DS3920_1112 [MAXIM]
Fast Current Mirror; 快速电流镜
| 型号： | DS3920_1112 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Fast Current Mirror |
| 文件： | 总7页 (文件大小：1386K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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19-5797; Rev 2; 12/11
General Description
Features
The DS3920 precision current mirror is designed for ava-
lanche photodiode (APD) and PIN photodiode biasing
and monitoring applications. The device offers a current
clamp to limit current through the APD and a current mir-
ror output that produces a signal proportional (5:1) to the
APD current. A diode is also provided to limit the voltage
at the current mirror output.
SꢀWideꢀVoltageꢀInputꢀRange:ꢀ2.97Vꢀtoꢀ76V
SꢀCurrentꢀMonitor
ꢀ Wideꢀ250nAꢀtoꢀ2mAꢀRange
ꢀ 5:1ꢀMirrorꢀRatio
ꢀ Fastꢀ50nsꢀTimeꢀConstant
SꢀCurrentꢀClampꢀ(4.4mAꢀorꢀ20mA,ꢀtyp)
SꢀVoltageꢀClampꢀProtectsꢀSubsequentꢀOutputꢀCircuitry
Sꢀ6-PinꢀSOT23ꢀ(MAX4007ꢀCompatible)
The device accepts a +2.97V to +76V current mirror
supply voltage. Internal current limiting (4.4mA or 20mA,
typ) protects the monitored device from a short circuit to
ground. The provided internal clamp diode protects the
current mirror output from overvoltage. Additionally, the
device features thermal shutdown if the die temperature
reaches +150NC.
Applications
Avalanche Photodiode (APD) Biasing
PIN Photodiode Monitoring
GEPON, GPON, 10GEPON, XGPON: ONU and OLT
The device is available in a 6-pin SOT23 package, and
operates over the -40NC to +85NC extended temperature
range.
Ordering Information appears at end of data sheet.
Typical Application Circuit
APD BIAS
R
FILTER
100Ω–1000Ω
3.3V
MIRIN
DIODE
C
FILTER
0.1μF
CURRENT
MONITOR
I
I
/5
MIROUT
MIROUT
THERMAL
SHUTDOWN
I
/5
GND
MIR MIROUT
V
OUT
CURRENT
LIMIT
R
OUT
1kΩ–5kΩ
DS3920
MIROUT
R
AGC
499Ω
ROSA
APD
TIA
For related parts and recommended products to use with this part, refer to: www.maxim-ic.com/DS3920.related
Forꢀpricing,ꢀdelivery,ꢀandꢀorderingꢀinformation,ꢀpleaseꢀcontactꢀMaximꢀDirectꢀatꢀ1-888-629-4642,ꢀ
orꢀvisitꢀMaxim’sꢀwebsiteꢀatꢀwww.maxim-ic.com.
����������������������������������������������������������������� ꢀMaxim Integrated Productsꢀ ꢀ 2
DS3920
Fast Current Mirror
ABSOLUTEꢀMAXIMUMꢀRATINGS
Voltage Range on MIRIN, MIROUT,
Operating Junction Temperature Range ......... -40NC to +150NC
Storage Temperature Range............................ -55NC to +135NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
and DIODE Relative to GND ............................-0.3V to +80V
Voltage Range on MIR
Relative to GND .............................. -0.3V to (V
+ 0.6V)
DIODE
Continuous Power Dissipation (T = +70NC)
A
SOT23 (derate 13.4mW/NC above +70NC).............1072.4mW
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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.
ELECTRICALꢀCHARACTERISTICS
(V
= 2.97V to 76V, T = -40NC to +85NC, unless otherwise noted.)
A
MIRIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
76
UNITS
V
MIRIN Voltage
V
2.97
MIRIN
MIRIN Current
I
I
= 2.5mA
4.4
5
mA
MIRIN
MIROUT
Diode Forward Current
I
mA
DF
I
I
= 100FA, T = +25NC
0.6
DF
A
Diode Forward Voltage
V
V
DF
= 5mA, T = +25NC
1.25
40
8
DF
A
DS3920T-001 version, T = +25NC
10
2.8
20
A
MIROUT Current Limit
MIROUT Series Resistance
MIR to MIROUT Ratio
I
mA
MIROUT
DS3920T-002 version, T = +25NC
4.4
A
R
(Note 1)
100
W
AGC
1FA to 2.5mA
0.190
0.180
0.200
0.200
4800
100
0.210
0.220
15,000
500
K
A/A
MIR
I
> 2.5mA
MIROUT
V
= 3V (Note 2)
(DI
/I
)
MIRIN
MIRIN
MIR MIR
Power-Supply Rejection Ratio
ppm/V
ns
/DV
V
= 30V or 60V (Notes 2, 3)
MIRIN
MIR Current Rise Time
(20%/80%)
t
(Note 4)
30
RC
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
T
(Note 3)
(Note 3)
+150
20
NC
NC
SHDN
T
HYST
Noteꢀ1:ꢀ See the Typical Application Circuit.
