MAX3806 Receiver for Optical Distance Measurement

EVALUATION KIT AVAILABLE
MAX3806
Receiver for Optical Distance Measurement
General Description
Benefits and Features
The MAX3806 is a high-gain linear preamplifier for distance measurement applications using a laser beam.
●● +5V Supply Voltage
●● Linearity Range Up to 40μAP
●● Overload Current Up to 2mAP
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 42nAP
(SNR = 3) to 40μAP. It can also withstand overload signals as large as 2mAP. The output stage is designed to
drive a high-impedance load to deliver the output-voltage
swing at the lowest possible power dissipation. 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).
●● 50mW Power Dissipation at +5.0V
●● 1.5pA/√Hz Noise Density at 60kΩ Gain
●● 14nARMS Input-Referred Noise at 60kΩ Gain
●● Selectable Gains (60kΩ, 30kΩ)
●● Selectable 14dB Attenuation
Ordering Information
The device is available in a 3mm x 3mm, 12-pin TQFN
package and operates over the -40°C to +105°C temperature range.
PART
TEMP RANGE
PINPACKAGE
TOP
MARK
MAX3806GTC+
-40°C to +105°C
12 TQFN-EP*
ABN
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Applications
●● Laser Sensors for Portable Distance Measurement
●● Laser Sensors for Industrial Applications
Pin Configuration appears at end of data sheet.
Typical Application Circuits
+5V
+5V TO +12V
SUPPLY FILTER
SUPPLY FILTER
VCC
PIN
SINGLE-CHANNEL RECEIVER
0.01µF
0.01µF
MAX3806
IN
OUT
LINEAR LIDAR Rx
C*
L*
ADC
0.01µF
GAIN
DIS
ATT
GND
+5V
* L AND C SET THE LOW-FREQUENCY CUTOFF REQUIRED FOR THE APPLICATION.
Typical Application Circuits continued at end of data sheet.
19-4700; Rev 1; 6/14
MAX1446
BUFF
MAX3806
Receiver for Optical Distance Measurement
Absolute Maximum Ratings
Supply Voltage Range, VCC...................................-0.5V to +6.0V
Voltage Range at ATT, DIS, GAIN...............-0.5V to (VCC + 0.5V)
Current Range at IN, OUT.......................................-4mA to +4mA
Continuous Power Dissipation (TA = +70°C)
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
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
(VCC = +4.5V to +5.5V, AC-coupled (C = 0.01μF) output load ≥ 2kΩ, TA = -40°C to +105°C. Typical values are at VCC = +5V,
TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
Power-Supply Current
ICC
CONDITIONS
MIN
(Note 2)
TYP
MAX
UNITS
10
15
mA
INPUT SPECIFICATIONS
Input-Referred Noise
Output noise up to
100MHz/(gain at 5MHz)
Input-Referred Noise
Density
Output noise centered
at 5MHz over 100Hz
band/(gain at 5MHz)
Input Impedance
CIN = 5pF, GAIN = 1
14
20
CIN = 5pF, GAIN = 0
21
27
CIN = 5pF, GAIN = 1
1.5
1.8
CIN = 5pF, GAIN = 0
1.7
2.3
At 1MHz, GAIN = 1
800
At 1MHz, GAIN = 0
300
nARMS
pA/√Hz
Ω
CMOS/TTL INPUT SPECIFICATIONS
Input High Voltage
VIH
2
VCC
V
Input Low Voltage
VIL
0
0.8
V
IIH, IIL
Input Current
Input Impedance
IIH
RPULLUP
RPULLDOWN
DIS input
±150
GAIN and ATT inputs
-180
DIS input
60
GAIN and ATT inputs
40
µA
kΩ
GENERAL SPECIFICATIONS
Small-Signal
Transimpedance
Small-Signal Bandwidth
f3dB
IIN ≤ 15μAP, GAIN = 1
44
60
77
IIN ≤ 50μAP, GAIN = 0
23
30
37
GAIN = 1, ATT = 0
25
49
GAIN = 0, ATT = 0
55
98
CIN = 5pF
Gain Peaking
5pF ≤ CIN ≤ 15pF
Attenuation Stability
ATT = 1; 20log(VOUT_ATT_ON/VOUT_ATT_OFF)
MHz
1
-13
-14
kΩ
dB
-15
dB
OUTPUT SPECIFICATIONS
Total Harmonic Distortion
Power-Supply Noise
Rejection GAIN = 1 -16
(Note 3)
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THD
PSNR
Frequency = 1MHz,
VOUT = 0.5VP
Frequency = 10MHz,
VOUT = 0.5VP
Noise frequency < 1MHz
GAIN = 1
-54
GAIN = 0
-53
GAIN = 1
-38
GAIN = 0
-47
GAIN = 1
-16
GAIN = 0
-23
dB
dB
Maxim Integrated │ 2
MAX3806
Receiver for Optical Distance Measurement
Electrical Characteristics (continued)
(VCC = +4.5V to +5.5V, AC-coupled (C = 0.01μF) output load ≥ 2kΩ, TA = -40°C to +105°C. Typical values are at VCC = +5V,
TA = +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
Frequency < 5MHz,
20log(VOUT_DISABLED/
VOUT_ENABLED)
Attenuation in Disable
Mode
Output Impedance
MIN
TYP
ATT = 0
-71
ATT = 1
-57
At 1MHz, DIS = 0, ATT = 0, GAIN = 0 or 1
51
At 1MHz, DIS = 0, ATT = 1, GAIN = 0 or 1
114
At 1MHz, DIS = 1, ATT = 0 or 1, GAIN = 0
or 1
9
MAX
UNITS
dB
Ω
kΩ
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 100mVP-P sinusoidal noise to the supply voltage. PSNR is defined as 20log(VOUT_NOISE/VCC_NOISE).
