LINER LT1399HV

LT1398/LT1399/LT1399HV
Low Cost Dual and Triple
300MHz Current Feedback
Amplifiers with Shutdown
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FEATURES
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DESCRIPTIO
300MHz Bandwidth on ± 5V (AV = 1, 2 and –1)
0.1dB Gain Flatness: 150MHz (AV = 1, 2 and –1)
Completely Off in Shutdown, 0µA Supply Current
High Slew Rate: 800V/µs
Wide Supply Range:
±2V(4V) to ±6V(12V) (LT1398/LT1399)
±2V (4V) to ±7.5V (15V) (LT1399HV)
80mA Output Current
Low Supply Current: 4.6mA/Amplifier
Fast Turn-On Time: 30ns
Fast Turn-Off Time: 40ns
16-Pin Narrow SO/Narrow SSOP Packages
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APPLICATIO S
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RGB Cable Drivers
LCD Drivers
Spread Spectrum Amplifiers
MUX Amplifiers
Composite Video Cable Drivers
Portable Equipment
The LT1398/LT1399 operate on all supplies from a single
4V to ±6V. The LT1399HV operates on all supplies from 4V
to ±7.5V.
Each amplifier draws 4.6mA when active. When disabled
each amplifier draws zero supply current and its output becomes high impedance. The amplifiers turn on in only 30ns
and turn off in 40ns, making them ideal in spread spectrum
and portable equipment applications.
The LT1398/LT1399/LT1399HV are manufactured on Linear Technology’s proprietary complementary bipolar process. The LT1399/LT1399HV are pin-for-pin upgrades to
the LT1260 optimized for use on ±5V/±7.5V supplies.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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The LT ®1399 and LT1399HV contain three independent
300MHz current feedback amplifiers, each with a shutdown pin. The LT1399HV is a higher voltage version of the
LT1399. The LT1398 is a two amplifier version of the
LT1399.
TYPICAL APPLICATIO
3-Input Video MUX Cable Driver
A
+
VIN A
RG
200Ω
CHANNEL
SELECT
B C
Square Wave Response
EN A
97.6Ω
1/3 LT1399
–
75Ω
CABLE
RF
324Ω
VOUT
+
VIN B
RG
200Ω
RG
200Ω
75Ω
OUTPUT
200mV/DIV
97.6Ω
1/3 LT1399
–
+
VIN C
EN B
RF
324Ω
TIME (10ns/DIV)
1398/99 TA02
97.6Ω
1/3 LT1399
–
RL = 100Ω
RF = RG = 324Ω
f = 10MHz
EN C
1399 TA01
RF
324Ω
1
LT1398/LT1399/LT1399HV
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AXI U
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ABSOLUTE
RATI GS
(Note 1)
Total Supply Voltage (V + to V –)
LT1398/LT1399 ................................................ 12.6V
LT1399HV ....................................................... 15.5V
Input Current (Note 2) ....................................... ±10mA
Output Current ................................................. ±100mA
Differential Input Voltage (Note 2) ........................... ±5V
Output Short-Circuit Duration (Note 3) ........ Continuous
Operating Temperature Range ............... – 40°C to 85°C
Specified Temperature Range (Note 4) .. – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Junction Temperature (Note 5) ............................ 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
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PACKAGE/ORDER I FOR ATIO
TOP VIEW
–IN A
1
+IN A
2
15 OUT A
*GND
3
14
V+
*GND
4
13 GND*
A
16 EN A
ORDER PART
NUMBER
LT1398CS
–IN R
1
+IN R
2
15 OUT R
*GND
3
14 V +
–IN G
4
12 OUT G
11 V –
*GND
5
12 GND*
+IN G
5
*GND
6
11 V –
*GND
6
+IN B
7
10 OUT B
+IN B
7
–IN B
8
–IN B
B
8
9
ORDER PART
NUMBER
TOP VIEW
EN B
R
G
B
16 EN R
LT1399CGN
LT1399CS
LT1399HVCS
13 EN G
10 OUT B
9
GN PART MARKING
EN B
1399
GN PACKAGE
S PACKAGE
16-LEAD PLASTIC SSOP 16-LEAD PLASTIC SO
S PACKAGE
16-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 100°C/W
TJMAX = 150°C, θJA = 120°C/W (GN)
TJMAX = 150°C, θJA = 100°C/W (S)
*Ground pins are not internally connected. For best channel isolation, connect to ground. Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
(LT1398/LT1399)
The ● denotes specifications which apply over the specified operating temperature range, otherwise specifications are at TA = 25°C.
