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