High Speed Synchronous Power
MOSFET Smart Driver
POWER MANAGEMENT
Description
The SC1405B is a Dual-MOSFET Driver with an internal
Overlap Protection Circuit to prevent shoot-through. Each
driver is capable of driving a 3000pF load in 15ns rise/
fall time and has ULTRA-LOW propagation delay from in-
put transition to the gate of the power FET’s. Adaptive
Overlap Protection circuit ensures that the synchronous
FET does not turn on until the top FET source has reached
a voltage low enough to prevent shoot-through. The de-
lay between the bottom gate going low to the top gate
transitioning high is externally programmable via a ca-
pacitor to minimize dead time. The bottom FET may be
disabled at light loads by keeping S_MOD low to trigger
asynchronous operation, thus saving the bottom FET’s
gate drive current and inductor ripple current. An inter-
nal voltage reference allows threshold adjustment for
an Output Over-Voltage protection circuitry, independent
of the PWM controller.
Under-Voltage-Lock-Out circuit is included to guarantee
that both driver outputs are off when Vcc is less than or
equal to 4.4V (typ) at supply ramp up (4.35V at supply
ramp down). A CMOS output provides status indication
of the 5V supply. A low enable input places the IC in stand-
by mode, reducing supply current to less than 10µA.
SC1405B is offered in a high pitch (.025” lead spacing)
TSSOP package.
SC1405B
Features
Fast rise and fall times (15ns with 3000pf load)
14ns max. Propagation delay (BG going low)
Adaptive and programmable shoot-through
protection
Wide input voltage range (4.5-25V)
Power saving asynchronous mode control
Output overvoltage protection/overtemp shutdown
Under-Voltage lock-out and power ready signal
Less than 10µA stand-by current (EN=low)
Improved drive version of SC1405TS
High frequency (to 1.2MHz) operation allows use of
small inductors and low cost capacitors in place of
electrolytics
Applications
High Density/Fast transient microprocessor power
supplies
Motor Drives/Class-D amps
High efficiency portable computers
Typical Application Circuit
INPUT POWER, 5-20V
+
Vcc
10uF,6.3V
+
.1uF
8
3
<<
>>
P_READY
PWM IN
(20KHz-1MHz)
47pF
7
2
4
6
1
5
14
13
12
SC1405
9
11
10
2.2
2.2
MTB75N03
75A,30V
5817
.22uF
1.7V@30A
+
+
+
+
+
MTB75N03
75A,30V
<<
DSPS_DR
Over-Voltage Sense
<<< Output Feedback to PWM
Controller
Revision: January 13, 2004
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SC1405B
POWER MANAGEMENT
Absolute Maximum Ratings
Parameter
V
CC
Supply Voltage
BST to PGND
BST to DRN
DRN to PGND
DRN to PGND Pulse
OVP_S to PGND
Input Pin
Continuous Power Dissipation
Thermal Impedance Junction to Case
Thermal Impedance Junction to Ambient
Operating Temperature Range
Storage Temperature Range
Lead Temperature (Soldering) 10 Sec.
Symbol
V
MAXSV
VMAX
BST-PGND
VMAX
BST-DRN
VMAX
DRN-PGN
VMAX
PULSE
VMAX
OVP SPGND
CO
Pd
θ
J C
θ
J A
T
J
T
STG
T
LEAD
T
AMB
= 25°C, T
J
= 125°C
T
CASE
= 25°C, T
J
= 125°C
t
PULSE
< 100ns
Conditions
Maximum
7
30
8
-2 to 25
-5 to 25
10
-0.3 to 8.3
0.66
2.56
40
150
0 to +125
-65 to +150
300
Units
V
V
V
V
V
V
V
W
°C/W
°C/W
°C
°C
°C
NOTE:
(1) Specification refers to application circuit in Figure 1.