For each amplifier: VCM = 0V, VS = ±5V, EN = 0V, pulse tested, unless otherwise noted. (Note 4)
SYMBOL
PARAMETER
VOS
Input Offset Voltage
CONDITIONS
MIN
TYP
MAX
1.5
10
12
●
∆VOS/∆T
IIN
+
Input Offset Voltage Drift
Noninverting Input Current
10
25
30
µA
µA
10
50
60
µA
µA
●
IIN–
Inverting Input Current
mV
mV
µV/°C
15
●
UNITS
●
en
Input Noise Voltage Density
f = 1kHz, RF = 1k, RG = 10Ω, RS = 0Ω
+ in
Noninverting Input Noise Current Density
– in
Inverting Input Noise Current Density
RIN
Input Resistance
VIN = ±3.5V
CIN
Input Capacitance
Amplifier Enabled
Amplifier Disabled
COUT
Output Capacitance
Amplifier Disabled
8.5
pF
VINH
Input Voltage Range, High
VS = ±5V
VS = 5V, 0V
4.0
4.0
V
V
2
4.5
nV/√Hz
f = 1kHz
6
pA/√Hz
f = 1kHz
25
pA/√Hz
1
MΩ
2.0
2.5
pF
pF
●
●
0.3
3.5
LT1398/LT1399/LT1399HV
ELECTRICAL CHARACTERISTICS
(LT1398/LT1399)
The ● denotes specifications which apply over the specified operating temperature range, otherwise specifications are at TA = 25°C.
For each amplifier: VCM = 0V, VS = ±5V, EN = 0V, pulse tested, unless otherwise noted. (Note 4)
SYMBOL
PARAMETER
CONDITIONS
VINL
Input Voltage Range, Low
VS = ±5V
VS = 5V, 0V
VOUTH
Maximum Output Voltage Swing, High
VS = ±5V, RL = 100k
VS = ±5V, RL = 100k
VS = 5V, 0V; RL = 100k
VOUTL
VOUTH
VOUTL
Maximum Output Voltage Swing, Low
Maximum Output Voltage Swing, High
Maximum Output Voltage Swing, Low
MIN
TYP
●
– 3.5
– 4.0
1.0
V
V
3.9
3.7
4.2
●
V
V
V
– 4.2
●
– 3.9
– 3.7
VS = ±5V, RL = 150Ω
VS = ±5V, RL = 150Ω
VS = 5V, 0V; RL = 150Ω
3.6
●
3.4
3.2
VS = ±5V, RL = 150Ω
VS = ±5V, RL = 150Ω
VS = 5V, 0V; RL = 150Ω
●
VS = ±5V, RL = 100k
VS = ±5V, RL = 100k
VS = 5V, 0V; RL = 100k
4.2
Common Mode Rejection Ratio
VCM = ±3.5V
●
– ICMRR
Inverting Input Current
Common Mode Rejection
VCM = ±3.5V
VCM = ±3.5V
●
PSRR
Power Supply Rejection Ratio
VS = ±2V to ±5V, EN = V –
●
+ IPSRR
Noninverting Input Current
Power Supply Rejection
VS = ±2V to ±5V, EN = V –
42
– 3.6
0.6
V
V
V
52
dB
16
22
µA/V
µA/V
1
2
3
µA/V
µA/V
2
7
µA/V
10
56
70
●
dB
– IPSRR
Inverting Input Current
Power Supply Rejection
AV
Large-Signal Voltage Gain
ROL
Transimpedance, ∆VOUT/∆IIN
IOUT
Maximum Output Current
RL = 0Ω
●
IS
Supply Current per Amplifier
VOUT = 0V
●
4.6
6.5
mA
Disable Supply Current per Amplifier
EN Pin Voltage = 4.5V, RL = 150Ω
●
0.1
100
µA
30
110
200
µA
µA
IEN
VS =
V
V
V
3.6
– 3.4
– 3.2
UNITS
V
V
V
0.8
CMRR
±2V to ±5V, EN = V –
MAX
●
VOUT = ±2V, RL = 150Ω
–
VOUT = ±2V, RL = 150Ω
50
65
40
100
mA
●
Slew Rate (Note 6)
AV = 10, RL = 150Ω
tON
Turn-On Delay Time (Note 7)
RF = RG = 324Ω, RL = 100Ω
tOFF
Turn-Off Delay Time (Note 7)
tr, tf
Small-Signal Rise and Fall Time
tPD
os
tS
kΩ
80
Enable Pin Current
SR
dB
500
800
V/µs
30
75
ns
RF = RG = 324Ω, RL = 100Ω
40
100
ns
RF = RG = 324Ω, RL = 100Ω, VOUT = 1VP-P
1.3
ns
Propagation Delay
RF = RG = 324Ω, RL = 100Ω, VOUT = 1VP-P
2.5
ns
Small-Signal Overshoot
RF = RG = 324Ω, RL = 100Ω, VOUT = 1VP-P
10
%
Settling Time
0.1%, AV = – 1, RF = RG = 309Ω, RL = 150Ω
25
ns
dG
Differential Gain (Note 8)
RF = RG = 324Ω, RL = 150Ω
0.13
%
dP
Differential Phase (Note 8)
RF = RG = 324Ω, RL = 150Ω
0.10
DEG
3
LT1398/LT1399/LT1399HV
ELECTRICAL CHARACTERISTICS
(LT1399HV)
The ● denotes specifications which apply over the specified operating temperature range, otherwise specifications are at TA = 25°C.