Typical Operating Characteristics
(Typical values are at VCC = +5V, TA = +25°C, CIN = 5pF, ATT = 0, unless otherwise noted.)
10
DIS = 1
8
6
4
1
GAIN = 0, ATT = 0
0.1
GAIN = 1, ATT = 1
0.01
GAIN = 0, ATT = 1
2
0
-40
-15
10
35
60
TEMPERATURE (°C)
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85
110
0.001
0.1
1
10
100
GAIN = 1, ATT = 0
95
MAX3806 toc03
FREQUENCY RESPONSE
105
TRANSIMPEDANCE (dBΩ)
DIS = 0
OUTPUT VOLTAGE vs. INPUT CURRENT
GAIN = 1, ATT = 0
OUTPUT VOLTAGE (VP)
SUPPLY CURRENT (mA)
14
12
10
MAX3806 toc02
SUPPLY CURRENT vs. TEMPERATURE
MAX3806 toc01
16
GAIN = 0, ATT = 0
90
85
GAIN = 1, ATT = 1
80
GAIN = 0, ATT = 1
75
70
65
100
INPUT CURRENT (µAP)
1000
60
0.1
1
10
100
FREQUENCY (MHz)
Maxim Integrated │ 3
MAX3806
Receiver for Optical Distance Measurement
Typical Operating Characteristics (continued)
(Typical values are at VCC = +5V, TA = +25°C, CIN = 5pF, ATT = 0, unless otherwise noted.)
20
TA = +105 NC
7
9
11
13
MAX3806 toc06
MAX3806 toc05
20
0.6
GAIN = 0
0.4
VCC = +4.5V
0.2
GAIN = 1
5
7
9
11
13
0
15
7
5
9
11
13
15
BANDWIDTH vs. INPUT CAPACITANCE
(GAIN = 0)
BANDWIDTH vs. INPUT CAPACITANCE
(GAIN = 0)
POWER-SUPPLY NOISE REJECTION
(SUPPLY NOISE = 100mVP-P)
TA = +25°C
TA = +105°C
60
40
TA = +25°C
VCC = +5.5V
100
80
9
11
13
-40
VCC = +4.5V
7
9
11
GAIN = 1, ATT = 1
-30
GAIN = 0, ATT = 1
-50
13
-60
15
100k
10k
1M
10M
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
15
14
TA = +105°C
TA = -40°C
13
12
TA = +25°C
11
7
9
11
13
INPUT CAPACITANCE (pF)
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15
16
TA = +25°C
GAIN = 1
BW = 100MHz
15
VCC = +5.5V
14
13
VCC = +5.0V
12
VCC = +4.5V
11
10
5
7
9
11
INPUT CAPACITANCE (pF)
13
15
1000
OUTPUT-REFERRED NOISE (µVRMS)
GAIN = 1
BW = 100MHz
INPUT-REFERRED NOISE (nARMS)
VCC = +5V
5
-20
40
5
GAIN = 0, ATT = 0
-10
60
0
15
MAX3806 toc10
16
7
GAIN = 1, ATT = 0
0
VCC = +5.0V
20
5
10
PSNR (dB)
TA = -40°C
120
MAX3806 toc08
VCC = +5V
MAX3806 toc09
INPUT CAPACITANCE (pF)
20
INPUT-REFERRED NOISE (nARMS)
0.8
INPUT CAPACITANCE (pF)
80
10
30
0
15
1.0
INPUT CAPACITANCE (pF)
100
0
40
MAX3806 toc11
120
5
VCC = +5.0V
10
BANDWIDTH (MHz)
0
VCC = +5.5V
GAIN PEAKING vs. INPUT
CAPACITANCE
TA = +25°C
950
GAIN = 1
BW = 100MHz
900
MAX3806 toc12
30
TA = +25°C
GAIN PEAKING (dB)
BANDWIDTH (MHz)
40
BANDWIDTH vs. INPUT CAPACITANCE
(GAIN = 1)
50
MAX3806 toc07
BANDWIDTH (MHz)
TA = +25 NC
10
BANDWIDTH (MHz)
VCC = +5.0V
TA = -40 NC
50
60
MAX3806 toc04
60
BANDWIDTH vs. INPUT CAPACITANCE
(GAIN = 1)
VCC = +5.5V
850
VCC = +5.0V
800
750
VCC = +4.5V
700
650
600
5
7
9
11
13
15
INPUT CAPACITANCE (pF)
Maxim Integrated │ 4
MAX3806
Receiver for Optical Distance Measurement
Typical Operating Characteristics (continued)
(Typical values are at VCC = +5V, TA = +25°C, CIN = 5pF, ATT = 0, unless otherwise noted.)
