NX9548
7A SINGLE CHANNEL MOBILE PWM SWITCHING REGULATOR
TARGET SPECIFICATION
Pb Free Product
FEATURES
DESCRIPTION
The NX9548 is buck switching converter in multi chip Internal Boost Schottky Diode
module designed for step down DC to DC converter in Ultrasonic mode operation available
portable applications. It is optimized to convert single Bus voltage operation from 4.5V to 20V
supply up to 20V bus voltage to as low as 0.75V outputLess than 1uA shutdown current with Enable low
voltage.The output current can be up to 7A. It can be Excellent dynamic response with constant on time
control
selected to operate in synchronous mode or non-synchronous mode to improve the efficiency at light load. Selectable between Synchronous CCM mode and
diode emulation mode to improve efficiency at light
Constant on time control provides fast response, good
load
line regulation and nearly constant frequency under wide
voltage input range. Over current protection and FB UVLOProgrammable switching frequency
followed by latch feature. Other features includes: inter- Current limit and FB UVLO with latch off
nal boost schottky diode, 5V gate drive capability
, power Over voltage protection with latch off
good indicator, over current protection, over voltage protection and adaptive dead band control.NX9548 is avail- UMPC, Notebook PCs and Desknotes
able in 5x5 MCM package.
Tablet PCs/Slates
APPLICATIONS
PGOOD
PGOOD
On board DC to DC such as
12V to 3.3V, 2.5V or 1.8V
Hand-held portable instruments
TYPICAL APPLICATION
TON
1M
1n
100k
VIN 8V~20V
D1
2x10uF
PVCC
5V
1u
VCC
1u
ENSW
/MODE
NX 9 5 48
10
HG
BST
1u
3.3uH
S1
D2
Vout 1.5V/7A
2R5TPE330MC
330uF
10k
OCP
VOUT
330p
FB
HDRV
GND
4.7
7.5k
7.5k
S2
Figure 1 - Typical application of 9548
ORDERING INFORMATION
Device
NX9548CMTR
Rev.0.1
03/06/12
Temperature
0 to 70oC
Package
5X5 MCM-32L
Pb-Free
Yes
1
NX9548
ABSOLUTE MAXIMUM RATINGS
VCC,PVCC to GND & BST to SW voltage ........... -0.3V to 6.5V
TON to GND ................................................. .... -0.3V to 28V
HDRV to SW Voltage ....................................... -0.3V to 6.5V
D1 to S1and D2 to S2 ........................................ 30V
All other pins .................................................... -0.3V to VCC+0.3V or 6.5V
Storage Temperature Range ............................... -65oC to 150oC
Operating Junction Temperature Range ............... -40oC to 125oC
ESD Susceptibility ........................................... 2kV
Power Dissipation ............................................. Internally Limited by OTP
CAUTION: Stresses above those listed in "ABSOLUTE MAXIMUM RA
TINGS", 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
VCC
FB
PGOOD
GND
HG
D1
D1
D1
32-LEAD PLASTIC MCM 5 x 5
32 31 30 29 28 27 26 25
24 TON
S1
1
S1
2
S1
3
D1
4
21 GND
D2
5
20 BST
D2
6
D2
7
D2
8
D1
(PAD2)
22 ENSW/MODE
19 D2
D2
(PAD3)
18
HDRV
17 NC
OCP
PVCC
S2
S2
S2
S2
10 11 12 13 14 15 16
S2
S2
9
Rev.0.1
03/06/12
23 VOUT
GND
(PAD1)
2
NX9548
ELECTRICAL SPECIFICATIONS
Unless otherwise specified, these specifications apply over Vcc = 5V
, VIN = 12V andTA= 0 to 70oC. Typical values
o
refer to TA = 25 C. Low duty cycle pulse testing is used which keep
s junction and case temperatures equal to the
ambient temperature.
