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Evaluation board available.
NEXSEM
HIGH SPEED 5V SYNCHRONOUS MOSFET DRIVER
DESCRIPTION
The NX3101 is a high frequency MOSFET driver designed
to drive two N-Channel MOSFETs in a synchronous rectified Step Down(BUCK) regulator topology. This driver
combined with other NEXSEM controllers such as NX2511
or NX2517 2 to 4 phase controller ICs makes a high
efficiency high performance Multiphase regulator designed for latest Microprocessor Vcore power as well as
other high current regulator applications. The IC is powered by a single 5V supply and its ultra low resistance
drivers minimizes switching losses for high frequency
applications using high gate capacitance MOSFETs. The
NX3101 features 0.44 ohm sink resistance for the lower
gate driver capable of holding the lower MOSFET gate
off during SW node fast dv/dt rise time, preventing shoot
through power loss.
NX3101
PRELIMINARY DATA SHEET
Pb Free Product
FEATURES
n Bus voltage operation from 3V to 25V
n High Peak Current Drive Capability
(Lower Driver Sink Resistance 0.44 ohm)
n High Frequency Operating Range(up to 2MHz)
n Minimal Propagation Delay
n Adaptive Non-overlap Control
n Output disable(ODB) signal turns both outputs
off
n Pb-free and RoHS compliant
APPLICATIONS
n Desktop and Notebook Microprocessor Vcore
regulator applications
n High Current Multiphase Converter
n High Efficiency / High Current Graphic Vcore
Multiphase
PWM
Controller
(eg.NX2511)
START
PWM1
PWM2
+5V
1uF
3
2
D1
C3
4 1
Vcc
ODB
IN
BST
Hdrv
SW
NX3101
Ldrv
C6
0.1uF
8
7
5
Gnd
6
Figure1 - Typical application of 3101
TYPICAL APPLICATION
L2 1uH
C5
1uF
M1
L1 1.5uH 1.5mohm
M2
Cin
2200uF
470uF
Co
8 x 1500uF,11mohm
C4
Vout
@VCORE
+12V
Rev. 2.1
04/24/06
ORDERING INFORMATION
Device Temperature Package Pb-Free
NX3101CSTR 0 to 70oC SOIC-8L Yes
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NEXSEM
CW
θ≈130/
PARAMETERS
SYM
TEST CONDITIONS
MIN
TYP
MAX
UNITS
VBST=12V, IN=5V
0.5
2
CL=0
CL=3nF
Shutdown Mode
ODB Threshold (Low)
ODB(L)
0.8
V
IN
Input Voltage low
IN(L)
0.8
V
bias-ODB
Vcc Quiescent Current Operating
NX3101
ABSOLUTE MAXIMUM RATINGS
Vcc to GND & BST to SW Voltage ................... 6.5V
BST to GND Voltage ...................................... 35V
SW to GND Voltage ...................................... 35V
ODB & IN to GND Voltage ............................... 6.5V
Storage Temperature Range ............................. -65oC to 150oC
Operating Junction Temperature Range ............. -40oC to 125oC
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
8-PIN PLASTIC SOIC (S)
o
8
HDrv
7
SW
6
GND
5
LDrv
BST
IN
ODB
VCC
JA
1
2
3
4
ELECTRICAL SPECIFICATIONS
Unless otherwise specified, these specifications apply over VCC =BST= 5V, SW=GND=0V, ODB=VCC, and TA =
0 to 125oC. Typical values refer to TA = 25oC.
Vcc Supply
Iq mA
Mode
VBST=12V, IN=0V 0.5 2
IN=Swch at 500Khz, 50% DC,
IN=Swch at 500Khz, 50% DC,
TBD
TBD
Vcc Quiescent Current
ODB
ODB Threshold (High) ODB(H) 2.4 V
ODB Current Ienb -2 2 uA
Propagation delay time Tprop 15 ns
Input voltage High IN (H) 2.4 V
Input Current I
Rev. 2.1
04/24/06
ODB=0V 0.5Iqsd
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2 uA
-2 2 uA
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NEXSEM
PARAMETERS
SYM
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Rise Time
THDrv(Rise)
10% to 90%
25 ns
Current
Current
Rise Time
TLDrv(Rise)
10% to 90%
25 ns
High, 10% to 10%
High
going High, 10% to 10%
Current
Current
High Side driver(CL=3300pF)
Output Impedance, Sourcing
R
(Hdrv) 0.85
source
NX3101
ohm
Output Impedance , Sinking
Fall Time THDrv(Fall) 90% to 10% 20 ns
Deadband Time Tdead(L to H) 30
Propagation Delay Tdelay(H) 10 ns
Low Side Driver(CL=3300pF)
Output Impedance, Sourcing
Output Impedance , Sinking
Fall Time TLDrv(Fall) 90% to 10% 20 ns
Deadband Time Tdead(H to L) 20
Propagation Delay Tdelay(L) 10 ns
R
(Hdrv) 0.65 ohm
sink
LDRV going Low to HDRV
IN going HI to LDRV going
R
(Ldrv) 0.85 ohm
source
R
(Ldrv) 0.5 ohm
source
SW going Low to LDRV going
IN going Low to LDRV going
Low
ns
ns
Rev. 2.1
04/24/06
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NEXSEM
PIN DESCRIPTIONS
Pin# Pin Symbol Pin Description
1 BST Bootstrap Pin. A capacitor is connected between BST and SW pins to generate the
floating bootstrap voltage for High-side Driver. The capacitor value is typically between
0.1uf to 1uF.
2 IN PWM input signal to the MOSFET drivers.
3 ODB Output disable pin. When high the internal circuitry is enabled. When low both high side
and low side drivers are turned off.
4 VCC Biasing supply both for the IC and low side driver, a minimum of 1uF ceramic cap should
be connected between this pin and PGND.
5 LDRV Output driver for low side MOSFET.
6 GND Power ground.
7 SW Switching point, this pin connects to the junction of external high-side and low-side
MOSFETs.
8 HDRV Output drive for high-side MOSFET.
NX3101
Rev. 2.1
04/24/06
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NEXSEM
NX3101
Figure 2 - Hdrv peak current
Figure 3 - Ldrv peak current
Rev. 2.1
04/24/06
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