General Description
The MAX4004/MAX4006 precision, high-side, current
monitors are specifically designed for monitoring photo-
diode current in fiber applications. They offer a connection
point for the reference current and a monitor output that
produces a signal proportional to the reference current.
The monitor output of the MAX4004 is a current propor-
tional to the reference current. The monitor output of the
MAX4006 is a voltage proportional to the reference cur-
rent. The current monitors have six decades of dynamic
range and monitor reference current of 250nA to 2.5mA
with better than 5% accuracy. The photodiode current can
be monitored from 10nA to 10mA with reduced accuracy.
The MAX4004/MAX4006 accept a +2.7V to +22V sup-
ply voltage, suitable for PIN photodiode applications.
(For higher voltage applications, refer to the MAX4007/
MAX4008 data sheet.) Internal current limiting (20mA,
typ) protects the device against short-circuit-to-ground
or excessive current conditions. A clamp diode protects
the monitor output from overvoltage. Additionally, these
devices feature thermal shutdown if the die temperature
reaches +150°C.
The MAX4004/MAX4006 are available in tiny, space-
saving 6-pin SOT23 packages, and operate over the
extended temperature range of -40°C to +85°C.
Applications
●Photodiode Current-Monitoring Systems
●Portable Instrumentation
●Medical Instrumentation
●Laboratory Instrumentation
●Consumer Electronics
●Current-to-Voltage Conversion
●Level Translation
Features
●Wide Reference Current Dynamic Range
• Guaranteed 250nA to 2.5mA with 5% Accuracy
• Extended 10nA to 10mA with 10% Monitor
Accuracy
●Current (MAX4004) or Voltage (MAX4006) Monitor
Output
●Reference Current-Limit Protection (20mA, typ)
●Voltage Clamp Protects Subsequent Output Circuitry
●+2.7V to +22V Wide Voltage Range Operation
●6-Pin SOT23 Packages
19-2742; Rev 3; 6/15
Typical Operating Circuit appears at end of data sheet.
Note: All devices are specified over the -40°C to +85°C operat-
ing temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
PART PIN-PACKAGE TOP MARK
MAX4004EUT-T 6 SOT23 ABNL
MAX4004EUT+T 6 SOT23 —
MAX4006EUT-T 6 SOT23 ABNN
PART PIN-PACKAGE INTERNAL
RESISTOR
TYPICAL
ACCURACY
MAX4004EUT-T 6 SOT23 None 5%
MAX4006EUT-T 6 SOT23 10kΩ 1%
GND
REFOUT
1 6 BIAS
5 N.C.
CLAMP
MAX4004
MAX4006
SOT23
TOP VIEW
2
3 4
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Pin Conguration
Ordering Information
Selector Guide
CLAMP to GND .....................................................-0.3V to +25V
BIAS, REF to GND ................................................-0.3V to +25V
OUT to GND ....................................... -0.3V to (VCLAMP + 0.6V)
Short-Circuit, REF to GND ........................................Continuous
Current into any Pin .........................................................±30mA
Continuous Power Dissipation (TA = +70°C)
6-Pin SOT23 (derate 8.7mW/°C above +70°C) ..........696mW
Operating Temperature Range ........................... -40°C to +85°C
Junction Temperature ...................................................... +150°C
Storage Temperature Range ............................ -65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
(VBIAS = 5V, GND = 0V, REF = Open, VOUT = 0V (MAX4004), CLAMP = Open, TA = -40°C to +85°C. Typical values are at TA = +25°C,
unless otherwise noted.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Bias Voltage Range VBIAS Inferred from power-supply rejection test 2.7 22 V
Bias Quiescent Current IBIAS
IREF = 250nA 40 100 µA
