LTC6102IMS#PBF Linear Technology, LTC6102IMS#PBF Datasheet - Page 20

• Manufacturer Part Number: LTC6102IMS#PBF
• Description: AMP, CURRENT SENSE, PRECISION, SMD
• Manufacturer: Linear Technology

Specifications of LTC6102IMS#PBF

• No. Of Amplifiers: 1
• Input Bias Current: 3nA
• Output Current Per Channel: 1mA
• Input Offset Voltage: 5µV
• Bandwidth: 200kHz
• Supply Voltage Range: 4V To 60V
• Supply Current: 650µA
• Rohs Compliant: Yes

LTC6102
LTC6102-1/LTC6102HV
pin. Figure 11 shows the LTC6102-1 with a 2.7M pull-up
resistor to limit the current to less than 20μA with a 60V
supply, which is enough to satisfy the input bias current
requirement.
Start-Up Current
The start-up current of the LTC6102 when the part is
powered on or enabled (LTC6102-1) consists of three
parts: the fi rst is the current necessary to charge the
V
V
voltage, this can require a signifi cant amount of start-up
current. The second source is the active supply current of
the LTC6102 amplifi er, which is not signifi cantly greater
during start-up than during normal operation. The third
source is the output current of the LTC6102, which upon
start-up may temporarily drive the output high. This could
cause milliamps of output current (limited mostly by the
APPLICATIONS INFORMATION
20
REG
REG
R
SENSE
bypass capacitor, which is nominally 0.1μF . Since the
voltage charges to approximately 4.5V below the V
R
2.7M
LOAD
BIAS
V
+
R
R
IN
IN
–
+
+IN
V
EN
–
R
IN
LTC6102-1
+
=
R
+
IN
Figure 11
–
–
R
SENSE
–
–INS
V
OUT
–INF
V
REG
+
6102 F11
R
OUT
V
OUT
0.1μF
+
input resistor R
the output limiting ESD structure in the LTC6102. This is
a temporary condition which will cease when the LTC6102
amplifi er settles into normal closed-loop operation.
When the LTC6102-1 is disabled, the internal amplifi er is
also shut down, which means that the discharge rate of
the 0.1μF capacitor is very low. This is signifi cant when the
LTC6102-1 is disabled to save power, because the recharg-
ing of the 0.1μF capacitor is a signifi cant portion of the
overall power consumed in startup. Figure 12 shows the
discharge rate of the 0.1μF capacitor after the LTC6102-1
is shut down at room temperature.
In a system where the LTC6102-1 is disabled for short
periods, the start-up power (and therefore the average
power) can be reduced since the V
is never signifi cantly discharged. The time required to
charge the V
the LTC6102-1 to start-up more quickly.
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
Figure 12. LTC6102-1 V
Bypass Capacitor Discharge when Disabled
0
REG
–2
IN
0
capacitor will also be reduced, allowing
) to fl ow into the output resistor and/or
2
4
TIME (ms)
6
8
REG
10
Voltage During
V
EN
REG
REG
12
T
V
A
+
= 25°C
= 12V
14
bypass capacitor
6102 F12
16
8.3
8.2
8.1
8.0
7.9
7.8
7.7
7.6
7.5
7.4
6102fd