Datasheet

LT3740
3
3740fc
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.
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C, V
IN
= 5V unless otherwise noted. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
SHDN Voltage to Enable Device
1.1 V
SHDN Voltage to Disable Device
0.5 V
TGATE On Voltage 5.5 V
TGATE Off Voltage 0.2 V
BGATE On Voltage 5.5 V
BGATE Off Voltage 0.2 V
TGATE Rise Time C
LOAD
= 3300pF 30 ns
TGATE Fall Time C
LOAD
= 3300pF 30 ns
BGATE Rise Time C
LOAD
= 3300pF 50 ns
BGATE Fall Time C
LOAD
= 3300pF 50 ns
PGOOD Threshold
720 740 765 mV
PGOOD Low Voltage I
PGOOD
= 100µA
0.2 V
PGOOD Current Capacity 500 µA
Internal Boost Switching Frequency 0.8 1 1.2 MHz
Internal Boost Switch Current Limit 360 440 520 mA
(BIAS – V
IN
) in Operation 7.8 V
(BIAS – V
IN
) to Start Controller 7.2 V
Note 2: The LT3740E is guaranteed to meet performance specifi cations
from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3: The minimum off time of the LT3740 application consists of the
minimum BGATE on time, the delay from TGATE OFF to BGATE ON (80ns)
and the delay from BGATE OFF to TGATE ON (80ns).
TYPICAL PERFORMANCE CHARACTERISTICS
Transient Response
Transient Response Shutdown Pin Start-Up
(T
A
= 25°C, unless otherwise noted)
LOAD STEP 0A TO 10A
V
IN
= 10V, V
OUT
= 2.5V
FIGURE 4 CIRCUIT
V
OUT
50mV/DIV
I
L
5A/DIV
3740 G01
20µs/DIV
LOAD STEP 0A TO 10A
V
IN
= 5V, V
OUT
= 1.8V
PAGE 17 CIRCUIT
V
OUT
50mV/DIV
I
L
5A/DIV
3740 G02
10µs/DIV
3740 G03
V
IN
= 10V, V
OUT
= 2.5V
I
LOAD
= 3A
SHDN
2V/DIV
V
O
2V/DIV
I
L
2A/DIV
2ms/DIV