MAX3806GTC+ [MAXIM]
Receiver for Optical Distance Measurement; 接收器的光学测距
| 型号： | MAX3806GTC+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Receiver for Optical Distance Measurement |
| 文件： | 总9页 (文件大小：1324K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-4700; Rev 0; 7/09
Receiver for Optical Distance Measurement
MAX3806
General Description
Features
The MAX3806 is a high-gain linear preamplifier for dis-
tance measurement applications using a laser beam.
♦ +5V Supply Voltage
♦ Linearity Range Up to 40µA
P
The device operates from a single +5.0V supply and
converts current from an AC-coupled photodiode into a
single-ended voltage signal. The input accepts single
pulses or bursts of pulses with widths down to 30ns.
The amplifier remains linear with input amplitudes from
♦ Overload Current Up to 2mA
P
♦ 50mW Power Dissipation at +5.0V
♦ 1.5pA/√Hz Noise Density at 60kΩ Gain
♦ 14nA Input-Referred Noise at 60kΩ Gain
42nA (SNR = 3) to 40µA . It can also withstand over-
P
P
RMS
load signals as large as 2mA . The output stage is
P
♦ Selectable Gains (60kΩ, 30kΩ)
♦ Selectable 14dB Attenuation
designed to drive a high-impedance load to deliver the
output-voltage swing at the lowest possible power dis-
sipation. The gain of the preamplifier stage is selected
using the GAIN pin to be 60kΩ or 30kΩ. There is also
an internal 14dB attenuator that is selected using the
ATT pin. The output stage can be disabled (high
impedance).
Ordering Information
PIN-
PACKAGE
TOP
MARK
PART
TEMP RANGE
The device is available in a 3mm x 3mm, 12-pin TQFN
package and operates over the -40°C to +105°C tem-
perature range.
MAX3806GTC+ -40°C to +105°C 12 TQFN-EP*
ABN
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Applications
Pin Configuration appears at end of data sheet.
LIDAR Sensors for Automotive Applications
(ACC, Stop&Go)
Laser Sensors for Portable Distance
Measurement
Laser Sensors for Industrial Applications
Typical Application Circuits
+5V
+5V TO +12V
SUPPLY FILTER
SINGLE-CHANNEL RECEIVER
SUPPLY FILTER
PIN
V
CC
0.01μF
0.01μF
IN
MAX3806
LINEAR LIDAR Rx
OUT
BUFF
MAX1446
ADC
C*
0.01μF
L*
GAIN
+5V
DIS
ATT
GND
* L AND C SET THE LOW-FREQUENCY CUTOFF REQUIRED FOR THE APPLICATION.
Typical Application Circuits continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Receiver for Optical Distance Measurement
ABSOLUTE MAXIMUM RATINGS
Supply Voltage Range, V
-0.5V to +6.0V
Continuous Power Dissipation (T = +70°C)
CC........................................
A
Voltage Range at ATT, DIS, GAIN
Current Range at IN, OUT
-0.5V to (V
+ 0.5V)
12-Pin TQFN-EP (derate 16.7mW/°C above +70°C)...1333mW
Storage Temperature Range.............................-55°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
................
CC
-4mA to +4mA
...........................................
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.
