140dB Range (1nA to 10mA)
SGM834A
Logarithmic Current-to-Voltage Converter
FUNCTIONAL BLOCK DIAGRAM
VPS
IREF
VOUT
Intercept Point
Reference
Voltage
0.6V
VPDB
-
Buffer
-
+
300Ω
Adaptive
Biasing
Active Shielding
BFNG
BFIN
QM
Q2
-
VSUM
INPT
0.5V
VPS
10kΩ
2V
VREF
VREF
VLOG
PWDN
-
+
C1
470pF
ILOG
VSUM
TCA
Voltage-to-Current
Conversion and
Temp-Compensation
VBE1
Q1
R1
750Ω
5kΩ
BIAS
Logarithmic Raw
Conversion TIA
SGM834A
GND
AGND
Figure 2. Functional Block Diagram
SG Micro Corp
www.sg-micro.com
FEBRUARY 2022
10