IREF = 2.5mA 3.6 4 mA
Reference Voltage VREF IREF = 2.5mA VBIAS - 1.1 VBIAS - 0.8 V
Thermal Shutdown
Engage Temperature TSHDN
REF shorted to GND, junction
temperature rising 150 °C
Trip-Point Temperature
Hysteresis THYS REF shorted to GND, junction
temperature falling 5 °C
Input Current Limit ILIM VREF = VBIAS - 5V 20 mA
MAX4004
Output Current Noise iNOUT
f = 0.1Hz to 10Hz IREF = 250nA 0.3
pARMS
IREF = 2.5mA 63
f = 0.1Hz to 10kHz IREF = 250nA 9.2
IREF = 2.5mA 1240
MAX4006
Output Voltage Noise eNOUT
f = 0.1Hz to 10Hz IREF = 250nA 0.041
µVRMS
IREF = 2.5mA 0.63
f = 0.1Hz to 10kHz IREF = 250nA 1.3
IREF = 2.5mA 12.5
Output Resistance ROUT
MAX4004 IREF = 250nA 50 GΩ
IREF = 2.5mA 5 MΩ
MAX4006 10 kΩ
Output Leakage REF = open 1 pA
Output Voltage Range VOUT
VBIAS = 2.7V to 22V, IREF = 0 to 1mA,
MAX4004: ΔIOUT/IOUT = ±1%,
MAX4006: ΔIVOUT/IOUT = ±1%
0 to VBIAS
- 1.5
0 to VBIAS -
0.85 V
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Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these
or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Electrical Characteristics
(VBIAS = 5V, GND = 0V, REF = Open, VOUT = 0V (MAX4004), CLAMP = Open, TA = -40°C to +85°C. Typical values are at TA = +25°C,
unless otherwise noted.) (Note 1)
Note 1: All devices are 100% tested at room temperature (TA = +25°C). All temperature limits are guaranteed by design.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Output Clamp Voltage VOUT -
VCLAMP
0.6 V
Output Clamp Leakage VCLAMP = 0 to 22V 1 pA
MAX4004 Current Gain IOUT/IREF
IREF = 250nA 0.09 0.099 0.11
mA/mAIREF = 2.5mA 0.094 0.095 0.106
IREF = 10mA, VBIAS = 12V 0.098
MAX4006
Transimpedance Gain VOUT/IREF
IREF = 250nA 0.9 0.995 1.1
V/mAIREF = 2.5mA 0.95 0.998 1.05
IREF = 10mA, VBIAS = 12V 0.992
Power-Supply
Rejection Ratio (PSRR)
(ΔIOUT/IOUT)
/ΔVBIAS
MAX4004:
VBIAS = 2.7V to 22V
IREF = 250nA 50 1000
ppm/V
IREF = 1mA 50 1000
(ΔVOUT/VOUT)
/ΔVBIAS
MAX4006:
VBIAS = 2.7V to 22V IREF = 1mA 50 1000
Power-Up Settling Time tS
IOUT settles within
0.1%, CIN = 10nF
between REF and GND
IREF = 250nA 7.5 ms
IREF = 2.5mA 90 µs
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Electrical Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
BIAS CURRENT
vs. REFERENCE CURRENT
MAX4004/6 toc02
IREF (A)
BIAS CURRENT (mA)
1m100µ10µ1µ100n
0.1
1
10
0.01
10n 10m
VBIAS = 5V
BIAS CURRENT
vs. TEMPERATURE
MAX4004/6 toc03
TEMPERATURE (°C)
BIAS CURRENT (mA)
603510-15
0.1
1
10
0.01
-40 85
IREF = 250nA
IREF = 2.5mA VBIAS = 5V
GAIN ERROR
vs. REFERENCE CURRENT
MAX4004/6 toc04
IREF (A)
GAIN ERROR (%)
1m100µ10µ1µ100n
-4
-3
-2
-1
0
1
2
3
4
5
-5
10n 10m
VBIAS = 5V
-4.0
-2.5
-3.0
-3.5
-2.0
-1.5
-1.0
-0.5
0
0.5
1.0
-40 10-15 35 60 85
GAIN ERROR vs. TEMPERATURE
MAX4004/6 toc05
TEMPERATURE (°C)
GAIN ERROR (%)
IREF = 10nA
IREF = 5mA
IREF = 2.5A
IREF = 250µA
IREF = 2.5µA
IREF = 250nA
VBIAS = 5V
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0
0.2
2 7 12 17 22
GAIN ERROR
vs. BIAS VOLTAGE
MAX4004/6 toc06
VBIAS (V)
GAIN ERROR (%)
IREF = 250nA
IREF = 25µA
IREF = 2.5mA
IREF = 5mA
BIAS CURRENT
vs. SUPPLY VOLTAGE
MAX4004/6 toc01
SUPPLY VOLTAGE (V)
BIAS CURRENT (mA)
20148
0.1
1
10
0.01
2 26
IREF = 250nA
IREF = 2.5mA
TRANSIENT RESPONSE
(VBIAS = 5V)
MAX4004/6 toc07
IOUT
0.1mA/div
IREF
1.0mA/div
400ns/div
0A
0A
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Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
40ms/div
STARTUP DELAY
(VBIAS = 5V, IREF = 250nA)
CH1
MAX4004/6 toc08
0V
0V
CH2
RREF = 16.8MΩ
R1 = 118MΩ
RTEST = 1.67MΩ
CH1: 2V/div
CH2: 10mV/div
VBIAS
RTEST
RREF
BIAS
CH2
13pF
CH1
R1
D.U.T.