MAX3806
ELECTRICAL CHARACTERISTICS
(V
= +4.5V to +5.5V, AC-coupled (C = 0.01µF) output load ≥ 2kΩ, T = -40°C to +105°C. Typical values are at V
= +5V,
CC
CC
A
T
= +25°C, unless otherwise noted.) (Note 1)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Power-Supply Current
I
(Note 2)
10
15
mA
CC
INPUT SPECIFICATIONS
C
C
= 5pF, GAIN = 1
= 5pF, GAIN = 0
14
21
20
27
Output noise up to
100MHz/(gain at 5MHz)
IN
IN
Input-Referred Noise
Input-Referred Noise Density
Input Impedance
nA
RMS
Output noise centered
at 5MHz over 100Hz
band/(gain at 5MHz)
C
C
= 5pF, GAIN = 1
= 5pF, GAIN = 0
1.5
1.7
1.8
2.3
IN
IN
pA/ꢀHz
At 1MHz, GAIN = 1
At 1MHz, GAIN = 0
800
300
ꢁ
CMOS/TTL INPUT SPECIFICATIONS
Input High Voltage
V
2
0
V
V
V
IH
CC
Input Low Voltage
V
0.8
IL
I
I
DIS input
±150
-180
IH, IL
Input Current
μA
I
GAIN and ATT inputs
DIS input
IH
R
60
40
PULLUP
Input Impedance
kꢁ
R
GAIN and ATT inputs
PULLDOWN
GENERAL SPECIFICATIONS
Small-Signal Transimpedance
I
I
ꢀ 15μA , GAIN = 1
44
23
25
55
60
30
49
98
1
77
37
IN
IN
P
kꢁ
ꢀ 50μA , GAIN = 0
P
GAIN = 1, ATT = 0
GAIN = 0, ATT = 0
Small-Signal Bandwidth
f
C
= 5pF
IN
MHz
3dB
Gain Peaking
5pF ꢀ C ꢀ 15pF
dB
dB
IN
Attenuation Stability
OUTPUT SPECIFICATIONS
ATT = 1; 20log(V
/V
)
-13
-14
-15
OUT_ATT_ON OUT_ATT_OFF
GAIN = 1
GAIN = 0
GAIN = 1
GAIN = 0
GAIN = 1
GAIN = 0
-54
-53
-38
-47
-16
-23
Frequency = 1MHz,
V
= 0.5V
P
OUT
Total Harmonic Distortion
THD
dB
dB
Frequency = 10MHz,
= 0.5V
V
OUT
P
Power-Supply Noise Rejection
(Note 3)
PSNR
Noise frequency < 1MHz
2
_______________________________________________________________________________________
Receiver for Optical Distance Measurement
MAX3806
ELECTRICAL CHARACTERISTICS (continued)
(V
= +4.5V to +5.5V, AC-coupled (C = 0.01µF) output load ≥ 2kΩ, T = -40°C to +105°C. Typical values are at V
= +5V,
CC
CC
A
T
= +25°C, unless otherwise noted.) (Note 1)
A
PARAMETER
SYMBOL
CONDITIONS
Frequency < 5MHz,
20log(V
MIN
TYP
MAX
UNITS
ATT = 0
ATT = 1
-71
Attenuation in Disable Mode
Output Impedance
/
dB
OUT_DISABLED
-57
V
)
OUT_ENABLED
At 1MHz, DIS = 0, ATT = 0, GAIN = 0 or 1
At 1MHz, DIS = 0, ATT = 1, GAIN = 0 or 1
51
ꢁ
114
At 1MHz, DIS = 1, ATT = 0 or 1, GAIN = 0
or 1
9
kꢁ
Note 1: AC specifications are guaranteed by design and characterization.
Note 2: Supply current is measured with OUT unterminated or AC-coupled.
Note 3: Measured by applying 100mV
sinusoidal noise to the supply voltage. PSNR is defined as 20log(V
/V
).
P-P
OUT_NOISE CC_NOISE
Typical Operating Characteristics
(Typical values are at V
= +5V, T = +25°C, C = 5pF, ATT = 0, unless otherwise noted.)
A IN
CC
OUTPUT VOLTAGE vs. INPUT CURRENT
SUPPLY CURRENT vs. TEMPERATURE
FREQUENCY RESPONSE
10
16
14
12
10
8
105
100
95
90
85
80
75
70
65
60
GAIN = 1, ATT = 0
GAIN = 1, ATT = 0
GAIN = 0, ATT = 0
GAIN = 1, ATT = 1
GAIN = 0, ATT = 1
DIS = 0
DIS = 1
1
0.1
GAIN = 0, ATT = 0
GAIN = 1, ATT = 1
6
0.01
0.001
4
GAIN = 0, ATT = 1
2
0
0.1
1
10
100
1000
-40
-15
10
35
60
85
110
0.1
1
10
100
INPUT CURRENT (µA )
TEMPERATURE (NC)
FREQUENCY (MHz)
P
_______________________________________________________________________________________
3
Receiver for Optical Distance Measurement
Typical Operating Characteristics (continued)
(Typical values are at V
= +5V, T = +25°C, C = 5pF, ATT = 0, unless otherwise noted.)
