IRF IRF7831PBF

PD - 95134B
IRF7831PbF
HEXFET® Power MOSFET
Applications
l High Frequency Point-of-Load
Synchronous Buck Converter for
Applications in Networking &
Computing Systems.
Benefits
l Very Low RDS(on) at 4.5V VGS
l Ultra-Low Gate Impedance
l Fully Characterized Avalanche Voltage
and Current
l 100% Tested for RG
l Lead-Free
VDSS
RDS(on) max
Qg (typ.)
30V 3.6m:@VGS = 10V
40nC
A
A
D
S
1
8
S
2
7
D
S
3
6
D
G
4
5
D
SO-8
Top View
Absolute Maximum Ratings
Max.
Units
VDS
Drain-to-Source Voltage
Parameter
30
V
VGS
Gate-to-Source Voltage
± 12
ID @ TA = 25°C
Continuous Drain Current, VGS @ 10V
21
ID @ TA = 70°C
Continuous Drain Current, VGS @ 10V
17
IDM
Pulsed Drain Current
170
PD @TA = 25°C
Power Dissipation
PD @TA = 70°C
Power Dissipation
TJ
Linear Derating Factor
Operating Junction and
TSTG
Storage Temperature Range
f
f
c
A
2.5
W
1.6
0.02
-55 to + 150
W/°C
°C
Thermal Resistance
Parameter
RθJL
RθJA
Junction-to-Drain Lead
Junction-to-Ambient
f
Typ.
Max.
Units
–––
20
°C/W
–––
50
Notes  through „ are on page 10
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1
6/30/05
IRF7831PbF
Static @ TJ = 25°C (unless otherwise specified)
Parameter
Min. Typ. Max. Units
V
Conditions
BVDSS
Drain-to-Source Breakdown Voltage
30
–––
–––
∆ΒVDSS/∆TJ
Breakdown Voltage Temp. Coefficient
–––
0.025
–––
V/°C Reference to 25°C, ID = 1mA
RDS(on)
Static Drain-to-Source On-Resistance
2.5
3.1
3.6
mΩ
3.0
3.7
4.4
VGS(th)
Gate Threshold Voltage
1.35
–––
2.35
V
Gate Threshold Voltage Coefficient
–––
- 5.7
–––
mV/°C
IDSS
Drain-to-Source Leakage Current
–––
–––
1.0
µA
–––
–––
150
Gate-to-Source Forward Leakage
–––
–––
100
Gate-to-Source Reverse Leakage
–––
–––
-100
VGS = 10V, ID = 20A
VGS = 4.5V, ID = 16A
∆VGS(th)
IGSS
VGS = 0V, ID = 250µA
e
e
VDS = VGS, ID = 250µA
VDS = 24V, VGS = 0V
VDS = 24V, VGS = 0V, TJ = 125°C
nA
VGS = 12V
VGS = -12V
gfs
Forward Transconductance
97
–––
–––
Qg
Total Gate Charge
–––
40
60
S
Qgs1
Pre-Vth Gate-to-Source Charge
–––
12
–––
Qgs2
Post-Vth Gate-to-Source Charge
–––
3.1
–––
Qgd
Gate-to-Drain Charge
–––
11
–––
ID = 16A
Qgodr
Gate Charge Overdrive
–––
14
–––
See Fig. 16
Qsw
Switch Charge (Qgs2 + Qgd)
–––
14
–––
Qoss
Output Charge
–––
22
–––
nC
RG
Gate Resistance
–––
1.4
2.5
Ω
td(on)
Turn-On Delay Time
–––
18
–––
VDD = 15V, VGS = 4.5V
tr
Rise Time
–––
10
–––
ID = 16A
td(off)
Turn-Off Delay Time
–––
17
–––
tf
Fall Time
–––
5.3
–––
Ciss
Input Capacitance
–––
6240
–––
Coss
Output Capacitance
–––
980
–––
Crss
Reverse Transfer Capacitance
–––
390
–––
VDS = 15V, ID = 16A
VDS = 15V
nC
ns
VGS = 4.5V
VDS = 16V, VGS = 0V
e
Clamped Inductive Load
VGS = 0V
pF
VDS = 15V
ƒ = 1.0MHz
Avalanche Characteristics
EAS
Parameter
Single Pulse Avalanche Energy
IAR
Avalanche Current
c
d
Typ.
Max.
Units
–––
100
mJ
–––
16
A
Diode Characteristics
Parameter
IS
Continuous Source Current
Min. Typ. Max. Units
–––
–––
2.5
–––
–––
170
(Body Diode)
ISM
A
Pulsed Source Current
(Body Diode)
c
Conditions
MOSFET symbol
showing the
integral reverse
VSD
Diode Forward Voltage
–––
–––
1.2
V
p-n junction diode.
