Document Outline
- DESCRIPTION
- FEATURES
- APPLICATIONS
- PIN CONFIGURATION
- ORDERING INFORMATION
- ABSOLUTE MAXIMUM RATINGS
- RECOMMENDED OPERATING CONDITIONS
- DC ELECTRICAL CHARACTERISTICS
- AC ELECTRICAL CHARACTERISTICS
- TEST CIRCUITS
- TYPICAL PERFORMANCE CHARACTERISTICS
- THEORY OF OPERATION
- BANDWIDTH CALCULATIONS
- NOISE
- DYNAMIC RANGE CALCULATIONS
- APPLICATION INFORMATION
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1
1995 Apr 26
853-1654 15170
DESCRIPTION
The NE5210 is a 7k
transimpedance wide band, low noise
amplifier with differential outputs, particularly suitable for signal
recovery in fiber-optic receivers. The part is ideally suited for many
other RF applications as a general purpose gain block.
FEATURES
Low noise: 3.5pA/
Hz
Single 5V supply
Large bandwidth: 280MHz
Differential outputs
Low input/output impedances
High power supply rejection ratio
High overload threshold current
Wide dynamic range
7k
differential transresistance
APPLICATIONS
Fiber-optic receivers, analog and digital
Current-to-voltage converters
PIN CONFIGURATION
1
2
3
4
5
6
7
8
14
13
12
11
10
9
GND2
GND2
NC
IIN
NC
VCC1
VCC2
GND1
GND1
GND1
GND1
GND2
OUT ()
OUT (+)
D Package
TOP VIEW
SD00318
Wideband gain block
Medical and scientific instrumentation
Sensor preamplifiers
Single-ended to differential conversion
Low noise RF amplifiers
RF signal processing
ORDERING INFORMATION
DESCRIPTION
TEMPERATURE RANGE
ORDER CODE
DWG #
14-Pin Plastic Small Outline (SO) Package
0 to +70
C
NE5210D
SOT108-1
ABSOLUTE MAXIMUM RATINGS
SYMBOL
PARAMETER
RATING
UNIT
V
CC
Power supply
6
V
T
A
Operating ambient temperature range
0 to +70
C
T
J
Operating junction temperature range
-55 to +150
C
T
STG
Storage temperature range
-65 to +150
C
P
DMAX
Power dissipation, T
A
=25
C (still air)
1
1.0
W
I
INMAX
Maximum input current
2
5
mA
NOTES:
1. Maximum dissipation is determined by the operating ambient temperature and the thermal resistance:
JA
=125
C/W.
2. The use of a pull-up resistor to V
CC
for the PIN diode, is recommended.
RECOMMENDED OPERATING CONDITIONS
SYMBOL
PARAMETER
RATING
UNIT
V
CC
Supply voltage
4.5 to 5.5
V
T
A
Ambient temperature range
0 to +70
C
T
J
Junction temperature range
0 to +90
C
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
2
DC ELECTRICAL CHARACTERISTICS
Min and Max limits apply over operating temperature range at V
CC
=5V, unless otherwise specified. Typical data applies at V
CC
=5V and
T
A
=25
C.
SYMBOL
PARAMETER
TEST CONDITIONS
LIMITS
UNIT
SYMBOL
PARAMETER
TEST CONDITIONS
Min
Typ
Max
UNIT
V
IN
Input bias voltage
0.6
0.8
0.95
V
V
O
Output bias voltage
2.8
3.3
3.7
V
V
OS
Output offset voltage
0
80
mV
I
CC
Supply current
21
26
32
mA
I
OMAX
Output sink/source current
1
3
4
mA
I
IN
Input current (2% linearity)
Test Circuit 8, Procedure 2
120
160
A
I
INMAX
Maximum input current
overload threshold
Test Circuit 8, Procedure 4
160
240
A
NOTES:
1. Test condition: output quiescent voltage variation is less than 100mV for 3mA load current.
AC ELECTRICAL CHARACTERISTICS
Typical data and Min/Max limits apply at V
CC
=5V and T
A
=25
C.