PARAMETER
SYM
Te st Condition
Min
TYP
MAX
Units
20
V
VIN
recommended voltage range
4.5
Shut down current
VCC,PVCC Supply
Input voltage range
ENSW = GND
V in
4.5
Operating quies cent c urrent
FB=0.85V, ENSW =5V
Shut down current
VCC UV LO
Under-voltage Loc kout
threshold
Falling V CC threshold
ON a nd OFF tim e
TON operating c urrent
ENSW
= GND
ON -time
Minimum off time
FB volta ge
Internal FB voltage
Input bias c urrent
Line regulation
OUTPUT volta ge
Output range
VOUT s hut down discharge
resistance
Soft start time
PGOOD
PGOOD high rising threshold
PGOOD delay after s oftstart
PGOOD propagation delay
filter
PGOOD hy steresis
PGOOD output s witch
impedance
PGOOD leakage current
ENSW /MODE th re shold
a nd bia s curre nt
V C C _UVLO
V
VIN= 15V, Rton= 1Mohm
=
IN 9V,VOUT
= 0.75V,Rton
=1Mohm
Vref
VCC from 4.5V to 5.5V
Synchronous M ode
Shutdown m ode
Input bias c urrent
Rev.0.1
03/06/12
5.5
1.8
4.1
3.9
V
4.5
4.3
A
V
V
uA
312
380
390
590
468
800
ns
ns
0.739
0.75
200
0.761
1
V
nA
%
5
V
-1
ENSW /MODE=GND
NOTE1
NOTE1
13
ENSW /MODE
= VCC
ENSW /MODE
= GND
u
15
0.75
Leave it open or use limits
in s pec
uA
mA
1
3.9
3.7
PFM/Non S ynchronous M ode
Ultrasonic M ode
1
30
1.5
ohm
ms
90
1.6
% V ref
ms
2
5
us
%
1
ohm
uA
80%
VCC
60%
VCC
2
0
-
5
5
VCC+
0.3V
80%
VCC
60%
VCC
0.8
u
V
V
V
V
A
uA
3
NX9548
PARAMETER
SYM
Te st Condition
Min
TYP
MAX
Units
SW ze ro cross com pa ra tor
Offset voltage
Curre nt Lim it
Ocset s etting c urrent
Ove r te m pe ra ture
Threshold
5
20
N
OTE1
Hysteresis
Unde r volta ge
FB threshold
Ove r volta ge
Over voltage tripp point
Inte rna l S chottky Diode
Forward voltage drop
Ouput Sta ge
High S ide M OSFET RD SON
Low S ide MOSFET R D SON
Output Current
forward c urrent= 50mA
24
mV
28
uA
155
o
C
15
o
C
70
% Vref
125
% Vref
500
mV
23
20
7
mohm
mohm
A
NOTE1: This parameter is guaranteed by design but not tested in production(GBNT).
Rev.0.1
03/06/12
4
NX9548
PIN DESCRIPTIONS
PIN #
1-3
PIN SYMBOL
PIN DESCRIPTION
S1
Source of high side MOSFET.These pins must be connected directly to the drain of
low side MOSFET via a plane connection.
4,30-32
PAD2
D1
Drain of high side MOSFET.
5-8,19,
PAD3
D2
Drain of low side MOSFET and the controller pin out SW.
9-14
S2
Source of low side MOSFET and need to be directly connected to power ground via
multiple vias.
15
PVCC
This pin provides the voltage supply to the lower MOSFET drivers. Place a high
frequency decoupling capacitor 1uF X5R from this pin to GND.
16
OCP
This pin is connected to the drain of the external low side MOSFET via resistor and
is the input of the over current protection(OCP) comparator. An internal current source
is flown from this pin to the external resistor which sets the OCP voltage across the
Rdson of the low side MOSFET. Current limit point is this voltage divided by the Rdson. Once this threshold is reached the chip is latched out.
17
NC
18
HDRV
20
BST
22
ENSW/
MODE
Switching converter enable input. Connect to VCC for PFM/Non synchronous mode,
connected to an external resistor divider equals to 70%VCC for ultrasonic, connected to GND for shutdown mode, floating or connected to 2V for the synchronous
mode.
23
VOUT
This pin is directly connected to the output of the switching regulator and senses the
VOUT voltage. An internal MOSFET discharges the output during turn off.
24
TON
VIN sensing input. A resistor connects from this pin to VIN will set the frequency. A
1nF capacitor from this pin to GND is recommended to ensure the proper operation.
25
VCC
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.
26
FB
27
PGOOD
21,28
PAD1
GND
29
HG
Rev.0.1
03/06/12
Not used.
High side gate driver output which needs to be connected to high side MOSFET gate
HG pin. A small value resistor may be placed between two pins to slow down the high
side MOSFET, reducing the ringing on SW nodes.
This pin supplies voltage to high side FET driver. A minimum high freq 0.47uF ceramic capacitor is placed as close as possible to and connected to this pin and
respected pin 19.A 4.7ohm resister is recommended in series with this capacitor.
This pin is the error amplifiers inverting input. This pin is connected via resistor
divider to the output of the switching regulator to set the output DC voltage from
0.75V to 3.3V.
PGOOD indicator for switching regulator. It requires a pull up resistor to Vcc or
lower voltage. When FB pin reaches 90% of the reference voltage PGOOD transitions from LO to HI state.
Ground pin.
High side MOSFET gate.