A IN
CC
BANDWIDTH vs. INPUT CAPACITANCE
(GAIN = 1)
BANDWIDTH vs. INPUT CAPACITANCE
(GAIN = 1)
GAIN PEAKING vs. INPUT
CAPACITANCE
60
50
40
30
20
10
0
60
1.0
0.8
0.6
0.4
0.2
0
V
= +5.0V
T = +25NC
A
CC
T
= -40 NC
A
V
= +5.5V
CC
50
40
30
20
10
0
MAX3806
V
CC
= +5.0V
T
A
= +25 NC
GAIN = 0
T
A
= +105 NC
V
CC
= +4.5V
11
GAIN = 1
5
5
5
7
9
11
13
15
5
5
5
7
9
13
15
5
10k
5
7
9
11
13
15
10M
15
INPUT CAPACITANCE (pF)
INPUT CAPACITANCE (pF)
INPUT CAPACITANCE (pF)
BANDWIDTH vs. INPUT CAPACITANCE
(GAIN = 0)
BANDWIDTH vs. INPUT CAPACITANCE
(GAIN = 0)
POWER-SUPPLY NOISE REJECTION
(SUPPLY NOISE = 100mV
)
P-P
120
100
80
60
40
20
0
120
100
80
60
40
20
0
10
0
GAIN = 1, ATT = 0
GAIN = 0, ATT = 0
V
= +5V
T = +25NC
A
CC
V
= +5.5V
T
= -40NC
CC
A
-10
-20
-30
-40
-50
-60
T
= +25NC
A
V
= +5.0V
CC
T
A
= +105NC
GAIN = 1, ATT = 1
V
= +4.5V
CC
GAIN = 0, ATT = 1
1M
7
9
11
13
15
7
9
11
13
15
100k
INPUT CAPACITANCE (pF)
INPUT CAPACITANCE (pF)
FREQUENCY (Hz)
INPUT-REFERRED NOISE
vs. INPUT CAPACITANCE
INPUT-REFERRED NOISE
vs. INPUT CAPACITANCE
OUTPUT-REFERRED NOISE
vs. INPUT CAPACITANCE
16
15
14
13
12
11
10
16
15
14
13
12
11
10
1000
950
900
850
800
750
700
650
600
V
= +5V
T
= +25NC
T = +25NC
A
GAIN = 1
BW = 100MHz
GAIN = 1
GAIN = 1
CC
A
BW = 100MHz
BW = 100MHz
V
V
= +5.5V
= +5.0V
CC
CC
V
V
= +5.5V
CC
T
A
= +105NC
T
= -40NC
A
= +5.0V
= +4.5V
CC
V
CC
V
CC
= +4.5V
T
= +25NC
A
7
9
11
13
15
7
9
11
13
15
7
9
11
13
INPUT CAPACITANCE (pF)
INPUT CAPACITANCE (pF)
INPUT CAPACITANCE (pF)
4
_______________________________________________________________________________________
Receiver for Optical Distance Measurement
MAX3806
Typical Operating Characteristics (continued)
(Typical values are at V
= +5V, T = +25°C, C = 5pF, ATT = 0, unless otherwise noted.)
A IN
CC
INPUT-REFERRED NOISE
vs. INPUT CAPACITANCE
INPUT-REFERRED NOISE
vs. INPUT CAPACITANCE
OUTPUT-REFERRED NOISE
vs. INPUT CAPACITANCE
700
650
600
550
500
450
26
25
24
23
22
21
20
19
18
26
V
= +5V
T
= +25NC
GAIN = 0
BW = 100MHz
GAIN = 0
T
A
= +25NC
CC
A
GAIN = 0
25
24
23
22
21
20
19
18
BW = 100MHz
BW = 100MHz
T
A
= +105NC
V
= +5.5V
CC
V
CC
= +5.5V
V
= +5.0V
CC
V
= +5.0V
T
= +25NC
CC
A
V
= +4.5V
CC
V
= +4.5V
CC
T
= -40NC
A
5
7
9
11
13
15
5
7
9
11
13
15
5
7
9
11
13
15
INPUT CAPACITANCE (pF)
INPUT CAPACITANCE (pF)
INPUT CAPACITANCE (pF)
TOTAL HARMONIC DISTORTION
vs. FREQUENCY
DISABLE SWITCH
(DC-BLOCK = 0.01µF, LOAD = 2kI)
MAX3806 toc17
0
-10
-20
-30
-40
-50
-60
V
= 0.5V
P
OUT
DIS
(5V/div)
GAIN = 1
OUT
(200mV/div)
GAIN = 0
0.1
1
10
100
100ns/div
FREQUENCY (MHz)
GAIN SWITCH
(DC-BLOCK = 0.01µF, LOAD = 2kI)
ATT SWITCH
(DC-BLOCK = 0.01µF, LOAD = 2kI)
MAX3806 toc18
MAX3806 toc19
ATT
(5V/div)
GAIN
(5V/div)
OUT
OUT
(200mV/div)
(500mV/div)
40µs/div
40µs/div
_______________________________________________________________________________________
5
Receiver for Optical Distance Measurement
Typical Operating Characteristics (continued)
(Typical values are at V
= +5V, T = +25°C, C = 5pF, ATT = 0, unless otherwise noted.)