TJ = 25°C, IS = 16A, VGS = 0V
trr
Reverse Recovery Time
–––
42
62
ns
TJ = 25°C, IF = 16A, VDD = 25V
Qrr
Reverse Recovery Charge
–––
31
47
nC
di/dt = 100A/µs
ton
Forward Turn-On Time
2
e
e
Intrinsic turn-on time is negligible (turn-on is dominated by LS+LD)
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IRF7831PbF
1000
VGS
10V
5.0V
4.5V
3.5V
3.0V
2.7V
2.5V
BOTTOM 2.25V
1000
VGS
10V
5.0V
4.5V
3.5V
3.0V
2.7V
2.5V
BOTTOM 2.25V
100
10
1
0.1
TOP
ID, Drain-to-Source Current (A)
ID, Drain-to-Source Current (A)
TOP
100
10
2.25V
1
20µs PULSE WIDTH
2.25V Tj = 25°C
0.01
0.1
0.1
1
10
100
0.1
VDS, Drain-to-Source Voltage (V)
1
10
100
VDS, Drain-to-Source Voltage (V)
Fig 1. Typical Output Characteristics
Fig 2. Typical Output Characteristics
1000.0
2.0
RDS(on) , Drain-to-Source On Resistance
ID, Drain-to-Source Current (Α)
20µs PULSE WIDTH
Tj = 150°C
100.0
(Normalized)
T J = 150°C
10.0
T J = 25°C
1.0
VDS = 15V
20µs PULSE WIDTH
0.1
2.0
2.5
3.0
3.5
VGS, Gate-to-Source Voltage (V)
Fig 3. Typical Transfer Characteristics
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ID = 20A
VGS = 10V
1.5
1.0
0.5
4.0
-60 -40 -20
0
20
40
60
80 100 120 140 160
T J , Junction Temperature (°C)
Fig 4. Normalized On-Resistance
Vs. Temperature
3
IRF7831PbF
100000
12
VGS = 0V,
f = 1 MHZ
Ciss = C gs + Cgd, C ds SHORTED
Crss = C gd
VGS, Gate-to-Source Voltage (V)
ID= 12A
C, Capacitance (pF)
Coss = Cds + Cgd
10000
Ciss
Coss
1000
Crss
10
8
6
4
2
0
100
1
10
0
100
40
60
80
100
Fig 6. Typical Gate Charge Vs.
Gate-to-Source Voltage
Fig 5. Typical Capacitance Vs.
Drain-to-Source Voltage
1000.0
1000
ID, Drain-to-Source Current (A)
ISD, Reverse Drain Current (A)
20
QG Total Gate Charge (nC)
VDS, Drain-to-Source Voltage (V)
100.0
OPERATION IN THIS AREA
LIMITED BY R DS(on)
100
T J = 150°C
10.0
1.0
T J = 25°C
100µsec
10
1msec
VGS = 0V
1
0.1
0.2
0.4
0.6
0.8
1.0
VSD, Source-toDrain Voltage (V)
Fig 7. Typical Source-Drain Diode
Forward Voltage
4
VDS= 24V
VDS= 15V
1.2
Tc = 25°C
Tj = 150°C
Single Pulse
0.1
1.0
10msec
10.0
100.0
1000.0
VDS , Drain-toSource Voltage (V)
Fig 8. Maximum Safe Operating Area
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IRF7831PbF
2.4
VGS(th) Gate threshold Voltage (V)
24
ID , Drain Current (A)
20
16
12
8
4
2.2
2.0
ID = 250µA
1.8
1.6
1.4
1.2
1.0
0
25
50
75
100
125
-75
150
-50
-25
0
25
50
75
100
125
150
T J , Temperature ( °C )
T J , Junction Temperature (°C)
Fig 10. Threshold Voltage Vs. Temperature
Fig 9. Maximum Drain Current Vs.
