LINER LTC6246HS6TRMPBF 180mhz, 1ma power efficient rail-to-rail i/o op amp Datasheet

LTC6246/LTC6247/LTC6248
180MHz, 1mA Power
Efficient Rail-to-Rail
I/O Op Amps
Description
Features
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
Gain Bandwidth Product: 180MHz
–3dB Frequency (AV = 1): 120MHz
Low Quiescent Current: 1mA Max
High Slew Rate: 90V/µs
Input Common Mode Range Includes Both Rails
Output Swings Rail-to-Rail
Low Broadband Voltage Noise: 4.2nV/√Hz
Power-Down Mode: 42μA
Fast Output Recovery
Supply Voltage Range: 2.5V to 5.25V
Input Offset Voltage: 0.5mV Max
Input Bias Current: 100nA
Large Output Current: 50mA
CMRR: 110dB
Open Loop Gain: 45V/mV
Operating Temperature Range: –40°C to 125°C
Single in 6-Pin TSOT-23
Dual in MS8, 2mm × 2mm Thin DFN,TS0T-23, MS10
Quad in MS16
Applications
n
n
n
n
n
n
n
Low Voltage, High Frequency Signal Processing
Driving A/D Converters
Rail-to-Rail Buffer Amplifiers
Active Filters
Video Amplifiers
Fast Current Sensing Amplifiers
Battery Powered Equipment
The LTC®6246/LTC6247/LTC6248 are single/dual/quad low
power, high speed unity gain stable rail-to-rail input/output
operational amplifiers. On only 1mA of supply current they
feature an impressive 180MHz gain-bandwidth product,
90V/µs slew rate and a low 4.2nV/√Hz of input-referred
noise. The combination of high bandwidth, high slew rate,
low power consumption and low broadband noise makes
these amplifiers unique among rail-to-rail input/output op
amps with similar supply currents. They are ideal for lower
supply voltage high speed signal conditioning systems.
The LTC6246 family maintains high efficiency performance
from supply voltage levels of 2.5V to 5.25V and is fully
specified at supplies of 2.7V and 5.0V.
For applications that require power-down, the LTC6246
and the LTC6247 in MS10 offer a shutdown pin which
disables the amplifier and reduces current consumption
to 42µA.
The LTC6246 family can be used as a plug-in replacement
for many commercially available op amps to reduce power
or to improve input/output range and performance.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
350kHz FFT Driving ADC
0
Low Noise Low Distortion Gain = 2 ADC Driver
–20
3.3V 2.5V
VIN
VDD VREF
+
AIN
LTC6246
–
499Ω
1%
499Ω
1%
10pF
LTC2366
GND
–30
CS
SDO
SCK
OVDD
624678 TA01a
MAGNITUDE (dB)
3.3V
fIN = 350.195kHz
fSAMP = 2.2Msps
SFDR = 82dB
SNR = 70dB
1024 POINT FFT
–10
–40
–50
–60
–70
–80
–90
–100
–110
0
200
400
600
800
FREQUENCY (kHz)
1000
624678 TA01b
624678fa
LTC6246/LTC6247/LTC6248
Absolute Maximum Ratings
(Note 1)
Total Supply Voltage (V+ to V –).................................5.5V
Input Current (+IN, –IN, SHDN) (Note 2)............... ±10mA
Output Current (Note 3)...................................... ±100mA
Operating Temperature Range (Note 4).. –40°C to 125°C
Specified Temperature Range (Note 5)... –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
Junction Temperature............................................ 150°C
Lead Temperature (Soldering, 10 sec)
(MSOP, TSOT Packages Only)................................ 300°C
Pin Configuration
TOP VIEW
+IN A 3
V– 4
9
+
–
–
+
–IN A 2
7
OUT B
6
–IN B
5
+IN B
TOP VIEW
TOP VIEW
V+
OUT A
–IN A
+IN A
V–
KC PACKAGE
8-LEAD PLASTIC UTDFN (2mm s 2mm)
TJMAX = 125°C, θJA = 102°C/W (NOTE 9)
EXPOSED PAD (PIN 9) IS V–, MUST BE SOLDERED TO PCB
1
2
3
4
–
+
+
–
8
8
7
6
5
V+
OUT B
–IN B
+IN B
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 163°C/W (NOTE 9)
1
2
3
4
SHDNA 5
OUT A
–IN A
+IN A
V–
–
+
+
–
OUT A 1
10
9
8
7
6
V+
OUT B
–IN B
+IN B
SHDNB
MS PACKAGE
10-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 160°C/W (NOTE 9)
TOP VIEW
–
+
+
–
+
–
16
15
14
13
12
11
10
9
TOP VIEW
OUT D
–IN D
+IN D
V–
+IN C
–IN C
OUT C
OUT 1
V– 2
+IN 3
TOP VIEW
6V
+ –
+
5 SHDN
4 –IN
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
MS PACKAGE
16-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 125°C/W (NOTE 9)
TJMAX = 150°C, θJA = 192°C/W (NOTE 9)
OUT A 1
–IN A 2
+IN A 3
V– 4
–
+
+
–
1
2
3
4
5
6
7
8
+
–
OUT A
–IN A
+IN A
V+
+IN B
–IN B
OUT B
8 V+
7 OUT B
6 –IN B
5 +IN B
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
TJMAX = 150°C, θJA = 195°C/W (NOTE 9)
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
SPECIFIED TEMPERATURE RANGE
LTC6246CS6#TRMPBF
LTC6246CS6#TRPBF
LTDWF
6-Lead Plastic TSOT-23
0°C to 70°C
LTC6246IS6#TRMPBF
LTC6246IS6#TRPBF
LTDWF
6-Lead Plastic TSOT-23
–40°C to 85°C
LTC6246HS6#TRMPBF
LTC6246HS6#TRPBF
LTDWF
6-Lead Plastic TSOT-23
–40°C to 125°C
LTC6247CKC#TRMPBF
LTC6247CKC#TRPBF
DWJT
8-Lead (2mm × 2mm) UTDFN
0°C to 70°C
LTC6247IKC#TRMPBF
LTC6247IKC#TRPBF
DWJT
8-Lead (2mm × 2mm) UTDFN
–40°C to 85°C
LTC6247CMS8#PBF
LTC6247CMS8#TRPBF
LTDWH
8-Lead Plastic MSOP
0°C to 70°C
LTC6247IMS8#PBF
LTC6247IMS8#TRPBF
LTDWH
8-Lead Plastic MSOP
–40°C to 85°C
LTC6247CTS8#TRMPBF
LTC6247CTS8#TRPBF
LTDWK
8-Lead Plastic TSOT-23
0°C to 70°C
LTC6247ITS8#TRMPBF
LTC6247ITS8#TRPBF
LTDWK
8-Lead Plastic TSOT-23
–40°C to 85°C
LTC6247HTS8#TRMPBF
LTC6247HTS8#TRPBF
LTDWK
8-Lead Plastic TSOT-23
–40°C to 125°C
624678fa
LTC6246/LTC6247/LTC6248
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
SPECIFIED TEMPERATURE RANGE
LTC6247CMS#PBF
LTC6247CMS#TRPBF
LTDWM
10-Lead Plastic MSOP
0°C to 70°C
LTC6247IMS#PBF
LTC6247IMS#TRPBF
LTDWM
10-Lead Plastic MSOP
–40°C to 85°C
LTC6248CMS#PBF