CC
A
IN
TRANSIENT RESPONSE
(LINEAR REGION, GAIN = 1)
TRANSIENT RESPONSE
(OVERLOAD REGION, GAIN = 1)
TRANSIENT RESPONSE
(OVERLOAD REGION, GAIN = 1)
MAX3806 toc20
MAX3806 toc21
MAX3806 toc22
ZOOM IN
ZOOM OUT
MAX3806
1µA
2mA
2mA
P
P
P
IN
IN
IN
OUT
OUT
OUT
60µs SETTLING TIME
60mV
P
1.4V
1.4V
P
P
0.01µF DC-BLOCK
2kI LOAD
20MHz BW LIMIT
20MHz BW LIMIT
20ns/div
100ns/div
10µs/div
Functional Diagram
MAX3806
IN
ATTENUATOR
OUT
V
CC
SWITCHABLE
IMPEDANCE
60kΩ OR 30kΩ
60kΩ
40kΩ
40kΩ
GAIN
ATT
DIS
6
_______________________________________________________________________________________
Receiver for Optical Distance Measurement
MAX3806
Pin Description
PIN
1, 12
2
NAME
FUNCTION
V
CC
5V Power-Supply Connection
IN
Amplifier Input. Accepts AC-coupled photodiode input current.
Supply Ground
3, 4
GND
CMOS/TTL Input. Assert this pin high to enable a 14dB attenuator in the amplifier. Force this pin low
to disable the attenuator. Contains internal 40kꢀ pulldown resistor. Connect to GND if not used.
5
6, 8, 11
7
ATT
N.C.
GAIN
Not Connected. This pin is not internally connected.
CMOS/TTL Input. Selects amplifier gain setting. Force high for 60kꢀ. Force low for 30kꢀ. Contains
internal 40kꢀ pulldown resistor.
Amplifier Output. An increase in current into the IN pin causes the voltage at the OUT pin to decrease.
OUT must be AC-coupled to a load of 2kꢀ or greater.
9
OUT
DIS
EP
CMOS/TTL Input. Force high to disable the output of the MAX3806. Force low to enable the output.
Contains internal 60kꢀ pullup resistor.
10
—
Exposed Pad. The exposed pad must be soldered to circuit board ground for proper thermal and
electrical performance.
Output Driver
The output driver is designed to drive an AC-coupled
Detailed Description
The MAX3806 preamplifier consists of a selectable-gain
transimpedance amplifier, a selectable 14dB attenuator,
and an output-driver block. The selectable-gain transim-
pedance amplifier linearly boosts the signal from the
photodiode. This block is followed by an attenuator
block that allows the user to attenuate the signal by
14dB selected by the ATT pin. The final block is the out-
put driver that can be disabled by asserting the DIS pin.
load with an impedance of 2kΩ or greater. The output
can be disabled by asserting the DIS pin high. When
the output is disabled, the OUT pin goes to a high-
impedance state. See Figure 1 for the equivalent output
circuit.
WARNING: The output is designed to be AC-coupled
to a high-impedance load. Operating the part with its
output DC-coupled to GND through a 2kΩ or less load
may damage the output.
Transimpedance Amplifier
The selectable-gain transimpedance amplifier is con-
trolled by the GAIN pin. See Table 1 for gain settings.
Applications Information
Settling Time
Settling time is the required time for the output to
achieve the final steady-state or AC amplitude swing
after a setting has been changed on the MAX3806. The
output common-mode voltage shifts when a change is
Attenuator
The attenuator block can be set to pass the signal
through to the output stage with 0dB of attenuation
(ATT forced low) or with 14dB of attenuation (ATT
forced high).
Table 1. Transimpedance Gain Settings
GAIN
TRANSIMPEDANCE (kꢀ)
LINEAR RANGE (μA )
BANDWIDTH (MHz)
P
0
1
30
60
I
I
ꢀ 40
ꢀ 20
98
49
IN
IN
_______________________________________________________________________________________
7
Receiver for Optical Distance Measurement
Layout Considerations
Noise performance and bandwidth are adversely affect-
ed by capacitance at the IN pad. Minimize capacitance
on this pad and select a low-capacitance photodiode.