SYMBOL
PARAMETER
TEST CONDITIONS
LIMITS
UNIT
SYMBOL
PARAMETER
TEST CONDITIONS
Min
Typ
Max
UNIT
R
T
Transresistance
(differential output)
DC tested, R
L
=
Test Circuit 8, Procedure 1
4.9
7
10
k
R
O
Output resistance
(differential output)
DC tested
16
30
42
R
T
Transresistance
(single-ended output)
DC tested, R
L
=
2.45
3.5
5
k
R
O
Output resistance
(single-ended output)
DC tested
8
15
21
f
3dB
Bandwidth (-3dB)
Test Circuit 1, T
A
=25
C
200
280
MHz
R
IN
Input resistance
60
C
IN
Input capacitance
7.5
pF
R/
V
Transresistance power
supply sensitivity
V
CC
=5
0.5V
9.6
20
%/V
R/
T
Transresistance ambient
temperature sensitivity
T
A
=T
A MAX
-T
A MIN
0.05
0.1
%/
C
I
N
RMS noise current spectral density
(referred to input)
f=10MHz, T
A
=25
C
Test Circuit 2
3.5
6
pA/
Hz
I
T
Integrated RMS noise current over
the bandwidth (referred to input)
C
S
=0
1
T
A
=25
C
Test Circuit 2
nA
I
T
Integrated RMS noise current over
the bandwidth (referred to input)
C
S
=0
1
f=100MHz
37
nA
I
T
the bandwidth (referred to input)
C
S
=0
1
f=200MHz
56
nA
I
T
f=300MHz
71
nA
C
S
=1pF
f=100MHz
40
C
S
=1pF
f=200MHz
66
S
=1pF
f=300MHz
89
PSRR
Power supply rejection ratio
2
(V
CC1
=V
CC2
)
DC tested,
V
CC
=0.1V
Equivalent AC test circuit 3
20
36
dB
PSRR
Power supply rejection ratio
2
(V
CC1
)
DC tested,
V
CC
=0.1V
Equivalent AC test circuit 4
20
36
dB
PSRR
Power supply rejection ratio
2
(V
CC2
)
DC tested,
V
CC
=0.1V
Equivalent AC test circuit 5
65
dB
PSRR
Power supply rejection ratio
2
(ECL
configuration)
f=0.1MHz, Test Circuit 6
23
dB
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
3
AC ELECTRICAL CHARACTERISTICS
(Continued)
SYMBOL
PARAMETER
TEST CONDITIONS
LIMITS
UNIT
SYMBOL
PARAMETER
TEST CONDITIONS
Min
Typ
Max
UNIT
V
OMAX
Maximum output voltage swing dif-
ferential
R
L
=
Test Circuit 8, Procedure 3
2.4
3.2
V
P-P
V
INMAX
Maximum input amplitude for
output duty cycle of 50
5%
3
Test Circuit 7
650
mV
P-P
t
R
Rise time for 50 mV
P-P
output signal
4
Test Circuit 7
0.8
1.2
ns
NOTES:
1. Package parasitic capacitance amounts to about 0.2pF
2. PSRR is output referenced and is circuit board layout dependent at higher frequencies. For best performance use RF filter in V
CC
line.
3. Guaranteed by linearity and overload tests.
4. t
R
defined as 20-80% rise time. It is guaranteed by a -3dB bandwidth test.
TEST CIRCUITS
Test Circuit 2
Test Circuit 1
RT [
VOUT
VIN
R
+ 2 @ S21 @ R
RT +
VOUT
VIN
R
+ 4 @ S21 @ R
SINGLE-ENDED
DIFFERENTIAL
RO [ ZO
1
) S22
1
* S22 *
33
RO + 2ZO
1
) S22
1
* S22 *
66
NETWORK ANALYZER
S-PARAMETER TEST SET
PORT 1
PORT 2
5V
33
IN
DUT
OUT
OUT
50
33
GND1
GND2
VCC1
VCC2
ZO = 50
0.1
F
RL = 50
R = 1k
0.1
F
0.1
F
SPECTRUM ANALYZER
5V
33
IN
DUT
OUT
OUT
33
GND1
GND2
VCC1
VCC2
0.1
F
RL = 50
0.1
F
AV = 60DB
NC
ZO = 50
ZO = 50
SD00319
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
4
TEST CIRCUITS
(Continued)
Test Circuit 4
Test Circuit 3
NETWORK ANALYZER
S-PARAMETER TEST SET
PORT 1
PORT 2
VCC2
VCC1
GND1
GND2
IN
CURRENT PROBE
1mV/mA
CAL
TEST
TRANSFORMER
NH0300HB
100
33
33
16
5V
OUT
OUT
BAL.