For each amplifier: VCM = 0V, VS = ±7.5V, EN = 0V, pulse tested, unless otherwise noted. (Note 4)
SYMBOL
PARAMETER
VOS
Input Offset Voltage
CONDITIONS
MIN
TYP
MAX
1.5
10
12
●
∆VOS/∆T
Input Offset Voltage Drift
IIN+
Noninverting Input Current
10
25
30
µA
µA
10
50
60
µA
µA
●
IIN–
Inverting Input Current
mV
mV
µV/°C
15
●
UNITS
●
en
Input Noise Voltage Density
f = 1kHz, RF = 1k, RG = 10Ω, RS = 0Ω, VS = ±5V
+ in
Noninverting Input Noise Current Density
f = 1kHz, VS = ±5V
6
pA/√Hz
– in
Inverting Input Noise Current Density
f = 1kHz, VS = ±5V
25
pA/√Hz
RIN
Input Resistance
VIN = ±6V
1
MΩ
CIN
Input Capacitance
Amplifier Enabled
Amplifier Disabled
2.0
2.5
pF
pF
COUT
Output Capacitance
Amplifier Disabled
8.5
pF
VINH
Input Voltage Range, High
VS = ±7.5V
VS = 7.5V, 0V
●
6
6.5
6.5
V
V
VINL
Input Voltage Range, Low
VS = ±7.5V
VS = 7.5V, 0V
●
–6
– 6.5
1.0
V
V
VOUTH
Maximum Output Voltage Swing, High
VS = ±7.5V, RL = 100k
VS = ±7.5V, RL = 100k
VS = 7.5V, 0V; RL = 100k
6.4
6.1
6.7
●
V
V
V
– 6.7
●
– 6.4
– 6.1
VS = ±7.5V, RL = 150Ω
VS = ±7.5V, RL = 150Ω
VS = 7.5V, 0V; RL = 150Ω
5.8
●
5.4
5.1
VS = ±7.5V, RL = 150Ω
VS = ±7.5V, RL = 150Ω
VS = 7.5V, 0V; RL = 150Ω
●
VOUTL
VOUTH
VOUTL
Maximum Output Voltage Swing, Low
Maximum Output Voltage Swing, High
Maximum Output Voltage Swing, Low
4.5
●
0.3
nV/√Hz
6.7
VS = ±7.5V, RL = 100k
VS = ±7.5V, RL = 100k
VS = 7.5V, 0V; RL = 100k
V
V
V
0.8
V
V
V
5.8
– 5.4
– 5.1
– 5.8
0.6
V
V
V
52
dB
CMRR
Common Mode Rejection Ratio
VCM = ±6V
●
– ICMRR
Inverting Input Current
Common Mode Rejection
VCM = ±6V
VCM = ±6V
●
PSRR
Power Supply Rejection Ratio
VS = ±2V to ±7.5V, EN = V –
●
+ IPSRR
Noninverting Input Current
Power Supply Rejection
VS = ±2V to ±7.5V, EN = V –
– IPSRR
Inverting Input Current
Power Supply Rejection
VS = ±2V to ±7.5V, EN =
AV
Large-Signal Voltage Gain
ROL
Transimpedance, ∆VOUT/∆IIN
IOUT
Maximum Output Current
RL = 0Ω
●
IS
Supply Current per Amplifier
VOUT = 0V
●
4.6
7
mA
Disable Supply Current per Amplifier
EN Pin Voltage = 7V, RL = 150Ω
●
0.1
100
µA
30
110
200
µA
µA
IEN
16
22
µA/V
µA/V
1
2
3
µA/V
µA/V
2
7
µA/V
10
56
70
●
V–
●
VOUT = ±4.5V, RL = 150Ω
–
VOUT = ±4.5V, RL = 150Ω
Enable Pin Current
●
4
42
50
65
40
100
dB
dB
kΩ
80
mA
LT1398/LT1399/LT1399HV
ELECTRICAL CHARACTERISTICS
(LT1399HV)
The ● denotes specifications which apply over the specified operating temperature range, otherwise specifications are at TA = 25°C.
For each amplifier: VCM = 0V, VS = ±7.5V, EN = 0V, pulse tested, unless otherwise noted. (Note 4)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
SR
Slew Rate (Note 6)
AV = 10, RL = 150Ω, VS = ±5V
500
800
tON
Turn-On Delay Time (Note 7)
RF = RG = 324Ω, RL = 100Ω, VS = ±5V
30
75
ns
tOFF
Turn-Off Delay Time (Note 7)
RF = RG = 324Ω, RL = 100Ω, VS = ±5V
40
100
ns
tr, tf
Small-Signal Rise and Fall Time
RF = RG = 324Ω, RL = 100Ω, VOUT = 1VP-P,
VS = ±5V
1.3
ns
tPD
Propagation Delay
RF = RG = 324Ω, RL = 100Ω, VOUT = 1VP-P,
VS = ±5V
2.5
ns
os
Small-Signal Overshoot
RF = RG = 324Ω, RL = 100Ω, VOUT = 1VP-P,
VS = ±5V
10
%
tS
Settling Time
0.1%, AV = – 1V, RF = RG = 309Ω, RL = 150Ω,
VS = ±5V
25
ns
dG
Differential Gain (Note 8)
RF = RG = 324Ω, RL = 150Ω, VS = ±5V
0.13
%
dP
Differential Phase (Note 8)
RF = RG = 324Ω, RL = 150Ω, VS = ±5V
0.10
DEG
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: This parameter is guaranteed to meet specified performance
through design and characterization. It has not been tested.
