that drives two N-channel MOSFETs in a synchronous
DC/DC converter with supply voltages up to 100V. This
powerful driver reduces switching losses in MOSFETs with
high gate capacitance.
The LTC4444 is configured for two supply-independent
inputs. The high side input logic signal is internally
level-shifted to the bootstrapped supply, which may
function at up to 114V above ground.
The LTC4444 contains undervoltage lockout circuits that
disable the external MOSFETs when activated. Adaptive
shoot-through protection prevents both MOSFETs from
conducting simultaneously.
For a similar driver in this product family, please refer to
the chart below.
PARAMETER
LTC4444
LTC4446
LTC4444-5
Shoot-Through Protection
Yes
No
Yes
Absolute Max TS
100V
100V
100V
MOSFET Gate Drive
7.2V to 13.5V 7.2V to 13.5V 4.5V to 13.5V
+
6.6V
6.6V
4V
V
CC
UV
6.15V
6.15V
3.55V
V
CC
UV
–
Bootstrap Supply Voltage to 114V
Wide V
CC
Voltage: 7.2V to 13.5V
Adaptive Shoot-Through Protection
2.5A Peak TG Pull-Up Current
3A Peak BG Pull-Up Current
1.2Ω TG Driver Pull-Down
0.55Ω BG Driver Pull-Down
5ns TG Fall Time Driving 1nF Load
8ns TG Rise Time Driving 1nF Load
3ns BG Fall Time Driving 1nF Load
6ns BG Rise Time Driving 1nF Load
Drives Both High and Low Side N-Channel MOSFETs
Undervoltage Lockout
Thermally Enhanced 8-Pin MSOP Package
APPLICATIONS
n
n
n
n
Distributed Power Architectures
Automotive Power Supplies
High Density Power Modules
Telecommunications
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
No R
SENSE
is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Protected by U.S. Patents, including 6677210.
TYPICAL APPLICATION
High Input Voltage Buck Converter
V
CC
7.2V TO 13.5V
BOOST
V
CC
PWM1
(FROM CONTROLLER IC)
PWM2
(FROM CONTROLLER IC)
TINP
BINP
GND
4444 TA01a
LTC4444 Driving a 1000pF Capacitive Load
BINP
5V/DIV
BG
10V/DIV
TINP
5V/DIV
TG-TS
10V/DIV
20ns/DIV
4444 TA01b
V
IN
100V
(ABS MAX)
TG
LTC4444
TS
BG
V
OUT
4444fb
1
LTC4444
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
TINP
BINP
V
CC
BG
1
2
3
4
9
GND
8
7
6
5
TS
TG
BOOST
NC
Supply Voltage
V
CC
......................................................... –0.3V to 14V
BOOST – TS ........................................... –0.3V to 14V
TINP Voltage ..................................................–2V to 14V
BINP Voltage ..................................................–2V to 14V
BOOST Voltage .........................................–0.3V to 114V
TS Voltage .................................................. –5V to 100V
Operating Junction Temperature Range
(Notes 2, 3) ........................................ –55°C to 150°C
Storage Temperature Range ..................–65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
MS8E PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 40°C/W,
θ
JC
= 10°C/W (NOTE 4)
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC4444EMS8E#PBF
LTC4444IMS8E#PBF
LTC4444HMS8E#PBF
LTC4444MPMS8E#PBF
TAPE AND REEL
LTC4444EMS8E#TRPBF
LTC4444IMS8E#TRPBF
LTC4444HMS8E#TRPBF
LTC4444MPMS8E#TRPBF
PART MARKING*
LTDBF
LTDBF
LTDBF
LTDBF
PACKAGE DESCRIPTION
8-Lead Plastic MSOP
8-Lead Plastic MSOP
8-Lead Plastic MSOP
8-Lead Plastic MSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–55°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
ELECTRICAL CHARACTERISTICS
SYMBOL
V
CC
I
VCC
UVLO
PARAMETER
Operating Voltage
DC Supply Current
Undervoltage Lockout Threshold
Gate Driver Supply, V
CC
The
l
denotes the specifications which apply over the full operating junction
temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
CC
= V
BOOST
= 12V, V
TS
= GND = 0V, unless otherwise noted.