0.1
F
0.1
F
10
F
0.1
F
0.1
F
50
UNBAL.
NETWORK ANALYZER
S-PARAMETER TEST SET
PORT 1
PORT 2
CURRENT PROBE
1mV/mA
CAL
TEST
TRANSFORMER
NH0300HB
100
33
33
16
5V
OUT
OUT
BAL.
50
UNBAL.
VCC1
VCC2
IN
0.1
F
0.1
F
10
F
0.1
F
0.1
F
0.1
F
10
F
5V
10
F
10
F
GND1
GND2
SD00320
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
5
TEST CIRCUITS
(Continued)
NETWORK ANALYZER
S-PARAMETER TEST SET
PORT 1
PORT 2
CURRENT PROBE
1mV/mA
CAL
TEST
TRANSFORMER
NH0300HB
100
33
33
16
5V
OUT
OUT
BAL.
50
UNBAL.
VCC2
VCC1
IN
0.1
F
0.1
F
10
F
0.1
F
0.1
F
0.1
F
10
F
5V
Test Circuit 6
Test Circuit 5
NETWORK ANALYZER
S-PARAMETER TEST SET
PORT 1
PORT 2
CURRENT PROBE
1mV/mA
CAL
TEST
TRANSFORMER
NH0300HB
100
33
33
16
OUT
OUT
BAL.
50
UNBAL.
GND2
GND1
VCC1
VCC2
IN
0.1
F
0.1
F
0.1
F
10
F
GND
0.1
F
10
F
5.2V
10
F
GND2
GND1
SD00321
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
6
TEST CIRCUITS
(Continued)
Test Circuit 7
OSCILLOSCOPE
33
33
1k
OUT
OUT
GND2
GND1
VCC1
VCC2
IN
0.1
F
0.1
F
PULSE GEN.
Measurement done using
differential wave forms
0.1
F
50
ZO = 50
A
B
ZO = 50
DUT
SD00322
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
7
TEST CIRCUITS
(Continued)
GND2
Test Circuit 8
OUT +
OUT
GND1
IN
DUT
IIN (
A)
5V
VOUT (V)
+
Typical Differential Output Voltage
vs Current Input
2.00
1.60
1.20
0.80
0.40
0.00
0.40
0.80
1.20
1.60
2.00
400
320
240
160
80
0
80
160
240
320
400
DIFFERENTIAL
OUTPUT VOL
T
AGE (V)
CURRENT INPUT (
A)
NE5210 TEST CONDITIONS
Procedure 1
RT measured at 60
A
RT = (VO1 VO2)/(+60
A (60
A))
Where: VO1 Measured at IIN = +60
A
VO2 Measured at IIN = 60
A
Procedure 2
Linearity = 1 ABS((VOA VOB) / (VO3 VO4))
Where: VO3 Measured at IIN = +120
A
VO4 Measured at IIN = 120
A
V
OA
+
R
T
@
(
)
120
m
A)
)
V
OB
V
OB
+
R
T
@
(
*
120
m
A)
)
V
OB
Procedure 3
VOMAX = VO7 VO8
Where: VO7 Measured at IIN = +260
A
VO8 Measured at IIN = 260
A
Procedure 4
IIN Test Pass Conditions:
VO7 VO5 > 20mV and V06 VO5 > 20mV
Where: VO5 Measured at IIN = +160
A
VO6 Measured at IIN = 160
A
VO7 Measured at IIN = +260
A
VO8 Measured at IIN = 260
A
SD00323
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
8
TYPICAL PERFORMANCE CHARACTERISTICS
DIFFERENTIAL
OUTPUT VOL
T
AGE (V)
DIFFERENTIAL
OUTPUT VOL
T
AGE (V)
OUTPUT VOL
T
AGE (V)
OUTPUT BIAS VOL
T
AGE (V)
AMBIENT TEMPERATURE (
C)
AMBIENT TEMPERATURE (
C)
NE5210 Supply Current
vs Temperature
NE5210 Output Bias Voltage
vs Temperature
Output Voltage
vs Input Current
NE5210 Input Bias Voltage
vs Temperature
NE5210 Output Bias Voltage
vs Temperature
Differential Output Voltage
vs Input Current
NE5210 Output Offset Voltage
vs Temperature
NE5210 Differential Output Swing
vs Temperature
Differential Output Voltage
