nx2155h Microsemi Corporation, nx2155h Datasheet

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nx2155h

Manufacturer Part Number
nx2155h
Description
Single Power Supply Synchronous Pwm Controller
Manufacturer
Microsemi Corporation
Datasheet
Rev.1.1
04/16/09
The NX2155H controller IC is a single input supply syn-
chronous Buck controller IC designed for step down DC
to DC converter applications. NX2155H is optimized to
convert bus voltages from 8V to 22V to output as low as
0.8V voltage. An internal regulator converts bus voltage
to 5V, which provides voltage supply to internal logic
and driver circuit. The NX2155H can operates at pro-
grammable frequency of 2MHz and employs loss-less
current limiting by sensing the Rdson of synchronous
MOSFET followed by hiccup feature.Feedback under
voltage triggers Hiccup.
Other features of the device are: Internal schottky di-
ode, thermal shutdown, 5V gate drive, adaptive
deadband control, internal digital soft start, 5VREG
undervoltage lock out and Shutdown capability via the
comp pin.
Note: XXX is date code. For example, 841 means that this NX2155H is packaged in the 41th week of
2008
SINGLE POWER SUPPLY SYNCHRONOUS PWM CONTROLLER
NX2155HCUPTR
Device
4.7u
4.22k
0.1u
5
7 RT
6
8
VIN
5VREG
COMP
Temperature
0 to 70
GND(PAD)
DESCRIPTION
o
C
Figure1 - Typical application of 2155H
HDRV
LDRV
OCP
BST
SW
FB
MSOP-EP-10L
3
2
1
10
4
9
Package
0.1u
1n
6k
10p
15k
n
n
n Programmable operational frequency of 2MHz
n Internal Digital Soft Start Function
n Less than 50 nS adaptive deadband
n
n Pb-free and RoHS compliant
n
n
n
n
n
n
M1
AO6800
12V to 3.3V, 2.5V or 1.8V
Single supply voltage from 8V to 22V
Internal 5V regulator
Current limit triggers hiccup by sensing Rdson of
Synchronous MOSFET
LCD TV
Graphic Card on board converters
Memory Vddq Supply in mother board applications
On board DC to DC such as
Hard Disk Drive
Set Top Box
1u
10u
Package Marking
180p
300
NX155HXXX
ORDERING INFORMATION
TYPICAL APPLICATION
+12V
VIN
49.9k
9.53k
2 x (10uF,10V,X5R)
ADVANCED DATA SHEET
APPLICATIONS
Pb-Free
Pb Free Product
Yes
FEATURES
NX2155H
+5V@2A
VOUT
1

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nx2155h Summary of contents

Page 1

... RT 8 COMP GND(PAD) Device Temperature NX2155HCUPTR Note: XXX is date code. For example, 841 means that this NX2155H is packaged in the 41th week of 2008 Rev.1.1 04/16/09 n Single supply voltage from 8V to 22V n Internal 5V regulator n Programmable operational frequency of 2MHz n Internal Digital Soft Start Function ...

Page 2

... OCP FB COMP RT SYM Test Condition V REF V =8V to 22V in 5V REG rising V =9V to 22V switching Switching with HDRV and LDRV open @2.2MHz NX2155H = Followings are bypass Low duty cycle A Min TYP MAX Units 0.8 V 0.784 0.816 0 4.75 5 ...

Page 3

... I=200mA sink THdrv(Rise) THdrv(Fall) Tdead(L to Ldrv going Low to Hdrv H) going High, 10%-10% R (Ldrv) I=200mA source R (Ldrv) I=200mA sink TLdrv(Rise) TLdrv(Fall) Tdead going Low to Ldrv L) going High, 10% to 10% forward current=20mA NX2155H Min TYP MAX Units 6 7.5 0.6 V 400 uS 2250 kHz 1.5 V 1.4 1 ...

Page 4

... This pin is connected to the source of the high side MOSFET and provides return 1 SW path for the high side driver. High side MOSFET gate driver. 2 HDRV Ground pin. PAD GND Low side MOSFET gate driver. 4 LDRV Oscillator's frequency can be set by using an external resistor from this pin GND. Rev.1.1 04/16/09 PIN DESCRIPTION NX2155H 4 ...

Page 5

... BLOCK DIAGRAM 5V VIN Regulator 5VREG 1.25V Bias Generator COMP 0.3V RT START 0.8V Digital ramp start Up FB COMP START GND Figure 2 - Simplified block diagram of the NX2155H Rev.1.1 04/16/09 UVLO 0.8V UVLO POR START OC OVP OSC Thermal S Q Shutdown R Hiccup Logic 0.6V CLAMP 1.3V CLAMP START NX2155H BST HDRV ...