LTC6248CMS#TRPBF
6248
16-Lead Plastic MSOP
0°C to 70°C
LTC6248IMS#PBF
LTC6248IMS#TRPBF
6248
16-Lead Plastic MSOP
–40°C to 85°C
LTC6248HMS#PBF
LTC6248HMS#TRPBF
6248
16-Lead Plastic MSOP
–40°C to 125°C
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
Electrical Characteristics
(VS = 5V) The l denotes the specifications which apply across the
specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 5V, 0V; VSHDN = 2V; VCM = VOUT = 2.5V,
unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
VOS
Input Offset Voltage
VCM = Half Supply
MIN
TYP
MAX
UNITS
50
l
–500
–1000
500
1000
µV
µV
–2.5
–3
0.1
l
2.5
3
mV
mV
–600
–1000
50
l
600
1000
µV
µV
–3.5
–4
0.1
l
3.5
4
mV
mV
VCM = V+ – 0.5V, NPN Mode
∆VOS
Input Offset Voltage Match
(Channel-to-Channel) (Note 8)
VCM = Half Supply
VCM = V+ – 0.5V, NPN Mode
VOS TC
Input Offset Voltage Drift
IB
Input Bias Current (Note 7)
VCM = Half Supply
Input Offset Current
–350
–550
–30
350
550
nA
nA
100
0
400
l
1000
1500
nA
nA
–250
–400
–10
l
250
400
nA
nA
–250
–400
–10
l
250
400
nA
nA
VCM = Half Supply
VCM = V+ – 0.5V, NPN Mode
en
µV/°C
l
VCM = V+ – 0.5V, NPN Mode
IOS
–2
l
Input Noise Voltage Density
f = 100kHz
4.2
nV/√Hz
Input 1/f Noise Voltage
f = 0.1Hz to 10Hz
1.6
µVP-P
in
Input Noise Current Density
f = 100kHz
2.0
pA/√Hz
CIN
Input Capacitance
Differential Mode
Common Mode
2
0.8
pF
pF
RIN
Input Resistance
Differential Mode
Common Mode
32
14
kΩ
MΩ
AVOL
Large Signal Voltage Gain
RL = 1k to Half Supply (Note 10)
30
14
45
l
V/mV
V/mV
5
2.5
15
l
V/mV
V/mV
78
76
110
l
dB
dB
RL = 100Ω to Half Supply (Note 10)
CMRR
Common Mode Rejection Ratio
VCM = 0V to 3.5V
624678fa
LTC6246/LTC6247/LTC6248
electrical characteristics
(VS = 5V) The l denotes the specifications which apply across the
specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 5V, 0V; VSHDN = 2V; VCM = VOUT = 2.5V,
unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
ICMR
Input Common Mode Range
PSRR
Power Supply Rejection Ratio
VS = 2.5V to 5.25V
VCM = 1V
Supply Voltage Range (Note 6)
VOL
Output Swing Low (VOUT
– V–)
MIN
l
0
l
69
65
l
2.5
No Load
TYP
VS
73
Output Swing High (V+ – VOUT)
No Load
mV
mV
70
110
160
mV
mV
160
250
450
mV
mV
70
100
150
mV
mV
130
175
225
mV
mV
300
500
750
mV
mV
–80
–35
–30
mA
mA
l
ISOURCE = 5mA
l
ISOURCE = 25mA
l
ISC
Output Short-Circuit Current
Sourcing
l
Sinking
l
IS
Supply Current per Amplifier
60
40
VCM = Half Supply
100
1
1.4
mA
mA
1.25
1.4
1.8
mA
mA
42
75
200
µA
µA
l
ISD
Disable Supply Current per Amplifier
VSHDN = 0.8V
l
ISHDNL
ISHDNH
SHDN Pin Current Low
SHDN Pin Current High
VL
SHDN Pin Input Voltage Low
VSHDN = 0.8V
–3
–4
–1.6
l
0
0
µA
µA
–300
–350
35
l
300
350
nA
nA
0.8
V
VSHDN = 2V
l
VH
SHDN Pin Input Voltage High
IOSD
Output Leakage Current Magnitude in
Shutdown
VSHDN = 0.8V, Output Shorted to Either
Supply
tON
Turn-On Time
tOFF
Turn-Off Time
BW
–3dB Closed Loop Bandwidth
AV = 1, RL = 1k to Half Supply
GBW
Gain-Bandwidth Product
f = 2MHz, RL = 1k to Half Supply
mA
mA
0.95
l
VCM = V+ – 0.5V
V
40
55
l
VOH
V
25
l
ISINK = 25mA
UNITS
dB
dB
5.25
l
ISINK = 5mA
MAX
l
2
V
100
nA
VSHDN = 0.8V to 2V
5
µs
VSHDN = 2V to 0.8V
2
µs
l
100
70
120
MHz
180
MHz
MHz
tS , 0.1%
Settling Time to 0.1%
AV = –1, VO = 2V Step RL = 1k
74
ns
tS , 0.01%
Settling Time to 0.01%
AV = –1, VO = 2V Step RL = 1k
202
ns
SR
Slew Rate
AV = –3.33, 4.6V Step (Note 11)
90
V/µs
V/µs
4
MHz
l
FPBW
Full Power Bandwidth
VOUT = 4VP-P (Note 13)
60
50
624678fa
LTC6246/LTC6247/LTC6248
electrical characteristics
(VS = 5V) The l denotes the specifications which apply across the
specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 5V, 0V; VSHDN = 2V; VCM = VOUT = 2.5V,
unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
HD2/HD3
Harmonic Distortion
RL = 1k to Half Supply
fC = 100kHz, VO = 2VP-P
fC = 1MHz, VO = 2VP-P
fC = 2MHz, VO = 2VP-P
110/90
88/80
78/62
RL = 100Ω to Half Supply
fC = 100kHz, VO = 2VP-P
fC = 1MHz, VO = 2VP-P
fC = 2MHz, VO = 2VP-P
90/79
66/60
59/51
ΔG
Differential Gain (Note 14)
AV = 1, RL = 1k, VS = ±2.5V
0.2
%
Δθ
Differential Phase (Note 14)
AV = 1, RL = 1k, VS = ±2.5V
0.08
Deg
Crosstalk
AV = –1, RL = 1k to Half Supply,
VOUT = 2VP-P, f = 1MHz
–90
dB
dBc
dBc
dBc
electrical characteristics
(VS = 2.7V) The l denotes the specifications which apply across the
specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 2.7V, 0V; VSHDN = 2V; VCM = VOUT =
1.35V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
VOS
Input Offset Voltage
VCM = Half Supply
MIN
TYP
MAX
UNITS
–100
–300
500
l
1000
1400
µV
µV
–1.75
–2.25
0.75
l
3.25
3.75
mV
mV
–700
–1000
–20
l
700
1000
µV
µV
–3.5
–4
0.1
l
3.5
4
mV
mV
VCM = V+ – 0.5V, NPN Mode
∆VOS
Input Offset Voltage Match
(Channel-to-Channel) (Note 8)
VCM = Half Supply
VCM = V+ – 0.5V, NPN Mode
VOS TC
Input Offset Voltage Drift
IB
Input Bias Current (Note 7)
VCM = Half Supply
Input Offset Current
–450
–600
–100
450
600
nA
nA
50
0
350
l
1000
1500
nA
nA
–250
–350
–10
l
250
350
nA
nA
–250
–350
–10
l
250
350
nA
nA
VCM = Half Supply
VCM = V+ – 0.5V, NPN Mode
en
µV/°C
l
VCM = V+ – 0.5V, NPN Mode
IOS
2
l
Input Noise Voltage Density
f = 100kHz
4.6
nV/√Hz
Input 1/f Noise Voltage
f = 0.1Hz to 10Hz
1.7
µVP-P
in
Input Noise Current Density
f = 100kHz
1.8
pA/√Hz
CIN
Input Capacitance
Differential Mode
Common Mode
2
0.8
pF
pF
RIN
Input Resistance
Differential Mode
