that drives two N-channel MOSFETs in a DC/DC converter
with supply voltages up to 100V. The powerful driver ca-
pability reduces switching losses in MOSFETs with high
gate capacitance. The LTC4446’s pull-up for the top gate
driver has a peak output current of 2.5A and its pull-down
has an output impedance of 1.2Ω. The pull-up for the bot-
tom gate driver has a peak output current of 3A and the
pull-down has an output impedance of 0.55Ω.
The LTC4446 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 LTC4446 contains undervoltage lockout circuits that
disable the external MOSFETs when activated.
The LTC4446 is available in the thermally enhanced 8-lead
MSOP package.
The LTC4446 does not have adaptive shoot-through pro-
tection. For similar drivers with adaptive shoot-through
protection, please refer to the chart below.
PARAMETER
LTC4446
LTC4444
LTC4444-5
Shoot-Through Protection
No
Yes
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 Up to 114V
Wide V
CC
Voltage: 7.2V to 13.5V
2.5A Peak Top Gate Pull-Up Current
3A Peak Bottom Gate Pull-Up Current
1.2Ω Top Gate Driver Pull-Down
0.55Ω Bottom Gate Driver Pull-Down
5ns Top Gate Fall Time Driving 1nF Load
8ns Top Gate Rise Time Driving 1nF Load
3ns Bottom Gate Fall Time Driving 1nF Load
6ns Bottom Gate 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
Telecommunication Systems
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 6677210.
TYPICAL APPLICATION
Two Switch Forward Converter
V
CC
7.2V TO 13.5V
BOOST
V
CC
PWM1
(FROM CONTROLLER IC)
PWM2
(FROM CONTROLLER IC)
TINP
BINP
GND
TG
LTC4446
TS
BG
V
IN
36V TO 72V
(100V ABS MAX)
LTC4446 Driving a 1000pF Capacitive Load
BINP
5V/DIV
BG
10V/DIV
TINP
5V/DIV
TG-TS
10V/DIV
20ns/DIV
4446 TA01a
4446 TA01b
•
•
TO
SECONDARY
CIRCUIT
4446f
1
LTC4446
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
TINP
BINP
V
CC
BG
1
2
3
4
8
7
6
5
TS
TG
BOOST
NC
9
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 Temperature Range (Note 2).... –40°C to 85°C
Junction Temperature (Note 3) ............................. 125°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
LTC4446EMS8E#PBF
LTC4446IMS8E#PBF
TAPE AND REEL
LTC4446EMS8E#TRPBF
LTC4446IMS8E#TRPBF
PART MARKING*
LTDPZ
LTDPZ
PACKAGE DESCRIPTION
8-Lead Plastic MSOP
8-Lead Plastic MSOP
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°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/
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= V
BOOST
= 12V, V
TS
= GND = 0V, unless otherwise noted.
SYMBOL
PARAMETER
Gate Driver Supply, V
CC
V
CC
Operating Voltage
DC Supply Current
I
VCC
UVLO
Undervoltage Lockout Threshold
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
ELECTRICAL CHARACTERISTICS
TYP
MAX
13.5
550
7.20
6.70
UNITS
V
μA
V
V
mV
μA
V
V
V
V
μA
V
mV
A
Ω
4446f
6.00
5.60
350
6.60
6.15
450
0.1
Bootstrapped Supply (BOOST – TS)
DC Supply Current
I
BOOST
Input Signal (TINP BINP)
,
BG Turn-On Input Threshold
V
IH(BG)
BG Turn-Off Input Threshold
V
IL(BG)
TG Turn-On Input Threshold
V
IH(TG)
TG Turn-Off Input Threshold
V
IL(TG)
Input Pin Bias Current
I
TINP(BINP)
High Side Gate Driver Output (TG)
TG High Output Voltage
V
OH(TG)
TG Low Output Voltage
V
OL(TG)
TG Peak Pull-Up Current
I
PU(TG)
TG Pull-Down Resistance
R
DS(TG)
2
3.25
2.75
3.25
2.75
±2
2.25
1.85
2.25
1.85
2.75
2.3
2.75
2.3
±0.01
0.7
120
2.5
1.2
I
TG
= –10mA, V
OH(TG)
= V
BOOST
– V
TG
I
TG
= 100mA, V
OL(TG)
= V
TG
–V
TS
l
l
l
220
2.2
1.7
2
LTC4446
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= V
BOOST
= 12V, V
TS
= GND = 0V, unless otherwise noted.
SYMBOL
PARAMETER
Low Side Gate Driver Output (BG)
BG High Output Voltage
V
OH(BG)
BG Low Output Voltage
V
OL(BG)
BG Peak Pull-Up Current
I
PU(BG)
BG Pull-Down Resistance
R
DS(BG)
CONDITIONS
I
BG
= –10mA, V
OH(BG)
= V
CC
– V
BG
I
BG
= 100mA
MIN
TYP
0.7
55
3
0.55
25
22
19
14
10
–3
8
80
5
50
6
60
3
30
MAX
UNITS
V
mV
A
Ω
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ELECTRICAL CHARACTERISTICS
l
l
l
110
1.1
45
40
35
30
35
25
2
Switching Time (BINP (TINP) is Tied to Ground While TINP (BINP) is Switching. Refer to Timing Diagram)
l
TG Low-High (Turn-On) Propagation Delay
t
PLH(TG)
l
TG High-Low (Turn-Off) Propagation Delay
t
PHL(TG)
l
BG Low-High (Turn-On) Propagation Delay
t
PLH(BG)
l
BG High-Low (Turn-Off) Propagation Delay
t
PHL(BG)
l
Delay Matching BG Turn-Off and TG Turn-On
t
DM(BGTG)
l
Delay Matching TG Turn-Off and BG Turn-On
t
DM(TGBG)
TG Output Rise Time
10% – 90%, C
L
= 1nF
t
r(TG)
10% – 90%, C
L
= 10nF
TG Output Fall Time
10% – 90%, C
L
= 1nF
t
f(TG)
10% – 90%, C
L
= 10nF
BG Output Rise Time
10% – 90%, C
L
= 1nF
t
r(BG)
10% – 90%, C
L
= 10nF
BG Output Fall Time
10% – 90%, C
L
= 1nF
t
f(BG)
10% – 90%, C
L
= 10nF
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 LTC4446E is guaranteed to meet specifications from
0°C to 85°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
–15
–25
with statistical process controls. The LTC4446I is guaranteed over the full
–40°C to 85°C operating temperature range.
Note 3:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
T
J
= T
A
+ (P
D
•
θ
JA
°C/W)
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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