Note 3: A heat sink may be required depending on the power supply
voltage and how many amplifiers have their outputs short circuited.
Note 4: The LT1398/LT1399/LT1399HV are guaranteed to meet specified
performance from 0°C to 70°C and are designed, characterized and
expected to meet these extended temperature limits, but are not tested at
– 40°C and 85°C. Guaranteed I grade parts are available, consult factory.
Note 5: TJ is calculated from the ambient temperature TA and the
power dissipation PD according to the following formula:
LT1398CS, LT1399CS, LT1399HVCS: TJ = TA + (PD • 100°C/W)
LT1399CGN: TJ = TA + (PD • 120°C/W)
MAX
UNITS
V/µs
Note 6: Slew rate is measured at ±2V on a ±3V output signal.
Note 7: Turn-on delay time (tON) is measured from control input to
appearance of 1V at the output, for VIN = 1V. Likewise, turn-off delay
time (tOFF) is measured from control input to appearance of 0.5V on
the output for VIN = 0.5V. This specification is guaranteed by design
and characterization.
Note 8: Differential gain and phase are measured using a Tektronix
TSG120YC/NTSC signal generator and a Tektronix 1780R Video
Measurement Set. The resolution of this equipment is 0.1% and 0.1°.
Ten identical amplifier stages were cascaded giving an effective
resolution of 0.01% and 0.01°.
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TYPICAL AC PERFOR A CE
VS (V)
AV
RL (Ω)
RF (Ω)
RG (Ω)
SMALL SIGNAL
– 3dB BW (MHz)
SMALL SIGNAL
0.1dB BW (MHz)
SMALL SIGNAL
PEAKING (dB)
±5
1
100
365
–
300
150
0.05
±5
2
100
324
324
300
150
0
±5
–1
100
309
309
300
150
0
5
LT1398/LT1399/LT1399HV
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TYPICAL PERFOR A CE CHARACTERISTICS
Closed-Loop Gain vs Frequency
(AV = 2)
4
2
8
2
0
GAIN (dB)
10
6
0
–2
4
–2
–4
2
–4
1M
10M
100M
VS = ±5V
FREQUENCY (Hz)
VIN = –10dBm
RF = 365Ω
RL = 100Ω
1G
1M
10M
100M
VS = ±5V
FREQUENCY (Hz)
VIN = –10dBm
RF = RG = 324Ω
RL = 100Ω
1398/99 G01
1M
10M
100M
VS = ±5V
FREQUENCY (Hz)
VIN = –10dBm
RF = RG = 309Ω
RL = 100Ω
Large-Signal Transient Response
(AV = 2)
TIME (5ns/DIV)
1398/99 G04
VS = ±5V
TIME (5ns/DIV)
VIN = ±1.25V
RF = RG = 324Ω
RL = 100Ω
2nd and 3rd Harmonic Distortion
vs Frequency
Large-Signal Transient Response
(AV = – 1)
70
HD3
80
90
70
AV = +1
100
5
4
10
100
1000 10000 100000
FREQUENCY (kHz)
1398/1399 G07
60
1
100
1398/1399 G08
+ PSRR
40
30
10
10
FREQUENCY (MHz)
– PSRR
50
20
TA = 25°C
RF = 324Ω
RL = 100Ω
VS = ± 5V
2
110
AV = +2
6
3
1
PSRR vs Frequency
7
HD2
1398/99 G06
80
PSRR (dB)
60
VS = ±5V
TIME (5ns/DIV)
VIN = ±2.5V
RF = RG = 309Ω
RL = 100Ω
8
OUTPUT VOLTAGE (VP-P)
TA = 25°C
40 RF = RG = 324Ω
RL = 100Ω
50 VS = ± 5V
VOUT = 2VPP
1398/99 G05
Maximum Undistorted Output
Voltage vs Frequency
30
1G
1398/99 G03
OUTPUT (1V/DIV)
OUTPUT (1V/DIV)
VS = ±5V
VIN = ±2.5V
RF = 365Ω
RL = 100Ω
6
1G
1398/99 G02
OUTPUT (1V/DIV)
Large-Signal Transient Response
(AV = 1)
DISTORTION (dB)
Closed-Loop Gain vs Frequency
(AV = – 1)
4
GAIN (dB)
GAIN (dB)
Closed-Loop Gain vs Frequency
(AV = 1)
TA = 25°C
RF = RG = 324Ω
RL = 100Ω
AV = +2
0
10k
100k
1M
10M
FREQUENCY (Hz)
100M
1398/1399 G09
LT1398/LT1399/LT1399HV
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TYPICAL PERFOR A CE CHARACTERISTICS
Input Voltage Noise and Current
