LTC3609
4
3609fb
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V unless otherwise noted.
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: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
as follows:
T
J
= T
A
+ (P
D
• 29°C/W) (θ
JA
is simulated per JESD51-7 high effective
thermal conductivity test board).
θ
JC
= 1°C/W (θ
JC
is simulated when heat sink is applied at the bottom
of the package).
Note 3:
The LTC3609 is tested in a feedback loop that adjusts V
FB
to
achieve a specified error amplifier output voltage (I
TH
). The specification at
85°C is not tested in production. This specification is assured by design,
characterization, and correlation to testing at 125°C.
Note
4: The LTC3609 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3609E is guaranteed to meet specifications from
0°C to 125°C 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
LTC3609I is guaranteed over the full –40°C to 125°C operating junction
temperature range. 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.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Internal V
CC
Regulator
V
INTVCC
Internal V
CC
Voltage 6V < V
IN
< 30V, V
EXTVCC
= 4V
l
4.7 5 5.5 V
∆V
LDO(LOADREG)
Internal V
CC
Load Regulation I
CC
= 0mA to 20mA, V
EXTVCC
= 4V –0.1 ±2 %
V
EXTVCC
EXTV
CC
Switchover Voltage I
CC
= 20mA, V
EXTVCC
Rising
l
4.5 4.7 V
∆V
EXTVCC
EXTV
CC
Switch Drop Voltage I
CC
= 20mA, V
EXTVCC
= 5V 150 300 mV
∆V
EXTVCC(HYS)
EXTV
CC
Switchover Hysteresis 500 mV
PGOOD Output
∆V
FBH
PGOOD Upper Threshold V
FB
Rising 7 10 13 %
∆V
FBL
PGOOD Lower Threshold V
FB
Falling –7 –10 –13 %
∆V
FB(HYS)
PGOOD Hysteresis V
FB
Returning 1 2.5 %
V
PGL
PGOOD Low Voltage I
PGOOD
= 5mA 0.15 0.4 V
Transient Response
Transient Response
(Discontinuous Mode)
Start-Up
LOAD STEP 0A TO 5A
V
IN
= 25V
V
OUT
= 2.5V
FCB = 0V
FIGURE 6 CIRCUIT
3609 G01
20µs/DIV
V
OUT
200mV/DIV
I
L
5A/DIV
I
LOAD
5A/DIV
LOAD STEP 1A TO 6A
V
IN
= 25V
V
OUT
= 2.5V
FCB = INTV
CC
FIGURE 6 CIRCUIT
3609 G02
20µs/DIV
V
OUT
200mV/DIV
I
L
5A/DIV
I
LOAD
5A/DIV
V
IN
= 12V
V
OUT
= 2.5V
R
LOAD
= 0.5Ω
FIGURE 6 CIRCUIT
3609 G03
40ms/DIV
RUN/SS
2V/DIV
V
OUT
1V/DIV
I
L
5A/DIV
Typical perForMance characTerisTics
