LTC3783
4
3783fb
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 LTC3783E is guaranteed to meet performance specifications
over the 0°C to 85°C operating temperature range. Specifications over
the –40°C to 85°C operating temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3783I is guaranteed to meet performance specifications over the full
–40°C to 125°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
• 43°C/W) for the DFN
T
J
= T
A
+ (P
D
• 38°C/W) for the TSSOP
The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are T
A
= 25°C. V
IN
= 12V, V
RUN
= 1.5V, V
SYNC
= 0V, V
FBP
= V
REF
, R
T
= 20k, unless otherwise specified.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
R
SYNC
SYNC Input Pull-Down Resistance 100 kΩ
t
ON(MIN)
Minimum On-Time With Sense Resistor, 10mV Overdrive
No R
SENSE
Mode
170
300
ns
ns
Low Dropout Regulator
V
INTVCC
INTV
CC
Regulator Output Voltage V
OV/FB
= 1.5V
l
6.5 7 7.5 V
UVLO INTV
CC
Undervoltage Lockout
Thresholds
Rising INTV
CC
Falling INTV
CC
Hysteresis
1.8
2.3
2.1
0.2
2.5 V
V
V
∆V
INTVCC
∆V
IN
INTV
CC
Line Regulation 12V ≤ V
IN
≤ 36V 2 6 mV/V
∆V
LDO(LOAD)
INTV
CC
Load Regulation 0 ≤ I
INTVCC
≤ 10mA –1 –0.1 %
V
DROPOUT
INTV
CC
Dropout Voltage V
IN
= 7V, I
INTVCC
= 10mA 300 500 mV
I
INTVCC(SD)
Bootstrap Mode INTV
CC
Supply
Current in Shutdown
V
SENSE
= 0V
V
SENSE
= 7V
25
15
µA
µA
GATE/PWMOUT Drivers
t
r(GATE)
GATE Driver Output Rise Time C
L
= 3300pF (Note 7) 15 ns
t
f(GATE)
GATE Driver Output Fall Time C
L
= 3300pF (Note 7) 8 ns
I
PK(GATE,RISE)
GATE Driver Peak Current Sourcing V
GATE
= 0V 0.5 A
I
PK(GATE,FALL)
GATE Driver Peak Current Sinking V
GATE
= 7V 1 A
V
PWMIN
PWMIN Pin Input Threshold Voltages Rising PWMIN
Falling PWMIN
Hysteresis
1.6
0.8
0.8
V
V
V
R
PWMIN
PWMIN Input Pull-Up Resistance 100 kΩ
t
r(PWMOUT)
PWMOUT Driver Output Rise Time C
L
= 3300pF (Note 7) 30 ns
t
f(PWMOUT)
PWMOUT Driver Output Fall Time C
L
= 3300pF (Note 7) 16 ns
I
PK(PWMOUT,RISE)
PWMOUT Driver Peak Current Sourcing V
PWMOUT
= 0V 0.25 A
I
PK(PWMOUT,FALL)
PWMOUT Driver Peak Current Sinking V
PWMOUT
= 7V 0.50 A
Note 4: The dynamic input supply current is higher due to power MOSFET
gate charging (Q
G
• f
OSC
). See Operation section.
Note 5: The LTC3783 is tested in a feedback loop which servos V
FBN
to
V
FBP
= V
VREF
with the I
TH
pin forced to the midpoint of its voltage range
(0.3V ≤ V
ITH
≤ 1.2V; midpoint = 0.75V).
Note 6: In a synchronized application, the internal slope compensation is
increased by 25%. Synchronizing to a significantly higher ratio will reduce
the effective amount of slope compensation, which could result in sub-
harmonic oscillation for duty cycles greater than 50%
Note 7: Rise and fall times are measured at 10% and 90% levels.
