NX2837CUPTR

NX2837CUPTR Datasheet

The NX2837 controller IC is a single power supply syn- n Single supply voltage from 9V to 22V chronous Buck controller IC designed for step down DC n Internal 5V regulator to DC converter applications. NX2837 is optimized to n Fixed 350kHz working frequency convert bus voltages from 9V to 22V to fixed 5V output. n Internal Digital Soft Start Function This switching 5V output is the input supply of an inter- n Fixed 5V switching output nal 3.3V LDO which can provide output current up to n Internal 700mA 3.3VLDO with Power Goood indicator 700mA. An internal regulator converts bus voltage to n Prebias Startup 5V, which provides voltage supply to internal logic and n Less than 50 nS adaptive deadband driver circuit. The NX2837 operates at 350kHz and em- n Fixed current limit triggers hiccup by sensing Rdson

Part	Datasheet
NX2837CUPTR	NX2837CUPTR (pdf)

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Evaluation board available SINGLE SUPPLY SYNCHRONOUS PWM CONTROLLER WITH FIXED 5V OUTPUT AND 3.3V/700mA LDO Pb Free Product The NX2837 controller IC is a single power supply syn- n Single supply voltage from 9V to 22V chronous Buck controller IC designed for step down DC n Internal 5V regulator to DC converter applications. NX2837 is optimized to n Fixed 350kHz working frequency convert bus voltages from 9V to 22V to fixed 5V output. n Internal Digital Soft Start Function This switching 5V output is the input supply of an inter- n Fixed 5V switching output nal 3.3V LDO which can provide output current up to n Internal 700mA 3.3VLDO with Power Goood indicator 700mA. An internal regulator converts bus voltage to n Prebias Startup 5V, which provides voltage supply to internal logic and n Less than 50 nS adaptive deadband driver circuit. The NX2837 operates at 350kHz and em- n Fixed current limit triggers hiccup by sensing Rdson ploys fixed loss-less current limiting by sensing the of Synchronous MOSFET Rdson of synchronous MOSFET followed by hiccup n Pb-free and RoHS compliant feature.Feedback under voltage triggers Hiccup. Other features of the device are Internal schottky di- n ode, 3.3V LDO power good indicator, Thermal shutdown, n 5V gate drive, Adaptive deadband control, Internal digi- n tal soft start, Vcc undervoltage lock out and Shutdown n capability via the comp pin. LCD TV Graphic Card on board converters On board DC to DC application Hard Disk Drive Set Top Box 6 VIN 1u 5 5VREG 10u BST 3 HDRV 2 220uF 0.1u AO4800 half 10uH NX2837 7 PGOOD 10k 10 LDO3 LDRV 4 OUT5 9 4.7u 8 COMP GND PAD 33p AO4800 half 28k 4.7n VIN +12V 1000uF VOUT Patent Pending Device NX2837CUPTR Figure1 - Typical application of 2837 ORDERING INFORMATION Temperature Package Frequency Pb-Free 0 to 70oC MSOP-EP-10L 350kHz Yes Package Marking NX2837XXX XXX is date code. For example, 735 means that this NX2837 is packaged in the 35th week of 2007 06/19/08 ABSOLUTE MAXIMUM RATINGS NOTE1 5VREG to GND & BST to SW voltage 6.5V BST to GND Voltage 30V VIN to GND Voltage 25V SW to GND -2V to 30V All other pins -0.3V to 6.5V Storage Temperature Range -65oC to 150oC Operating Junction Temperature Range -40oC to 125oC NOTE1 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 10-LEAD PLASTIC MSOP-EP 46oC/W SW 1 HDRV 2 BST 3 LDRV 4 5VREG 5 GND PAD 10 LDO3 9 OUT5 8 COMP 7 PGOOD 6 VIN ELECTRICAL SPECIFICATIONS Unless otherwise specified, these specifications apply over Vin = 12V, and T =0 to 70oC. Followings are bypass A capacitors:CVIN=1uF, C5VREG=10uF, CLDO3=10uF, all X5R ceramic capacitors. Typical values refer to TA = 25oC. Low duty cycle pulse testing is used which keeps junction and case temperatures equal to the ambient temperature. PARAMETER OUT5 Voltage OUT5 Voltage OUT5 Voltage line regulation 5V REG 5VREG Output 5VREG UVLO 5VREG UVLO Hysteresis 5VREG Line Regulation 5VREG Max Current Supply Voltage Vin Voltage Range Input Voltage Current Static Input Voltage Current Dynam ic SYM V5 Test Condition VIN=9V to 22V 5V REG rising VIN=9V to 30V Vin No switching Switching with HDRV and LDRV open Min TYP MAX Units 06/19/08 PARAMET ER Vin UVLO Vin-Threshold Vin-Hysteresis SS Soft Start time Oscillator Rt Frequency Ramp-Amplitude Voltage Max Duty Cycle Min Controlable On Time Error Amplifiers T ransconductance Comp SD Threshold OUT5 UVLO OUT5 UVLO threshold High Side Driver CL=2200pF Output Impedance , Sourcing Output Impedance , Sinking Rise Time Fall Tim e Deadband Time Low Side Driver CL=2200pF Output Impedance, Sourcing Current Output Impedance, Sinking Current Rise Time Fall Tim e Deadband Time LDO Output Voltage Line regulation Load regulation current lim it OCP threshold 3.3V Power Good T hreshold Voltage as % of Vref Hysteresis Over temperature T hreshold Hysteresis Internal Schottky Diode Forward voltage drop Test Condition Vin_UVLO VCC Rising Vin_Hyst VCC Falling FS V R AM P Rsource Hdrv R sink H drv THdrv Rise THdrv Fall Tdead L to I=200mA I=200mA Ldrv going Low to Hdrv going High, 10%-10% Rsource Ldrv

