MAXIM MAX4004EUT-T

19-2742; Rev 1; 5/03
High-Accuracy, High-Side Current Monitors
in SOT23
Applications
Photodiode Current-Monitoring Systems
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
Ordering Information
TOP
MARK
PART
TEMP RANGE
PIN-PACKAGE
MAX4004EUT-T
-40°C to +85°C
6 SOT23-6
ABNL
MAX4006EUT-T
-40°C to +85°C
6 SOT23-6
ABNN
Portable Instrumentation
Medical Instrumentation
Laboratory Instrumentation
Consumer Electronics
Current-to-Voltage Conversion
Pin Configuration
Level Translation
Selector Guide
INTERNAL
TYPICAL
RESISTOR ACCURACY
PART
PIN-PACKAGE
MAX4004EUT-T
6 SOT23-6
None
5%
MAX4006EUT-T
6 SOT23-6
10kΩ
1%
TOP VIEW
CLAMP 1
GND 2
MAX4004
MAX4006
OUT 3
Typical Operating Circuit appears at end of data sheet.
6
BIAS
5
N.C.
4
REF
SOT23
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1
MAX4004/MAX4006
General Description
The MAX4004/MAX4006 precision, high-side, current
monitors are specifically designed for monitoring photodiode 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
proportional to the reference current. The monitor output of the MAX4006 is a voltage proportional to the reference current. 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 supply
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, spacesaving 6-pin SOT23 packages, and operate over the
extended temperature range of -40°C to +85°C.
MAX4004/MAX4006
High-Accuracy, High-Side Current Monitors
in SOT23
ABSOLUTE MAXIMUM RATINGS
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
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)
PARAMETER
SYMBOL
Bias Voltage Range
VBIAS
Bias Quiescent Current
IBIAS
Reference Voltage
VREF
CONDITIONS
Inferred from power-supply
rejection test
TYP
2.7
MAX
UNITS
22
V
IREF = 250nA
40
100
µA
IREF = 2.5mA
3.6
4
mA
VBIAS - 0.8
V
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
Thermal Shutdown
Engage Temperature
IREF = 2.5mA
f = 0.1Hz to 10Hz
MAX4004
Output Current Noise
iNOUT
f = 0.1Hz to 10kHz
f = 0.1Hz to 10Hz
MAX4006
Output Voltage Noise
eNOUT
f = 0.1Hz to 10kHz
Output Resistance
ROUT
Output Leakage
Output Voltage Range
2
MIN
VOUT
MAX4004
VBIAS - 1.1
IREF = 250nA
0.3
IREF = 2.5mA
63
IREF = 250nA
9.2
IREF = 2.5mA
1240
IREF = 250nA
0.041
IREF = 2.5mA
0.63
IREF = 250nA
1.3
pARMS
µVRMS
IREF = 2.5mA
12.5
IREF = 250nA
50
GΩ
IREF = 2.5mA
5
MΩ
MAX4006
10
kΩ
REF = open
1
pA
0 to VBIAS
- 0.85
V
VBIAS = 2.7V to 22V, IREF = 0 to 1mA,
MAX4004: ∆IOUT/IOUT = ±1%,
MAX4006: ∆VOUT/IOUT = ±1%
0 to VBIAS
- 1.5
_______________________________________________________________________________________
High-Accuracy, High-Side Current Monitors
in SOT23
(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
Output Clamp Voltage
SYMBOL
MIN
VOUT VCLAMP
Output Clamp Leakage
MAX4004 Current Gain
CONDITIONS
VOUT/IREF
1
0.099
0.11
IREF = 2.5mA
0.094
0.095
0.106
0.9
0.995
1.1
IREF = 2.5mA
0.95
0.998
1.05
Power-Up Settling Time
MAX4004:
VBIAS = 2.7V to 22V
(∆VOUT/VOUT)
/∆VBIAS
MAX4006:
VBIAS = 2.7V to 22V
tS
V/mA
0.992
IREF = 250nA
50
1000
IREF = 1mA
50
1000
IREF = 1mA
50
1000
IOUT settles within 0.1%, IREF = 250nA
CIN = 10nF between
IREF = 2.5mA
REF and GND
mA/mA
0.098
IREF = 250nA
IREF = 10mA, VBIAS = 12V
Power-Supply Rejection
Ratio (PSRR)
pA
0.09
(∆IOUT/IOUT)
/∆VBIAS
UNITS
V
IREF = 250nA
IREF = 10mA, VBIAS = 12V
MAX4006
Transimpedance Gain
MAX
0.6
VCLAMP = 0 to 22V
IOUT/IREF
TYP
ppm/V
7.5
ms
90
µs
Note 1: All devices are 100% tested at room temperature (TA = +25°C). All temperature limits are guaranteed by design.