Common Mode
32
12
kΩ
MΩ
AVOL
Large Signal Voltage Gain
RL = 1k to Half Supply
(Note 12)
15
7.5
25
l
V/mV
V/mV
RL = 100Ω to Half Supply
(Note 12)
2
1.3
7.5
l
V/mV
V/mV
624678fa
LTC6246/LTC6247/LTC6248
electrical characteristics
(VS = 2.7V) The l denotes the specifications which apply across the
specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 2.7V, 0V; VSHDN = 2V; VCM = VOUT =
1.35V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
CMRR
Common Mode Rejection Ratio
VCM = 0V to 1.2V
ICMR
Input Common Mode Range
PSRR
Power Supply Rejection Ratio
VS = 2.5V to 5.25V
VCM = 1V
Supply Voltage Range (Note 6)
VOL
Output Swing Low (VOUT – V–)
MIN
TYP
80
78
100
l
l
0
l
69
65
l
2.5
No Load
73
Output Swing High (V+ – VOUT)
No Load
mV
mV
80
125
160
mV
mV
110
175
225
mV
mV
60
85
100
mV
mV
135
190
225
mV
mV
180
275
400
mV
mV
–35
–20
–15
mA
mA
l
ISOURCE = 10mA
l
ISC
Short Circuit Current
Sourcing
l
Sinking
l
IS
Supply Current per Amplifier
25
20
VCM = Half Supply
50
1
1.3
mA
mA
1
1.3
1.7
mA
mA
22
50
90
µA
µA
l
ISD
Disable Supply Current per Amplifier
VSHDN = 0.8V
l
ISHDNL
ISHDNH
SHDN Pin Current Low
SHDN Pin Current High
VSHDN = 0.8V
mA
mA
0.89
l
VCM = V+ – 0.5V
V
40
55
l
ISOURCE = 5mA
dB
dB
5.25
l
VOH
V
20
l
ISINK = 10mA
UNITS
dB
dB
VS
l
ISINK = 5mA
MAX
–1
–1.5
–0.5
l
0
0
µA
µA
–300
–350
45
l
300
350
nA
nA
0.8
V
VSHDN = 2V
VL
SHDN Pin Input Voltage
l
VH
SHDN Pin Input Voltage
l
IOSD
Output Leakage Current Magnitude in Shutdown VSHDN = 0.8V, Output Shorted to Either
Supply
tON
Turn-On Time
tOFF
2.0
V
100
nA
VSHDN = 0.8V to 2V
5
µs
Turn-Off Time
VSHDN = 2V to 0.8V
2
µs
BW
–3dB Closed Loop Bandwidth
AV = 1, RL = 1k to Half Supply
GBW
Gain-Bandwidth Product
f = 2MHz, RL = 1k to Half Supply
l
80
50
100
MHz
150
MHz
tS , 0.1
Settling Time to 0.1%
AV = –1, VO = 2V Step RL = 1k
119
ns
tS , 0.01
Settling Time to 0.01%
AV = –1, VO = 2V Step RL = 1k
170
ns
SR
Slew Rate
AV = –1, 2V Step
55
V/µs
624678fa
LTC6246/LTC6247/LTC6248
electrical characteristics
(VS = 2.7V) The l denotes the specifications which apply across the
specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 2.7V, 0V; VSHDN = 2V; VCM = VOUT =
1.35V, unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
FPBW
Full Power Bandwidth
VOUT = 2VP-P (Note 13)
3.3
MHz
Crosstalk
AV = –1, RL = 1k to Half Supply,
VOUT = 2VP-P, f = 1MHz
–90
dB
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The inputs are protected by back-to-back diodes. If any of
the input or shutdown pins goes 300mV beyond either supply or the
differential input voltage exceeds 1.4V the input current should be limited
to less than 10mA. This parameter is guaranteed to meet specified
performance through design and/or characterization. It is not production
tested.
Note 3: A heat sink may be required to keep the junction temperature
below the absolute maximum rating when the output current is high.
Note 4: The LTC6246C/LTC6247C/LTC6248C and LTC6246I/LTC6247I/
LTC6248I are guaranteed functional over the temperature range of –40°C
to 85°C. The LTC6246H/LTC6247H/LTC6248H are guaranteed functional
over the temperature range of –40°C to 125°C.
Note 5: The LTC6246C/LTC6247C/LTC6248C are guaranteed to meet
specified performance from 0°C to 70°C. The LTC6246C/LTC6247C/
LTC6248C are designed, characterized and expected to meet specified
performance from –40°C to 85°C but are not tested or QA sampled at
these temperatures. The LTC6246I/LTC6247I/LTC6248I are guaranteed
to meet specified performance from –40°C to 85°C. The LTC6246H/
LTC6247H/LTC6248H are guaranteed to meet specified performance from
–40°C to 125°C.
MIN
TYP
MAX
UNITS
Note 6: Minimum supply voltage is guaranteed by power supply rejection
ratio test.
Note 7: The input bias current is the average of the average of the currents
through the positive and negative input pins.
Note 8: Matching parameters are the difference between amplifiers A and
D and between B and C on the LTC6248; between the two amplifiers on the
LTC6247.
Note 9: Thermal resistance varies with the amount of PC board metal
connected to the package. The specified values are with short traces
connected to the leads with minimal metal area.
Note 10: The output voltage is varied from 0.5V to 4.5V during
measurement.
Note 11: Middle 80% of the output waveform is observed. RL = 1k at half
supply.
Note 12: The output voltage is varied from 0.5V to 2.2V during
measurement.
Note 13: FPBW is determined from distortion performance in a gain of +2
configuration with HD2, HD3 < –40dBc as the criteria for a valid output.
Note 14: Differential gain and phase are measured using a Tektronix
TSG120YC/NTSC signal generator and a Tektronix 1780R video
measurement set.
Typical Performance Characteristics
VOS Distribution, VCM = VS/2
(MS, PNP Stage)
22
25
VS = 5V, 0V
20 V = 2.5V
CM
18
16
VS = 5V, 0V
14 VCM = 4.5V
VS = 5V, 0V
VCM = 2.5V
14
12
10
8
6
PERCENT OF UNITS (%)
20
16
PERCENT OF UNITS (%)
PERCENT OF UNITS (%)
VOS Distribution, VCM = V+ – 0.5V
(MS, NPN Stage)
VOS Distribution, VCM = VS/2
(TSOT-23, PNP Stage)
15
10
5
4
10
8
6
4
2
2
0
–375
12
–250 –150 –50 50 150 250
INPUT OFFSET VOLTAGE (µV)
350
624678 G01
0
–175 –125 –75 –25 25
75 125
INPUT OFFSET VOLTAGE (µV)
175
624678 G02
0
–2000
–1200
–400
400
1200
INPUT OFFSET VOLTAGE (µV)
2000
624678 G03
624678fa
LTC6246/LTC6247/LTC6248