CONDITIONS
MIN
7.2
TINP = BINP = 0V
V
CC
Rising
V
CC
Falling
Hysteresis
TINP = BINP = 0V
BINP Ramping High
BINP Ramping Low
TINP Ramping High
TINP Ramping Low
l
l
l
l
l
l
TYP
MAX
13.5
UNITS
V
μA
V
V
mV
μA
V
V
V
V
μA
4444fb
350
6.00
5.60
6.60
6.15
450
0.1
2.25
1.85
2.25
1.85
2.75
2.3
2.75
2.3
±0.01
550
7.20
6.70
Bootstrapped Supply (BOOST – TS)
I
BOOST
V
IH(BG)
V
IL(BG)
V
IH(TG)
V
IL(TG)
I
TINP(BINP)
DC Supply Current
BG Turn-On Input Threshold
BG Turn-Off Input Threshold
TG Turn-On Input Threshold
TG Turn-Off Input Threshold
Input Pin Bias Current
2
3.25
2.75
3.25
2.75
±2
Input Signal (TINP BINP)
,
2
LTC4444
ELECTRICAL CHARACTERISTICS
SYMBOL
V
OH(TG)
V
OL(TG)
I
PU(TG)
R
DS(TG)
V
OH(BG)
V
OL(BG)
I
PU(BG)
R
DS(BG)
t
PLH(TG)
t
PHL(TG)
t
PLH(BG)
t
PHL(BG)
t
r(TG)
t
f(TG)
t
r(BG)
t
f(BG)
PARAMETER
TG High Output Voltage
TG Low Output Voltage
TG Peak Pull-Up Current
TG Pull-Down Resistance
BG High Output Voltage
BG Low Output Voltage
BG Peak Pull-Up Current
BG Pull-Down Resistance
TG Low-High Propagation Delay
TG High-Low Propagation Delay
BG Low-High Propagation Delay
BG High-Low Propagation Delay
TG Output Rise Time
TG Output Fall Time
BG Output Rise Time
BG Output Fall Time
10% – 90%, C
L
= 1nF
10% – 90%, C
L
= 10nF
10% – 90%, C
L
= 1nF
10% – 90%, C
L
= 10nF
10% – 90%, C
L
= 1nF
10% – 90%, C
L
= 10nF
10% – 90%, C
L
= 1nF
10% – 90%, C
L
= 10nF
I
BG
= –10mA, V
OH(BG)
= V
CC
– V
BG
I
BG
= 100mA
l
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating junction
temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
CC
= V
BOOST
= 12V, V
TS
= GND = 0V, unless otherwise noted.
CONDITIONS
I
TG
= –10mA, V
OH(TG)
= V
BOOST
– V
TG
I
TG
= 100mA, V
OL(TG)
= V
TG
–V
TS
l
l
l
MIN
TYP
0.7
120
MAX
UNITS
V
High Side Gate Driver Output (TG)
250
2.5
mV
A
Ω
V
125
1.25
50
45
40
35
mV
A
Ω
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
1.7
2.5
1.2
0.7
55
Low Side Gate Driver Output (BG)
2
3
0.55
25
22
19
14
8
80
5
50
6
60
3
30
Switching Time [BINP (TINP) is Tied to Ground While TINP (BINP) is Switching. Refer to Timing Diagram]
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
The LTC4444 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC4444E is guaranteed to meet specifications from 0°C
to 85°C junction temperature. Specifications over the –40°C to 125°C
operating junction temperature range are assured by design, charac-
terization and correlation with statistical process controls. The LTC4444I
is guaranteed over the –40°C to 125°C operating temperature range, the
LTC4444H is guaranteed over the –40°C to 150°C operating temperature
range and the LTC4444MP is tested and guaranteed over the full –55°C to
150°C operating junction temperature range. High junction temperatures
degrade operating lifetimes; operating lifetime is derated for junction
temperatures greater than 125°C. Note that the maximum ambient
temperature consistent with these specifications is determined by specific
operating conditions in conjunction with board layout, the rated package
thermal impedance and other environmental factors.
Note 3:
The junction temperature (T
J
, in °C) is calculated from the ambient
temperature (T
A
, in °C) and power dissipation (P
D
, in watts) according to
the formula:
T
J
= T
A
+ (P
D
•
θ
JA
)
where
θ
JA
(in °C/W) is the package thermal impedance.
Note 4:
Failure to solder the exposed back side of the MS8E package to the
PC board will result in a thermal resistance much higher than 40°C/W.
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