_______________________________________________________________________________________
3
MAX4004/MAX4006
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
1
IREF = 250nA
10
BIAS CURRENT (mA)
VBIAS = 5V
BIAS CURRENT (mA)
IREF = 2.5mA
MAX4004/6 toc02
10
MAX4004/6 toc01
10
1
0.1
0.01
8
14
26
20
100n
1µ
10µ
100µ
0.1
10m
1m
-40
-15
IREF (A)
VBIAS = 5V
4
3
60
GAIN ERROR vs. TEMPERATURE
1
0
-1
VBIAS = 5V
IREF = 10nA
0.5
0
GAIN ERROR (%)
2
-0.5
-1.0
IREF = 250nA
-1.5
IREF = 2.5µA
-2.0
-2
-2.5
-3
-3.0
-4
-3.5
-5
IREF = 250µA
IREF = 2.5A
IREF = 5mA
-4.0
10n
100n
1µ
10µ
100µ
1m
10m
-40
-15
10
35
60
IREF (A)
TEMPERATURE (°C)
GAIN ERROR
vs. BIAS VOLTAGE
TRANSIENT RESPONSE
(VBIAS = 5V)
85
MAX4004/6 toc07
MAX4004/6 toc06
0.2
0
-0.2
IREF = 250nA
-0.4
IREF = 25µA
IREF
1.0mA/div
0A
-0.6
-0.8
IREF = 2.5mA
IOUT
0.1mA/div
-1.0
0A
-1.2
IREF = 5mA
-1.4
2
7
12
17
22
400ns/div
VBIAS (V)
4
35
1.0
MAX4004/6 toc04
5
10
TEMPERATURE (°C)
GAIN ERROR
vs. REFERENCE CURRENT
GAIN ERROR (%)
1
0.01
10n
SUPPLY VOLTAGE (V)
GAIN ERROR (%)
VBIAS = 5V
IREF = 250nA
0.01
2
IREF = 2.5mA
MAX4004/6 toc05
0.1
BIAS CURRENT
vs. TEMPERATURE
BIAS CURRENT
vs. REFERENCE CURRENT
MAX4004/6 toc03
BIAS CURRENT
vs. SUPPLY VOLTAGE
BIAS CURRENT (mA)
MAX4004/MAX4006
High-Accuracy, High-Side Current Monitors
in SOT23
_______________________________________________________________________________________
85
High-Accuracy, High-Side Current Monitors
in SOT23
MAX4004/6 toc09
STARTUP DELAY
(VBIAS = 5V, IREF = 2.5mA)
MAX4004/6 toc08
STARTUP DELAY
(VBIAS = 5V, IREF = 250nA)
CH1
CH1
0V
CH1
0V
VBIAS
BIAS
D.U.T.
REF
OUT
VBIAS
CH1
BIAS
D.U.T.
REF
OUT
R1
CH2
CH2
R1
CH2
RREF
13pF
CH2
RREF
RTEST
13pF
0V
RTEST
0V
40ms/div
4ms/div
RREF = 1.68kΩ
R1 = 0Ω
RTEST = 14.0kΩ
CH1: 2V/div
CH2: 1V/div
STARTUP DELAY
(VBIAS = 2.7V, IREF = 250nA)
CH1
SHORT-CIRCUIT RESPONSE
(VBIAS = 5V)
MAX4004/6 toc11
MAX4004/6 toc10
STARTUP DELAY
(VBIAS = 2.7V, IREF = 2.5mA)
MAX4004/6 toc12
RREF = 16.8MΩ
R1 = 118MΩ
RTEST = 1.67MΩ
CH1: 2V/div
CH2: 10mV/div
TA = +148°C
CH1
A
0V
CH1
0V
VBIAS
CH1
CH2
RREF
CH2
CH2
RREF
13pF
13pF
0A
RTEST
RTEST
0V
CH1
R1
R1
CH2
C
BIAS
D.U.T.
