300pF)

Output Impedance , Sourcing

Current Rsource(Hdrv) I=200mA 1.5 ohm

Output Impedance , Sinking

Current Rsink(Hdrv) I=200mA 1.5 ohm

Rise Time

THdrv(Rise)

10% to 90%

Fall Time THdrv(Fall) 90% to 10% 50 ns

Deadband Time Tdead(L to

Ldrv going Low to Hdrv going

High, 10% to 10% 30 ns

Low Side Driver

(CL=3300pF)

Output Impedance, Sourcing

Current

Rsource(Ldrv) I=200mA 1.5 ohm

Output Impedance, Sinking

Current

Rsink(Ldrv) I=200mA 0.5 ohm

Rise Time TLdrv(Rise) 10% to 90% 50 ns

Fall Time TLdrv(Fall) 90% to 10% 50 ns

Over temperature

Threshold 155 o

Hysteresis 15 o

10 nsDeadband Time Tdead(H to

L) SW going Low to Ldrv going

High, 10% to 10%

NX2147

Rev. 1.6

03/09/09

Rev. 1.8

12/28/09

PARAMETER SYM Test Condition Min TYP MAX Units

ENSW/MODE threshold and

bias current

PFM/Non Synchronous Mode

80%

VCC

VCC+0

.3V V

Ultrasonic Mode

60%

VCC

80%

VCC V

Synchronous Mode

Leave it open or use limits in

spec 2

60%

VCC V

Shutdown mode 00.8 V

ENSW/MODE=VCC 1 uA

ENSW/MODE=GND -1 uA

Under voltage protection

Under voltage trigger point 70 %VP

Over voltage protection

Over voltage tripp point 125 %VP

Internal Schottky Diode

Forward voltage drop forward current=50mA 500 mV

Input bias current

NX2147

Rev. 1.6

03/09/09

Rev. 1.8

12/28/09

PIN DESCRIPTIONS

PIN NUMBER PIN SYMBOL PIN DESCRIPTION

This pin is directly connected to the output of the switching regulator and

senses the VOUT voltage. An internal MOSFET with 20ohms rdson dis-

charges the output during turn off.

This pin supplies the internal 5V bias circuit. A 1uF X7R ceramic capacitor is

placed as close as possible to this pin and ground pin.

This pin is connected via resistor divider to VREF_OC pin to set the output

DC voltage from 0.5V to VREF 2.5V.

This pin is a drain of an internal signal MOSFET. When it is connected via

resistor to the VP pin,and the GPIO0 pin is set low, it reduces the VP

voltage by paralleling this resistor to the fixed resistor from VP to GND.

This pin is a drain of an internal signal MOSFET. When it is connected via

resistor to the VP pin,and the GPIO_1 pin is set low, it reduces the VP

voltage by paralleling this resistor to the fixed resistor from VP to GND.

A logic level input signal that controls the D1 pin. A low signal turns the

internal D1 MOSFET on and a High turns it off.

Power ground.

Low side gate driver output.

Provide the voltage supply to the lower MOSFET drivers. Place a high

frequency decoupling capacitor 1uF X5R to this pin.

Reference output voltage. A resistor divider from this pin to VP pin sets the

output voltage. The total resistance from this pin to GND also sets the OCP

threshold voltage. Note that when GPIO0 and GPIO1 pins are high the

reference divider is at its highest voltage. The nominal voltage of Vref is

2.5V.

This pin is connected to source of high side FETs and provide return path for

the high side driver. It is also the input of zero current sensing comparator.

High side gate driver output.

This pin supplies voltage to high side FET driver. A high freq 1uF X7R

ceramic capacitor and 2.2ohm resistor in series are recommended to be

placed as close as possible to and connected to this pin and SW pin.

A logic level input signal that controls the D0 pin. A low signal turns the

internal D0 MOSFET on and a High turns it off.

Switching converter enable input. Connect to VCC for PFM/Non synchronous

mode, connected to an external resistor divider equals to 70%VCC for ultra-

sonic, connected to GND for shutdown mode, floating or connected to 2V for

the synchronous mode.

VIN sensing input. A resistor connects from this pin to VIN will set the fre-

quency. A 1nF capacitor from this pin to GND is recommended to ensure the

proper operation.

Analog ground.

