ltc6360 Linear Technology Corporation, ltc6360 Datasheet - Page 20

• Manufacturer Part Number: ltc6360
• Description: Very Low Noise Single-ended Sar Adc Driver With True Zero Output
• Manufacturer: Linear Technology Corporation

LTC6360
applicaTions inForMaTion
Interfacing to High Voltage Signals
Using the amplifier in the inverting configuration, with a
fixed input common mode voltage, allows the input signal
to traverse a swing beyond the LTC6360 supply rails.
A practical application for the inverting gain configuration
is translating a high voltage signal to a range suitable for
a low voltage SAR ADC. For a clean interface, two condi-
tions must be met:
1. The gain is selected so that full-scale signals at HV
2. V
20
are translated at the output of the LTC6360 to the ap-
propriate full-scale range for the ADC.
V
the average level of the input voltage.
OUT
FS
HV
Figure 12. Interfacing a ±10V Input Signal to a 5V ADC
+
–
IN
is the ADC full-scale input voltage and HV
0V
V
1.67V
= V
1
1.67k
10k
10V
FS
–10V
/2 when HV
+IN
–IN
+
–
10pF
2k
0.1µF
SHDN
5V
OUT
10
IN
LTC6360
330pF
is centered at HV
CHARGE
PUMP
CPI
V
OUT
V
CC
0.1µF
V
2V
0.1µF
DD
CPO
GND
6360 F12
0V
4V
NOM
1µF
10µF
, where
NOM
5V
IN
is
Applying the above constraints to the design equations
gives values for R
Applying these formulas to the case where ±10V input
signal is to be translated to a 0V to 4V full-scale range
yields the values shown in Figure 12.
I
PD
Figure 13. Low Noise, True Zero 1MΩ DC Precise Photodiode
Transimpedance Amplifier
V
R
CPI
1
F
SFH213
PHOTODIODE
= [V
10k
/ R
1µF
G
FS
=
/2 + R
[
0.1µF
[
C4
V
HV
OUT(MAX)
R3
10M
IN(MAX)
F
F
/R
5V
/R
R5
2k
J1 NXP
BF862
R2
1k
G
G
and V1:
• HV
– V
– HV
C6
0.1µF
NOM
–
+
OUT(MIN)
5V
IN(MIN)
U3
0.1µF
]/(1 + R
LTC2054
C5
]
]
R6
1k
F
/R
50fF (PARASITIC)
CPO CPI
–
+
LTC6360
G
)
5V
C1
CPO
U1
1M
R1
6360 F13
CPI
10µF
(10)
6360f
(9)