vs Input Current
AMBIENT TEMPERATURE (
C)
10
10 20
30 40
50 60 70
80
32
30
28
26
24
22
20
18
0
T
OT
AL
SUPPL
Y
CURRENT (mA)
(I + I )
CC1
CC2
3.50
3.46
3.42
3.38
3.34
3.30
10
10 20
30 40
50 60 70
80
0
OUTPUT BIAS VOL
T
AGE (V)
VCC = 5.0V
PIN 14
PIN 12
10
10 20
30 40
50 60 70
80
900
0
INPUT BIAS VOL
T
AGE (mV)
850
800
750
700
5.5V
5.0V
4.5V
10
10 20
30 40
50 60 70
80
20
0
OUTPUT OFFSET VOL
T
AGE (mV)
0
20
40
60
5.5V
5.0V
4.5V
AMBIENT TEMPERATURE (
C)
80
VOS = VOUT12 VOUT14
10
10 20
30 40
50 60 70
80
0
AMBIENT TEMPERATURE (
C)
4.1
3.9
3.7
3.5
3.3
3.1
2.9
2.7
PIN 14
5.5V
5.0V
4.5V
DIFFERENTIAL
OUTPUT SWING (V)
10
10 20
30 40
50 60 70
80
0
4.0
3.8
3.6
3.4
3.2
3.0
2.8
2.6
AMBIENT TEMPERATURE (
C)
5.5V
5.0V
4.5V
2.4
2.2
DC TESTED
RL =
4.5
3.0
2.5
300.0
0
+300.0
INPUT CURRENT (
A)
+25
C
+125
C
+85
C
55
C
+125
C
+85
C
2.0
0
2.0
300.0
0
+300.0
INPUT CURRENT (
A)
5.5V
5.0V
4.5V
5.5V
5.0V
4.5V
2.0
0
2.0
300.0
0
+300.0
INPUT CURRENT (
A)
+125
C
+85
C
+25
C
55
C
SD00324
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
9
TYPICAL PERFORMANCE CHARACTERISTICS
(Continued)
8
7
6
5
4
3
2
1
0
1
GAIN (dB)
POPULA
TION (%)
Gain vs Frequency
Gain vs Frequency
NE5210 Differential Transresistance
vs Temperature
Gain vs Frequency
Gain vs Frequency
NE5210 Bandwidth vs Temperature
Gain and Phase Shift
vs Frequency
NE5210 Typical
Bandwidth Distribution
(70 Parts from 4 Wafer Lots)
Gain and Phase Shift
vs Frequency
50
40
30
20
10
0
223
255
287
319
351
383
FREQUENCY (MHz)
PIN 12
SINGLE-ENDED
RL = 50
VCC = 5.0V
TA = 25
C
AMBIENT TEMPERATURE (
C)
8.6
10
10 20 30 40 50 60 70
80
0
DIFFERENTIAL
TRANSRESIST
ANCE (k )
RL =
8.4
8.2
8.0
7.8
7.6
7.4
5.5V
5.0V
4.5V
450
10
10 20 30 40 50 60 70
80
0
BANDWIDTH (MHz)
AMBIENT TEMPERATURE (
C)
400
350
300
250
200
5.5V
5.0V
4.5V
PIN 12
PIN 12
VCC = 5V
TA = 25
C
8
7
6
5
4
3
2
1
0
1
1
10
100
1000
FREQUENCY (MHz)
GAIN (dB)
180
90
0
90
180
PHASE ( )
o
1
10
100
1000
FREQUENCY (MHz)
PIN 12
VCC = 5V
8
7
6
5
4
3
2
1
0
1
GAIN (dB)
55
C
+125
C
+85
C
25
C
+125
C
55
C
1
10
100
1000
FREQUENCY (MHz)
PIN 12
VCC = 5V
RL = 50
5.0V
5.5V
4.5V
8
7
6
5
4
3
2
1
0
1
GAIN (dB)
1
10
100
1000
FREQUENCY (MHz)
PIN 12
VCC = 5V
RL = 50
5.0V
5.5V
4.5V
1
10
100
1000
FREQUENCY (MHz)
PIN 14
8
7
6
5
4
3
2
1
0
1
GAIN (dB)
VCC = 5V
55
C
+125
C
25
C
85
C
PIN 14
8
7
6
5
4
3
2
1
0
1
1
10
100
1000
FREQUENCY (MHz)
GAIN (dB)
360
270
180
90
0
PHASE ( )
o
VCC = 5V
TA = 25
C
RL =
SINGLE-ENDED
SD00325
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
10
TYPICAL PERFORMANCE CHARACTERISTICS
(Continued)
FREQUENCY (MHz)
NE5210 Output Resistance
vs Temperature
NE5210 Output Resistance
vs Temperature
NE5210 Output Resistance
vs Temperature
Output Resistance
