December 2001
1
MIC921
MIC921
Micrel
MIC921
45MHz Low-Power SC-70 Op Amp
Final Information
General Description
The MIC921 is a high-speed operational amplifier with a gain-
bandwidth product of 45MHz. The part is unity gain stable. It
has a very low 300
A supply current, and features the
IttyBitty
TM
SC-70 and SOT-23-5 package.
Supply voltage range is from
2.5V to
9V, allowing the
MIC921 to be used in low-voltage circuits or applications
requiring large dynamic range.
The MIC921 is stable driving any capacitative load and
achieves excellent PSRR and CMRR, making it much easier
to use than most conventional high-speed devices. Low
supply voltage, low power consumption, and small packing
make the MIC921 ideal for portable equipment. The ability to
drive capacitative loads also makes it possible to drive long
coaxial cables.
Features
45MHz gain bandwidth product
61MHz 3dB bandwidth
300
A supply current
SC-70 or SOT-23-5 packages
3200V/
s slew rate
Drives any capacitive load
112dB CMRR
Unity gain stable
Applications
Video
Imaging
Ultrasound
Portable equipment
Line drivers
Ordering Information
Part Number
Junction Temp. Range
Package
MIC921BM5
40
C to +85
C
SOT-23-5*
MIC921BC5
40
C to +85
C
SC-70
*Contact factory for availability of SOT-23-5 package.
Micrel, Inc. 1849 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 944-0970 http://www.micrel.com
Pin Description
Pin Number
Pin Name
Pin Function
1
IN+
Noninverting Input
2
V
Negative Supply (Input)
3
IN
Inverting Input
4
OUT
Output: Amplifier Output
5
V+
Positive Supply (Input)
Pin Configuration
IN+
V
OUT
IN
1
3
4
5
2
V+
A38
Part
Identification
SOT-23-5 or SC-70
Functional Pinout
IN+
V
OUT
IN
1
3
4
5
2
V+
SOT-23-5 or SC-70
MIC921
Micrel
MIC921
2
December 2001
Absolute Maximum Ratings
(Note 1)
Supply Voltage (V
V+
V
V
) ........................................... 20V
Differentail Input Voltage (
V
IN+
V
IN
) .......... 4V, Note 3
Input Common-Mode Range (V
IN+
, V
IN
) .......... V
V+
to V
V
Lead Temperature (soldering, 5 sec.) ....................... 260
C
Storage Temperature (T
S
) ........................................ 150
C
ESD Rating, Note 4 ................................................... 1.5kV
Operating Ratings
(Note 2)
Supply Voltage (V
S
) .......................................
2.5V to
9V
Junction Temperature (T
J
) ......................... 40
C to +85
C
Package Thermal Resistance
SC70-5 .............................................................. 450
C/W
SOT23-5 ............................................................ 260
C/W
Electrical Characteristics (
5V)
V+ = +5V, V = 5V, V
CM
= 0V, R
L
= 10M
; T
J
= 25
C, bold values indicate 40
C
T
J
+85
C; unless noted.
