LT1801IMS8#TRPBF Linear Technology, LT1801IMS8#TRPBF Datasheet - Page 17

• Manufacturer Part Number: LT1801IMS8#TRPBF
• Description: IC OPAMP R-R IN/OUT DUAL 8-MSOP
• Manufacturer: Linear Technology

Specifications of LT1801IMS8#TRPBF

• Amplifier Type: General Purpose
• Number Of Circuits: 2
• Output Type: Rail-to-Rail
• Slew Rate: 20 V/µs
• Gain Bandwidth Product: 70MHz
• Current - Input Bias: 400nA
• Voltage - Input Offset: 700µV
• Current - Supply: 1.8mA
• Current - Output / Channel: 50mA
• Voltage - Supply, Single/dual (±): 2.3 V ~ 12.6 V, ±1.15 V ~ 6.3 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• -3db Bandwidth: -

TYPICAL APPLICATIONS
Single Supply 1A Laser Driver Amplifi er
Figure 4 shows the LT1801 used in a 1A laser driver ap-
plication. One of the reasons the LT1801 is well suited to
this control task is that its 2.3V operation ensures that it
will be awaked during power-up and operated before the
circuit can otherwise cause signifi cant current to fl ow in
the 2.1V threshold laser diode. Driving the noninverting
input of the LT1801 to a voltage V
on of the high current NPN transistor, FMMT619 and the
laser diode. A current equal to V
laser diode. The LT1801 low offset voltage and low input
IN
IN
100mA/DIV
will control the turning
/R1 fl ows through the
DO NOT FLOAT
Figure 4. Single Supply 1A Laser Driver Amplifi er
V
IN
Figure 5. 500mA Pulse Response
+
–
1/2 LT1801
50ns/DIV
bias current allows it to control the current that fl ows
through the laser diode precisely. The overall circuit is
a 1A per volt V-to-I converter. Frequency compensation
components R2 and C1 are selected for fast but zero-
overshoot time domain response to avoid overcurrent
conditions in the laser. The time domain response of this
circuit, measured at R1 and given a 500mV 230ns input
pulse, is shown in Figure 5. While the circuit is capable
of 1A operation, the laser diode and the transistor are
thermally limited due to power dissipation, so they must
be operated at low duty cycles.
C1
39pF
10Ω
330Ω
R3
R2
5V
18012 F05
Q1
ZETEX
FMMT619
R1
1Ω
18012 F04
IR LASER
INFINEON
SFH495
LT1801/LT1802
17
18012fc