REF OUT
4ms/div
STARTUP DELAY
(VBIAS = 5V, IREF = 2.5mA)
CH1
MAX4004/6 toc09
0V
0V
CH2
RREF = 1.68kΩ
R1 = 0Ω
RTEST = 14.0kΩ
CH1: 2V/div
CH2: 1V/div
VBIAS
RTEST
RREF
BIAS
CH2
13pF
CH1
R1
D.U.T.
REF OUT
10ms/div
STARTUP DELAY
(VBIAS = 2.7V, IREF = 250nA)
CH1
MAX4004/6 toc10
0V
0V
CH2
RREF = 8.8MΩ
R1 = 0Ω
RTEST = 8.1MΩ
CH1: 1V/div
CH2: 50mV/div
VBIAS
RTEST
RREF
BIAS
CH2
13pF
CH1
R1
D.U.T.
REF OUT
10ms/div
STARTUP DELAY
(VBIAS = 2.7V, IREF = 2.5mA)
CH1
MAX4004/6 toc11
0V
0V
CH2
RREF = 794Ω
R1 = 0Ω
RTEST = 4.01kΩ
CH1: 1V/div
CH2: 200mV/div
VBIAS
RTEST
RREF
BIAS
CH2
13pF
CH1
R1
D.U.T.
REF OUT
20ms/div
SHORT-CIRCUIT RESPONSE
(VBIAS = 5V)
MAX4004/6 toc12
0A
CH1
CH1: IBIAS, 10mA/div
A: REF SHORTS TO GND
B: CURRENT LIMIT ACTIVE
C: THERMAL SHUTDOWN
AB
C
TA = +148°C
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Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
PIN NAME FUNCTION
MAX4004 MAX4006
1 1 CLAMP Clamp Voltage Input. External potential used for voltage
clamping of VOUT.
2 2 GND Ground
3 — OUT Current-Monitor Output. OUT sources a current of 1/10th IREF.
4 4 REF Reference Current Output. REF provides the source current to
the cathode of the photodiode.
5 5 N.C. No Connection. Not internally connected.
6 6 BIAS Bias Voltage Input. Bias voltage for photodiode.
— 3 OUT
Current-Monitor Output. OUT presents a voltage proportional to
IREF at 1V/mA. An internal 10kΩ resistor connects OUT to GND
(see Functional Diagram).
10ms/div
SHORT-CIRCUIT RESPONSE
(VBIAS = 22V)
MAX4004/6 toc13
0A
CH1
CH1: IBIAS, 10mA/div
A: REF SHORTS TO GND
B: CURRENT LIMIT ACTIVE
C: THERMAL SHUTDOWN
ABC
TA = +120°C
VOLTAGE DROP
vs. REFERENCE CURRENT
MAX4004/6 toc14
REFERENCE CURRENT (A)
VBIAS - VREF (V)
1m100µ10µ1µ
0.20
0.40
0.60
0.80
1.00
1.20
1.40
0
100n 10m
A: TA = -40°C
B: TA = +25°C
C: TA = +85°C
D: TA = +100°C
A
B
C
D
VBIAS = 2.7V
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Typical Operating Characteristics (continued)
Pin Conguration
Detailed Description
The MAX4004/MAX4006 are versatile current monitors
intended for monitoring DC photodiode current in fiber
applications (see the Functional Diagram). The MAX4004
output is a current that is exactly one-tenth of the refer-
ence current. The MAX4006 outputs a voltage that is pro-
portional to the reference current with a transimpedance
gain of 1V/mA achieved by a factory-trimmed, internal
10kΩ resistor.
Both current devices have six decades of dynamic range
and monitor reference current ranging from 250nA to
2.5mA, the nominal operating range, with better than
5% accuracy across the entire reference current, bias
voltage, and temperature ranges. The corresponding
monitor outputs produce 25nA to 0.25mA (MAX4004) and
0.25mV to 2.5V (MAX4006). When the reference currents
are extended to the broader range of 10nA to 10mA, an
accuracy of less than 10% is maintained. Internal current
limiting (20mA, typ) protects the device against short-
circuit-to-ground conditions, and a thermal shutdown fea-
ture reduces both the reference current and the monitor
current to zero if the die temperature reaches +150°C.
The MAX4004/MAX4006 accept a +2.7V to +22V sup-
ply voltage, suitable for PIN photodiode applications.
A clamping diode, shown in the Functional Diagram, is
provided to protect subsequent output circuitry from an
overvoltage condition.
Applications Information
Clamping the Monitor Output Voltage
CLAMP provides a means for diode clamping the voltage
at OUT, thus VOUT is limited to VCLAMP + 0.6V. CLAMP
can be connected to either an external supply, to BIAS,
or can be left floating if voltage clamping is not required.