vs Frequency
NE5210 Power Supply Rejection Ratio
vs Temperature
Group Delay
Output Step Response
0
2
4
6
8
10
12
14
16
18
20
(ns)
VCC = 5V
TA = 25
C
20mV/Div
VCC = 5V
TA = 25
C
10
8
6
4
2
0
0.1 20
40
60
80 100 120 140 160 180 200
DELA
Y
(ns)
40
39
38
37
36
35
34
33
10 0
10 20
30 40
50 60
70
80
POWER SUPPL
Y
REJECTION RA
TIO (dB)
AMBIENT TEMPERATURE (
C)
VCC1 = VCC2 = 5.0V
VCC =
0.1V
DC TESTED
OUTPUT REFERRED
17
16
15
14
13
10 0
10 20
30 40
50 60
70
80
AMBIENT TEMPERATURE (
C)
OUTPUT RESIST
ANCE ( )
PIN 14
OUTPUT REFERRED
4.5V
5.0V
5.5V
16
15
14
13
12
10 0
10 20
30 40
50 60
70
80
OUTPUT RESIST
ANCE ( )
PIN 12
OUTPUT REFERRED
4.5V
5.0V
5.5V
AMBIENT TEMPERATURE (
C)
17
16
15
14
13
10 0
10 20
30 40
50 60
70
80
OUTPUT RESIST
ANCE ( )
VCC = 5.0V
DC TESTED
5.0V
AMBIENT TEMPERATURE (
C)
12
PIN 14 ROUT
PIN 12 ROUT
5.0V
80
70
60
50
40
30
20
10
0
OUTPUT RESIST
ANCE ( )
FREQUENCY (MHz)
0.1
1
10
100 200
PIN 12
PIN 14
VCC = 5.0V
TA = 25
C
SD00326
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
11
THEORY OF OPERATION
Transimpedance amplifiers have been widely used as the
preamplifier in fiber-optic receivers. The NE5210 is a wide
bandwidth (typically 280MHz) transimpedance amplifier designed
primarily for input currents requiring a large dynamic range, such as
those produced by a laser diode. The maximum input current before
output stage clipping occurs at typically 240
A. The NE5210 is a
bipolar transimpedance amplifier which is current driven at the input
and generates a differential voltage signal at the outputs. The
forward transfer function is therefore a ratio of the differential output
voltage to a given input current with the dimensions of ohms. The
main feature of this amplifier is a wideband, low-noise input stage
which is desensitized to photodiode capacitance variations. When
connected to a photodiode of a few picoFarads, the frequency
response will not be degraded significantly. Except for the input
stage, the entire signal path is differential to provide improved
power-supply rejection and ease of interface to ECL type circuitry. A
block diagram of the circuit is shown in Figure 1. The input stage
(A1) employs shunt-series feedback to stabilize the current gain of
the amplifier. The transresistance of the amplifier from the current
source to the emitter of Q
3
is approximately the value of the
feedback resistor, R
F
=3.6k
. The gain from the second stage (A2)
and emitter followers (A3 and A4) is about two. Therefore, the
differential transresistance of the entire amplifier, R
T
is
R
T
+
V
OUT
(diff)
I
IN
+
2R
F
+
2(3.6K)
+
7.2k
W
The single-ended transresistance of the amplifier is typically 3.6k
.