Typical Performance Characteristics
VOS Distribution, VCM = V+ – 0.5V
(TSOT-23, NPN Stage)
VOS vs Temperature
(MS10, PNP Stage)
18
500
VOLTAGE OFFSET (µV)
14
PERCENT OF UNITS (%)
2500
VS = 5V, 0V
400 VCM = 2.5V
6 DEVICES
300
12
10
8
6
VS = 5V, 0V
2000 VCM = 4.5V
6 DEVICES
1500
VOLTAGE OFFSET (µV)
VS = 5V, 0V
16 VCM = 4.5V
200
100
0
–100
500
0
–500
–1000
–200
–1500
2
–300
–2000
0
–2000
–400
–55 –35 –15
–1200
–400
400
1200
INPUT OFFSET VOLTAGE (µV)
2000
5 25 45 65 85 105 125
TEMPERATURE (°C)
600
400
2500
500
2000
400
1500
300
1000
500
0
–500
0
–55 –35 –15
5 25 45 65 85 105 125
TEMPERATURE (°C)
–200
–400
–500
–55°C
25°C
–1.0
–1.5
–2.0
–100 –75 –50 –25 0
25 50
OUTPUT CURRENT (mA)
75
100
624678 G10
0
0.5 1 1.5 2 2.5 3 3.5 4 4.5
INPUT COMMON MODE VOLTAGE (V)
Input Bias Current
vs Common Mode Voltage
800
VS = ±2.5V
0 TA = 25°C
VS = 5V, 0V
600
–10
–15
–20
–25
125°C
25°C
400
–5
200
0
–200
–55°C
–400
–600
–800
–1000
–1200
–30
–35
5
624678 G09
INPUT BIAS CURRENT (nA)
CHANGE IN OFFSET VOLTAGE (µV)
0.5
125°C
–300
5
125°C
25°C
–100
Warm-Up Drift vs Time
VS = ±2.5V
1.0
–55°C
0
624678 G08
Offset Voltage vs Output Current
–0.5
100
VS = 2.7V, 0V
–1500 VCM = 2.2V
6 DEVICES
–2000
–55 –35 –15 5 25 45 65 85 105 125
TEMPERATURE (°C)
624678 G07
1.5
VS = 5V, 0V
200
–1000
200
0
Offset Voltage
vs Input Common Mode Voltage
OFFSET VOLTAGE (µV)
VOLTAGE OFFSET (µV)
VS = 2.7V, 0V
VCM = 1.35V
1000 6 DEVICES
800
5 25 45 65 85 105 125
TEMPERATURE (°C)
624678 G06
VOS vs Temperature
(MS10, NPN Stage)
1200
2.0
–2500
–55 –35 –15
624678 G05
VOS vs Temperature
(MS10, PNP Stage)
VOLTAGE OFFSET (µV)
1000
4
624678 G04
VOS (mV)
VOS vs Temperature
(MS10, NPN Stage)
–1400
0
20
40 60 80 100 120 140 160
TIME AFTER POWER-UP (s)
624678 G11
–1600
0
0.5
1 1.5 2 2.5 3 3.5 4 4.5
COMMON MODE VOLTAGE (V)
5
624678 G12
624678fa
LTC6246/LTC6247/LTC6248
Typical Performance Characteristics
Input Bias Current vs Temperature
VCM = 4.5V
400
300
200
100
VCM = 2.5V
0
–100
–200
–55
–25
65
5
35
TEMPERATURE (°C)
95
1.0
0.5
0
0.5
0
1
3
2
624678 G13
1.25
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
4 5 6 7
TIME (1s/DIV)
0.60
TA = –55°C
0.40
TA = 25°C
0.20
in, VCM = 4.5V
9
8
0.1
10
10
1
25°C
SHUTDOWN CURRENT
–0.25
–55°C
0.75
0.50
0.25
1
3
2
4
TOTAL SUPPLY VOLTAGE (V)
0
5
–0.50
–0.75
–1.00
–55°C
–1.25
–1.50
–1.75
25°C
–2.00
0
0.5
624678 G16
12
125°C
1.5 2 2.5 3 3.5 4
SHDN PIN VOLTAGE (V)
4.5
5
Minimum Supply Voltage,
VCM = VS/2 (PNP Operation)
5
OFFSET VOLTAGE (mV)
–55°C
6
4
25°C
2
125°C
VCM = VCC – 0.5V
3
2
1
0
0
–2
–1
125°C
25°C
2
2.5
3.5
3
4
4.5
5
TOTAL SUPPLY VOLTAGE (V)
5.5
624678 G19
0
0.5
1.5 2 2.5 3 3.5 4
SHDN PIN VOLTAGE (V)
1
2
2.5
–55°C
3.5
3
4
4.5
5
TOTAL SUPPLY VOLTAGE (V)
5.5
624678 G20
4.5
5
624678 G18
Output Saturation Voltage
vs Load Current (Output High)
Minimum Supply Voltage,
VCM = V+ – 0.5V (NPN Operation)
4
8
–2.50
624678 G17
10
OFFSET VOLTAGE (mV)
1
10M
VS = 5V, 0V
0
125°C
10
OUTPUT HIGH SATURATION VOLTAGE (V)
0
1k 10k 100k 1M
FREQUENCY (Hz)
SHDN Pin Current
vs SHDN Pin Voltage
–2.25
0
100
624678 G15
0.25
VS = 5V, 0V
1.00
0.80
in, VCM = 2.5V
1.0
Supply Current Per Amplifier
vs SHDN Pin Voltage
1.20
TA = 125°C
en, VCM = 2.5V
10
624678 G14
Supply Current
vs Supply Voltage (Per Amplifier)
1.00
en, VCM = 4.5V
100
–1.0
–1.5
125
1000
VS = ±2.5V
VOLTAGE NOISE (nV/√Hz)
CURRENT NOISE (pA/√Hz)
500
VOLTAGE NOISE (500nV/DIV)
INPUT BIAS CURRENT (nA)
1.5
VS = 5V, 0V
600
SHDN PIN CURRENT (µA)
700
Input Noise Voltage and Noise
Current vs Frequency
0.1Hz to 10Hz Voltage Noise
VS = ±2.5V
1
TA = 25°C
TA = 125°C
0.1
TA = –55°C
0.01
0.01
0.1
1
10
LOAD CURRENT (mA)
100
624678 G21
624678fa
LTC6246/LTC6247/LTC6248
Typical Performance Characteristics
Output Saturation Voltage
vs Load Current (Output Low)
120
1
TA = 125°C
TA = 25°C
TA = –55°C
0.01
0.01
0.1
1
10
LOAD CURRENT (mA)
100
TA = –55°C
100
SINK
80
60
20
0
–20
–40
TA = 125°C
–60
SOURCE
–80
RL = 100 TO GROUND
–6
0
–12
0.1
1
10
FREQUENCY (MHz)
30
20
10
50
VS = ±1.35V
VS = ±2.5V
0
VS = ±1.35V
–50
0
–10
–20
100k
1M
10M
FREQUENCY (Hz)
–100
100M 300M
624678 G28
GAIN BANDWIDTH (MHz)
GAIN (dB)
GAIN
TA = 25°C
RL = 1k
100
PHASE (DEG)
40
1.5 2 2.5 3 3.5
OUTPUT VOLTAGE (V)
1
4
200
180
Gain vs Frequency (AV = 2)
VS = ±2.5V
TA = 25°C
RF = RG = 1k
RL = 1k
0.1
1
10
FREQUENCY (MHz)
100
624678 G27
Gain Bandwidth and Phase
Margin vs Temperature
70
60
PHASE MARGIN
50
GAIN BANDWIDTH PRODUCT
160
140
120
100
2.5
3
4
3.5
4.5
TOTAL SUPPLY VOLTAGE (V)
5
4.5
5
624678 G29
70
TA = 25°C
RL = 1k
60
PHASE MARGIN
300
VS = ±2.5V
50
VS = ±1.35V
40
250
200
PHASE MARGIN (DEG)
50
0.5
–18
0.01
100
PHASE MARGIN (DEG)
150
VS = ±2.5V
0
–6
–12
VS = ±2.5V
TA = 25°C
RL = 1k
Gain Bandwidth and Phase
Margin vs Supply Voltage
TA = 25°C
70 RL = 1k
RL = 100 TO GROUND
624678 G26
Open Loop Gain and Phase
vs Frequency
PHASE
12
6
–24
0.01
2.5 2.7
80
RL = 1k TO GROUND
624678 G24
Gain vs Frequency (AV = 1)
624678 G25
60
–500
0
–18
1
1.5
2
OUTPUT VOLTAGE (V)
–200
GAIN (dB)
TA = 25°C
VS = 2.7V, 0V
GAIN (dB)
INPUT VOLTAGE (µV)
6
RL = 1k TO GROUND
0.5
0
–100
624678 G23
RL = 1k TO MID SUPPLY
0
RL = 1k TO MID SUPPLY
100
–400
TA = 25°C
–100
1.25 1.45 1.65 1.85 2.05 2.25 2.45 2.65
POWER SUPPLY VOLTAGE (±V)
Open Loop Gain
RL = 100 TO MID SUPPLY
RL = 100 TO MID SUPPLY
200
–300
TA = –55°C
624678 G22
1000
900
800
700
600
500
400
300
200
100
0
–100
