Datasheet
LTC3856
3
3856f
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3856EFE#PBF LTC3856EFE#TRPBF LTC3856FE 38-Lead Plastic TSSOP –40°C to 125°C
LTC3856IFE#PBF LTC3856IFE#TRPBF LTC3856FE 38-Lead Plastic TSSOP –40°C to 125°C
LTC3856EUH#PBF LTC3856EUH#TRPBF 3856
32-Lead (5mm × 5mm) Plastic QFN
–40°C to 125°C
LTC3856IUH#PBF LTC3856IUH#TRPBF 3856
32-Lead (5mm × 5mm) Plastic QFN
–40°C to 125°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/
elecTrical characTerisTics
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Main Control Loops
V
IN
Input Voltage 4.5 38 V
V
OUT
Output Voltage 0.6 5.0 V
V
FB
Regulated Feedback Voltage I
TH
Voltage = 1.2V, E-Grade (Note 4)
I
TH
Voltage = 1.2V, I-Grade (Note 4)
l
l
0.5955
0.593
0.600
0.600
0.6045
0.607
V
V
I
FB
Feedback Current (Note 4) –15 –50 nA
V
REFLNREG
Reference Voltage Line Regulation V
IN
= 4.5V to 38V (Note 4) 0.002 0.02 %/V
V
LOADREG
Output Voltage Load Regulation (Note 4)
Measured in Servo Loop, ∆I
TH
Voltage = 1.2V to 0.7V
Measured in Servo Loop, ∆I
TH
Voltage = 1.2V to 1.6V
l
l
0.01
–0.01
0.1
–0.1
%
%
g
m
Transconductance Amplifier g
m
I
TH
= 1.2V, Sink/Source 5µA (Note 4) 2.0 mmho
I
Q
Input DC Supply Current
Normal Mode
Shutdown
(Note 5)
V
IN
= 15V
V
RUN
= 0V
4.0
40
70
mA
µA
DF
MAX
Maximum Duty Factor In Dropout; f
OSC
= 500kHz 93 94 %
UVLO Undervoltage Lockout V
INTVCC
Ramping Down
l
3.0 3.2 3.4 V
UVLO Hyst UVLO Hysteresis 0.6 V
V
OVL
Feedback Overvoltage Lockout Measured at V
FB
l
0.64 0.66 0.68 V
I
SENSE
+
SENSE
+
Pins Bias Current Each Channel, V
SENSE1,2
= 3.3V
l
±1 ±2 µA
I
TEMP
DCR Tempco Compensation Current V
ITEMP
= 0.3V
l
9 10 11 µA
I
TK/SS
Soft-Start Charge Current V
TK/SS
= 0V
l
1.0 1.25 1.5 µA
V
RUN
RUN Pin On Threshold V
RUN
Rising
l
1.1 1.22 1.35 V
V
RUNHYS
RUN Pin On Hysteresis 80 mV
V
SENSE(MAX)
Maximum Current Sense Threshold
(E-Grade)
V
FB
= 0.5V, V
SENSE1,2
= 3.3V
I
LIM
= 0V
I
LIM
= Float
I
LIM
= INTV
CC
l
l
l
25
45
68
30
50
75
35
55
82
mV
mV
mV
V
SENSE(MAX)
Maximum Current Sense Threshold
(I-Grade)
V
FB
= 0.5V, V
SENSE1,2
= 3.3V
I
LIM
= 0V
I
LIM
= Float
I
LIM
= INTV
CC
l
l
l
23
43
66
30
50
75
37
57
84
mV
mV
mV
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 15V, V
RUN
= 5V, unless otherwise noted.