EXPOSED PAD (PIN 13) IS PGND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LTC7860EMSE#PBF
LTC7860IMSE#PBF
LTC7860HMSE#PBF
LTC7860MPMSE#PBF
TAPE AND REEL
LTC7860EMSE#TRPBF
LTC7860IMSE#TRPBF
LTC7860HMSE#TRPBF
LTC7860MPMSE#TRPBF
PART MARKING*
7860
7860
7860
7860
PACKAGE DESCRIPTION
12-Lead Plastic MSOP
12-Lead Plastic MSOP
12-Lead Plastic MSOP
12-Lead Plastic MSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–55°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
2
7860f
For more information
www.linear.com/LTC7860
LTC7860
elecTrical characTerisTics
SYMBOL
Input Supply
V
IN
V
UVLO
I
Q
Input Voltage Operating Range
Undervoltage Lockout
(V
IN
-V
CAP
) Ramping Up Threshold
(V
IN
-V
CAP
) Ramping Down Threshold
Hysteresis
FREQ = 0V, V
FB
= 0.83V (No Load)
RUN = 0V
l
l
l
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. (Note 3) V
IN
= 12V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
3.5
3.25
3.00
3.50
3.25
0.25
0.77
7
0.791
–0.005
–0.1
–50
–50
V
FB
= 0.77V
V
SENSE
= V
IN
V
RUN
Rising
V
SS
= 0V
TMR = 1.1V, V
FB
= 0.83V
TMR = 1.1V, V
FB
= 0.77V
TMR = 1.1V, V
FB
= 0.77V
V
FB
= 0.77V
V
FB
= 0.77V
l
l
l
l
l
TYP
MAX
60
3.8
3.50
1.2
12
0.809
0.005
0.1
50
50
103
2
1.32
UNITS
V
V
V
V
mA
µA
V
%/V
%
mS
nA
nA
mV
µA
V
mV
µA
Input DC Supply Current
Shutdown Supply Current
Output Sensing
V
REG
Regulated Feedback Voltage V
REG
= (V
FB
– V
FBN
) V
ITH
= 1.2V (Note 4)
Feedback Voltage Line Regulation
Feedback Voltage Load Regulation
g
m(EA)
I
FB
I
FBN
V
ILIM
I
SENSE
V
RUN
I
SS
Fault Timer
I
TPU
I
TPDR
I
TPDC
V
GTH
V
RTH
T
SETI(1µF)
T
SETR(1µF)
T
RSTC(1µF)
DTY
TSTR
TMR Pull-Up Current
TMR Pull-Down Current Restart
TMR Pull-Down Current Cool Down
TMR Gate Off Threshold
TMR Restart Threshold
TMR Set Time Initial for Fault Detection for 1µF
(T
SETI
= V
GTH
/I
TPU
)
TMR Set Time Repeat for Fault Detection for 1µF
(T
SETI
= (V
GTH
– V
RTH
)/I
TPU
)
TMR Restart Cool Down Time for 1µF
(T
RSTC
= (V
GTH
– V
RTH
)/I
TPDC
)
TMR Restart Duty Cycle in a Sustained Fault
(DTY
TSTR
= T
SETR
/T
RSTC
)
l
0.800
–0.015
1.8
–10
–10
95
0.1
V
IN
= 3.8V to 60V (Note 4)
V
ITH
= 0.6V to 1.8V (Note 4)
V
ITH
= 1.2V, ∆I
ITH
= ±5µA (Note 4)
Error Amplifier Transconductance
Feedback Input Bias Current
Feedback Negative Input Bias Current
Current Limit Threshold (V
IN
-V
SENSE
)
SENSE Pin Input Current
RUN Pin Enable Threshold
RUN Pin Hysteresis
Soft-Start Pin Charging Current
Current Sensing
85
Start-Up and Shutdown
1.22
1.26
150
10
–35
1.0
1.25
37
–30
40
1.3
1.29
240
44
32
732
3.5
4.5
5.5
50
1.6
1.35
–25
µA
µA
µA
V
mV
ms/µF
ms/µF
ms/µF
%
Switching Frequency
For more information
www.linear.com/LTC7860
3
7860f
LTC7860
elecTrical characTerisTics
SYMBOL
PARAMETER
Programmable Switching Frequency
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. (Note 3) V
IN
= 12V, unless otherwise noted.
CONDITIONS
R
FREQ
= 24.9kΩ
R
FREQ
= 64.9kΩ
R
FREQ
= 105kΩ
FREQ = 0V
FREQ = Open
V
FB
= 0V, FREQ = 0V
MIN
375
320
485
TYP
105
440
810
350
535
18
220
I
GATE
= 0mA
Gate High
Gate Low
l
MAX
505
380
585
UNITS
kHz
kHz
kHz
kHz
kHz
%
ns
Low Switching Frequency
High Switching Frequency
f
FOLD
t
ON(MIN)
Gate Driver
V
CAP
R
UP
R
DN
Gate Bias LDO Output Voltage (V
IN
-V
CAP
)
Gate Pull-Up Resistance
Gate Pull-Down Resistance
Foldback Frequency as Percentage of
Programmable Frequency
Minimum On-Time
7.6
8.0
2
0.9
8.5
V
Ω
Ω
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 junction temperature (T
J
in °C) is calculated from the ambient
temperature (T
A
in °C) and power dissipation (P
D
in Watts) as follows:
T
J
= T
A
+ (P
D
•
θ
JA
)
where
θ
JA
(in °C/W) is the package thermal impedance provided in the Pin
Configuration section for the corresponding package.
Note 3:
The LTC7860 is tested under pulsed load conditions such that T
J
≈ T
A
. The LTC7860E is guaranteed to meet performance specifications
from 0°C to 85°C operating junction temperature range. The LTC7860E
specifications over the –40°C to 125°C operating junction temperature
range are assured by design, characterization and correlation with
statistical process controls. The LTC7860I is guaranteed to meet
performance specifications over the –40°C to 125°C operating junction
temperature range, the LTC7860H is guaranteed over the –40°C to 150°C
operating junction temperature range, and the LTC7860MP 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. 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.
Note 4:
The LTC7860 is tested in a feedback loop that adjust V
REG
or (V
FB
– V
FBN
) to achieve a specified error amplifier output voltage
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