–200
–300
300
TA = 125°C
40
TA = 25°C
VS = 5V, 0V
400
TA = 25°C
GAIN BANDWIDTH (MHz)
0.1
Open Loop Gain
500
INPUT VOLTAGE (µV)
VS = ±2.5V
OUTPUT SHORT-CIRCUIT CURRENT (mA)
OUTPUT LOW SATURATION VOLTAGE (V)
10
Output Short-Circuit Current
vs Power Supply Voltage
GAIN BANDWIDTH PRODUCT
VS = ±2.5V
150
100
–55 –35 –15
VS = ±1.35V
5 25 45 65 85 105 125
TEMPERATURE (°C)
624678 G30
624678fa
10
LTC6246/LTC6247/LTC6248
Typical Performance Characteristics
10
1
AV = 2
AV = 1
0.1
0.01
0.001
100k
1M
10M
100M
FREQUENCY (Hz)
90
80
70
60
50
40
30
20
10
0
–10
1G
10
100
1k
RISING, VS = ±2.5V
80
FALLING, VS = ±1.35V
VS = ±2.5V
70 VOUT = 100mVP-P
AV = 1
VIN
60
RS = 10Ω
AV = 1
–
+
RS VOUT
5 25 45 65 85 105 125
TEMPERATURE (°C)
30
–40
–100
–110
–120
0.01
RL = 1kΩ, 3RD
RL = 1kΩ, 2ND
0.1
1
FREQUENCY (MHz)
10
624678 G37
DISTORTION (dBc)
DISTORTION (dBc)
–90
100
10k 100k 1M 10M 100M
FREQUENCY (Hz)
1k
500Ω
500Ω
VIN
RS = 10Ω
50
RS
AV = 2
VOUT
CL
RS = 20Ω
40
30
–
+
RS = 49.9Ω
VS = ±2.5V
= 200mVP-P
V
10 ROUT
F = RG = 500Ω,
AV = 2
0
100
1000
10
CAPACITIVE LOAD (pF)
RS = 49.9Ω
10
100
1000
CAPACITIVE LOAD (pF)
10000
Distortion vs Frequency
(AV = 1, 2.7V)
–70
–80
–90
–40
Distortion vs Frequency
(AV = 2, 5V)
VS = ±2.5V
–50 VOUT = 2VP-P
AV = 2
RL = 100Ω, 3RD
RL = 100Ω, 3RD
–60
RL = 100Ω, 2ND
RL = 1kΩ, 2ND
RL = 1kΩ, 3RD
–70
–90
–100
–110
–110
0.1
1
FREQUENCY (MHz)
10
624678 G38
RL = 100Ω, 2ND
–80
–100
–120
0.01
10000
624678 G36
–60
–80
10
20
VS = ±1.35V
–50 VOUT = 1VP-P
AV = 1
–70 RL = 100Ω, 2ND
0
60
CL
624678 G35
VS = ±2.5V
–50 VOUT = 2VP-P
AV = 1
RL = 100Ω, 3RD
10
70
RS = 20Ω
40
0
Distortion vs Frequency
(AV = 1, 5V)
–60
20
80
624678 G34
–40
30
Series Output Resistor
vs Capacitive Load (AV = 2)
50
10
40
–55 –35 –15
POSITIVE SUPPLY
40
Series Output Resistor
vs Capacitive Load (AV = 1)
20
RISING, VS = ±1.35V
60
NEGATIVE SUPPLY
50
624678 G33
OVERSHOOT (%)
FALLING, VS = ±2.5V
OVERSHOOT (%)
SLEW RATE (V/µs)
80
AV = –1, RL = 1k, VOUT = 4VP-P (±2.5V),
2VP-P (±1.35V) SLEW RATE MEASURED
AT MIDDLE 2/3 OF OUTPUT
100
60
624678 G31
Slew Rate vs Temperature
120
VS = ±2.5V
TA = 25°C
70
–10
10k 100k 1M 10M 100M 1G
FREQUENCY (Hz)
624678 G31
140
80
POWER SUPPLY REJECTION RATIO (dB)
AV = 10
TA = 25°C
VS = ±2.5V
100
DISTORTION (dBc)
100
OUTPUT IMPEDANCE (Ω)
110
VS = ±2.5V
COMMON MODE REJECTION RATIO (dB)
1000
Power Supply Rejection Ratio
vs Frequency
Common Mode Rejection Ratio
vs Frequency
Output Impedance vs Frequency
–120
0.01
RL = 1kΩ, 3RD
RL = 1kΩ, 2ND
0.1
1
FREQUENCY (MHz)
10
624678 G39
624678fa
11
LTC6246/LTC6247/LTC6248
Typical Performance Characteristics
DISTORTION (dBc)
–60 RL = 100Ω, 2ND
–70
RL = 1kΩ, 2ND
–80
RL = 1kΩ, 3RD
–90
–100
VS = ±1.35V
–110 VOUT = 1VP-P
AV = 2
–120
0.1
1
0.01
FREQUENCY (MHz)
10
624678 G40
VS = ±2.5V
180 AV = 1
T = 25°C
160 A
4
3
2
VS = ±2.5V
TA = 25°C
RL = 1kΩ
1 HD2, HD3 < –40dBc
AV = 2
AV = –1
0
0.1
1
0.01
FREQUENCY (MHz)
200
–
+
1k
160 VIN
140
VOUT
100
60
10mV
10mV
10
0
–4
–3
–2
–1
0
1
2
OUTPUT STEP (V)
3
4
624678 G42
Large Signal Response
0V
1V/DIV
VOUT
1.6V/DIV
20
–2
1mV
0V
10mV
–3
1mV
80
20
VSHDN
2.5V/DIV
10mV
–4
100
0V
60
40
120
40
1mV
1mV
80
140
SHDN Pin Response Time
1k
120
VOUT
1k
VS = ±2.5V
AV = –1
TA = 25°C
1k
180
VIN
–
+
624678 G41
Settling Time vs Output Step
(Inverting)
SETTLING TIME (ns)
200
5
SETTLING TIME (ns)
–50
0
Settling Time vs Output Step
(Noninverting)
RL = 100Ω, 3RD
OUTPUT VOLTAGE SWING (VP-P)
–40
Maximum Undistorted Output
Signal vs Frequency
Distortion vs Frequency
AV = 2, 2.7V)
–1
0
1
2
OUTPUT STEP (V)
3
4
AV = 1
VS = ±2.5V
RL = 1k
VIN = 1.6V
624678 G44
10µs/DIV
AV = 1
VS = ±2.5V
RL = 1k
200ns/DIV
624678 G45
624678 G43
Small Signal Response
Output Overdriven Recovery
0V
VIN
1V/DIV
0V
25mV/DIV
0V
VOUT
2V/DIV
AV = 1
VS = ±2.5V
RL = 1k
50ns/DIV
624678 G46
AV = ±2
VS = ±2.5V
RL = 1k
VIN = 3VP-P
100ns/DIV
624678 G47
624678fa
12
LTC6246/LTC6247/LTC6248
Pin Functions
–IN: Inverting Input of Amplifier. Valid input range from V–
to V+.
V– : Negative Supply Voltage. Typically 0V. This can be made
a negative voltage as long as 2.5V ≤ (V+ – V–) ≤ 5.25V.
+IN: Non-Inverting Input of Amplifier. Valid input range
from V– to V+.
SHDN: Active Low Shutdown. Threshold is typically 1.1V
referenced to V–. Floating this pin will turn the part on.
V+ : Positive Supply Voltage. Allowed applied voltage
ranges from 2.5V to 5.25V when V– = 0V.
OUT: Amplifier Output. Swings rail-to-rail and can typically
source/sink over 50mA of current at a total supply of 5V.
Applications Information
Circuit Description
The LTC6246/LTC6247/LTC6248 have an input and output
signal range that extends from the negative power supply
to the positive power supply. Figure 1 depicts a simplified
schematic of the amplifier. The input stage is comprised
of two differential amplifiers, a PNP stage, Q1/Q2, and an
NPN stage, Q3/Q4 that are active over different common
mode input voltages. The PNP stage is active between
the negative supply to nominally 1.2V below the positive
supply. As the input voltage approaches the positive supply, the transistor Q5 will steer the tail current, I1, to the
current mirror, Q6/Q7, activating the NPN differential pair
and the PNP pair becomes inactive for the remaining input
common mode range. Also, at the input stage, devices Q17
to Q19 act to cancel the bias current of the PNP input pair.
