LT1620 Linear Technology, LT1620 Datasheet - Page 3

• Manufacturer Part Number: LT1620
• Description: Rail-to-Rail Current Sense Amplifier
• Manufacturer: Linear Technology

PI FU CTIO S
ELECTRICAL C
IN
SYMBOL PARAMETER
Current Sense Amplifier
V
V
V
I
Transconductance Amplifier
g
A
V
V
I
V
End-of-Cycle Comparator
V
V
I
V
V
IN
to inductor side of current sense resistor. Common mode
voltage range is 0V to 32V.
IN
to load side of current sense resistor. Common mode
voltage range is 0V to 32V.
SENSE: Sense Amplifier A
shifted output for PWM controller current sense input. The
sense output is designed to have an inherent offset to
The
temperature range.
B(IN
BPROG
BPROG2
m
OSAVG
OSAVG2
SENSE
V
OLIOUT
PROG
OSPROG
PROG2
HYST
OLMODE
CC
+
+
–
U
= 16.8V, V
+
: Sense Amplifier Negative Input. Typically connected
: Sense Amplifier Positive Input. Typically connected
: 5V 10% Power Supply Input.
, IN
denotes specifications which apply over the full operating
–
)
Input Offset - Measured at 10 Output
(V
Input Offset - Measured at 20 Output
(V
No-Load Output Offset
Input Bias Current (Sink)
Input Bias Current (Source)
Amplifier Transconductance
Amplifier Voltage Gain
I
PROG Input Range
Input Bias Current
Input Offset Voltage
(V
PROG2 Input Range
Input Hysteresis
Input Bias Current
Output Logic Low Output (Sink)
OUT
AVG
AVG2
AVG
U
CC
Saturation Limit (Sink)
)
– V
)
= 5V, V
PROG
)
U
IOUT
HARA TERISTICS
= 2V, T
V
= – 1 Output. Used as level-
A
C
= 25 C unless otherwise noted.
CONDITIONS
V
35mV V
V
V
0V V
0V V
V
V
1V V
I
I
I
Measured at PROG Pin
I
Measured at AVG2 Pin
Measured at PROG2 Pin
I
I
IOUT
IOUT
IOUT
IOUT
MODE
MODE
CC
CM
CC
CC
CM
= 0V, V
= 0V (Note 2)
= 50 A
= 200 A
= 1mA
= 130 A
V
V
V
= 0.5mA
= 10mA
ID
CM
IOUT
CM
CM
CM
ID
35mV
ID
32V, V
32V
32V
32V (Note 2)
3V
125mV
= 80mV
ID
= 0V, Referenced to V
Note 1: Absolute Maximum Ratings are those values beyond which the
life of a device may be impaired.
Note 2: Input bias currents are disabled when V
with common mode voltage present at IN
ensure continuity around zero inductor current. Typical out-
put is –3mV with differential input voltage (IN
AVG: Sense Amplifier A
Transconductance Amplifier Positive Input. Used as inte-
gration node for average current control. Integration time
constant is calculated using 2.5k typical output imped-
ance.
PROG: Transconductance Amplifier Negative Input. Pro-
gram node for average current delivered to load during
current mode operation. Average current delivered to load
imposes voltage differential at current sense amplifier
CC
V
V
CC
CC
3000
2200
– 0.1
MIN
– 10
200
185
– 3
– 4
– 3
– 4
– 7
– 8
60
– 1.25
– 2.5
LT1620/LT1621
V
+
3500
0.05
0.10
0.35
TYP
= –10 Output and
270
4.0
0.1
0.5
, IN
– 3
80
20
15
20
–
.
CC
is removed, even
V
CC
4000
4800
MAX
5.25
5.50
0.15
0.30
0.65
400
430
V
0.5
1.2
15
+
– 0.15
3
4
3
4
7
8
CC
– IN
–
) = 0.
UNITS
3
mho
mho
mV
mV
mV
mV
mV
mV
mA
mA
mV
mV
mV
dB
nA
nA
A
A
V
V
V
V
V
V
V