LT6203CDD#PBF Linear Technology, LT6203CDD#PBF Datasheet - Page 17

• Manufacturer Part Number: LT6203CDD#PBF
• Description: IC OPAMP R-R IN/OUT DUAL LP 8DFN
• Manufacturer: Linear Technology

Specifications of LT6203CDD#PBF

• Amplifier Type: General Purpose
• Number Of Circuits: 2
• Output Type: Rail-to-Rail
• Slew Rate: 25 V/µs
• Gain Bandwidth Product: 100MHz
• Current - Input Bias: 3.8µA
• Voltage - Input Offset: 2600µV
• Current - Supply: 2.8mA
• Current - Output / Channel: 40mA
• Voltage - Supply, Single/dual (±): 2.5 V ~ 12.6 V, ±1.25 V ~ 6.3 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-DFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• -3db Bandwidth: -

Low Noise, Low Power 1MΩ AC
Photodiode Transimpedance Amplifi er
Figure 3 shows the LT6202 applied as a transimpedance
amplifi er (TIA). The LT6202 forces the BF862 ultralow-noise
JFET source to 0V, with R3 ensuring that the JFET has an
I
the input of the LT6202 and making it suitable for the high
impedance feedback elements R1 and R2. The BF862 has
a minimum I
–0.3V and –1.2V. The JFET gate and the LT6202 output
TYPICAL APPLICATIONS
DRAIN
of 1mA. The JFET acts as a source follower, buffering
V
BIAS
–
Figure 3. Low Noise, Low Power 1MΩ
AC Photodiode Transimpedance Amplifi er
DSS
4.99k
R3
of 10mA and a pinchoff voltage between
V
V
S
S
–
+
PHILIPS
BF862
V
BIAS
–
499k
R1
–
+
Figure 4. Precision Low Noise, Low Power Transimpedance Amplifi er
LT6202
V
R4
10M
S
= ±5V
–
+
LTC2050HV
499k
1pF
C1
R2
0.1μF
C2
LT6202/03/04 F03
V
OUT
10k
R5
1μF
C3
therefore sit at a point slightly higher than one pinchoff
voltage below ground (typically about –0.6V). When the
photodiode is illuminated, the current must come from the
LT6202’s output through R1 and R2, as in a normal TIA.
Amplifi er input noise density and gain-bandwidth product
were measured at 2.4nV/Hz and 100MHz, respectively.
Note that because the JFET has a high g
1/80Ω, its attenuation looking into R3 is only about 2%.
Gain-bandwidth product was measured at 100MHz and
the closed-loop bandwidth using a 3pF photodiode was
approximately 1.4MHz.
Precision Low Noise, Low Power, 1MΩ
Photodiode Transimpedance Amplifi er
Figure 4 shows the LT6202 applied as a transimpedance
amplifi er (TIA), very similar to that shown in Figure 3.
In this case, however, the JFET is not allowed to dictate
the DC-bias conditions. Rather than being grounded, the
LT6202’s noninverting input is driven by the LTC2050
to the exact state necessary for zero JFET gate voltage.
The noise performance is nearly identical to that of the
circuit in Figure 3, with the additional benefi t of excellent
DC performance. Input offset was measured at under
200μV and output noise was within 2mV
bandwidth.
4.99k
R3
V
V
S
S
–
+
PHILIPS
BF862
LT6202/LT6203/LT6204
499k
–
+
R1
LT6202
V
S
= ±5V
499k
1pF
C1
R2
LT6202/03/04 F04
V
OUT
m
P-P
, approximately
over a 20MHz
17
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