When Q1/Q2 are active, the current in Q16 is controlled to
be the same as the current in Q1 and Q2. Thus, the base
current of Q16 is nominally equal to the base current of
the input devices. The base current of Q16 is then mirrored
by devices Q17 to Q19 to cancel the base current of the
input devices Q1/Q2. A pair of complementary common
emitter stages, Q14/Q15, enable the output to swing from
rail-to-rail.
V+
V+
+
ESDD1
I2
R3
V–
ESDD2
+
I1
D6
D8
D5
D7
–IN
CC
Q4
Q3
Q1
Q16
Q17
Q18
Q19
Q7
ESDD5
V–
OUT
Q9
V+
I3
Q2
BUFFER
AND
OUTPUT BIAS
Q10
V–
C2
+
VBIAS
Q5
Q15
Q13
ESDD3
ESDD4
R5
Q12
Q11
+IN
R4
ESDD6
Q8
C1
Q6
R1
R2
V–
Q14
624678 F01
Figure 1. LTC6246/LTC6247/LTC6248 Simplified Schematic Diagram
624678fa
13
LTC6246/LTC6247/LTC6248
APPLICATIONS INFORMATION
Input Offset Voltage
Input Protection
The offset voltage will change depending upon which
input stage is active. The PNP input stage is active from
the negative supply rail to approximately 1.2V below the
positive supply rail, then the NPN input stage is activated
for the remaining input range up to the positive supply rail
with the PNP stage inactive. The offset voltage magnitude
for the PNP input stage is trimmed to less than 500µV with
5V total supply at room temperature, and is typically less
than 150μV. The offset voltage for the NPN input stage
is typically less than 1.7mV with 5V total supply at room
temperature.
The input stages are protected against a large differential
input voltage of 1.4V or higher by 2 pairs of back-to-back
diodes to prevent the emitter-base breakdown of the input
transistors. In addition, the input and shutdown pins have
reverse biased diodes connected to the supplies. The current in these diodes must be limited to less than 10mA.
The amplifiers should not be used as comparators or in
other open loop applications.
Input Bias Current
The LTC6246 family uses a bias current cancellation circuit to compensate for the base current of the PNP input
pair. When the input common mode voltage is less than
200mV, the bias cancellation circuit is no longer effective
and the input bias current magnitude can reach a value
above 1µA. For common mode voltages ranging from
0.2V above the negative supply to 1.2V below the positive
supply, the low input bias current of the LTC6246 family
allows the amplifiers to be used in applications with high
source resistances where errors due to voltage drops
must be minimized.
Output
The LTC6246 family has excellent output drive capability.
The amplifiers can typically deliver over 50mA of output
drive current at a total supply of 5V. The maximum output current is a function of the total supply voltage. As
the supply voltage to the amplifier decreases, the output
current capability also decreases. Attention must be paid
to keep the junction temperature of the IC below 150°C
(refer to the Power Dissipation Section) when the output
is in continuous short circuit. The output of the amplifier
has reverse-biased diodes connected to each supply. If
the output is forced beyond either supply, extremely high
current will flow through these diodes which can result
in damage to the device. Forcing the output to even 1V
beyond either supply could result in several hundred milliamps of current through either diode.
ESD
The LTC6246 family has reverse-biased ESD protection
diodes on all inputs and outputs as shown in Figure 1.
There is an additional clamp between the positive and negative supplies that further protects the device during ESD
strikes. Hot plugging of the device into a powered socket
must be avoided since this can trigger the clamp resulting
in larger currents flowing between the supply pins.
Capacitive Loads
The LTC6246/LTC6247/LTC6248 are optimized for high
bandwidth and low power applications. Consequently they
have not been designed to directly drive large capacitive
loads. Increased capacitance at the output creates an additional pole in the open loop frequency response, worsening the phase margin. When driving capacitive loads, a
resistor of 10Ω to 100Ω should be connected between the
amplifier output and the capacitive load to avoid ringing
or oscillation. The feedback should be taken directly from
the amplifier output. Higher voltage gain configurations
tend to have better capacitive drive capability than lower
gain configurations due to lower closed loop bandwidth
and hence higher phase margin. The graphs titled Series
Output Resistor vs Capacitive Load demonstrate the transient response of the amplifier when driving capacitive
loads with various series resistors.
624678fa
14
LTC6246/LTC6247/LTC6248
Applications Information
Feedback Components
Power Dissipation
When feedback resistors are used to set up gain, care
must be taken to ensure that the pole formed by the
feedback resistors and the parasitic capacitance at the
inverting input does not degrade stability. For example if
the amplifier is set up in a gain of +2 configuration with
gain and feedback resistors of 5k, a parasitic capacitance
of 5pF (device + PC board) at the amplifier’s inverting
input will cause the part to oscillate, due to a pole formed
at 12.7MHz. An additional capacitor of 5pF across the
feedback resistor as shown in Figure 2 will eliminate any
ringing or oscillation. In general, if the resistive feedback
network results in a pole whose frequency lies within the
closed loop bandwidth of the amplifier, a capacitor can be
added in parallel with the feedback resistor to introduce
a zero whose frequency is close to the frequency of the
pole, improving stability.
The LTC6246 and LTC6247 contain one and two amplifiers
respectively. Hence the maximum on-chip power dissipation for them will be less than the maximum on-chip
power dissipation for the LTC6248, which contains four
amplifiers.
5pF
5k
–
CPAR
VOUT
+
5k
VIN
624678 F02
Figure 2. 5pF Feedback Cancels Parasitic Pole
Shutdown
The LTC6246 and LTC6247MS have SHDN pins that can
shut down the amplifier to 42µA typical supply current.
The SHDN pin needs to be taken below 0.8V above the
negative supply for the amplifier to shut down. When left
floating, the SHDN pin is internally pulled up to the positive
supply and the amplifier remains on.
The LTC6248 is housed in a small 16-lead MS package and
typically has a thermal resistance (θJA) of 125°C/ W. It is
necessary to ensure that the die’s junction temperature
does not exceed 150°C. The junction temperature, TJ, is
calculated from the ambient temperature, TA, power dissipation, PD, and thermal resistance, θJA:
TJ = TA + (PD • θJA)
The power dissipation in the IC is a function of the supply
voltage, output voltage and load resistance. For a given
supply voltage with output connected to ground or supply,
the worst-case power dissipation PD(MAX) occurs when
the supply current is maximum and the output voltage at
half of either supply voltage for a given load resistance.
PD(MAX) is approximately (since IS actually changes with
output load current) given by:
2
V 
PD(MAX) = (VS •IS(MAX) ) +  S  / RL
 2
Example: For an LTC6248 in a 16-lead MS package operating
on ±2.5V supplies and driving a 100Ω load to ground, the
worst-case power dissipation is approximately given by
PD(MAX)/Amp = (5 • 1.3mA) + (1.25)2/100 = 22mW
If all four amplifiers are loaded simultaneously then the
total power dissipation is 88mW.
At the Absolute Maximum ambient operating temperature,
the junction temperature under these conditions will be:
TJ = TA + PD • 125°C/W
= 125 + (0.088W • 125°C/W) = 136°C
which is less than the absolute maximum junction temperature for the LTC6248 (150°C).
Refer to the Pin Configuration section for thermal resistances of various packages.
624678fa
15
LTC6246/LTC6247/LTC6248
Typical Applications
12-Bit ADC Driver
Figure 3 shows the LTC6246 driving an LTC2366 12-bit A/D
converter. The low wideband noise of the LTC6246 maintains a 70dB SNR even without the use of an intermediate
antialiasing RC filter. On a single 3.3V supply with a 2.5V
reference, a full –1dBFS output can be obtained without
the amplifier transitioning between input regions, thus
minimizing crossover distortion. Figure 4 shows an FFT
obtained with a sampling rate of 2.2Msps and a 350kHz
input waveform. Spurious free dynamic range is a quite
handsome 82dB.
