MAX4206 Datasheet, PDF (1/17 Pages) Maxim Integrated Products – Precision Transimpedance Logarithmic Amplifier with Over 5 Decades of Dynamic Range

19-3071; Rev 0; 12/03
EVAALVUAAILTAIOBNLEKIT _{Precision Transimpedance Logarithmic}
Amplifier with Over 5 Decades of Dynamic Range
General Description
The MAX4206 logarithmic amplifier computes the log
ratio of an input current relative to a reference current
(externally or internally generated) and provides a cor-
responding voltage output with a default 0.25V/decade
scale factor. The device operates from a single +2.7V
to +11V supply or from dual ±2.7V to ±5.5V supplies
and is capable of measuring five decades of input cur-
rent across a 10nA to 1mA range.
The MAX4206’s uncommitted op amp can be used for
a variety of purposes, including filtering noise, adding
offset, and adding additional gain. A 0.5V reference is
also included to generate an optional precision current
reference using an external resistor, which adjusts the
log intercept of the MAX4206. The output-offset voltage
and the adjustable scale factor are also set using exter-
nal resistors.
The MAX4206 is available in a space-saving 16-pin thin
QFN package (4mm x 4mm x 0.8mm), and is specified
for operation over the -40°C to +85°C extended temper-
ature range.
Applications
Photodiode Current Monitoring
Portable Instrumentation
Medical Instrumentation
Analog Signal Processing
Pin Configuration
TOP VIEW
(LEADS ON BOTTOM)
16 15 14 13
N.C. 1
REFVOUT 2
GND 3
V_EE 4
MAX4206
12 CMVOUT
11 REFISET
10 V_CC
9 N.C.
5678
THIN QFN
Features
♦ +2.7V to +11V Single-Supply Operation
♦ ±2.7V to ±5.5V Dual-Supply Operation
♦ 5 Decades of Dynamic Range (10nA to 1mA)
♦ Monotonic Over a 1nA to 1mA Range
♦ 0.25V/Decade Internally Trimmed Output Scale
Factor
♦ Adjustable Output Scale Factor
♦ Adjustable Output Offset Voltage
♦ Internal 10nA to 10µA Reference Current Source
♦ 0.5V Input Common-Mode Voltage
♦ Small 16-Pin Thin QFN Package (4mm x 4mm x
0.8mm)
♦ -40°C to +85°C Operating Temperature Range
♦ Evaluation Kit Available
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX4206ETE
-40°C to +85°C 16 Thin QFN-EP*
*EP = Exposed Paddle.
Typical Operating Circuit
I_IN
0.1µF
C_COMP
R_COMP
C_COMP
R_COMP
0.1µF
R_SET
V_CC
V_CC
LOGIIN
REFIOUT
REFIIN
V_OUT
LOGV2
R2
SCALE
R1
MAX4206
REFVOUT
CMVIN
CMVOUT
LOGV1
REFISET
OSADJ
GND V_EE
0.1µF
R_OS
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