Datasheet

LTC3824
3
3824fg
elecTrical characTerisTics
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 LTC3824 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3824E is guaranteed to meet performance specifications
from 0°C to 85°C operating junction temperature. Specifications over
the –40°C to 125°C operating junction temperature range are assured by
design characterization and correlation with statistical process controls.
The LTC3824I is guaranteed over the –40°C to 125°C operating junction
temperature range. The LTC3824H is guaranteed over the –40°C to 150°C
operating junction temperature range. The LTC3824MP is guaranteed
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
CC
= 12V, R
SET
= 392k, C
CAP
= 0.1µF. No load on any
outputs, unless otherwise specified.
PARAMETER CONDITIONS MIN TYP MAX UNITS
V
C
Low I
VC
= 0 0.35 0.5 V
V
C
Source Current V
VC
= 0.5V to 1.3V, V
FB
= V
REF
–100mV (V
SYNC
= 0V) 15 µA
V
C
Sink Current V
VC
= 0.7V to 1.3V, V
FB
= V
REF
+100mV (V
SYNC
= 0V) 15 µA
V
C
Threshold for Switching Off V
SYNC/MODE
= 0V (Note 4)
l
0.4 V
Soft-Start Current I
SS
V
SS
= 0.1V to 1.5V
l
3
2.5
5 7.5
8
µA
µA
V
C
Burst Mode Threshold V
CC
≤ 60V, V
C
Rising, SYNC/MODE Open 0.84 V
V
C
Burst Mode Threshold Hysteresis V
CC
≤ 60V 0.04 V
SENSE Voltage at Burst Mode Operation (V
CC
–V
SENSE
) at 30% Duty Cycle
70% Duty Cycle
30
20
mV
mV
Current Limit Threshold (V
CC
–V
SENSE
) V
CC
≤ 60V: LTC3824E/LTC3824I
LTC3824MP/LTC3824H
l
l
80
75
100
100
120
120
mV
mV
FB Overvoltage Threshold V
C
= 1.6V 8 %
Sense Input Current V
SENSE
= V
CC
0.1 2 µA
Oscillator
Switching Frequency R
SET
= 392k: LTC3824E/LTC3824I
LTC3824MP/LTC3824H
l
l
170
170
200
200
230
240
kHz
kHz
R
SET
= 200k
l
320 400 460 kHz
Synchronization Pulse Threshold
on SYNC Pin
Rising Edge V
SYNC
1.3 V
Synchronization Frequency Range R
SET
= 392k
R
SET
= 200k
l
l
230
460
300
600
kHz
kHz
V
RSET
R
SET
= 392k 1.2 V
Minimum On-Time (Measured at GATE Pin) CCM Operation (Note 5) 350 ns
Switching Frequency Foldback V
FB
= 0.3V
l
35 50 75 kHz
Gate Driver
GATE Bias Voltage (V
CC
–V
CAP
) 9V ≤ V
CC
≤ 60V, I
GATE
= 10mA: LTC3824E/LTC3824I
LTC3824MP/LTC3824H
l
l
7.0
6.8
7.9
7.9
8.8
8.9
V
V
V
CC
= 12V, I
GATE
= 15mA
l
6.8 V
GATE Bias Voltage (V
CAP
–GND) 4V ≤ V
CC
≤ 8V, I
GATE
= 10mA
6V ≤ V
CC
≤ 8V, I
GATE
= 15mA
l
0.2 0.85 1.5
2.8
V
V
GATE High Voltage (V
CC
–V
GATE
) 4V ≤ V
CC
≤ 60V, I
GATE
= –15mA 0.5 0.8 V
GATE Peak Source Current C
GATE
= 10nF 2.5 A
GATE Low Voltage (V
GATE
–V
CAP
) 8V ≤ V
CC
≤ 60V, I
GATE
= 15mA
4V ≤ V
CC
< 8V, I
GATE
= 10mA
0.1
0.05
0.5 V
V
GATE Peak Sink Current C
GATE
= 10nF 2.5 A
and tested 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. 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 junction to ambient thermal
impedance.