Electrical Characteristics - DC Operating Specifications
Unless specified: -0 <
θ
J
< 125°C; V
CC
= 6V; 4V < V
BST
< 26V
Parameter
Pow er Supply
Supply Voltage
Quiescent Current
Quiescent Current, operating
PR D Y
High Level Output Voltage
Low Level Output Voltage
Sink Current
Symbol
Conditions
Min
Typ
Max
Units
V
CC
Iq_stby
Iq_op
E N = 0V
V
CC
= 5V, CO = 0V
4.15
5
6.0
10
V
µA
mA
1
V
OH
V
OL
I
O_SINK
V
CC
= 4.6V, lload = 10mA
V
CC
< UVLO threshold,
lload = 10µA
VPRDY = 0.4V
4.5
4.55
0.1
0.2
V
V
mA
5
10
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SC1405B
POWER MANAGEMENT
Electrical Characteristics - DC Operating Specifications
Parameter
D S P S _D R
High Level Output Voltage
Low Level Output Voltage
Under Voltage Lockout
Start Threshold
Hysteresis
Logic Active Threshold
Overvoltage Protection
Trip Threshold
Hysteresis
S_MOD
High Level Input Voltage
Low Level Input Voltage
Enable
High Level Input Voltage
Low Level Input Voltage
CO
High Level Input Voltage
Low Level Input Voltage
Thermal Shutdow n
Over Temperature Trip Point
Hysteresis
High-Side Driver
Peak Output Current
Output Resistance
I
PKH
Rsrc
TG
Rsink
TG
Low -Side Drive
Peak Output Current
Output Resistance
I
PKL
Rsrc
BG
Rsink
BG
duty cycle < 2%, tpw < 100µs,
TJ = 125°C,
V
V S
= 4.6V,
V
BG
= 4V (src)
or V
LOWDR
= 0.5V (sink)
3
1.2
duty cycle < 2%, tpw < 100µs,
TJ = 125°C, V
BST
- V
DRN
= 4.5V,
V
TG
= 4.0V (src)+V
DRN
or VTG = 0.5V (sink)+VDRN
3
1
.7
T
OTP
T
HYST
165
10
o
o
Symbol
Conditions
Min
Typ
Max
Units
V
OH
V
OL
V
START
Vhys
UVLO
V
AC T
V
TRIP
Vhys
OVP
V
IH
V
IL
V
IH
V
IL
V
IH
V
IL
V
CC
= 4.6V, Cload = 100pF
V
CC
= 4.6V, Cload = 100pF
4.15
0.05
4.2
4.4
0.05
1.5
1.145
1.2
0.8
2.0
0.8
1.255
4.6
V
V
V
V
V
V
V
V
V
2.0
0.8
V
V
2.0
0.8
V
V
C
C
A
Ω
A
Ω
1.0
2004 Semtech Corp.
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SC1405B
POWER MANAGEMENT
Electrical Characteristics - AC Operating Specifications
Parameter
High Side Driver
rise time
fall time
propagation delay time,
TG going high
propagation delay time,
TG going low
Low -Side Driver
rise time
fall time
propagation delay time,
BG going high
propagation delay time,
TG going low
Under-Voltage Lockout
V_5 ramping up
V_5 ramping down
PR D Y
EN is transitioning from low to
high
tpdhPRDY
V_5 >UVLO threshold, Delay
measured from EN > 2.0V to
PRDY > 3.5V
V_5 >UVLO threshold, Delay
measured from EN < 0.8V to
PRDY < 10% of V_5V
10
µs
tpdh
UVLO
tpdh
UVLO
EN is High
EN is High
10
10
us
us
tr
BG
tr
BG
tpdh
BGHI
tpdl
BG
CI = 3nF, V
CI = 3nF, V
V S
V S
Symbol
Conditions
Min
Typ
Max
Units
tr
TG1
tf
TG
tpdh
TG
tpdl
TG
CI = 3nF, V
BST
- V
DRN
= 4.6V,
CI = 3nF, V
BST
- V
DRN
= 4.6V,
CI = 3nF, V
BST
- V
DRN
= 4.6V,
C-delay=0
CI = 3nF, V
BST
- V
DRN
= 4.6V,
14
12
20
15
23
19
32
24
ns
ns
ns
ns
= 4.6V,
= 4.6V,
15
13
12
7
24
21
19
12
ns
ns
ns
ns
CI = 3nF, V
BST
- V
DRN
= 4.6V,
C-delay=0
CI = 3nF, V
V S
= 4.6V,
DRN <1V
EN is transitioning fro high to low
D S P S _D R
rise/fall time
propagation delay, DSPS_DR
going high
propagation delay, DSPS_DR
goes low
Overvoltage Protection
propagation delay
tpdhUVLO
500
µs
tr
DSPS DR.
tpdh
DSPS DR
tpdl
DSPS DR
CI = 100 pf, V_5 = 4.6V
S_MOD goes high and BG
goes high or S_MOD goes low
S_MOD goes high and BG
goes low
20
10
10
ns
ns
ns
tpdh
OVP S
V_5 + 4.6V, TJ = 125
O
C,
OVP_S > 1.2V to BG > 90%
of V _5
1
µs
Note:
(1) This device is ESD sensitive. Use of standard ESD handling precautions is required.
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Microcontroller MCU
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