Case Temperature
Thermal Response ( Z thJA )
100
10
D = 0.50
0.20
0.10
0.05
1
0.02
0.01
τJ
0.1
R1
R1
τJ
τ1
R2
R2
R3
R3
R5
R5
τC
τ2
τ1
τ3
τ2
τ3
Ci= τi/Ri
C
0.01
R4
R4
τ4
τ5
τ4
τ5
τ
Ri (°C/W)
τi (sec)
0.514
2.445
20.64
17.80
8.604
0.000182
0.030949
0.36354
6.99
109
Notes:
1. Duty Factor D = t1/t2
2. Peak Tj = P dm x Zthja + Tc
SINGLE PULSE
( THERMAL RESPONSE )
0.001
1E-006
1E-005
0.0001
0.001
0.01
0.1
1
10
100
t1 , Rectangular Pulse Duration (sec)
Fig 11. Maximum Effective Transient Thermal Impedance, Junction-to-Ambient
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5
IRF7831PbF
D.U.T
RG
VGS
20V
DRIVER
L
VDS
+
V
- DD
IAS
A
0.01Ω
tp
Fig 12a. Unclamped Inductive Test Circuit
V(BR)DSS
EAS, Single Pulse Avalanche Energy (mJ)
500
15V
ID
11A
13A
BOTTOM 16A
TOP
400
300
200
100
0
tp
25
50
75
100
125
150
Starting T J, Junction Temperature (°C)
Fig 12c. Maximum Avalanche Energy
Vs. Drain Current
LD
I AS
VDS
Fig 12b. Unclamped Inductive Waveforms
+
VDD D.U.T
VGS
Current Regulator
Same Type as D.U.T.
Pulse Width < 1µs
Duty Factor < 0.1%
50KΩ
12V
Fig 14a. Switching Time Test Circuit
.2µF
.3µF
D.U.T.
+
V
- DS
VDS
90%
VGS
3mA
10%
IG
ID
Current Sampling Resistors
Fig 13. Gate Charge Test Circuit
6
VGS
td(on)
tr
td(off)
tf
Fig 14b. Switching Time Waveforms
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IRF7831PbF
D.U.T
Driver Gate Drive
ƒ
+
‚
„
•
•
•
•
D.U.T. ISD Waveform
Reverse
Recovery
Current
+
dv/dt controlled by RG
Driver same type as D.U.T.
ISD controlled by Duty Factor "D"
D.U.T. - Device Under Test
P.W.
Period
*

RG
D=
VGS=10V
Circuit Layout Considerations
• Low Stray Inductance
• Ground Plane
• Low Leakage Inductance
Current Transformer
-
-
Period
P.W.
+
VDD
+
-
Body Diode Forward
Current
di/dt
D.U.T. VDS Waveform
Diode Recovery
dv/dt
Re-Applied
Voltage
Body Diode
VDD
Forward Drop
Inductor Curent
ISD
Ripple ≤ 5%
* VGS = 5V for Logic Level Devices
Fig 15. Peak Diode Recovery dv/dt Test Circuit for N-Channel
HEXFET® Power MOSFETs
Id
Vds
Vgs
Vgs(th)
Qgs1 Qgs2
Qgd
Qgodr
Fig 16. Gate Charge Waveform
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7
IRF7831PbF
Power MOSFET Selection for Non-Isolated DC/DC Converters
Control FET
Synchronous FET
Special attention has been given to the power losses
in the switching elements of the circuit - Q1 and Q2.
Power losses in the high side switch Q1, also called
the Control FET, are impacted by the Rds(on) of the
MOSFET, but these conduction losses are only about
one half of the total losses.
The power loss equation for Q2 is approximated
by;
*
Ploss = Pconduction + Pdrive + Poutput
(
2
Ploss = Irms × Rds(on)
)
Power losses in the control switch Q1 are given
by;
+ (Qg × Vg × f )
Ploss = Pconduction+ Pswitching+ Pdrive+ Poutput
⎛Q
⎞
+ ⎜ oss × Vin × f + (Qrr × Vin × f )
⎝ 2
⎠
This can be expanded and approximated by;
Ploss = (Irms × Rds(on ) )
2
⎛
⎞ ⎛
Qgs 2
⎞
Qgd
+⎜I ×
× Vin × f ⎟ + ⎜ I ×
× Vin × f ⎟
ig
ig
⎝
⎠ ⎝
⎠
+ (Qg × Vg × f )
+
⎛ Qoss
× Vin × f ⎞
⎝ 2
⎠
This simplified loss equation includes the terms Qgs2
and Qoss which are new to Power MOSFET data sheets.
Qgs2 is a sub element of traditional gate-source
charge that is included in all MOSFET data sheets.
The importance of splitting this gate-source charge
into two sub elements, Qgs1 and Qgs2, can be seen from
Fig 16.
Qgs2 indicates the charge that must be supplied by
the gate driver between the time that the threshold
voltage has been reached and the time the drain current rises to Idmax at which time the drain voltage begins to change. Minimizing Qgs2 is a critical factor in
reducing switching losses in Q1.
Qoss is the charge that must be supplied to the output capacitance of the MOSFET during every switching cycle. Figure A shows how Qoss is formed by the
parallel combination of the voltage dependant (nonlinear) capacitance’s Cds and Cdg when multiplied by
the power supply input buss voltage.
8
*dissipated primarily in Q1.