5
NX9548
BLOCK DIAGRAM
BST
HDRV HG
D1
VCC
Bias
TON
4.3/4.1
ON time
pulse
genearation
VOUT
Disable_B
Thermal
shutdown
POR
start
ODB
HD
R
S
FET Driver
HD_IN
Q
S1
D2
FB
Mini offtime
400ns
OCP_COMP
S2
VREF=0.75V
start
POR
FBUVLO_latch
soft start
Diode
emulation
HD
PVCC
VCC
ENSW
/MODE
1M
1M
Disable
MODE
SELECTION
PFM_nonultrasonic
Sync
OCP
FB
1.25*Vref/0.7VREF OCP_COMP
OVP
GND
FB
FBUVLO_latch
PGOOD
0.7*Vref
SS_finished
VOUT
VOUT
start
0.9*Vref
Figure 2 - Simplified block diagram of the NX9548
Rev.0.1
03/06/12
6
NX9548
Demoboard design and waveforms
sdfd
27 PGOOD
PGOOD
TON
R6
10k
15
5V
C6
1u
C7
1u
PVCC
25 VCC
ENSW
22 /MODE
29
18
HG
HDRV
NX9548
R5 10
D1
BST
24
R1 1M
C3
1n
4,30-32,PAD2
C1
2 x 4.7uF,25V,X5R
20
S1 1-3
5-8,19,PAD3
D2
VOUT
C2
10uF,25V,X5R
R6 4.7
C4
1u
OCP 16
VIN 8V~20V
DO5010H-332MLD
L1 3.3uH
Vout 1.5V/7A
2R5TPE330MC
C5 330uF
R2
10k
23
FB 26
C8
330p
GND
S2
9-14
21,28,PAD1
R3
7.5k
R4
7.5k
Figure 3 - Demoboard schematic of NX9548
Rev.0.1
03/06/12
7
NX9548
Bill of Materials
Item
1
2
3
4
5
6
7
8
9
10
11
12
13
Rev.0.1
03/06/12
Quantity
2
1
1
3
1
1
1
2
2
1
1
1
1
Reference
C1
C2
C3
C4,C6,C7
C5
C8
R1
R2,R6
R3,R4
R5
R6
L1
U1
Part
4.7uF,25V,X5R
10uF,25V,X5R
1nF,50V,X7R
1uF,10V,X7R
2R5TPE330MC
330pF
1MEG
10k
7.5k
10
4.7
DO5010H-332MLD
NX9548
Manufacturer
SANYO
COILCRAFT
MICROSEMI
8
NX9548
Demoboard Waveforms
Fig.4 Startup when 5V is present and 12V bus is
started up, output load current is at 1.5A.
Fig.6 Shutdown when 12V bus is present and 5V is
shuted down.
Fig.8 5A step response(VIN=5V)
Rev.0.1
03/06/12
Fig.5 Startup when 12V bus is present and 5V is
started up.
Fig.7Output ripple (VIN=15V IOUT=1.2A)
Fig.9 5A step response(VIN=20V)
9
NX9548
NX9548 Efficiency
NX9548 Efficiency @ 12V VIN, 600kHz
100.00%
95.00%
90.00%
85.00%
VOUT=1.0V
VOUT=1.2V
VOUT=1.5V
VOUT=1.8V
80.00%
VOUT=3.3V
VOUT=5.0V
75.00%
70.00%
65.00%
50
1050
2050
3050
4050
5050
6050
7050
Load Current (mA)
Fig.11 Output efficiency at different output voltage
Fig. 11 efficiency data uses the same schematic as Fig.3, except for R1 is adjusted to have 600kHz working
frequency and inductor values specified in table below.
VOUT
1V, 1.2V, 1.5V
1.8V
3.3V
Rev.0.1
03/06/12
INDUCTOR
Coilcraft DO5010P‐152HC, 1.5uH
Coilcraft DO5010P‐222HC, 2.2uH
Coilcraft DO5010P‐332HC, 3.3uH
11
NX9548
APPLICATION INFORMATION
Symbol Used In Application Information:
VIN
- Input voltage
VOUT
- Output voltage
IOUT
- Output current
Output Inductor Selection
The value of inductor is decided by inductor ripple
current and working frequency. Larger inductor value normally means smaller ripple current. However if the in-
DVRIPPLE - Output voltage ripple
FS
is around 220kHz.
ductance is chosen too large, it brings slow response
- Working frequency
and lower efficiency. The ripple current is a design free-
DIRIPPLE - Inductor current ripple
dom which can be decided by design engineer according to various application requirements. The inductor value
Design Example
The following is typical application for NX9548, the
schematic is figure 1.
can be calculated by using the following equations:
LOUT =
VIN = 8 to 22V
( VIN -VOUT ON) × T
IRIPPLE
...(3)
IRIPPLE =k × IOUTPUT
VOUT=1.5V
FS=220kHz
where k is percentage of output current.
In this example, inductor from COILCRAFT
DO5010H-332 with L=3.3uH is chosen.
IOUT=7A
DVRIPPLE