The simplified schematic in Figure 2 shows how an input current is
converted to a differential output voltage. The amplifier has a single
input for current which is referenced to Ground 1. An input current
from a laser diode, for example, will be converted into a voltage by
the feedback resistor R
F
. The transistor Q1 provides most of the
open loop gain of the circuit, A
VOL
70. The emitter follower Q
2
minimizes loading on Q
1
. The transistor Q
4
, resistor R
7
, and V
B1
provide level shifting and interface with the Q
15
Q
16
differential
pair of the second stage which is biased with an internal reference,
V
B2
. The differential outputs are derived from emitter followers Q
11
Q
12
which are biased by constant current sources. The collectors of
Q
11
Q
12
are bonded to an external pin, V
CC2
, in order to reduce
the feedback to the input stage. The output impedance is about 17
single-ended. For ease of performance evaluation, a 33
resistor is
used in series with each output to match to a 50
test system.
INPUT
OUTPUT +
OUTPUT
A1
A2
A3
A4
RF
SD00327
Figure 1. NE5210 Block Diagram
BANDWIDTH CALCULATIONS
The input stage, shown in Figure 3, employs shunt-series feedback
to stabilize the current gain of the amplifier. A simplified analysis can
determine the performance of the amplifier. The equivalent input
capacitance, C
IN
, in
parallel with the source, I
S
, is approximately 7.5pF, assuming that
C
S
=0 where C
S
is the external source capacitance.
Since the input is driven by a current source the input must have a
low input resistance. The input resistance, R
IN
, is the ratio of the
incremental input voltage, V
IN
, to the corresponding input current, I
IN
and can be calculated as:
R
IN
+
V
IN
I
IN
+
R
F
1
)
A
VOL
+
3.6K
71
+
51
W
More exact calculations would yield a higher value of 60
.
Thus C
IN
and R
IN
will form the dominant pole of the entire amplifier;
f
*
3dB
+
1
2
p
R
IN
C
IN
Assuming typical values for R
F
= 3.6k
, R
IN
= 60
, C
IN
= 7.5pF
f
*
3dB
+
1
2
p
7.5pF 60
+
354MHz
INPUT
OUT
OUT+
PHOTODIODE
VB2
+
+
R1
R3
R12
R13
R5
R4
R7
R14
R15
Q1
Q3
Q2
Q4
Q15
Q16
Q11
Q12
GND2
GND1
VCC2
VCC1
R2
SD00328
Figure 2. Transimpedance Amplifier
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
12
VCC
VEQ3
VIN
IIN
INPUT
IF
IB
Q1
Q2
Q3
R2
R3
R4
RF
R1
IC1
SD00329
Figure 3. Shunt-Series Input Stage
The operating point of Q1, Figure 2, has been optimized for the
lowest current noise without introducing a second dominant pole in
the pass-band. All poles associated with subsequent stages have
been kept at sufficiently high enough frequencies to yield an overall
single pole response. Although wider bandwidths have been
achieved by using a cascode input stage configuration, the present
solution has the advantage of a very uniform, highly desensitized
frequency response because the Miller effect dominates over the
external photodiode and stray capacitances. For example, assuming
a source capacitance of 1pF, input stage voltage gain of 70, R
IN
=
60
then the total input capacitance, C
IN
= (1+7.5) pF which will
lead to only a 12% bandwidth reduction.
