LTC3900
3
3900fb
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
TMRDIS
Timer Discharge Time C
TMR
= 1000pF, R
TMR
= 4.7k
l
40 120 ns
V
TMRMAX
Timer Pin Clamp Voltage C
TMR
= 1000pF, R
TMR
= 4.7k 2.5 V
Current Sense
I
CS
+ CS
+
Input Current V
CS
+ = 0V
l
±1 µA
I
CS
– CS
–
Input Current V
CS
– = 0V
l
±1 µA
V
CSMAX
CS
+
Pin Clamp Voltage I
IN
= 5mA, V
SYNC
= –5V 11 V
V
CS
Current Sense Threshold Voltage V
CS
– = 0V
LTC3900E/LTC3900I (Note 5)
LTC3900H/LTC3900MP (Note 5)
l
l
7.5
3
1
10.5 13.5
18
20
mV
mV
mV
SYNC Input
I
SYNC
SYNC Input Current V
SYNC
= ±10V
l
±1 ±10 µA
V
SYNCP
SYNC Input Positive Threshold
SYNC Positive Input Hysteresis
(Note 6)
l
1.0 1.4
0.2
1.8 V
V
V
SYNCN
SYNC Input Negative Threshold
SYNC Negative Input Hysteresis
(Note 6)
l
–1.8 –1.4
0.2
–1.0 V
V
Driver Output
R
ONH
Driver Pull-Up Resistance I
OUT
= –100mA
LTC3900E/LTC3900I
LTC3900H/LTC3900MP
l
l
0.9 1.2
1.6
2.0
Ω
Ω
Ω
R
ONL
Driver Pull-Down Resistance I
OUT
= 100mA
LTC3900E/LTC3900I
LTC3900H/LTC3900MP
l
l
0.9 1.2
1.6
2.0
Ω
Ω
Ω
I
PK
Driver Peak Output Current (Note 6) 2 A
Switching Characteristics (Note 7)
t
d
SYNC Input to Driver Output Delay C
FG
= C
CG
= 4700pF, V
SYNC
= ±5V
LTC3900E/LTC3900I
LTC3900H/LTC3900MP
l
l
60
120
150
ns
ns
t
SYNC
Minimum SYNC Pulse Width V
SYNC
= ±5V
l
75 ns
t
r
, t
f
Driver Rise/Fall Time C
FG
= C
CG
= 4700pF, V
SYNC
= ±5V 15 ns
elecTrical characTerisTics
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V unless otherwise specified. (Notes 2, 3)
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 LTC3900 is tested under pulsed load conditions such that
T
J
≈
T
A
. The LTC3900E 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 LTC3900I is guaranteed over the –40°C to 125°C operating
junction temperature range. The LTC3900H is guaranteed over the full
–40°C to 150°C operating junction temperature range. The LTC3900MP
is guaranteed 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 thermal
impedance.
Note 3: 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 4: Supply current in normal operation is dominated by the current
needed to charge and discharge the external MOSFET gates. This current
will vary with supply voltage, switching frequency and the external
MOSFETs used.
Note 5: The current sense comparator threshold has a 0.33%/°C
temperature coefficient (TC) to match the TC of the external MOSFET
R
DS(ON)
.
Note 6: Guaranteed by design, not subject to test.
Note 7: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured from ±1.4V at SYNC input to 20%/80% levels at the
driver output.
