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MAX4007EUT-T中文资料

General Description

The MAX4007/MAX4008 precision, high-side, high-volt-age current monitors are specifically designed for mon-itoring 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 MAX4007 is a current proportional to the reference cur-rent. The monitor output of the MAX4008 is a voltage proportional to the reference current. The current moni-tors have six decades of dynamic range and monitor reference currents of 250nA to 2.5mA with better than 5% accuracy. The photodiode current can be moni-tored from 10nA to 10mA with reduced accuracy.

The MAX4007/MAX4008 accept a supply voltage of +2.7V to +76V, suitable for APD or PIN photodiode appli-cations. Internal current limiting (20mA, typ) protects the devices against short circuit to ground. A clamp diode protects the monitor output from overvoltage. Additionally,these devices feature thermal shutdown if the die temper-ature reaches +150°C.

The MAX4007/MAX4008 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% Monitor Accuracy

Extended 10nA to 10mA with 10% Monitor Accuracy ?Current (MAX4007) or Voltage (MAX4008) Monitor Outputs ?Reference Current-Limit Protection (20mA, typ)?Voltage Clamp Protects Subsequent Output Circuitry ?+2.7V to +76V Wide Voltage Range Operation ?6-Pin SOT23 Packages

MAX4007/MAX4008

High-Accuracy, 76V , High-Side

Current Monitors in SOT23

________________________________________________________________Maxim Integrated Products 1

Pin Configuration

Ordering Information

19-2743; Rev 3; 4/07

For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at https://www.wendangku.net/doc/0215591335.html,.

Typical Operating Circuit appears at end of data sheet.

Note:All devices are specified over the -40°C to +85°C operating temperature range.

M A X 4007/M A X 4008

High-Accuracy, 76V , High-Side Current Monitors in SOT232_______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

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.

CLAMP to GND ......................................................-0.3V to +80V BIAS, REF to GND..................................................-0.3V to +80V OUT to GND.........................................-0.3V to (V CLAMP + 0.6V)Short Circuit, REF to GND..........................................Continuous Current into Any Pin..........................................................±30mA Continuous Power Dissipation (T A = +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

MAX4007/MAX4008

High-Accuracy, 76V , High-Side

Current Monitors in SOT23

_______________________________________________________________________________________3

ELECTRICAL CHARACTERISTICS (continued)

(V BIAS = 40V, GND = 0V,REF = open, V OUT = 0V (MAX4007), CLAMP = open, T A = -40°C to +85°C. Typical values are at T A = +25°C,unless otherwise noted.) (Note 1)

M A X 4007/M A X 4008

High-Accuracy, 76V , High-Side Current Monitors in SOT234_______________________________________________________________________________________

Typical Operating Characteristics

(T A = +25°C, unless otherwise noted.)

GAIN ERROR vs. TEMPERATURE

TEMPERATURE (°C)

-15

-40

G A I N E R R O R (%)

123456789-1

GAIN ERROR vs. BIAS VOLTAGE

V BIAS (V)

20.5

39.057.5

76.0

2.0

G A I N E R R O R (%)-1.4

-1.2-1.0-0.8-0.6-0.4-0.200.2

400ns/div

TRANSIENT RESPONSE

(V BIAS = 40V)

A: CH2, 5V/div, I REF = 0 TO 2.5mA B: CH1, 1V/div, I OUT = 0 TO 0.25mA

40V BIAS

CH2

CH1

6.3k Ω10k Ω

12.1k Ω

D.U.T.REF OUT

0V CH2CH1

STARTUP DELAY

(V BIAS = 40V, I REF = 250nA)

20ms/div

R REF = 158m ΩR1 = 118m ΩR TEST = 1.67m ΩCH1: 10V/div

CH2: 20mV/div V BIAS R TEST

R REF

BIAS CH2

13pF

CH1

D.U.T.REF OUT

BIAS CURRENT vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

B I A S

C U R R E N T (m A )

0.1

0.01

BIAS CURRENT

vs. REFERENCE CURRENT

I REF (A)

B I A S

C U R R E N T

(m A )

100μ

10μ1μ

100n

0.10

1.00

10.00

100.00

0.01

10n

10m

BIAS CURRENT vs. TEMPERATURE

TEMPERATURE (°C)

B I A S

C U R R E N T (m A )

-15

0.1

0.01

-40

GAIN ERROR vs.REFERENCE CURRENT

I REF (A)

100n

1μ

10μ100μ

1m 10m

10n

G A I N E R R O R (%)

-4-3-2-1012345-50V

0V CH2CH1

STARTUP DELAY

(V BIAS = 40V, I REF = 2.5mA)

20ms/div

R REF = 15.8k ΩR1 = 0Ω

R TEST = 140k ΩCH1: 10V/div CH2: 10V/div

V BIAS R TEST

R REF

BIAS

CH2

13pF

CH1

D.U.T.REF OUT

MAX4007/MAX4008

High-Accuracy, 76V , High-Side

Current Monitors in SOT23

_______________________________________________________________________________________5

CH2CH1STARTUP DELAY (V BIAS = 5V, I REF = 250nA)

