NX9548 EVAL BOARD USER GUIDE
NX9548 EVALUATION BOARD
USER GUIDE
NX9548 9A Single Channel Mobile PWM Switching Regulator
Microsemi
NX9548 EVAL BOARD USER GUIDE
Table of Contents
Introduction to Product ..............................................................................................2
Key Features ..............................................................................................................3
Applications ...............................................................................................................3
Part Specific Information ...........................................................................................3
Schematic of Evaluation Board .................................................................................4
Layout of Evaluation Board .......................................................................................5
Bill of Material ...........................................................................................................8
Recommended Operating Condition........................................................................10
Efficiency .................................................................................................................11
Dynamic Load Response .........................................................................................12
Start up and Shut down ............................................................................................14
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Introduction to Product
The NX9548 is buck switching converter in multi chip module designed for step down DC to DC
converter in portable applications. It is optimized to convert single supply up to 24V bus voltage
to as low as 0.75V output voltage. The output current can be up to 9A.
It can be selected to operate in synchronous mode or non-synchronous mode to improve the
efficiency at light load. Constant on time control provides fast response, good line regulation and
nearly constant frequency under wide voltage input range. Over current protection and FB
UVLO followed by latch feature.
Other features includes: internal boost schottky diode, 5V gate drive capability, power good
indicator, over current protection, over voltage protection and adaptive dead band
control.NX9548 is available in 5x5 MCM package.
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Key Features

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






Internal Boost Schottky Diode
Ultrasonic Mode Operation Available
Bus Voltage Operation From 4.5V to 24V
Less Than 1uA Shutdown Current with Enable Low
Excellent Dynamic Response with Constant On Time Control
Selectable Between Synchronous CCM Mode and Diode Emulation Mode to Improve
Efficiency at Light Load
Programmable Switching Frequency
Current Limit and FB UVLO with Latch Off
Over Voltage Protection with Latch Off
Applications




UMPC, Notebook OCs and Desknotes
Tablet PCs/Slates
On Board DC to DC Such as 12V to 3.3V, 2.5V or 1.8V
Hand-Held portable Instruments
Part Specific Information
IC Part Number
Description
NX9548CMTR
Plastic 5mm x 5mm MCM – 32L
Evaluation Board Part Number
Description
NX9548 EVALUATION BOARD
Evaluation PCB for NX9548
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Schematic of Evaluation Board
Figure 1 Schematic of Evaluation Board
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Layout of Evaluation Board
Figure 2 Top Silk Screen
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Figure 3 Top Layer
Figure 4 Second Layer
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Figure 5 Third Layer
Figure 6 Bottom Layer
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Bill of Material
Item
1
2
3
4
5
MISCELLANEOUS COMPON ENTS
Part Description
Reference
Microsemi IC – NX9548
U1
Test Point
SW, PGOOD, DISABLESW
Terminal
5V, VOUT, VBUS, 5VGND,
GND
Scope Test Point
JVOUT
Jumper8_dual/100
JP3
Qty
1
3
5
1
1
CAPACITORS
Item
6
7
8
9
10
11
12
13
14
15
16
Part Description
1uF
10uF/25V
4.7uF/25V
1nF
0.1uF
0.1uF Aluminum Capacitor
25TQC33M
4.7uF/6.3V/X5R
2R5TPE330MC
330pF
470pF
Item
17
18
19
20
21
22
23
24
25
26
27
Part Description
1MOhm
10Ohm
10kOhm
2.15Ohm
0Ohm
10.5kOhm
100kOhm
7.5kOhm
60kOhm
40kOhm
1kOhm
Reference
C2, C17
C6
C7, C8
C10
C11, C23
C12
C13
C15
C16
C19
C24
Qty
2
1
2
1
2
1
1
1
1
1
1
Reference
R3
R5, R13
R7
R8
R12
R16
R17, R80, R81
R18
R78
R79
R82
Qty
1
2
1
1
1
1
3
1
1
1
1
RESISTORS
Microsemi
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NX9548 EVAL BOARD USER GUIDE
INDUCTOR
Item Part Description
27
DO5010H-332HC
Reference
L2
Qty
1
Reference
M1
Qty
1
Reference
D2(ADD ON)
Qty
1
MOSFET
Item Part Description
28
2N7002
DIODE
Item Part Description
29
MBR0530T1
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Recommended Operating Condition
Description
Input Voltage
Output Current
Operating Ambient Temperature
Non Synchronous Mode
Synchronous Mode
Shut Down Chip
Symbol
VIN
IOUT
TA
ENSW/MODE
ENSW/MODE
ENSW/MODE
Min
4.5
0
0
VCC
Floating or 2V
Pull to GND
Max
24
9
70
VCC
Unit
V
A
°C
Pull to GND
VOUT is Set by The Following Equation
VOUT = VFB * (1 + 7.5k / RFB) VFB=0.75V ( RFB = R18 )
12V
5V
Power Supply
Power Supply
LOAD
Figure 7 Power Supply and Load Connection
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Efficiency
+
NX9548 Efficiency @ 12V VIN, 600kHz
100
95
90
85
Efficiency (%)
80
75
70
65
60
55
VOUT=1.0V
VOUT=1.2V
VOUT=1.5V
VOUT=1.8V
VOUT=3.3V
VOUT=5.0V
50
0
1
2
3
4
5
6
7
Load Current (A)
Figure 8 Efficiency Plot of NX9548
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Dynamic Load Response
Step Response in PFM Mode When VIN=5V
Figure 9 Step response VIN=5V
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Step Response in PFM Mode When VIN=20V
Figure 10 Step response in PFM mode when VIN=20V
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Start up and Shut down
Start up and Shut down at No Load
Figure 11 Start up and Shut down, No Load
Microsemi
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NX9548 EVAL BOARD USER GUIDE
Start up When 12V Bus is Present and 5V is Started up
Figure 12 Start up when 12V bus is present and 5V is started up
Microsemi
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