NOISE
Most of the currently installed fiber-optic systems use non-coherent
transmission and detect incident optical power. Therefore, receiver
noise performance becomes very important. The input stage
achieves a low input referred noise current (spectral density) of
3.5pA/
Hz. The transresistance configuration assures that the
external high value bias resistors often required for photodiode
biasing will not contribute to the total noise system noise. The
equivalent input
RMS
noise current is strongly determined by the
quiescent current of Q
1
, the feedback resistor R
F
, and the
bandwidth; however, it is not dependent upon the internal
Miller-capacitance. The measured wideband noise was 66nA
RMS
in
a 200MHz bandwidth.
DYNAMIC RANGE CALCULATIONS
The electrical dynamic range can be defined as the ratio of
maximum input current to the peak noise current:
Electrical dynamic range, D
E
, in a 200MHz bandwidth assuming
I
INMAX
= 240
A and a wideband noise of I
EQ
=66nA
RMS
for an
external source capacitance of C
S
= 1pF.
D
E
+
20log
(Max. input current) (PK)
(Peak noise current) (RMS)
@
2
+
20 log
(240
@
10
*
6
)
( 2 66 10
*
9
)
+
68dB
In order to calculate the optical dynamic range the incident optical
power must be considered.
For a given wavelength
; (meters)
Energy of one Photon = hc
l
watt sec (Joule)
Where h=Planck's Constant = 6.6
10
-34
Joule sec.
c = speed of light = 3
10
8
m/sec
c /
= optical frequency (Hz)
No. of incident photons/sec= where P=optical incident power
No. of incident photons/sec =
P
hs
l
where P = optical incident power
No. of generated electrons/sec =
h @
P
hs
l
where
= quantum efficiency
+
no. of generated electron hole paris
no. of incident photons
N
I
+ h @
P
hs
l @
e Amps (Coulombs sec.)
where e = electron charge = 1.6
10
-19
Coulombs
Responsivity R =
h @
e
hs
l
Amp/watt
I
+
P
@
R
Assuming a data rate of 400 Mbaud (Bandwidth, B=200MHz), the
noise parameter Z may be calculated as:
1
Z
+
I
EQ
qB
+
66
@
10
*
9
(1.6
@
10
*
19
)(200
@
10
6
)
+
2063
where Z is the ratio of
RMS
noise output to the peak response to a
single hole-electron pair. Assuming 100% photodetector quantum
efficiency, half mark/half space digital transmission, 850nm
lightwave and using Gaussian approximation, the minimum required
optical power to achieve 10
-9
BER is:
P
avMIN
+
12
hc
l
B Z
+
12 2.3
@
10
*
19
200
@
10
6
2063
+
1139nW
+ *
29.4dBm
where h is Planck's Constant, c is the speed of light,
is the
wavelength. The minimum input current to the NE5210, at this input
power is:
I
avMIN
+
qP
avMIN
l
hc
+
1139
@
10
*
9
@
1.6
@
10
*
19
2.3
@
10
*
19
= 792nA
Choosing the maximum peak overload current of I
avMAX
=240
A, the
maximum mean optical power is:
P
avMAX
+
hcI
avMAX
l
q
+
2.3
@
10
*
19
1.6
@
10
*
19
240
@
10
*
6
Thus the optical dynamic range, D
O
is:
D
O
= P
avMAX
- P
avMIN
= -4.6 -(-29.4) = 24.8dB.
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
13
This represents the maximum limit attainable with the NE5210
operating at 200MHz bandwidth, with a half mark/half space digital
transmission at 850nm wavelength.
APPLICATION INFORMATION
Package parasitics, particularly ground lead inductances and
parasitic capacitances, can significantly degrade the frequency
response. Since the NE5210 has differential outputs which can feed
back signals to the input by parasitic package or board layout
capacitances, both peaking and attenuating type frequency
response shaping is possible. Constructing the board layout so that
Ground 1 and Ground 2 have very low impedance paths has
produced the best results. This was accomplished by adding a
ground-plane stripe underneath the device connecting Ground 1,
Pins 811, and Ground 2, Pins 1 and 2 on opposite ends of the
SO14 package. This ground-plane stripe also provides isolation
between the output return currents flowing to either V
CC2
or Ground
2 and the input photodiode currents to flowing to Ground 1. Without
this ground-plane stripe and with large lead inductances on the
board, the part may be unstable and oscillate near 800MHz. The
easiest way to realize that the part is not functioning normally is to
measure the DC voltages at the outputs. If they are not close to their
quiescent values of 3.3V (for a 5V supply), then the circuit may be
oscillating. Input pin layout necessitates that the photodiode be
physically very close to the input and Ground 1. Connecting Pins 3
and 5 to Ground 1 will tend to shield the input but it will also tend to
increase the capacitance on the input and slightly reduce the
bandwidth.