Reducing PCB capacitance can be accomplished by
removing the ground plane underneath the connection
from the photodiode to the IN pin and by keeping the
photodiode as close as possible to the MAX3806.
V
CC
200Ω
V
CC
Use broadband power-supply filtering techniques to
achieve the best sensitivity and noise performance.
MAX3806
400Ω
100Ω
OUT
Exposed-Pad Package and Thermal
Considerations
The exposed pad on the 12-pin TQFN provides a very
low thermal resistance path for heat removal from the IC.
The pad is also electrical ground on the MAX3806 and
must be soldered to the circuit board ground for proper
thermal and electrical performance. Refer to Application
Note 862: HFAN-08.1: Thermal Considerations of QFN
and Other Exposed-Paddle Packages for additional
information.
Figure 1. Equivalent Output Circuit
made to either the GAIN or ATT setting. Table 2 pro-
vides typical output common-mode voltages for the
combination of settings. Settling time is proportional to
the RC time constant set by the output DC-blocking
capacitor, load, and MAX3806 output impedance. For
example, a 0.01µF DC-blocking capacitor, 2kΩ load,
and 51Ω output impedance provide an RC time con-
stant of approximately 20µs. After changing the GAIN
or ATT setting, the system should wait at least three to
four time constants before analyzing received signals.
Pin Configuration
TOP VIEW
9
8
7
DIS 10
N.C. 11
6
5
4
N.C.
ATT
Settling time is also required when changing the DIS
setting. When DIS is asserted high, the output disables
to high impedance and typically settles to steady state
within 200ns. When DIS is deasserted, the output
enables and typically settles to steady state within 50ns.
MAX3806
V
12
GND
CC
*EP
3
+
Overload Recovery Time
Transistors saturate when the amplifier is overloaded,
resulting in output distortion. Overload typically occurs
1
2
with signals greater than 20µA (GAIN = 1) or 40µA
P
P
THIN QFN
(3mm × 3mm)
(GAIN = 0). It can withstand overload signals as large
as 2mA . Recovery time depends on the amplitude and
P
duration of the overload pulse.
*EXPOSED PAD
Table 2. Output Common-Mode Voltages
OUTPUT COMMON-MODE
GAIN
ATT
Package Information
VOLTAGE (V)
For the latest package outline information and land patterns, go
0
0
1
1
0
1
0
1
1.65
0.33
1.82
0.36
to www.maxim-ic.com/packages.
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
12 TQFN-EP
T1233+1
21-0136
8
_______________________________________________________________________________________
Receiver for Optical Distance Measurement
MAX3806
Typical Application Circuits (continued)
+5V
+5V TO +12V
SUPPLY FILTER
+5V
+5V
+5V
+5V
SUPPLY FILTER
PIN
V
CC
7kΩ
3kΩ
0.01μF
0.01μF
0.01μF
0.01μF
IN
IN
IN
IN
MAX3806
LINEAR LIDAR Rx
OUT
OUT
OUT
OUT
C*
L*
GAIN
+5V
DIS
ATT
GND
GND
GND
GND
MULTIPLE-CHANNEL RECEIVER
DIS0
+5V
+5V TO +12V
SUPPLY FILTER
SUPPLY FILTER
PIN
V
CC
7kΩ
3kΩ
+5V
MAX3806
LINEAR LIDAR Rx
C*
MAX4311
4:1 MUX/AMP
L*
GAIN
+5V
DIS
ATT
IN0
IN1
IN2
IN3
0.01μF
DIS1
0.01μF
BUFF
MAX1446
ADC
+5V
0.01μF
+5V TO +12V
SUPPLY FILTER
A0
A1
SUPPLY FILTER
PIN
V
CC
7kΩ
3kΩ
MAX3806
LINEAR LIDAR Rx
C*
L*
GAIN
+5V
DIS
ATT
DIS2
+5V
DIS0
DIS1
DIS2
DIS3
+5V TO +12V
SUPPLY FILTER
SUPPLY FILTER
PIN
V
CC
7kΩ
3kΩ
MAX3806
LINEAR LIDAR Rx
MICROCONTROLLER/DSP
C*
L*
GAIN
+5V
DIS
ATT
DIS3
* L AND C SET THE LOW-FREQUENCY CUTOFF REQUIRED FOR THE APPLICATION.
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9
© 2009 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
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