Noise vs Frequency
100k
100
100
– IN
+IN
10
EN
1
10
30
10
RF = RG = 324Ω
RL = 50Ω
AV = +2
VS = ± 5V
1
0.1
0.01
10k
100 300 1k 3k 10k 30k 100k
FREQUENCY (Hz)
OUTPUT IMPEDANCE (DISABLED) (Ω)
OUTPUT IMPEDANCE (Ω)
100k
1M
10M
FREQUENCY (Hz)
Maximum Capacitive Load
vs Feedback Resistor
900
1500
2100
2700
FEEDBACK RESISTANCE (Ω)
RF = RG = 324Ω
VS = ± 5V
OVERSHOOT < 2%
30
20
10
100
CAPACITIVE LOAD (pF)
10
4
EN = 0V
3
2
0
1000
0
5
– 10
4
ENABLE PIN CURRENT (µA)
1
0
–1
–2
RL = 150Ω
VS = ± 5V
EN = 0V
– 30
– 40
EN = –5V
– 50
– 60
– 70
–4
–5
50
25
0
75 100
–50 –25
AMBIENT TEMPERATURE (°C)
125
1398/1399 G16
2
7
3
5
6
4
SUPPLY VOLTAGE (± V)
– 80
– 50 – 25
8
9
Positive Supply Current per
Amplifier vs Temperature
– 20
2
1
1398/1399 G15
Enable Pin Current
vs Temperature
RL = 150Ω
EN = V –
1398/1399 G14
Output Voltage Swing
vs Temperature
RL = 100k
5
1
1398/1399 G13
OUTPUT VOLTAGE SWING (V)
Supply Current vs Supply Voltage
0
3300
100M
6
SUPPLY CURRENT (mA)
RF = RG
AV = +2
VS = ± 5V
PEAKING ≤ 5dB
OUTPUT SERIES RESISTANCE (Ω)
CAPACITIVE LOAD (pF)
10
1M
10M
FREQUENCY (Hz)
1398/1399 G12
40
100
–3
1k
Capacitive Load
vs Output Series Resistor
1000
RL = 100k
10k
1398/1399 G11
1398/1399 G10
1
300
RF = 365Ω
AV = +1
VS = ± 5V
100
100k
100M
50
100
25
75
0
AMBIENT TEMPERATURE (°C)
125
1398/1399 G17
POSITIVE SUPPLY CURRENT PER AMPLIFIER (mA)
INPUT NOISE (nV/√Hz OR pA/√Hz)
1000
3
Output Impedance (Disabled)
vs Frequency
Output Impedance vs Frequency
5.00
VS = ± 5V
EN = – 5V
4.75
4.50
EN = 0
4.25
4.00
3.75
3.50
3.25
3.00
–50 –25
75 100
0
50
25
AMBIENT TEMPERATURE (°C)
125
1398/1399 G18
7
LT1398/LT1399/LT1399HV
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TYPICAL PERFOR A CE CHARACTERISTICS
Input Offset Voltage
vs Temperature
3.0
Input Bias Currents
vs Temperature
15
VS = ± 5V
VS = ± 5V
12
INPUT BIAS CURRENT (µA)
INPUT OFFSET VOLTAGE (mV)
2.5
2.0
1.5
1.0
0.5
0
IB+
9
6
3
IB–
0
–3
– 0.5
–1.0
– 50 – 25
75 100
50
25
AMBIENT TEMPERATURE (°C)
0
–6
–50 –25
125
50
100
25
75
0
AMBIENT TEMPERATURE (°C)
1398/1399 G19
1398/99 G20
All Hostile Crosstalk
ALL HOSTILE CROSSTALK (dB)
–10
–20
–30
–40
All Hostile Crosstalk (Disabled)
–10
RF = RG = 324Ω
RL = 100Ω
AV = +2
R
G
B
–20
ALL HOSTILE CROSSTALK (dB)
0
125
–50
–60
–70
–80
–90
–30
–40
RF = RG = 324Ω
RL = 100Ω
AV = +2
R
G
B
–50
–60
–70
–80
–90
–100
–100
100k
1M
10M
FREQUENCY (Hz)
100M
500M
–110
100k
1M
10M
FREQUENCY (Hz)
1398/1399 G21
100M
500M
1398/1399 G24
Propagation Delay
Rise Time and Overshoot
OS = 10%
INPUT
100mV/DIV
OUTPUT
200mV/DIV
tPD = 2.5ns
AV = +2
TIME (500ps/DIV)
RL = 100Ω
RF = RG = 324Ω
8
1398/1399 G22
VOUT
200mV/DIV
tr = 1.3ns
AV = +2
TIME (500ps/DIV)
RL = 100Ω
RF = RG = 324Ω
1398/1399 G23
LT1398/LT1399/LT1399HV
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PIN FUNCTIONS
LT1398
LT1399, LT1399HV
– IN A (Pin 1): Inverting Input of A Channel Amplifier.
– IN R (Pin 1): Inverting Input of R Channel Amplifier.
+ IN A (Pin 2): Noninverting Input of A Channel Amplifier.
+ IN R (Pin 2): Noninverting Input of R Channel Amplifier.
GND (Pins 3, 4, 5, 6): Ground. Not connected internally.
GND (Pin 3): Ground. Not connected internally.
+ IN B (Pin 7): Noninverting Input of B Channel Amplifier.
– IN G (Pin 4): Inverting Input of G Channel Amplifier.