For the synchronous MOSFET Q2, Rds(on) is an important characteristic; however, once again the importance of gate charge must not be overlooked since
it impacts three critical areas. Under light load the
MOSFET must still be turned on and off by the control IC so the gate drive losses become much more
significant. Secondly, the output charge Qoss and reverse recovery charge Qrr both generate losses that
are transfered to Q1 and increase the dissipation in
that device. Thirdly, gate charge will impact the
MOSFETs’ susceptibility to Cdv/dt turn on.
The drain of Q2 is connected to the switching node
of the converter and therefore sees transitions between ground and Vin. As Q1 turns on and off there is
a rate of change of drain voltage dV/dt which is capacitively coupled to the gate of Q2 and can induce
a voltage spike on the gate that is sufficient to turn
the MOSFET on, resulting in shoot-through current .
The ratio of Qgd/Qgs1 must be minimized to reduce the
potential for Cdv/dt turn on.
Figure A: Qoss Characteristic
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IRF7831PbF
SO-8 Package Outline
D
5
A
8
6
7
6
5
H
E
1
2
3
0.25 [.010]
4
A
e
e1
8X b
0.25 [.010]
MIL LIME T E RS
MIN
MAX
MIN
A
.0532
.0688
1.35
1.75
A1
.0040
.0098
0.10
0.25
b
.013
.020
0.33
0.51
c
.0075
.0098
0.19
0.25
D
.189
.1968
4.80
5.00
E
.1497
.1574
3.80
4.00
e
.050 B AS IC
1.27 B AS IC
e1
6X
INCHE S
DIM
B
MAX
.025 B AS IC
0.635 B AS IC
H
.2284
.2440
5.80
6.20
K
.0099
.0196
0.25
0.50
L
.016
.050
0.40
1.27
y
0°
8°
0°
8°
K x 45°
A
C
y
0.10 [.004]
A1
8X L
8X c
7
C A B
F OOT PR INT
NOT E S :
1. DIME NS IONING & T OL E R ANCING PE R AS ME Y14.5M-1994.
8X 0.72 [.028]
2. CONT R OL L ING DIME NS ION: MIL LIME T E R
3. DIME NS IONS AR E S HOWN IN MIL L IME T E R S [INCHE S ].
4. OU T L INE CONF OR MS T O JE DE C OU T L INE MS -012AA.
5 DIME NS ION DOE S NOT INCL UDE MOL D PROT RU S IONS .
MOL D PR OT RU S IONS NOT T O E XCE E D 0.15 [.006].
6 DIME NS ION DOE S NOT INCL UDE MOL D PROT RU S IONS .
MOL D PR OT RU S IONS NOT T O E XCE E D 0.25 [.010].
6.46 [.255]
7 DIME NS ION IS T HE L E NGT H OF L E AD F OR S OL DE R ING T O
A S UB S T R AT E .
3X 1.27 [.050]
8X 1.78 [.070]
SO-8 Part Marking
E XAMPLE : T HIS IS AN IRF 7101 (MOS F E T )
INT E R NAT IONAL
R E CT IF IE R
L OGO
XXXX
F 7101
DAT E CODE (YWW)
P = DE S IGNAT E S L E AD-F RE E
PRODU CT (OPT IONAL)
Y = LAS T DIGIT OF T HE YE AR
WW = WE E K
A = AS S E MB LY S IT E CODE
L OT CODE
PART NU MB E R
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9
IRF7831PbF
SO-8 Tape and Reel
TERMINAL NUMBER 1
12.3 ( .484 )
11.7 ( .461 )
8.1 ( .318 )
7.9 ( .312 )
FEED DIRECTION
NOTES:
1. CONTROLLING DIMENSION : MILLIMETER.
2. ALL DIMENSIONS ARE SHOWN IN MILLIMETERS(INCHES).
3. OUTLINE CONFORMS TO EIA-481 & EIA-541.
330.00
(12.992)
MAX.
14.40 ( .566 )
12.40 ( .488 )
NOTES :
1. CONTROLLING DIMENSION : MILLIMETER.
2. OUTLINE CONFORMS TO EIA-481 & EIA-541.
Notes:
 Repetitive rating; pulse width limited by
max. junction temperature.
‚ Starting TJ = 25°C, L = 0.76mH
RG = 25Ω, IAS = 16A.
ƒ Pulse width ≤ 400µs; duty cycle ≤ 2%.
„ When mounted on 1 inch square copper board
Data and specifications subject to change without notice.
This product has been designed and qualified for the Consumer market.
Qualifications Standards can be found on IR’s Web site.
IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310) 252-7105
TAC Fax: (310) 252-7903
Visit us at www.irf.com for sales contact information.6/05
10
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