23
TA = +25°C
22
21
20
TA = -40°C
19
18
5
7
9
11
13
TA = +25°C
25
VCC = +5.5V
24
23
VCC = +5.0V
22
21
VCC = +4.5V
20
19
18
15
GAIN = 0
BW = 100MHz
5
INPUT CAPACITANCE (pF)
7
9
11
13
15
INPUT CAPACITANCE (pF)
700
TA = +25°C
650
GAIN = 0
BW = 100MHz
VCC = +5.5V
VCC = +5.0V
600
550
VCC = +4.5V
500
450
5
7
9
11
13
15
INPUT CAPACITANCE (pF)
TOTAL HARMONIC DISTORTION
vs. FREQUENCY
DISABLE SWITCH
(DC-BLOCK = 0.01µF, LOAD = 2kΩ)
MAX3806 toc17
VOUT = 0.5VP
-10
MAX3806 toc16
0
OUTPUT-REFERRED NOISE
vs. INPUT CAPACITANCE
MAX3806 toc15
TA = +105°C
24
26
OUTPUT-REFERRED NOISE (µVRMS)
25
GAIN = 0
BW = 100MHz
INPUT-REFERRED NOISE
vs. INPUT CAPACITANCE
MAX3806 toc14
VCC = +5V
INPUT-REFERRED NOISE (nARMS)
INPUT-REFERRED NOISE (nARMS)
26
MAX3806 toc13
INPUT-REFERRED NOISE
vs. INPUT CAPACITANCE
DIS
(5V/div)
THD (dB)
-20
GAIN = 1
OUT
(200mV/div)
-30
-40
GAIN = 0
-50
-60
1
0.1
10
100
100ns/div
FREQUENCY (MHz)
GAIN SWITCH
(DC-BLOCK = 0.01µF, LOAD = 2kΩ)
ATT SWITCH
(DC-BLOCK = 0.01µF, LOAD = 2kΩ)
MAX3806 toc18
MAX3806 toc19
GAIN
(5V/div)
ATT
(5V/div)
OUT
(200mV/div)
OUT
(500mV/div)
40µs/div
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40µs/div
Maxim Integrated │ 5
MAX3806
Receiver for Optical Distance Measurement
Typical Operating Characteristics (continued)
(Typical values are at VCC = +5V, TA = +25°C, CIN = 5pF, ATT = 0, unless otherwise noted.)
TRANSIENT RESPONSE
(LINEAR REGION, GAIN = 1)
TRANSIENT RESPONSE
(OVERLOAD REGION, GAIN = 1)
MAX3806 toc20
TRANSIENT RESPONSE
(OVERLOAD REGION, GAIN = 1)
MAX3806 toc21
MAX3806 toc22
ZOOM IN
1µAP
ZOOM OUT
2mAP
IN
OUT
2mAP
IN
IN
OUT
OUT
60mVP
1.4VP
60µs SETTLING TIME
1.4VP
20MHz BW LIMIT
0.01µF DC-BLOCK
2kI LOAD
20MHz BW LIMIT
100ns/div
20ns/div
10µs/div
Functional Diagram
MAX3806
IN
ATTENUATOR
OUT
VCC
SWITCHABLE
IMPEDANCE
60k OR 30k
60kΩ
40kΩ
GAIN
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40kΩ
ATT
DIS
Maxim Integrated │ 6
MAX3806
Receiver for Optical Distance Measurement
Pin Description
PIN
NAME
1, 12
VCC
FUNCTION
2
IN
3, 4
GND
Supply Ground
5
ATT
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 40kΩ pulldown resistor. Connect to GND if not used.
6, 8, 11
N.C.
Not Connected. This pin is not internally connected.