Symbol
Parameter
Condition
Min
Typ
Max
Units
V
OS
Input Offset Voltage
0.43
5
mV
V
OS
V
OS
Temperature Coefficient
1
V/
C
I
B
Input Bias Current
0.13
0.6
A
I
OS
Input Offset Current
0.06
0.3
A
V
CM
Input Common-Mode Range
CMRR > 72dB
3.25
+3.25
V
CMRR
Common-Mode Rejection Ratio
2.5V < V
CM
< +2.5V
75
87
dB
PSRR
Power Supply Rejection Ratio
3.5V < V
S
<
9V
95
105
dB
A
VOL
Large-Signal Voltage Gain
R
L
= 2k, V
OUT
=
2V
70
84
dB
R
L
= 100
, V
OUT
=
1V
85
dB
V
OUT
Maximum Output Voltage Swing
positive, R
L
= 2k
+3.0
3.7
V
negative, R
L
= 2k
3.7
3.0
V
positive, R
L
= 200
+1.5
3.0
V
negative, R
L
= 200
, Note 5
2.5
1.0
V
GBW
Unity Gain-Bandwidth Product
A
V
= 1, C
L
= 1.7pF
37
MHz
PM
Phase Margin
46
BW
3dB Bandwidth
A
V
= 1, R
L
= 1k
, C
L
= 1.7pF
53
MHz
SR
Slew Rate
C=1.7pF, Gain=1, V
OUT
=5V, peak to peak,
1500
V/
s
negative SR = 1300V/
s
I
SC
Short-Circuit Output Current
source
45
57
mA
sink
20
40
mA
I
S
Supply Current
No Load
0.30
0.50
mA
Input Voltage Noise
f = 10kHz
12
nV
Hz
Input Current Noise
f = 10kHz
0.7
pA
Hz
Electrical Characteristics
V+ = +9V, V = 9V, V
CM
= 0V, R
L
= 10M
; T
J
= 25
C, bold values indicate 40
C
T
J
+85
C; unless noted
Symbol
Parameter
Condition
Min
Typ
Max
Units
V
OS
Input Offset Voltage
0.4
5
mV
V
OS
Input Offset Voltage
1
V/
C
Temperature Coefficient
I
B
Input Bias Current
0.13
0.6
A
I
OS
Input Offset Current
0.06
0.3
A
V
CM
Input Common-Mode Range
CMRR > 75dB
7.25
+7.25
V
CMRR
Common-Mode Rejection Ratio
2.5V < V
CM
< +2.5V
75
87
dB
December 2001
3
MIC921
MIC921
Micrel
Symbol
Parameter
Condition
Min
Typ
Max
Units
PSRR
Power Supply Rejection Ratio
3.5V < V
S
<
9V
95
105
dB
A
VOL
Large-Signal Voltage Gain
R
L
= 2k, V
OUT
=
3V
75
86
dB
R
L
= 100
, V
OUT
=
1V
92
dB
V
OUT
Maximum Output Voltage Swing
positive, R
L
= 2k
+6.5
7.6
V
negative, R
L
= 2k
7.6
6.2
V
GBW
Unity Gain-Bandwidth Product
A
V
= 1, C
L
= 1.7pF
45
MHz
PM
Phase Margin
40
BW
3dB Bandwidth
A
V
= 1, R
L
= 1k
, C
L
= 1.7pF
61
MHz
SR
Slew Rate
C=1.7pF, Gain=1, V
OUT
=5V, peak to peak,
3200
V/
s
negative SR = 2500V/
s
I
SC
Short-Circuit Output Current
source
40
59
mA
sink
25
45
mA
I
S
Supply Current
No Load
0.36
0.6
mA
Input Voltage Noise
f = 10kHz
12
nV
Hz
Input Current Noise
f = 10kHz
0.7
pA
Hz
Note 1.
Exceeding the absolute maximum rating may damage the device.
Note 2.
The device is not guaranteed to function outside its operating rating.
Note 3.
Exceeding the maximum differential input voltage will damage the input stage and degrade performance (in particular, input bias current is
likely to change).
Note 4.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Note 5.
Output swing limited by the maximum output sink capability, refer to the short-circuit current vs. temperature graph in "Typical Characteristics."