Page 6

... R8 4.7u 2 HDRV OCP R1 6k 4.22k 4 LDRV 15k COMP * R7 and C7 are optional. Figure 3 - Simplified demoboard schematic of NX2155H Rev.1.1 04/16/09 sdfd CIN2 CIN1 10uF,16V 0.1uF M1B AO6800 HDRV BRL3225T1R0M COUT1 R7 10uF,16V 10 M1A AO6800 LDRV 1 C7 470p GND C6 ...

Page 7

... Rev.1.1 04/16/09 Reference Part 0.1u 4.7uF,6.3V,X5R 180p 1n 10p 470p 10uF,16V,X5R 10uF,10V,X5R BRL3225T1R0M AO6800 4.22k 6k 300 49.9k 9.53k 15k 10 0 NX2155H/MSOP-EP10 NEXSEM INC. NX2155H Manufacturer TAIYO YUDEN AOS 7 ...

Page 8

... SW 10V/DIV, CH4 OUTPUT CURRENT 2A/DIV) Fig.6 OCP protection during output short(CH1 VOUT 2V/DIV, CH4 OUTPUT CURRENT 5A/DIV) 100.00% 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% 0 500 1000 1500 Iout (mA) Fig.8 Output efficiency Rev.1.1 04/16/09 Fig.5 Startup( CH1 VOUT 2V/DIV) Fig.7 Output dynamic response(CH1 VOUT AC 200mV/DIV, CH4 OUTPUT CURRENT 500mA/DIV) 2000 2500 NX2155H 8 ...

Page 9

... Demoboard Layout Rev.1.1 04/16/09 Figure 9 Top layer Figure 10 Ground layer NX2155H 9 ...

Page 10

... Rev.1.1 04/16/09 Figure 11 Power layer Figure 12 Bottom layer NX2155H 10 ...

Page 11

... C4 0. HDRV 30k R1 10 OCP 3k 4 LDRV 30k C22 33p C21 1n 8 COMP Figure 13 - Simplified demoboard schematic of NX2155H Rev.1.1 04/16/09 BUS C18 100u/16v C9 C10 22u/25V 22u/25V M1 HDRV DO5010H-222MLD M2 R17 LDRV 4 2.15 C13 1000p R9 100k R8 C23 R10 19 ...

Page 12

... C22 9 1 C23 R3, R10 18 1 R17 Rev.1.1 04/16/09 Part Manufacturer 0.1u 4.7u 22u/25V/X5R 1000p 47uF/6.3V/X5R 100u/16v 1n 33p 220p DO5010H-222MLD COILCRAFT BSC119N03S INFINEON BSC029N025S INFINEON 3k 30k 750 100k 19.1k 2.15 NX2155/MSOP-EP10 NEXSEM INC. NX2155H 12 ...

Page 13

... CH4 INDUCTOR CURRENT 5A/DIV) Fig.16 OCP protection during output short(CH2 VOUT 2V/DIV, CH4 OUTPUT CURRENT 5A/DIV) Fig.18 Output efficiency Rev.1.1 04/16/09 Fig.15 Startup( CH1 VOUT 2V/DIV, CH4 INDUCTOR CURRENT 5A/DIV) Fig.17 Output dynamic response(CH2 VOUT AC 200mV/DIV, CH4 OUTPUT CURRENT 5A/DIV) NX2155H 13 ...

Page 14

... RIPPLE ...( OUT where F the compensator. Their locations are shown in figure 20. The transfer function of type III compensator for transconductance amplifier is given by OUT NX2155H o phase shift , o and the gain crossing 0dB with - 1 ...( ...( ...

Page 15

... Gain For this type of compensator <F <<F LC ESR Ve power stage loop gain F ESR Figure 21 - Bode plot of Type II compensator NX2155H ... ( ... ( ... ( ...

Page 16

... The frequency can be set by external Rt resistor. and R selection The relationship between frequency and RT pin is shown as follows. 2500 2000 1500 1000 500 0 3 Figure 25 - Frequency versus Rt resistor NX2155H R DSON +V OCP SW vbus I OCP OCP SW R OCP R OCP DSON NX2155H Frequency Rt(kohm ...

Page 17

... MSOP 10 PIN WITH EXPOSED PAD OUTLINE DIMENSIONS NOTE: ALL DIMENSIONS ARE DISPLAYED IN INCHES. Rev.1.1 04/16/09 NX2155H 17 ...

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