VOUT

VCC

GPIO1

PGND

LDRV

PVCC

VREF_OC

HDRV

BST

GPIO0

ENSW/

MODE

TON

PAD

NX2147

Rev. 1.6

03/09/09

Rev. 1.8

12/28/09

BLOCK DIAGRAM

Figure 2 - Simplified block diagram of the NX2147

VIN

BST(13)

HDRV(12)

LDRV(8)

SW(11)

PVCC(9)

FET Driver

start ODB

HD_IN

start

VOUT(1)

DO(5)

ENSW

/MODE(15)

start POR

VREF_OC(10)

TON(16)

VREF

FBUVLO_latch

Mini offtime

400ns

OCP_COMP

Diode

emulation

OCP_COMP

0.7*Vref

1.25*Vref/0.7VREF

VOUT

OVP

FBUVLO_latch

VOUT

Sync

PFM_nonultrasonic

4.3/4.1

VCC(2) Bias POR

Disable

Disable_B

VIN

1.8V

Thermal

shutdown

soft start

ON time

pulse

genearation

VOUT

MODE

SELECTION

VCC1M

AGND(PAD)

PGND(7)

VP(3)

GPIO0(14)

SCHIMTTER

TRIGGER

D1(4)

GPIO1(6)

SCHIMTTER

TRIGGER

VREF_OC

R1+R2

NX2147

Rev. 1.6

03/09/09

Rev. 1.8

12/28/09

Figure 3 - Demo board schematic

VIN 7V~22V

TON

HDRV

BST

LDRV

VREF_OC

VOUT

ENSW

/MODE

10 VCC

PVCC

Vout (see table below) /12A

AGND

499k

10 8

1u 1u

2R5TPE330MC

200k

FDS6294

FDS6676AS

1uH

N X 2 1 4 7

330uF

PGND

GPIO0

GPIO1

10n

0.1u

100k

88.7k

634k

R3 R4

C1 C2

C6 Lo

CI1

2x10uF

CO1

470p

C7 LOAD

2.2

TYPICAL APPLICATION

(VIN=7V to 22V, VOUT=1.09V/12A)

GPIO0 GPIO1 VOUT(V)

1 1 1.17

0 1 1.09

1 0 0.95

0 0 0.9

VOUT TABLE:

NX2147

Rev. 1.6

03/09/09

Rev. 1.8

12/28/09

Bill of Materials

Item Quantity Reference Value Manufacture

1 2 CI1 10uF/X5R/25V

2 1 CO1 2R5TPE330MC SANYO

3 2 C1,C2 1uF

4 2 C3,C6 0.1uF

5 1 C4 10nF

6 1 C5 1nF

7 1 C7 470p

8 1 Lo RL-8250-1.4-1R0M RENCO

9 1 M1 FDS6294 FAIRCHILD

10 1M2 FDS6676AS FAIRCHILD

11 1R1 10

12 1R2 100k

13 1R3 88.7k

14 1R4 200k

15 1R5 634k

16 1R6 499k

17 1R7 10

18 1R8 2.2

19 1U1 NX2147 NEXSEM INC.

NX2147

Rev. 1.6

03/09/09

Rev. 1.8

12/28/09

Fig.5 10A step response( CH1 VOUT AC 50mV/DIV,

CH4 Output current 5A/DIV)

Demoboard waveforms

Fig.4 Start up( CH1 VOUT 1V/DIV, CH4 Output

current 5A/DIV)

Fig.6 Soft turn off(CH1 ENSW 2V/DIV, CH2 VOUT

0.5V/DIV)

Fig.8 D1=0, D0 from low to high(CH1 D0 2V/DIV,

CH2 VOUT 0.1V/DIV 0.8V OFFSET, CH3 INDUC-

TOR CURRENT 5A/DIV, CH4 VP 0.1V/DIV 0.8V

OFFSET)

OUTPUT EFFICIENCY (VIN=12V,VOUT=1.09V)

10 100 1000 10000

OUTPUT CURRENT (mA)

OUTPUT EFFICIENCY (%)

Fig.9 Output efficiency

Fig.7 D0=0, D1 from low to high(CH1 D0 2V/DIV,

CH2 VOUT 0.1V/DIV 0.8V OFFSET, CH3 INDUC-

TOR CURRENT 5A/DIV, CH4 VP 0.1V/DIV 0.8V

OFFSET)

NX2147

Rev. 1.6

03/09/09

Rev. 1.8

12/28/09

MLPQ 16 PIN 3 x 3 PACKAGE OUTLINE DIMENSIONS

SYMBOL

NAME MIN MAX MIN MAX

A0.700 0.800 0.028 0.031

A1 0.000 0.050 0.000 0.002

B0.180 0.300 0.007 0.012

D2.950 3.050 0.116 0.120

D2 1.600 1.750 0.063 0.069

E2.950 3.050 0.116 0.120

E2 1.600 1.750 0.063 0.069

L0.325 0.450 0.013 0.018

0.203REF

0.50BSC

1.5REF

Dimensions In Inches

0.008REF

0.50BSC

0.059REF

Dimensions In Millimeters