MIC921
Micrel
MIC921
4
December 2001
Test Circuits
2k
10k
10k
10k
0.1
F
0.1
F
0.1
F
10
F
50
50
50
0.1
F
10
F
All resistors:
1% metal film
Output
Input
Input
V+
V
MIC921
4
5
3
1
2
BNC
BNC
BNC
PSRR vs. Frequency
R2 4k
S2
S1
0.1
F
10
F
0.1
F
10
F
10pF
10pF
V+
V
MIC921
4
5
3
1
2
BNC
R4 27k
R3 27k
R1
20
R5
20
100pF
To
Dynamic
Analyzer
Noise Measurement
0.1
F
10
F
0.1
F
10
F
V+
V
MIC921
4
5
3
1
2
BNC
R7c 2k
R7b 200
R7a 100
Input
R6
5k
R2
5k
R3
200k
R4
250
R5
5k
Output
R1 5k
BNC
All resistors 1%
V
V
R2
R1
R2
R
R4
OUT
ERROR
=
+
+
+
+
1
5
R7
CMRR vs. Frequency
V+
V
IN
V
MIC921
4
5
3
1
2
300
50
V
OUT
FET Probe
1k
C
L
0.1
F
10
F
0.1
F
10
F
Closed Loop Frequency Response Measurement
December 2001
5
MIC921
MIC921
Micrel
Typical Characteristics
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
-40 -20
0
20
40
60
80 100
OFFSET VOLTAGE (mV)
TEMPERATURE (
C)
Offset Voltage
vs. Temperature
V
=
2.5V
V
=
5V
V
=
9V
0.10
0.15
0.20
0.25
0.30
0.35
-40 -20
0
20
40
60
80 100
SUPPLY CURRENT (mA)
TEMPERATURE (
C)
Supply Current
vs. Temperature
V
=
2.5V
V
=
9V
V
=
5V
0.20
0.22
0.24
0.26
0.28
0.30
0.32
0.34
0.36
0.38
0.40
0.42
2.5
3.8
5.1
6.4
7.7
9
SUPPLY CURRENT (mA)
SUPPLY VOLTAGE (V)
Supply Current
vs. Supply Voltage
40
C
+85
C
+25
C
0
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2.00
2.20
-900
-540
-180
180
540
900
OFFSET VOLTAGE (mV)
COMMON-MODE VOLTAGE (V)
Offset Voltage vs.
Common-Mode Voltage
40
C
+85
C
+25
C
V
=
2.5V
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
-3.4
-2.7
-2.0
-1.4
-0.7
0.0
0.7
1.4
2.0
2.7
3
OFFSET VOLTAGE (mV)
COMMON-MODE VOLTAGE (V)
Offset Voltage vs.
Common-Mode Voltage
40
C
+85
C
+25
C
V
=
5V
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
-7.40
-5.92
-4.44
-2.96
-1.48
0
1.48
2.96
4.44
5.92
7.40
OFFSET VOLTAGE (mV)
COMMON-MODE VOLTAGE (V)
Offset Voltage vs.
Common-Mode Voltage
40
C
+85
C
+25
C
V
=
9V
0
10
20
30
40
50
60
70
80
90
100
110
2
3.4
4.8
6.2
7.6
9
OUTPUT CURRENT (mA)
SUPPLY VOLTAGE (
V)
Short-Circuit Current vs.
Supply Voltage (Sourcing)
40
C
25
C
85
C
-5.0
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0
0.5
-45.0
-40.5
-36.0
-31.5
-27.0
-22.5
-18.0
-13.5
-9.0
-4.5
0
OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
Output Voltage vs.
Output Current (Sinking)
40
C
25
C
85
C
V
=
5V
-5.0
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0
0.5
0 8 16 24 32 40 48 56 64 72 80
OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
Output Voltage vs.
Output Current (Sourcing)
40
C
25
C
85
C
V
=
9V
-9.0
-8.1
-7.2
-6.3
-5.4
-4.5
-3.6
-2.7
-1.8
-0.9
0
0.9
-50-45-40-35-30-25-20-15-10 -5 0
OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
Output Voltage vs.
Output Current (Sinking)
40
C
25
C
85
C
V
=
9V
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
0
8 16 24 32 40 48 56 64 72 80
OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
Output Voltage vs.
Output Current (Sourcing)
40
C
25
C
85
C
V
=
5V
-70
-63
-56
-49
-42
-35
-28
-21
-14
-7
0
7
2.0
3.4
4.8
6.2
7.6
9.0
SHORT CIRCUIT CURRENT (mA)
SUPPLY VOLTAGE (V)
Short Circuit Current vs.
Supply Voltage (Sinking)
40
C
25
C
85
C
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