PDF Datasheet Preview

Evaluation board available

SINGLE SUPPLY SYNCHRONOUS PWM CONTROLLER WITH

FIXED 5V OUTPUT AND 3.3V/700mA LDO

Pb Free Product

The NX2837 controller IC is a single power supply syn- n Single supply voltage from 9V to 22V chronous Buck controller IC designed for step down DC n Internal 5V regulator to DC converter applications. NX2837 is optimized to n Fixed 350kHz working frequency convert bus voltages from 9V to 22V to fixed 5V output. n Internal Digital Soft Start Function This switching 5V output is the input supply of an inter- n Fixed 5V switching output nal 3.3V LDO which can provide output current up to n Internal 700mA 3.3VLDO with Power Goood indicator 700mA. An internal regulator converts bus voltage to n Prebias Startup 5V, which provides voltage supply to internal logic and n Less than 50 nS adaptive deadband driver circuit. The NX2837 operates at 350kHz and em- n Fixed current limit triggers hiccup by sensing Rdson
ploys fixed loss-less current limiting by sensing the of Synchronous MOSFET

Rdson of synchronous MOSFET followed by hiccup n Pb-free and RoHS compliant
feature.Feedback under voltage triggers Hiccup.

Other features of the device are Internal schottky di- n
ode, 3.3V LDO power good indicator, Thermal shutdown, n
5V gate drive, Adaptive deadband control, Internal digi- n
tal soft start, Vcc undervoltage lock out and Shutdown n
capability via the comp pin.

LCD TV Graphic Card on board converters On board DC to DC application Hard Disk Drive Set Top Box
6 VIN 1u
5 5VREG 10u

BST 3 HDRV 2
220uF
0.1u AO4800 half 10uH

NX2837
7 PGOOD
10k 10 LDO3

LDRV 4

OUT5 9 4.7u 8

COMP

GND PAD 33p

AO4800 half
28k 4.7n

VIN +12V
1000uF

VOUT

Patent Pending

Device NX2837CUPTR

Figure1 - Typical application of 2837
ORDERING INFORMATION

Temperature Package

Frequency Pb-Free
0 to 70oC

MSOP-EP-10L 350kHz Yes

Package Marking NX2837XXX XXX is date code. For example, 735 means that this NX2837 is packaged in the 35th week of 2007
06/19/08

ABSOLUTE MAXIMUM RATINGS NOTE1
5VREG to GND & BST to SW voltage 6.5V BST to GND Voltage 30V VIN to GND Voltage 25V SW to GND -2V to 30V All other pins -0.3V to 6.5V Storage Temperature Range -65oC to 150oC Operating Junction Temperature Range -40oC to 125oC

NOTE1 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
10-LEAD PLASTIC MSOP-EP
46oC/W

SW 1 HDRV 2

BST 3 LDRV 4 5VREG 5

GND PAD
10 LDO3 9 OUT5 8 COMP 7 PGOOD 6 VIN

ELECTRICAL SPECIFICATIONS

Unless otherwise specified, these specifications apply over Vin = 12V, and T =0 to 70oC. Followings are bypass A
capacitors:CVIN=1uF, C5VREG=10uF, CLDO3=10uF, all X5R ceramic capacitors. Typical values refer to TA = 25oC. Low duty cycle pulse testing is used which keeps junction and case temperatures equal to the ambient temperature.

PARAMETER OUT5 Voltage OUT5 Voltage OUT5 Voltage line regulation 5V REG 5VREG Output 5VREG UVLO 5VREG UVLO Hysteresis 5VREG Line Regulation 5VREG Max Current Supply Voltage Vin Voltage Range Input Voltage Current Static Input Voltage Current Dynam ic

SYM V5

Test Condition VIN=9V to 22V
5V REG rising VIN=9V to 30V

Vin No switching

Switching with HDRV and LDRV open

Min TYP MAX Units
06/19/08

PARAMET ER Vin UVLO Vin-Threshold Vin-Hysteresis SS Soft Start time Oscillator Rt Frequency Ramp-Amplitude Voltage Max Duty Cycle Min Controlable On Time

Error Amplifiers T ransconductance Comp SD Threshold

OUT5 UVLO OUT5 UVLO threshold High Side Driver CL=2200pF Output Impedance , Sourcing Output Impedance , Sinking Rise Time Fall Tim e Deadband Time

Low Side Driver CL=2200pF Output Impedance, Sourcing Current Output Impedance, Sinking Current Rise Time Fall Tim e Deadband Time

LDO Output Voltage Line regulation Load regulation current lim it OCP threshold 3.3V Power Good T hreshold Voltage as % of Vref Hysteresis Over temperature T hreshold Hysteresis Internal Schottky Diode Forward voltage drop

Test Condition

Vin_UVLO VCC Rising Vin_Hyst VCC Falling

FS V R AM P

Rsource Hdrv

R sink H drv THdrv Rise THdrv Fall Tdead L to

I=200mA I=200mA

Ldrv going Low to Hdrv going High, 10%-10%

Rsource Ldrv

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Datasheet ID: NX2837CUPTR 649088