Using PIN Photodiodes in Fiber
Applications
When using the MAX4004/MAX4006 to monitor PIN
photodiode currents in fiber applications, several issues
must be addressed. In applications where the photodiode
must be fully depleted, keep track of voltages budgeted
for each component with respect to the available supply
voltage(s). The current monitor requires as much as 1.2V
between BIAS and REF, which must be considered as
part of the overall voltage budget.
Additional voltage margin can be created if a negative
supply is used in place of a ground connection, as long
as the overall voltage drop experienced by the MAX4004/
MAX4006 is less than or equal to 22V. For this type of
application, the MAX4004 is suggested so the output can
be referenced to “true” ground and not the negative sup-
ply. The MAX4004’s output current can be referenced as
desired with either a resistor to ground or a transimped-
ance amplifier. Take care to ensure that output voltage
excursions do not interfere with the required margin
between BIAS and OUT.
CURRENT
CLAMP
10x
BIAS
REF
CLAMP
OUT
1x
GND
MAX4004
CURRENT
MONITOR
CURRENT
CLAMP
10x
BIAS
REF
CLAMP
OUT
1x
MAX4006
CURRENT
MONITOR
10kΩ
GND
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Functional Diagrams
In many fiber applications, OUT is connected directly to
an ADC that operates from a supply voltage that is less
than the voltage at BIAS. Connecting the MAX4004/
MAX4006’s clamping diode output, CLAMP, to the ADC
power supply helps avoid damage to the ADC. Without
this protection, voltages can develop at OUT that can
destroy the ADC. This protection is less critical when
OUT is connected directly to subsequent transimpedance
amplifiers (linear or logarithmic) that have low-impedance,
near-ground-referenced inputs. If a transimpedance amp
is used on the low side of the photodiode, its voltage drop
must also be considered. Leakage from the clamping
diode is most often insignificant over nominal operating
conditions, but grows with temperature.
To maintain low levels of wideband noise, lowpass filter-
ing the output signal is suggested in applications where
only DC measurements are required. Determining the
required filtering components is straightforward, as the
MAX4004 exhibits a very high output impedance (> 5MΩ),
while the MAX4006 exhibits an output resistance of 10kΩ.
In some applications where pilot tones are used to identify
specific fiber channels, higher bandwidths are desired
at OUT to detect these tones. Consider the minimum
and maximum currents to be detected, then consult the
frequency response and noise typical operating curves.
If the minimum current is too small, insufficient monitor
bandwidth could result, while too high of a current could
result in excessive monitor noise across the desired
bandwidth.
Bypassing and External Components
In applications where power-supply noise can interfere
with DC diode measurements, additional filtering is sug-
gested. Such noise is commonly seen when switching
power supplies are used to generate the photodiode bias
voltage. As shown in the typical operating circuit, a pi filter
(two 0.22μF capacitors and one 2.2μH inductor) greatly
suppress power-supply switching noise. If such a filter is
already present in the bias-generating circuit, only a sim-
ple bypass capacitor at the BIAS pin is suggested. The
output lowpass filter, a 10kΩ resistor and a 10nF capaci-
tor, further reduce permeating power-supply noise as well
as other wideband noise that might otherwise restrict
measurements at low signal levels. Again, reducing the
bandwidth of the OUT signal can affect performance of
pilot-tone systems.
To restrict high-frequency photodiode signals from affect-
ing the current monitor and BIAS power supply, an RF
choke and 10nF capacitor can be added. The capaci-
tance presented to REF should not exceed 10nF; larger
values increase startup time and could cause the thermal
shutdown circuit to activate during startup.
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CURRENT
CLAMP
PIN
PHOTODIODE
+2.7V TO +22V 2.2µH
0.22µF
10nF
10kΩ
0.22µF
10x
BIAS
REF
CLAMP
OUT
1x
ADC
TIA
GND
+5V
+5V
TO LIMITING
AMPLIFIER
HIGH-SPEED DATA PATH
MAX4004
CURRENT
MONITOR
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Typical Operating Circuit
Chip Information
TRANSISTOR COUNT: 195
PROCESS: BiCMOS
PACKAGE TYPE PACKAGE CODE DOCUMENT NO. LAND PATTERN NO.
6 SOT23 U6SN-1 21-0058 90-0175
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
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Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 1/03 Initial release —
1 5/03 Removed QFN package and revised Typical Operating Characteristics 1, 2, 4, 8, 9, 11, 12
2 2/06 Removed MAX4009 reference from data sheet 8
3 6/15 Updated Ordering Information 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
