3
LTC3832/LTC3832-1
sn3832 3832fs
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
VCC
Supply Current Figure 2, V
SHDN
= V
CC
● 0.7 1.6 mA
V
SHDN
= 0V ● 110 µA
I
PVCC
PV
CC
Supply Current Figure 2, V
SHDN
= V
CC
(Note 3) ● 20 30 mA
V
SHDN
= 0V ● 0.1 10 µA
f
OSC
Internal Oscillator Frequency FREQSET Floating ● 230 300 360 kHz
V
SAWL
V
COMP
at Minimum Duty Cycle 1.2 V
V
SAWH
V
COMP
at Maximum Duty Cycle 2.2 V
V
COMPMAX
Maximum V
COMP
V
FB
= 0V, PV
CC1
= 8V 2.85 V
∆f
OSC
/∆I
FREQSET
Frequency Adjustment 10 kHz/µA
A
V
Error Amplifier Open-Loop DC Gain Measured from FB to COMP, ● 50 65 dB
SENSE
+
and SENSE
–
Floating, (Note 4)
g
m
Error Amplifier Transconductance Measured from FB to COMP, ● 1600 2000 2400 µmho
SENSE
+
and SENSE
–
Floating, (Note 4)
I
COMP
Error Amplifier Output Sink/Source Current 100 µA
I
MAX
I
MAX
Sink Current V
IMAX
= V
CC
81216 µA
(Note 10)
● 41220 µA
I
MAX
Sink Current Tempco V
IMAX
= V
CC
(Note 6) 3300 ppm/°C
V
IH
SHDN Input High Voltage ● 2.4 V
V
IL
SHDN Input Low Voltage ● 0.8 V
I
IN
SHDN Input Current V
SHDN
= V
CC
● 0.1 1 µA
I
SS
Soft-Start Source Current V
SS
= 0V, V
IMAX
= 0V, V
IFB
= V
CC
● –8 –12 –18 µA
I
SSIL
Maximum Soft-Start Sink Current V
IMAX
= V
CC
, V
IFB
= 0V, 1.6 mA
In Current Limit V
SS
= V
CC
(Note 8), PV
CC1
= 8V
R
SENSE
SENSE Input Resistance 23.7 kΩ
R
SENSEFB
SENSE to FB Resistance 18 kΩ
t
r
, t
f
Driver Rise/Fall Time Figure 2, PV
CC1
= PV
CC2
= 5V (Note 5) ● 80 250 ns
t
NOV
Driver Nonoverlap Time Figure 2, PV
CC1
= PV
CC2
= 5V (Note 5) ● 25 120 250 ns
DC
MAX
Maximum G1 Duty Cycle Figure 2, V
FB
= 0V (Note 5), PV
CC1
= 8V ● 91 95 %
The ● denotes specifications that apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. V
CC
, PV
CC1
, PV
CC2
= 5V, unless otherwise noted. (Note 2)
ELECTRICAL CHARACTERISTICS
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 3: Supply current in normal operation is dominated by the current
needed to charge and discharge the external FET gates. This will vary with
the LTC3832 operating frequency, operating voltage and the external FETs
used.
Note 4: The open-loop DC gain and transconductance from the SENSE
+
and SENSE
–
pins to COMP pin will be (A
V
)(0.6/2.5) and (g
m
)(0.6/2.5)
respectively.
Note 5: Rise and fall times are measured using 10% and 90% levels. Duty
cycle and nonoverlap times are measured using 50% levels.
Note 6: Guaranteed by design, not subject to test.
Note 7: PV
CC1
must be higher than V
CC
by at least 2.5V for G1 to operate
at 95% maximum duty cycle and for the current limit protection circuit to
be active.
Note 8: The current limiting amplifier can sink but cannot source current.
Under normal (not current limited) operation, the output current will be
zero.
Note 9: The LTC3832E/LTC3832-1E are guaranteed to meet performance
specifications from 0°C to 70°C. Specifications over the –40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 10: The minimum and maximum limits for I
MAX
over temperature
includes the intentional temperature coefficient of 3300ppm/°C. This
induced temperature coefficient counteracts the typical temperature
coefficient of the external power MOSFET on-resistance. This results in a
relatively flat current limit over temperature for the application.