– IN B (Pin 8): Inverting Input of B Channel Amplifier.
+ IN G (Pin 5): Noninverting Input of G Channel Amplifier.
EN B (Pin 9): B Channel Enable Pin. Logic low to enable.
GND (Pin 6): Ground. Not connected internally.
OUT B (Pin 10): B Channel Output.
+ IN B (Pin 7): Noninverting Input of B Channel Amplifier.
V – (Pin 11): Negative Supply Voltage, Usually – 5V.
– IN B (Pin 8): Inverting Input of B Channel Amplifier.
GND (Pins 12, 13): Ground. Not connected internally.
EN B (Pin 9): B Channel Enable Pin. Logic low to enable.
V + (Pin 14): Positive Supply Voltage, Usually 5V.
OUT B (Pin 10): B Channel Output.
OUT A (Pin 15): A Channel Output.
V – (Pin 11): Negative Supply Voltage, Usually – 5V.
EN A (Pin 16): A Channel Enable Pin. Logic low to enable.
OUT G (Pin 12): G Channel Output.
EN G (Pin 13): G Channel Enable Pin. Logic low to enable.
V + (Pin 14): Positive Supply Voltage, Usually 5V.
OUT R (Pin 15): R Channel Output.
EN R (Pin 16): R Channel Enable Pin. Logic low to enable.
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Feedback Resistor Selection
The small-signal bandwidth of the LT1398/LT1399/
LT1399HV is set by the external feedback resistors and the
internal junction capacitors. As a result, the bandwidth is
a function of the supply voltage, the value of the feedback
resistor, the closed-loop gain and the load resistor. The
LT1398/LT1399 have been optimized for ±5V supply
operation and have a – 3dB bandwidth of 300MHz at a gain
of 2. The LT1399HV provides performance similar to the
LT1399. Please refer to the resistor selection guide in the
Typical AC Performance table.
Capacitance on the Inverting Input
Current feedback amplifiers require resistive feedback
from the output to the inverting input for stable operation.
Take care to minimize the stray capacitance between the
output and the inverting input. Capacitance on the inverting input to ground will cause peaking in the frequency
response (and overshoot in the transient response).
Capacitive Loads
The LT1398/LT1399/LT1399HV can drive many capacitive loads directly when the proper value of feedback
resistor is used. The required value for the feedback
resistor will increase as load capacitance increases and as
closed-loop gain decreases. Alternatively, a small resistor
(5Ω to 35Ω) can be put in series with the output to isolate
the capacitive load from the amplifier output. This has the
advantage that the amplifier bandwidth is only reduced
when the capacitive load is present. The disadvantage is
that the gain is a function of the load resistance.
9
LT1398/LT1399/LT1399HV
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Power Supplies
The LT1398/LT1399 will operate from single or split
supplies from ±2V (4V total) to ±6V (12V total). The
LT1399HV will operate from single or split supplies from
±2V (4V total) to ±7.5V (15V total). It is not necessary to
use equal value split supplies, however the offset voltage
and inverting input bias current will change. The offset
voltage changes about 600µV per volt of supply mismatch. The inverting bias current will typically change
about 2µA per volt of supply mismatch.
Slew Rate
Unlike a traditional voltage feedback op amp, the slew rate
of a current feedback amplifier is not independent of the
amplifier gain configuration. In a current feedback amplifier, both the input stage and the output stage have slew rate
limitations. In the inverting mode, and for gains of 2 or more
in the noninverting mode, the signal amplitude between the
input pins is small and the overall slew rate is that of the
output stage. For gains less than 2 in the noninverting mode,
the overall slew rate is limited by the input stage.
The input slew rate of the LT1398/LT1399/LT1399HV is
approximately 600V/µs and is set by internal currents and
capacitances. The output slew rate is set by the value of the
feedback resistor and internal capacitance. At a gain of 2
with 324Ω feedback and gain resistors and ±5V supplies,
the output slew rate is typically 800V/µs. Larger feedback
resistors will reduce the slew rate as will lower supply
voltages.
Enable/ Disable
Each amplifier of the LT1398/LT1399/LT1399HV has a
unique high impedance, zero supply current mode which
is controlled by its own EN pin. These amplifiers are
designed to operate with CMOS logic; the amplifiers draw
zero current when these pins are high. To activate each
amplifier, its EN pin is normally pulled to a logic low.
However, supply current will vary as the voltage between
the V + supply and EN is varied. As seen in Figure 1, +I S
does vary with (V + – VEN), particularly when the voltage
difference is less than 3V. For normal operation, it is
important to keep the EN pin at least 3V below the V +
supply. If a V + of less than 3V is desired, and the amplifier
10
will remain enabled at all times, then the EN pin should be
tied to the V – supply. The enable pin current is approximately 30µA when activated. If using CMOS open-drain
logic, an external 1k pull-up resistor is recommended to
ensure that the LT1399 remains disabled in spite of any
CMOS drain-leakage currents.