Noteꢀ2:ꢀ 1V DC change applied to MIRIN; 100FA at MIROUT; 4.99kI load to ground on MIR.
Noteꢀ3:ꢀ Guaranteed by design; not production tested.
Noteꢀ4:ꢀ Rising MIROUT transition from 10FA to 1mA; 15V < V
< 76V.
OUT
����������������������������������������������������������������� ꢀMaxim Integrated Productsꢀ ꢀ 3
DS3920
Fast Current Mirror
Typical Operating Characteristics
(T = +25°C, unless otherwise noted.)
A
MIRIN CURRENT vs. MIRIN VOLTAGE
MIRIN CURRENT vs. MIROUT CURRENT
10
1
100
10
V
= 40V
MIRIN
I
= 2.5mA
MIROUT
1
0.1
0.01
I
= 1µA
MIROUT
0.1
0.01
0
20
40
60
80
85
85
0.001
0.01
0.1
1
10
V
(V)
I
(mA)
MIRIN
MIROUT
MIRIN CURRENT vs. TEMPERATURE
GAIN ERROR vs. MIROUT CURRENT
10
1
5
4
V
= 40V
MIRIN
I
= 2.5mA
MIROUT
3
2
1
0
-1
-2
-3
-4
-5
0.1
0.01
I
= 1µA
MIROUT
V
= 40V
MIRIN
-40
-15
10
35
60
0.001
0.01
0.1
1
10
TEMPERATURE (°C)
I
(mA)
MIROUT
GAIN ERROR vs. MIRIN VOLTAGE
GAIN ERROR vs. TEMPERATURE
2.0
1.5
5
4
I
= 1µA
MIROUT
I
= 2.5mA
MIROUT
3
1.0
2
0.5
I
= 1µA
MIROUT
1
I
= 2.5mA
MIROUT
0
0
-1
-2
-3
-4
-5
I
= 250µA
MIROUT
I
= 5mA
-0.5
-1.0
-1.5
-2.0
MIROUT
I
= 10mA
MIROUT
I
= 10mA
MIROUT
V
= 40V
MIRIN
0
20
40
60
80
-40
-15
10
35
60
V
(V)
TEMPERATURE (°C)
MIRIN
����������������������������������������������������������������� ꢀMaxim Integrated Productsꢀ ꢀ 4
DS3920
Fast Current Mirror
Typical Operating Characteristics (continued)
(T = +25°C, unless otherwise noted.)
A
TRANSIENT RESPONSE
(V = 40V)
STARTUP DELAY
STARTUP DELAY
= 40V, I = 2.5mA)
MIROUT
DS3920 toc09
(V
= 40V, I
= 1µA)
(V
MIRIN
BIAS
MIROUT
MIRIN
DS3920 toc07
DS3920 toc08
40V
40V
CH1
0V
CH1
0V
CH1
CH1
A
B
MIRIN
D.U.T
MIRIN
D.U.T
MIR
MIROUT
CH2
MIR
MIROUT
CH2
R2
5kΩ
R1
38MΩ
R2
5kΩ
R1
15.6kΩ
40V
MIRIN
D.U.T
MIR
CH2
5kΩ
MIROUT
CH1
CH2
0V
CH2
0V
100kΩ
5kΩ
500ns/div
= 375µA TO 7.5mA
200µs/div
200µs/div
A: CH1, 1V/div, I
CH1: 20V/div
CH2: 20V/div
CH1: 20V/div
CH2: 20V/div
MIROUT
A: CH2; 5V/div, I = 75µA TO 1.5mA
MIR
STARTUP DELAY
STARTUP DELAY
= 5V, I = 2.5mA)
(V
= 5V, I
= 1µA)
(V
MIRIN
MIRIN
MIROUT
MIROUT
DS3920 toc10
DS3920 toc11
5V
5V
CH1
CH1
CH1
0V
CH1
0V
MIRIN
D.U.T
MIRIN
D.U.T
MIR
MIROUT
CH2
MIR
MIROUT
CH2
R2
5kΩ
R1
4.6MΩ
R2
5kΩ
R1
1.7kΩ
CH2
0V
CH2
0V
200µs/div
200µs/div
CH1: 2V/div
CH2: 2V/div
CH1: 2V/div
CH2: 2V/div
����������������������������������������������������������������� ꢀMaxim Integrated Productsꢀ ꢀ 5
DS3920
Fast Current Mirror
Typical Operating Characteristics (continued)
(T = +25°C, unless otherwise noted.)