As with any high-frequency device, some precautions must be
observed in order to enjoy reliable performance. The first of these is
the use of a well-regulated power supply. The supply must be
capable of providing varying amounts of current without significantly
changing the voltage level. Proper supply bypassing requires that a
good quality 0.1
F high-frequency capacitor be inserted between
V
CC1
and V
CC2
, preferably a chip capacitor, as close to the package
pins as possible. Also, the parallel combination of 0.1
F capacitors
with 10
F tantalum capacitors from each supply, V
CC1
and V
CC2
, to
the ground plane should provide adequate decoupling. Some
applications may require an RF choke in series with the power
supply line. Separate analog and digital ground leads must be
maintained and printed circuit board ground plane should be
employed whenever possible.
Figure 4 depicts a 50Mb/s TTL fiber-optic receiver using the BPF31,
850nm LED, the NE5210 and the NE5214 post amplifier.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LED
CPKDET
THRESH
GNDA
FLAG
JAM
VCCD
VCCA
GNDD
TTLOUT
IN1B
IN1A
CAZP
CAZN
OUT1B
IN8B
OUT1A
IN8A
RHYST
RPKDET
NE5214
GND
GND
GND
OUT
GND
GND
OUT
VCC
VCC
NC
IIN
NC
GND
GND
NE5210
R2
220
D1
LED
C9
100pF
100pF
C7
.01
F
47
F
C1
C2
GND
+VCC
0.1
F
R4
4k
R3
47k
VOUT (TTL)
L3
10
H
L2
10
H
C11
C10
.01
F
.01
F
C13
C12
10
F
10
F
C8
L1
10
H
BPF31
OPTICAL
INPUT
R1
100
C5
1.0
F
C6
.01
F
.01
F
C4
10
F
C3
NOTE:
The NE5210/NE5217 combination can operate at data rates in excess of 100Mb/s NRZ
The capacitor C7 decreases the NE5210 bandwidth to improve overall S/N ratio in the DC50MHz band, but does create extra high frequency noise
on the NE5210 VCC pin(s).
SD00330
Figure 4. A 50Mb/s Fiber Optic Receiver
Philips Semiconductors
Product specification
NE5210
Transimpedance amplifier (280MHz)
1995 Apr 26
14
GND 2
GND 2
NC
INPUT
NC
GND 1
GND 1
GND 1
GND 1
OUT (+)
GND 2
OUT ()
1
2
3
4
5
6
7
8
9
10
11
12
13
14
VCC1
VCC 2
SD00488
ECN No.: 06027
1992 Mar 13
Figure 5. NE5210 Bonding Diagram
Die Sales Disclaimer
Due to the limitations in testing high frequency and other parameters
at the die level, and the fact that die electrical characteristics may
shift after packaging, die electrical parameters are not specified and
die are not guaranteed to meet electrical characteristics (including
temperature range) as noted in this data sheet which is intended
only to specify electrical characteristics for a packaged device.
All die are 100% functional with various parametrics tested at the
wafer level, at room temperature only (25
C), and are guaranteed to
be 100% functional as a result of electrical testing to the point of
wafer sawing only. Although the most modern processes are
utilized for wafer sawing and die pick and place into waffle pack
carriers, it is impossible to guarantee 100% functionality through this
process. There is no post waffle pack testing performed on
individual die.
Since Philips Semiconductors has no control of third party
procedures in the handling or packaging of die, Philips
Semiconductors assumes no liability for device functionality or
performance of the die or systems on any die sales.
Although Philips Semiconductors typically realizes a yield of 85%
after assembling die into their respective packages, with care
customers should achieve a similar yield. However, for the reasons
stated above, Philips Semiconductors cannot guarantee this or any
other yield on any die sales.
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