5.0
TA = 25°C
V + = 5V
4.5
4.0
V – = 0V
3.5
+IS (mA)
APPLICATI
3.0
V – = – 5V
2.5
2.0
1.5
1.0
0.5
0
0
1
2
4
3
V + – VEN (V)
5
6
7
1398/99 F01
Figure 1. + IS
vs (V +
– VEN)
OUTPUT
EN
VS = ±5V
VIN = 1V
RF = 324Ω
RG = 324Ω
RL = 100Ω
1398/99 F02
Figure 2. Amplifier Enable Time, AV = 2
OUTPUT
EN
VS = ±5V
VIN = 1V
RF = 324Ω
RG = 324Ω
RL = 100Ω
1398/99 F03
Figure 3. Amplifier Disable Time, AV = 2
LT1398/LT1399/LT1399HV
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The enable/disable times are very fast when driven from
standard 5V CMOS logic. Each amplifier enables in about
30ns (50% point to 50% point) while operating on ±5V
supplies (Figure 2). Likewise, the disable time is approximately 40ns (50% point to 50% point) (Figure 3).
EN A
EN B
OUTPUT
Differential Input Signal Swing
To avoid any breakdown condition on the input transistors, the differential input swing must be limited to ±5V. In
normal operation, the differential voltage between the
input pins is small, so the ±5V limit is not an issue. In the
disabled mode however, the differential swing can be the
same as the input swing, and there is a risk of device
breakdown if input voltage range has not been properly
considered.
3-Input Video MUX Cable Driver
The application on the first page of this data sheet shows
a low cost, 3-input video MUX cable driver. The scope
photo below (Figure 4) displays the cable output of a
30MHz square wave driving 150Ω. In this circuit the
active amplifier is loaded by the sum of RF and RG of each
disabled amplifier. Resistor values have been chosen to
keep the total back termination at 75Ω while maintaining
a gain of 1 at the 75Ω load. The switching time between
any two channels is approximately 32ns when both
enable pins are driven.
When building the board, care was taken to minimize
trace lengths at the inverting input. The ground plane was
also pulled away from RF and RG on both sides of the
board to minimize stray capacitance.
VS = ±5V
VINA = VINB = 2VP-P
at 3.58MHz
1398/99 F05
20ns/DIV
Figure 5. 3-Input Video MUX Switching Response (AV = 2)
Using the LT1399 to Drive LCD Displays
Driving the current crop of XGA and UXGA LCD displays
can be a difficult problem because they require drive
voltages of up to 12V, are usually a capacitive load of over
300pF, and require fast settling. The LT1399HV is particularly well suited for driving these LCD displays because it is capable of swinging more than ±6V on ±7.5V
supplies, and it can drive large capacitive loads with a
small series resistor at the output, minimizing settling
time. As seen in Figures 6 and 7, at a gain of +3 with a
16.9Ω output series resistor and a 330pF load, the
LT1399HV is capable of settling to 0.1% in 30ns for a 6V
step. Similarly, a 12V output step settles in 70ns.
VIN
VOUT
OUTPUT
200mV/DIV
VS = ±5V
RF = 324Ω
RG = 162Ω
RS = 16.9Ω
CL = 330pF
20ns/DIV
1398/99 AI06
Figure 6. LT1399/LT1399HV Large-Signal Pulse Response
RL = 150Ω
RF = RG = 324Ω
f = 10MHz
5ns/DIV
1398/99 F04
Figure 4. Square Wave Response
11
LT1398/LT1399/LT1399HV
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resistor R11, which yields a 75Ω input impedance at the
R input when considered in parallel with R8. R8 connects
to the inverting input of a second LT1398 amplifier (A2),
which also sums the weighted G and B inputs to create a
–0.5 • Y output. LT1398 amplifier B1 then takes the
–0.5 • Y output and amplifies it by a gain of –2, resulting
in the Y output. Amplifier A1 is configured in a noninverting gain of 2 with the bottom of the gain resistor R2 tied
to the Y output. The output of amplifier A1 thus results in
the color-difference output R-Y.
VIN
VOUT
VS = ±7.5V
RF = 324Ω
RG = 162Ω
RS = 16.9Ω
CL = 330pF
1398/99 F07
50ns/DIV
Figure 7. LT1399HV Output Voltage Swing
Buffered RGB to Color-Difference Matrix
Two LT1398s can be used to create buffered colordifference signals from RGB inputs (Figure 8). In this
application, the R input arrives via 75Ω coax. It is routed
to the noninverting input of LT1398 amplifier A1 and to
a 1082Ω resistor R8. There is also an 80.6Ω termination
The B input is similar to the R input. It arrives via 75Ω
coax, and is routed to the noninverting input of LT1398
amplifier B2, and to a 2940Ω resistor R10. There is also
a 76.8Ω termination resistor R13, which yields a 75Ω
input impedance when considered in parallel with R10.
R10 also connects to the inverting input of amplifier A2,
adding the B contribution to the Y signal as discussed
above. Amplifier B2 is configured in a noninverting gain
of 2 configuration with the bottom of the gain resistor R4
tied to the Y output. The output of amplifier B2 thus
results in the color-difference output B-Y.