7
GAIN
CMOS/TTL Input. Selects amplifier gain setting. Force high for 60kΩ. Force low for 30kΩ. Contains
internal 40kΩ pulldown resistor.
9
OUT
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 2kΩ or greater.
10
DIS
CMOS/TTL Input. Force high to disable the output of the MAX3806. Force low to enable the output.
Contains internal 60kΩ pullup resistor.
—
EP
Exposed Pad. The exposed pad must be soldered to circuit board ground for proper thermal and
electrical performance.
5V Power-Supply Connection
Amplifier Input. Accepts AC-coupled photodiode input current.
Detailed Description
Output Driver
The MAX3806 preamplifier consists of a selectable-gain
transimpedance amplifier, a selectable 14dB attenuator, and an output-driver block. The selectable-gain
transimpedance 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 output
driver that can be disabled by asserting the DIS pin.
Transimpedance Amplifier
The selectable-gain transimpedance amplifier is controlled by the GAIN pin. See Table 1 for gain settings.
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).
The output driver is designed to drive an AC-coupled 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.
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 made
Table 1. Transimpedance Gain Settings
GAIN
TRANSIMPEDANCE (kΩ)
LINEAR RANGE (μAP)
BANDWIDTH (MHz)
0
30
IIN ≤ 40
98
1
60
IIN ≤ 20
49
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Maxim Integrated │ 7
MAX3806
Receiver for Optical Distance Measurement
Layout Considerations
VCC
Noise performance and bandwidth are adversely affected
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.
200
VCC
400
OUT
Use broadband power-supply filtering techniques to
achieve the best sensitivity and noise performance.
Exposed-Pad Package and Thermal
Considerations
TOP VIEW
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.
Table 2. Output Common-Mode Voltages
GAIN
ATT
OUTPUT COMMON-MODE VOLTAGE (V)
0
0
1.65
0
1
0.33
1
0
1.82
1
1
0.36
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9
8
7
DIS 10
MAX3806
N.C. 11
*EP
+
2
VCC
1
6
N.C.
5
ATT
4
GND
3
GND
VCC 12
Overload Recovery Time
Transistors saturate when the amplifier is overloaded,
resulting in output distortion. Overload typically occurs
with signals greater than 20μAP (GAIN = 1) or 40μAP
(GAIN = 0). It can withstand overload signals as large
as 2mAP. Recovery time depends on the amplitude and
duration of the overload pulse.
GAIN
Pin Configuration
N.C.
to either the GAIN or ATT setting. Table 2 provides 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 constant 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.
IN
Figure 1. Equivalent Output Circuit
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.
OUT
100
THIN QFN
(3mm ¥ 3mm)
*EXPOSED PAD
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.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN
NO.
12 TQFN-EP
T1233+3
21-0136
90-0018
Maxim Integrated │ 8
MAX3806
Receiver for Optical Distance Measurement
Typical Application Circuits (continued)
+5V
+5V TO +12V
SUPPLY FILTER
SUPPLY FILTER
VCC
+5V
PIN
MAX3806
IN
LINEAR LIDAR Rx
C*
7kΩ
0.01F
OUT
3kΩ
L*
GAIN
DIS
ATT
GND
+5V
MULTIPLE-CHANNEL RECEIVER
DIS0
+5V
+5V TO +12V
SUPPLY FILTER
SUPPLY FILTER
VCC
+5V
PIN
MAX3806
IN
LINEAR LIDAR Rx
C*
7kΩ
0.01F
3kΩ
L*
GAIN
DIS
ATT
+5V
OUT
GND
+5V
MAX4311
4:1 MUX/AMP
IN0
DIS1
0.01F
0.01F
IN1
IN3
+5V TO +12V
SUPPLY FILTER
SUPPLY FILTER
VCC
+5V
PIN
MAX3806
IN
LINEAR LIDAR Rx
C*
A0
MAX1446
BUFF
IN2
+5V
ADC
0.01F
A1
7kΩ
0.01F
OUT
3kΩ
L*
GAIN
DIS
ATT
GND
+5V
DIS2
+5V
+5V TO +12V
DIS1
SUPPLY FILTER
+5V
SUPPLY FILTER
DIS2
VCC
PIN
MAX3806
IN
LINEAR LIDAR Rx
C*
L*
DIS0
0.01F
7kΩ
OUT
3kΩ
GAIN
DIS
ATT
DIS3
MICROCONTROLLER/DSP
GND
+5V
DIS3
* L AND C SET THE LOW-FREQUENCY CUTOFF REQUIRED FOR THE APPLICATION.
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Maxim Integrated │ 9
MAX3806
Receiver for Optical Distance Measurement
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
0
7/09
Initial release
1
6/14
Removed automotive reference from Applications section and corrected page
code
DESCRIPTION
—
1, 8
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.
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 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 and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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