MAX4007/8 toc1040ms/div

R REF = 16.8m ΩR1 = 118m ΩR TEST = 1.67m ΩCH1: 2V/div CH2: 10V/div

V BIAS R TEST

R REF

BIAS CH2

13pF

CH1

D.U.T.REF OUT

CH2

CH1

STARTUP DELAY

(V BIAS = 5V, I REF = 2.5mA)

MAX4007/8 toc114ms/div

R REF = 1.68k Ω

R1 = 0Ω

R TEST = 14.0k ΩCH1: 2V/div CH2: 1V/div

V BIAS R TEST

R REF

BIAS

CH2

13pF

CH1

D.U.T.REF OUT

CH1

20ms/div

SHORT-CIRCUIT RESPONSE

(V BIAS = 40V)

MAX4007/8 toc12

CH1: I BIAS , 10.0mA/div A: REF SHORTS TO GND B: CURRENT LIMIT ACTIVE C: THERMAL SHUTDOWN D: POST COOL-DOWN RETRY

T A = +85°C

CH10A

40ms/div

SHORT-CIRCUIT RESPONSE

(V BIAS = 76V)

MAX4007/8 toc13

CH1: I BIAS , 10.0mA/div A: REF SHORTS TO GND B: CURRENT LIMIT ACTIVE C: THERMAL SHUTDOWN D: POST COOL-DOWN RETRY

T A = +85°C

VOLTAGE DROP

vs. REFERENCE CURRENT

REFERENCE CURRENT (A)

1μ

10μ

100μ

10m

100n

V B I A S - V R E F (V )

00.20

0.400.600.801.00

1.201.40

Typical Operating Characteristics (continued)

(T A = +25°C, unless otherwise noted.)

M A X 4007/M A X 4008

High-Accuracy, 76V , High-Side Current Monitors in SOT23

Functional Diagrams

MAX4007/MAX4008

High-Accuracy, 76V , High-Side

Current Monitors in SOT23

_______________________________________________________________________________________7

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 MAX4007/MAX4008 accept a supply voltage of +2.7V to +76V, suitable for APD photodiode applica-tions. A clamping diode, shown in the Functional Diagram , is provided to protect subsequent output cir-cuitry from an overvoltage condition.

Applications Information

Clamping the Monitor Output Voltage

CLAMP provides a means for diode clamping the volt-age at OUT; thus, V OUT is limited to V CLAMP + 0.6V.CLAMP can be connected to either an external supply,to BIAS, or may be left floating if voltage clamping is not required.

Using APD or PIN Photodiodes in Fiber

Applications

When using the MAX4007/MAX4008 to monitor APD or PIN photodiode currents in fiber applications, several issues must be addressed. In applications where the photodiode must be fully depleted, keep track of volt-ages budgeted for each component with respect to the available supply voltage(s). The current monitors require as much as 1.1V between BIAS and REF, which must be considered 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 MAX4007/MAX4008 is less than or equal to 76V. For this type of application, the MAX4007 is suggested so the output can be referenced to “true” ground and not the negative supply. The MAX4007’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. 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 MAX4007/MAX4008s’ clamping diode output, CLAMP,to the ADC power supply helps avoid damage to the ADC. Without this protection, voltages can develop at OUT that might 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 insignif-icant over nominal operating conditions, but grows with temperature.

To maintain low levels of wideband noise, lowpass fil-tering the output signal is suggested in applications where only DC measurements are required.Determining the required filtering components is straightforward, as the MAX4007 exhibits a very high output impedance (>5M Ω), while the MAX4008 exhibits an output resistance of 10k Ω.

In some applications where pilot tones are used to iden-tify specific fiber channels, higher bandwidths are desired at OUT to detect these tones. Consider the mini-mum and maximum currents to be detected, then con-sult the frequency response and noise typical operating curves. If the minimum current is too small, insufficient bandwidth could result, while too high a current could result in excessive 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 induc-tor) greatly suppresses power-supply switching noise. If such a filter is already present in the bias generating cir-cuit, only a simple bypass capacitor at the BIAS pin is suggested. The output lowpass filter, a 10k Ωresistor 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 monitors 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.

M A X 4007/M A X 4008

High-Accuracy, 76V , High-Side Current Monitors in SOT238_______________________________________________________________________________________

Chip Information

TRANSISTOR COUNT: 195PROCESS: BiCMOS

Typical Operating Circuit

MAX4007/MAX4008

High-Accuracy, 76V , High-Side

Current Monitors in SOT23

_______________________________________________________________________________________9

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 https://www.wendangku.net/doc/0215591335.html,/packages .)

M A X 4007/M A X 4008

High-Accuracy, 76V , High-Side Current Monitors in SOT23Maxim cannot assume re sponsibility for use of any circuitry othe r than circuitry e ntire ly e mbodie d in a Maxim product. No circuit pate nt lice nse s 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?2007 Maxim Integrated Products

is a registered trademark of Maxim Integrated Products, Inc.

Revision History

Pages changed at Rev 3: 1, 3, 10

Package Information (continued)

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to https://www.wendangku.net/doc/0215591335.html,/packages .)