LTC1874 Linear Technology, LTC1874 Datasheet - Page 2

• Manufacturer Part Number: LTC1874
• Description: Dual Constant Frequency Current Mode Step-Down DC/DC Controller
• Manufacturer: Linear Technology

ABSOLUTE
(Note 1)
Input Supply Voltage (V
SENSE
V
PGATE Peak Output Current (< 10 s) ....................... 1A
Storage Ambient Temperature Range ... – 65 C to 150 C
Operating Temperature Range (Note 2) .. – 40 C to 85 C
Junction Temperature (Note 3) ............................. 150 C
Lead Temperature (Soldering, 10 sec).................. 300 C
ELECTRICAL CHARACTERISTICS
LTC1874
apply over the full operating temperature range, otherwise specifications are at T
(Note 2)
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LTC1874E is 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 3: T
dissipation P
PARAMETER
Input DC Supply Current (Per Controller)
Undervoltage Lockout Threshold
Shutdown Threshold (at I
Start-Up Current Source
Regulated Feedback Voltage
Output Voltage Line Regulation
Output Voltage Load Regulation
V
Overvoltage Protect Threshold
Overvoltage Protect Hysteresis
Oscillator Frequency
Gate Drive Rise Time
Gate Drive Fall Time
Peak Current Sense Voltage
2
FB
FB
Normal Operation
Sleep Mode
Shutdown
UVLO
T
Input Current
, I
J
= T
TH
J
–
A
/RUN Voltages ..............................– 0.3V to 2.4V
, PGATE Voltages ............. – 0.3V to (V
is calculated from the ambient temperature T
+ (P
D
according to the following formula:
D
•
JA
C/W)
W
MAXIMUM
TH
/RUN)
IN
, PV
W W
IN
) ...............– 0.3V to 10V
RATINGS
A
CONDITIONS
V
T
I
(Note 5)
V
Typicals at V
V
V
T
2.4V V
I
Measured at V
V
C
C
(Note 6)
and power
TH
TH
U
A
A
IN
IN
ITH
FB
FB
LOAD
LOAD
2.4V V
2.4V V
2.4V V
V
= 0 C to 70 C (Note 5)
= – 40 C to 85 C (Note 5)
/RUN Sinking 5 A (Note 5)
/RUN Sourcing 5 A (Note 5)
IN
Falling
Rising
= 0.8V
= 0V
/RUN = 0V
IN
< UVLO Threshold
= 3000pF
= 3000pF
+ 0.3V)
IN
All specifications apply to each controller. The
IN
IN
IN
IN
9.8V (Note 5)
FB
9.8V
9.8V
9.8V, V
= 4.2V (Note 4)
ITH
PACKAGE/ORDER
Consult factory for parts specified with wider operating temperature ranges.
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
Note 5: Each controller in the LTC1874 is individually tested in a feedback
loop that servos V
Note 6: Peak current sense voltage is reduced dependent upon duty cycle
to a percentage of value as given in Figure 2.
/RUN = 0V
I
SENSE1
TH
PGATE2
PGND2
/RUN2
GND1
PV
V
V
16-LEAD NARROW PLASTIC SSOP
FB1
IN1
IN2
–
T
JMAX
1
2
3
4
5
6
7
8
A
= 25 C. V
= 150 C,
GN PACKAGE
TOP VIEW
FB
to the output of the error amplifier.
JA
= 135 C/ W
IN
= 4.2V unless otherwise specified.
16
15
14
13
12
11
10
9
PV
PGATE1
PGND1
I
V
GND2
SENSE2
V
TH
FB2
IN2
0.780
0.770
0.820
IN1
/RUN1
1.55
1.85
0.15
0.25
MIN
500
–
INFORMATION
U
denotes specifications that
0.800
0.800
0.860
0.35
0.05
TYP
270
230
550
120
120
GN PART MARKING
2.0
2.3
0.5
2.5
2.5
10
20
40
40
8
6
ORDER PART
LTC1874EGN
NUMBER
W
0.820
0.830
0.895
1874
MAX
2.35
2.40
0.55
0.85
420
370
650
22
10
50
mV/ A
mV/ A
UNITS
U
mV/V
kHz
kHz
mV
mV
nA
ns
ns
A
A
A
A
V
V
V
A
V
V
V