A
SHORT-CIRCUIT RESPONSE
(V = 40V)
SHORT-CIRCUIT RESPONSE
(V
= 76V)
VOLTAGE DROP vs. MIROUT CURRENT
MIRIN
MIRIN
DS3920 toc12
DS3920 toc13
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
T = +40°C
A
T = +40°C
A
V
= 2.97V
MIRIN
A
F
E
D
B
A
D
B
C
F
E
C
T = -40°C
A
CH1
0A
CH1
T = +25°C
A
0A
T = +100°C
A
T = +85°C
A
20ms/div
, 5mA/div
20ms/div
, 5mA/div
MIROUT
0.001
0.01
0.1
1
10
100
I
(mA)
CH1: I
CH1: I
MIROUT
MIROUT
A: MIROUT SHORTS TO GND THROUGH 10Ω
B: CURRENT LIMIT ACTIVE
A: MIROUT SHORTS TO GND THROUGH 10Ω
B: CURRENT LIMIT ACTIVE
C: THERMAL SHUTDOWN
C: THERMAL SHUTDOWN
D: POST COOL-DOWN REENTRY
E: THERMAL SHUTDOWN
D: POST COOL-DOWN REENTRY
E: THERMAL SHUTDOWN
F: POST COOL-DOWN REENTRY
F: POST COOL-DOWN REENTRY
Pin Configuration
Pin Description
PIN
NAME
FUNCTION
TOP VIEW
Protection Diode. External potential used
for voltage clamping of V . If unused,
1
DIODE
+
MIR
DIODE
1
2
3
6
5
4
MIRIN
N.C.
this pin can be left unconnected.
2
3
GND
MIR
Ground
DS3920
Mirror Current Monitor Output, 5:1 Ratio
GND
MIR
Current Mirror Voltage Output. Connect to
4
MIROUT photodiode bias pin. Photodiode
provides reference current for the mirror.
MIROUT
No Connection. Not internally
connected.
SOT23
5
6
N.C.
MIRIN
Current Voltage Bias
����������������������������������������������������������������� ꢀMaxim Integrated Productsꢀ ꢀ 6
DS3920
Fast Current Mirror
Current Clamp
The device features a current clamping circuit to protect
Detailed Description
The DS3920 provides a fast, precision current mirror for
the photodiode by limiting the amount of current from
MIROUT to no more than IMIROUT. See the Ordering
Information for available current clamp options.
photodiode-monitoring applications. The current mirror
is accurate across a large dynamic range. The mirror
response time is fast enough to comply with GPON Rx
burst-mode monitoring requirements. The device has a
built-in current limiting feature to protect photodiodes
from large signal inputs, and an included thermal shut-
down. A diode is provided to limit the voltage at the MIR
output.
Diode Protection
A diode is internally connected from the MIR to DIODE
pins. This enables an external voltage applied to DIODE
to limit the voltage on MIR. The voltage applied to DIODE
should be equal to the desired VMIR limit minus the diode
forward voltage drop, or VMIR - VDF
.
Current Mirror
The mirror output is typically connected to an analog-
to-digital converter (ADC) using a resistor to convert the
mirrored current into a voltage. The resistor to ground
should be selected so that the ADC’s full-scale voltage is
reached when the maximum mirrored current is reached.
For example, given that the maximum monitored current
through the APD is 2mA, 1.25V ADC full scale, and a 5:1
mirror ratio, the correct resistor is approximately 3.2kI.
Thermal Shutdown
As a safety feature, the device has a thermal shutdown
circuit that turns off the MIROUT and MIR currents when
the internal die temperature exceeds TSHDN. The thermal
shutdown mechanism has a built-in hysteresis of THYST
Thus, the MIROUT and MIR currents resume once the
device has cooled to TSHDN - THYST
.
.
The mirror response time is dominated by the amount of
capacitance placed on the output.
Ordering Information
PART
DS3920T-001+
TEMPꢀRANGE
-40NC to +85NC
-40NC to +85NC
-40NC to +85NC
-40NC to +85NC
TYPꢀCURRENTꢀLIMITꢀ(mA)
PIN-PACKAGE
6 SOT23
20
20
DS3920T-001+T
DS3920T-002+
DS3920T-002+T
6 SOT23
4.4
4.4
6 SOT23
6 SOT23
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Package Information
For the latest package outline information and land patterns (footprints), go to www.maxim-ic.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.
PACKAGEꢀTYPE
PACKAGEꢀCODE
OUTLINEꢀNO.
21-0058
LANDꢀPATTERNꢀNO.
90-0175
6 SOT23
U6SN+1
DS3920
Fast Current Mirror
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
0
3/11
Initial release
Changed the MIROUT -002 version current limit value from 2.9mA (typ) to 4.4mA
(typ); updated the Electrical Characteristics I values for -002 version from
—
MIROUT
1
2
8/11
1, 2, 6
1
2mA (min), 2.9mA (typ), 4.4mA (max) to 2.8mA (min), 4.4mA (typ), 8mA (max) and
added T = +25°C test conditions
A
12/11
Added R
and R
resistor values to the Typical Application Circuit
FILTER
OUT
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. 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 Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
7
©
2011 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
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