3.3V 2.5V
3.3V
VDD VREF
+
VIN
AIN
LTC6246
–
499Ω
1%
499Ω
1%
CS
SDO
LTC2366
GND
SCK
OVDD
624678 F03
10pF
Low Noise Low Power DC-Accurate Single Supply
Photodiode Amplifier
Figure 5 shows the LTC6246 applied as a low power high
performance transimpedance amplifier for a photodiode.
A low noise JFET Q1 acts as a current buffer, with R2 and
R3 imposing a low frequency gain of approximately 1.
Transimpedance gain is set by feedback resistor R1 to
1MΩ. R4 and R5 set the LTC6246 inputs at 1V below
the 3V rail, with C3 reducing their noise contribution.
By feedback this 1V also appears across R2, setting the
JFET quiescent current at 1mA completely independent
of its pinchoff voltage and IDSS characteristics. It does
this by placing the JFETs 1mA VGS at the gate referenced
to the source, which is sitting 1V above ground. For this
JFET, that will typically be about 500mV, and this voltage
is imposed as a reverse voltage on the photodiode PD1.
At zero IPD photocurrent, the output sits at the same voltage and rises as photocurrent increases. As mentioned
before, R2 and R3 set the JFET gain to 1 at low frequency.
R1
1M, 1%
Figure 3. Single Supply 12-Bit ADC Driver
0
fIN = 350.195kHz
fSAMP = 2.2Msps
SFDR = 82dB
SNR = 70dB
1024 POINT FFT
–10
–20
MAGNITUDE (dB)
–30
C1
0.1pF
3V
IPD
Q1
NXP
BF862
PD1
OSRAM
SFH213
C2
6.8nF
FILM
OR NPO
–40
–50
R2
1k
3V
+
VOUT = VR + IPD • 1M
LTC6246
–
R3
1k
C3
0.1µF
–60
–70
–80
3V
R6
10M
–90
–100
–110
0
200
400
600
800
FREQUENCY (kHz)
R4
10k
+
Figure 4. 350kHz FFT Showing 82dB SFDR
3V
R7
1k
LT6003
1000
624678 F04
R5
20k
–
VR
C4
1µF
624678 F05
–3dB BW = 700kHz
ICC = 2.2mA
OUTPUT NOISE = 160µVRMS MEASURED ON A 1MHz BW
VOUT IS REFERRED TO VR
AT ZERO PHOTOCURRENT, VOUT = VR
Figure 5. Low Noise Low Power DC Accurate
Single Supply Photodiode Amplifier
624678fa
16
LTC6246/LTC6247/LTC6248
Typical Applications
60dB 5.5MHz Gain Block
This is not the lowest noise configuration for a transistor, as
downstream noise sources appear at the input completely
unattenuated. At low frequency, this is not a concern for a
transimpedance amplifier because the noise gain is 1 and
the output noise is dominated by the 130nV/√Hz of the 1MΩ
R1. However, at increasing frequencies the capacitance
of the photodiode comes into play and the circuit noise
gain rises as the 1MΩ feedback looks back into lower and
lower impedance. But capacitor C2 comes to the rescue.
In addition to the obvious quenching of noise source R3,
capacitor C2 increases the JFET gain to about 30 at high
frequency effectively attenuating the downstream noise
contributions of R2 and the op amp input noise. Thus the
circuit achieves low input voltage noise at high frequency
where it is most needed. Amplifier LT6003 is used to
buffer the output voltage of the photodiode and R7 and
C4 are used to filter out the voltage noise of the LT6003.
Bandwidth to 700kHz was achieved with this circuit, with
integrated output noise being 160µVRMS up to 1MHz. Total
supply current was a very low 2.2mA.
Figure 6 shows the LTC6247 configured as a low power
high gain high bandwidth block. Two amplifiers each
configured with a gain of 31V/V, are cascaded in series. A
660nF capacitor is used to limit the DC gain of the block
to around 30dB to minimize output offset voltage. Figure 7
shows the frequency response of the block. Mid-band
voltage gain is approximately 60dB with a –3dB frequency
of 5.5MHz, thus resulting in a gain-bandwidth product of
5.5GHz with only 1.9mA of quiescent supply current.
Single 2.7V Supply 4MHz 4th Order Butterworth Filter
Benefitting from low voltage operation and rail-to-rail
output, a low power filter that is suitable for antialiasing
can be built as shown in Figure 8. On a 2.7V supply the
filter has a passband of approximately 4MHz with 2VP-P
input signal and a stopband attenuation that is greater than
–75dB at 43MHz as shown in Figure 9. The resistor and
capacitor values can be scaled to reduce noise at the cost
of large signal power consumption and distortion.
65
60
1.5k
–
2.5V
1/2LTC6247
VIN
+
55
50
2.5V
1k
–
660nF
1/2LTC6247
+
–2.5V
–2.5V
GAIN (dB)
50Ω
30k
VOUT
45
40
35 VS = ±2.5V
VIN = 4.5mVP-P
30 RL = 1kΩ
DC GAIN = 30dB
25 (DUE TO 660nF DC BLOCKING CAP)
OUTPUT OFFSET = 4mV
20
10k
100k
1M
FREQUENCY (kHz)
624678 F06
Figure 6. 60dB 5.5MHz Gain Block
10M
624678 F07
Figure 7
10
910Ω
1.1k
0
–10
12pF
5.6pF
2.7k
56pF
–
1/2LTC6247
+
–20
2.7V
1.1k
2.3k
120pF
1.2V
–
2.7V
1/2LTC6247
VOUT
+
–30
–40
–50
–60
–70
624678 F08
Figure 8. Single 2.7V Supply 4MHz
4th Order Butterworth Filter
GAIN (dB)
VIN
910Ω
–80 VS = 2.7V, 0V
–90 VIN = 2VP-P
RL = 1kΩ to 0V
–100
10k
100k
1M
10M
FREQUENCY (kHz)
100M
624678 F09
Figure 9
624678fa
17
LTC6246/LTC6247/LTC6248
Package Description
KC Package
8-Lead Plastic UTDFN (2mm × 2mm)
(Reference LTC DWG # 05-08-1749 Rev Ø)
1.37 p0.05
R = 0.115
TYP 5
R = 0.05
TYP
2.00 p0.10
0.70 p0.05
2.55 p0.05
0.64 p0.05
1.15 p0.05
2.00 p0.10
PACKAGE
OUTLINE
1.37 p 0.10
8
0.40 p 0.10
PIN 1 NOTCH
R = 0.20 OR
0.25 s 45o
CHAMFER
0.64 p 0.10
PIN 1 BAR
TOP MARK
(SEE NOTE 6)
0.25 p 0.05
0.45 BSC
1.35 REF
(KC8) UTDFN 0107 REVØ
4
0.55 p0.05
0.125 REF
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
1
0.23 p 0.05
0.45 BSC
1.35 REF
BOTTOM VIEW—EXPOSED PAD
0.00 – 0.05
NOTE:
1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660 Rev F)
3.00 p 0.102
(.118 p .004)
(NOTE 3)
0.889 p 0.127
(.035 p .005)
5.23
(.206)
MIN
0.42 p 0.038
(.0165 p .0015)
TYP
3.20 – 3.45
(.126 – .136)
0.65
(.0256)
BSC
0.254
(.010)
8
7 6 5
3.00 p 0.102
(.118 p .004)
(NOTE 4)
4.90 p 0.152
(.193 p .006)
DETAIL “A”
0.52
(.0205)
REF
0o – 6o TYP
GAUGE PLANE
0.53 p 0.152
(.021 p .006)
RECOMMENDED SOLDER PAD LAYOUT
DETAIL “A”
1
1.10
(.043)
MAX
2 3
4
0.86
(.034)