REF
OUT
BIAS
D.U.T.
REF
OUT
B
VBIAS
0V
10ms/div
RREF = 8.8MΩ
R1 = 0Ω
RTEST = 8.1MΩ
CH1: 1V/div
CH2: 50mV/div
10ms/div
RREF = 794Ω
R1 = 0Ω
RTEST = 4.01kΩ
CH1: 1V/div
CH2: 200mV/div
20ms/div
CH1: IBIAS, 10mA/div
A: REF SHORTS TO GND
B: CURRENT LIMIT ACTIVE
C: THERMAL SHUTDOWN
_______________________________________________________________________________________
5
MAX4004/MAX4006
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
VOLTAGE DROP
vs. REFERENCE CURRENT
SHORT-CIRCUIT RESPONSE
(VBIAS = 22V)
TA = +120°C
MAX4004/6 toc14
1.40
MAX4004/6 toc13
VBIAS = 2.7V
1.20
1.00
A
B
VBIAS - VREF (V)
MAX4004/MAX4006
High-Accuracy, High-Side Current Monitors
in SOT23
C
CH1
0.80
A
0.60
B
0.40
0A
C
0.20
A: TA = -40°C
B: TA = +25°C
C: TA = +85°C
D: TA = +100°C
D
0
100n
10ms/div
1µ
10µ
100µ
1m
10m
REFERENCE CURRENT (A)
CH1: IBIAS, 10mA/div
A: REF SHORTS TO GND
B: CURRENT LIMIT ACTIVE
C: THERMAL SHUTDOWN
Pin Description
PIN
6
NAME
FUNCTION
MAX4004
MAX4006
1
1
CLAMP
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).
Clamp Voltage Input. External potential used for voltage
clamping of VOUT.
_______________________________________________________________________________________
High-Accuracy, High-Side Current Monitors
in SOT23
BIAS
BIAS
MAX4004
MAX4006
CURRENT
MONITOR
10x
CURRENT
MONITOR
10x
1x
1x
CLAMP
CLAMP
OUT
CURRENT
CLAMP
REF
REF
GND
OUT
CURRENT
CLAMP
10kΩ
GND
Detailed Description
Applications Information
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 reference current. The MAX4006 outputs a voltage
that is proportional to the reference current with a transimpedance gain of 1V/mA achieved by a factorytrimmed, internal 10kΩ resistor.
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.
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 feature 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
supply 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.
Clamping the Monitor Output Voltage
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 supply. The MAX4004’s output current can
be referenced as desired with either a resistor to
ground or a transimpedance amplifier. Take care to
ensure that output voltage excursions do not interfere
with the required margin between BIAS and OUT.
_______________________________________________________________________________________
7
MAX4004/MAX4006
Functional Diagrams
MAX4004/MAX4006
High-Accuracy, High-Side Current Monitors
in SOT23
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 filtering 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. See the MAX4009 family for devices
intended for fiber applications using pilot tones.
8
Bypassing and External Components
In applications where power-supply noise can interfere
with DC diode measurements, additional filtering is suggested. 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 simple bypass capacitor at the BIAS pin is suggested. The output lowpass filter, a 10kΩ resistor and a
10nF capacitor, 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
affecting the current monitor and BIAS power supply, an
RF choke and 10nF capacitor can be added. The
capacitance presented to REF should not exceed 10nF;
larger values increase startup time and could cause the
thermal shutdown circuit to activate during startup.
_______________________________________________________________________________________
High-Accuracy, High-Side Current Monitors
in SOT23
+2.7V TO +22V
2.2µH
0.22µF
0.22µF
BIAS
+5V
CURRENT
MONITOR
10x
1x
CLAMP
CURRENT
CLAMP
REF
+5V
OUT
ADC
10kΩ
MAX4004
10nF
GND
PIN
PHOTODIODE
TIA
TO LIMITING
AMPLIFIER
HIGH-SPEED DATA PATH
Chip Information
TRANSISTOR COUNT: 195
PROCESS: BiCMOS
_______________________________________________________________________________________
9
MAX4004/MAX4006
Typical Operating Circuit
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
6LSOT.EPS
MAX4004/MAX4006
High-Accuracy, High-Side Current Monitors
in SOT23
PACKAGE OUTLINE, SOT-23, 6L
21-0058
F
1
1
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2003 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.