Datasheet
LTC3731
3
3731fc
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3731CG#PBF LTC3731CG#TRPBF LTC3731CG 36-Lead Plastic SSOP 0°C to 70°C
LTC3731IG#PBF LTC3731IG#TRPBF LTC3731IG 36-Lead Plastic SSOP –40°C to 85°C
LTC3731CUH#PBF LTC3731CUH#TRPBF 3731
32-Lead (5mm × 5mm) Plastic QFN
0°C to 70°C
LTC3731IUH#PBF LTC3731IUH#TRPBF 3731I
32-Lead (5mm × 5mm) Plastic QFN
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= V
RUN/SS
= 5V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Main Control Loop
V
REGULATED
Regulated Voltage at IN
+
V
ITH
= 1.2V (Note 3)
LTC3731I
l
l
0.596
0.594
0.591
0.600
0.600
0.604
0.606
0.609
V
V
V
V
SENSEMAX
Maximum Current Sense Threshold V
EAIN
= 0.5V, V
ITH
Open,
V
SENSE1
–
, V
SENSE2
–
, V
SENSE3
–
= 0.6V, 1.8V
LTC3731I
l
l
65
62
60
75
75
85
88
90
mV
mV
mV
I
MATCH
Maximum Current Threshold Match Worst-Case Error at V
SENSEMAX
–5 5 %
V
LOADREG
Output Voltage Load Regulation (Note 3)
Measured in Servo Loop, ∆I
TH
Voltage = 1.2V to 0.7V
LTC3731I
Measured in Servo Loop, ∆I
TH
Voltage = 1.2V to 2V
LTC3731I
l
l
l
l
0.1
0.1
–0.1
–0.1
0.5
0.7
–0.5
–0.7
%
%
%
%
V
REFLNREG
Output Voltage Line Regulation V
CC
= 4.5V to 7V 0.03 %/V
g
m
Transconductance Amplifier g
m
I
TH
= 1.2V, Sink/Source 25µA (Note 3)
LTC3731I
l
l
4
3
5
5
6
7
mmho
mmho
g
mOL
Transconductance Amplifier GBW I
TH
= 1.2V (g
m
• Z
L
, Z
L
= Series 1k-100kΩ-1nF) 3 MHz
V
FCB
Forced Continuous Threshold
LTC3731I
l
l
0.58
0.54
0.60
0.60
0.62
0.66
V
V
I
FCB
FCB Bias Current V
FCB
= 0.65V 0.2 0.7 µA
V
BINHIBIT
Burst Inhibit Threshold Measured at FCB Pin V
CC
– 1.5 V
CC
– 0.7 V
CC
– 0.3 V
UVR Undervoltage RUN/SS Reset V
CC
Lowered Until the RUN/SS Pin is Pulled Low 3.3 3.8 4.5 V
UVADJ Undervoltage Lockout Threshold 1.13 1.18 1.23 V
I
UVADJ
Undervoltage Bias Current At UVADJ Threshold 0.2 50 nA
I
Q
Input DC Supply Current
Normal Mode
Shutdown
(Note 4)
V
CC
= 5V
V
RUN/SS
= 0V
2.3
50
3.5
100
mA
µA
I
RUN/SS
Soft-Start Charge Current V
RUN/SS
= 1.9V –0.8 –1.5 –2.5 µA