REF
0.18
(.007)
SEATING
PLANE
0.22 – 0.38
(.009 – .015)
TYP
0.65
(.0256)
BSC
0.1016 p 0.0508
(.004 p .002)
MSOP (MS8) 0307 REV F
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
624678fa
18
LTC6246/LTC6247/LTC6248
Package Description
MS Package
10-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1661 Rev E)
0.889 ± 0.127
(.035 ± .005)
5.23
(.206)
MIN
3.20 – 3.45
(.126 – .136)
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
0.50
0.305 ± 0.038
(.0197)
(.0120 ± .0015)
BSC
TYP
RECOMMENDED SOLDER PAD LAYOUT
0.254
(.010)
10 9 8 7 6
3.00 ± 0.102
(.118 ± .004)
(NOTE 4)
4.90 ± 0.152
(.193 ± .006)
DETAIL “A”
0.497 ± 0.076
(.0196 ± .003)
REF
0° – 6° TYP
GAUGE PLANE
1 2 3 4 5
0.53 ± 0.152
(.021 ± .006)
DETAIL “A”
0.18
(.007)
SEATING
PLANE
0.86
(.034)
REF
1.10
(.043)
MAX
0.17 – 0.27
(.007 – .011)
TYP
0.50
(.0197)
BSC
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.1016 ± 0.0508
(.004 ± .002)
MSOP (MS) 0307 REV E
624678fa
19
LTC6246/LTC6247/LTC6248
Package Description
MS Package
16-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1669 Rev Ø)
0.889 p 0.127
(.035 p .005)
5.23
(.206)
MIN
3.20 – 3.45
(.126 – .136)
4.039 p 0.102
(.159 p .004)
(NOTE 3)
0.50
(.0197)
BSC
0.305 p 0.038
(.0120 p .0015)
TYP
RECOMMENDED SOLDER PAD LAYOUT
0.254
(.010)
DETAIL “A”
3.00 p 0.102
(.118 p .004)
(NOTE 4)
4.90 p 0.152
(.193 p .006)
0o – 6o TYP
0.280 p 0.076
(.011 p .003)
REF
16151413121110 9
GAUGE PLANE
0.53 p 0.152
(.021 p .006)
DETAIL “A”
0.18
(.007)
SEATING
PLANE
1.10
(.043)
MAX
0.17 – 0.27
(.007 – .011)
TYP
1234567 8
0.50
(.0197)
BSC
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.86
(.034)
REF
0.1016 p 0.0508
(.004 p .002)
MSOP (MS16) 1107 REV Ø
624678fa
20
LTC6246/LTC6247/LTC6248
Package Description
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
0.62
MAX
2.90 BSC
(NOTE 4)
0.95
REF
1.22 REF
3.85 MAX 2.62 REF
1.4 MIN
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45
6 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
0.09 – 0.20
(NOTE 3)
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
1.90 BSC
S6 TSOT-23 0302 REV B
624678fa
21
LTC6246/LTC6247/LTC6248
Package Description
TS8 Package
8-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1637)
0.52
MAX
2.90 BSC
(NOTE 4)
0.65
REF
1.22 REF
1.4 MIN
3.85 MAX 2.62 REF
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.22 – 0.36
8 PLCS (NOTE 3)
0.65 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
0.09 – 0.20
(NOTE 3)
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
1.95 BSC
TS8 TSOT-23 0802
624678fa
22
LTC6246/LTC6247/LTC6248
Revision History
REV
DATE
DESCRIPTION
PAGE NUMBER
A
2/10
Changes to Graph G15
9
624678fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
23
LTC6246/LTC6247/LTC6248
Typical Application
700kHz, 1MΩ Single Supply Photodiode Amplifier
Output Noise Spectrum
R1
1M, 1%
R2
1k
PD1
OSRAM
SFH213
Q1
NXP
BF862
C2
6.8nF
FILM
OR NPO
3V
200
5V/DIV
LED DRIVER
VOLTAGE
C1
0.1pF
3V
IPD
Transient Response
R3
1k
R4
10k
20nV/√Hz/DIV
3V
+
–
C3
0.1µF
500mV/DIV
OUTPUT
WAVEFORM
0V
VOUT ≈ 0.5V + IPD • 1M
LTC6246
–3dB BW = 700kHz
ICC = 2.2mA
OUTPUT NOISE = 153µVRMS
MEASURED ON A 1MHz BW
0
10kHz
100kHz
500ns/DIV
1MHz
624678 TA02c
624678 TA02b
R5
20k
624678 TA02a
Related Parts
PART NUMBER DESCRIPTION
COMMENTS
Operational Amplifiers
LT1818/LT1819 Single/Dual Wide Bandwidth, High Slew Rate Low Noise and
Distortion Op Amps
400MHz, 9mA, 6nV/√Hz, 2500V/µs, 1.5mV –85dBc at 5MHz
LT1806/LT1807 Single/Dual Low Noise Rail-to-Rail Input and Output Op Amps 325MHz, 13mA, 3.5nV/√Hz, 140V/µs, 550µV, 85mA Output Drive
LT6230/LT6231/ Single/Dual/Quad Low Noise Rail-to-Rail Output Op Amps
LT6232
215MHz, 3.5mA, 1.1nV/√Hz, 70V/µs, 350µV
LT6200/LT6201 Single/Dual Ultralow Noise Rail-to-Rail Input/Output Op Amps 165MHz, 20mA, 0.95nV/√Hz, 44V/µs, 1mV
LT6202/LT6203/ Single/Dual/Quad Ultralow Noise Rail-to-Rail Op Amp
LT6204
100MHz, 3mA, 1.9nV/√Hz, 25V/µs, 0.5mV
LT1468
90MHz, 3.9mA, 5nV/√Hz, 22V/µs, 175µV,
–96.5dB THD at 10VP-P, 100kHz
16-Bit Accurate Precision High Speed Op Amp
LT1803/LT1804/ Single/Dual/Quad Low Power High Speed Rail-to-Rail Input
LT1805
and Output Op Amps
85MHz, 3mA, 21nV√Hz, 100V/µs, 2mV
LT1801/LT1802 Dual/Quad Low Power High Speed Rail-to-Rail Input and
Output Op Amps
80MHz, 2mA, 8.5nV√Hz, 25V/µs, 350µV
LT6552
Single Supply Rail-to-Rail Output Video Difference Amplifier
75MHz (–3dB), 13.5mA, 55.5nV/√Hz, 350V/µs, 20mV
LT1028
Ultralow Noise, Precision High Speed Op Amps
75MHz, 9.5mA, 0.85nV/√Hz, 11V/µs, 40µV
LT6233/LT6234/ Single/Dual/Quad Low Noise Rail-to-Rail Output Op Amps
LT6235
60MHz, 1.2mA, 1.2nV/√Hz, 15V/µs, 0.5mV
LT6220/LT6221/ Single/Dual/Quad Low Power High Speed Rail-to-Rail Input
LT6222
and Output Op Amps
60MHz, 1mA, 10nV/√Hz, 20V/µs, 350µV
LT6244
50MHz, 7.4mA, 8nV/√Hz, 35V/µs, 100µV, Input Bias Current = 1pA
Dual High Speed CMOS Op Amp
LT1632/LT1633 Dual/Quad Rail-to-Rail Input and Output Precision Op Amps
45MHz, 4.3mA, 12nV/√Hz, 45V/µs, 1.35mV
LT1630/LT1631 Dual/Quad Rail-to-Rail Input and Output Op Amps
30MHz, 3.5mA, 6nV/√Hz, 10V/µs, 525µV
LT1358/LT1359 Dual/Quad Low Power High Speed Op Amps
25MHz, 2.5mA, 8nV/√Hz, 600V/µs, 800µV, Drives All Capacitive Loads
ADC’s
LTC2366
3Msps, 12-Bit ADC Serial I/O
72dB SNR, 7.8mW No Data Latency TSOT-23 Package
LTC2365
1Msps, 12-Bit ADC Serial I/O
73dB SNR, 7.8mW No Data Latency TSOT-23 Package
LTC1417
Low Power 14-Bit 400ksps ADC Parallel I/O
Single 5V or ±5V Supplies, 0V to 4.096V or ±2.048V Input Range
LTC1274
Low Power 12-Bit 400ksps ADC Parallel I/O
10mW Single 5V or ±5V Supplies, 0V to 4.096V or ±2.048V Input Range
624678fa
24 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
LT 0210 REV A • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2009