+
75Ω
SOURCES
R8
1082Ω
A1
1/2 LT1398
R
R11
80.6Ω
–
R1
324Ω
R9
549Ω
R7
324Ω
G
R12
86.6Ω
R-Y
R10
2940Ω
B
R13
76.8Ω
–
A2
1/2 LT1398
+
R6
162Ω
R5
324Ω
R2
324Ω
–
B1
1/2 LT1398
Y
+
R4
324Ω
–
ALL RESISTORS 1%
VS = ±5V
B2
1/2 LT1398
+
Figure 8. Buffered RGB to Color-Difference Matrix
12
R3
324Ω
B-Y
1398/99 F08
LT1398/LT1399/LT1399HV
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The G input also arrives via 75Ω coax and adds its
contribution to the Y signal via a 549Ω resistor R9, which
is tied to the inverting input of amplifier A2. There is also
an 86.6Ω termination resistor R12, which yields a 75Ω
termination when considered in parallel with R9. Using
superposition, it is straightforward to determine the
output of amplifier A2. Although inverted, it sums the R,
G and B signals in the standard proportions of 0.3R,
0.59G and 0.11B that are used to create the Y signal.
Amplifier B1 then inverts and amplifies the signal by 2,
resulting in the Y output.
R10, giving an amplification of – 0.37. This results in a
contribution at the output of A2 of 0.37Y – 0.37B.
If we now sum the three contributions at the output of A2,
we get:
A2OUT = 3.40Y – 1.02R – 0.37B
It is important to remember though that Y is a weighted
sum of R, G and B such that:
Y = 0.3R + 0.59G + 0.11B
If we substitute for Y at the output of A2 we then get:
A2OUT = (1.02R – 1.02R) + 2G + (0.37B – 0.37B)
= 2G
Buffered Color-Difference to RGB Matrix
The LT1399 can be used to create buffered RGB outputs
from color-difference signals (Figure 9). The R output is
a back-terminated 75Ω signal created using resistor R5
and LT1399 amplifier A1 configured for a gain of +2 via
324Ω resistors R3 and R4. The noninverting input of
amplifier A1 is connected via 1k resistors R1 and R2 to
the Y and R-Y inputs respectively, resulting in cancellation of the Y signal at the amplifier input. The remaining
R signal is then amplified by A1.
The back-termination resistor R11 then halves the output
of A2 resulting in the G output.
R1
1k
Y
R2
1k
A1
1/3 LT1399
R-Y
–
The B output is also a back-terminated 75Ω signal
created using resistor R16 and amplifier A3 configured
for a gain of +2 via 324Ω resistors R14 and R15. The
noninverting input of amplifier A3 is connected via 1k
resistors R12 and R13 to the Y and B-Y inputs respectively, resulting in cancellation of the Y signal at the
amplifier input. The remaining B signal is then amplified
by A3.
The G output is the most complicated of the three. It is a
weighted sum of the Y, R-Y and B-Y inputs. The Y input
is attenuated via resistors R6 and R7 such that amplifier
A2’s noninverting input sees 0.83Y. Using superposition,
we can calculate the positive gain of A2 by assuming that
R8 and R9 are grounded. This results in a gain of 2.41 and
a contribution at the output of A2 of 2Y. The R-Y input is
amplified by A2 with the gain set by resistors R8 and R10,
giving an amplification of –1.02. This results in a contribution at the output of A2 of 1.02Y – 1.02R. The B-Y input
is amplified by A2 with the gain set by resistors R9 and
+
R
R3
324Ω
R4
324Ω
R6
205Ω
+
R7
1k
R8
316Ω
R5
75Ω
A2
1/3 LT1399
–
R11
75Ω
G
R10
324Ω
R9
845Ω
B-Y
R12
1k
R13
1k
ALL RESISTORS 1%
VS = ± 5V
+
A3
1/3 LT1399
–
R16
75Ω
B
R14
324Ω
R15
324Ω
1398/99 F09
Figure 9. Buffered Color-Difference to RGB Matrix
13
LT1398/LT1399/LT1399HV
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V+
+IN
–IN
OUT
EN
V–
14
1398/99 SS
LT1398/LT1399/LT1399HV
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PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
GN Package
16-Lead Plastic SSOP (Narrow 0.150)
(LTC DWG # 05-08-1641)
0.189 – 0.196*
(4.801 – 4.978)
0.009
(0.229)
REF
16 15 14 13 12 11 10 9
0.229 – 0.244
(5.817 – 6.198)
0.150 – 0.157**
(3.810 – 3.988)
1
0.015 ± 0.004
× 45°
(0.38 ± 0.10)
0.007 – 0.0098
(0.178 – 0.249)
4
2 3
5 6
7
0.053 – 0.068
(1.351 – 1.727)
8
0.004 – 0.0098
(0.102 – 0.249)
0° – 8° TYP
0.016 – 0.050
(0.406 – 1.270)
0.025
(0.635)
BSC
0.008 – 0.012
(0.203 – 0.305)
* DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
GN16 (SSOP) 0398
S Package
16-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.386 – 0.394*
(9.804 – 10.008)
16
15
14
13
12
11
10
9
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
2
3
4
5
6
0.053 – 0.069
(1.346 – 1.752)
0.014 – 0.019
(0.355 – 0.483)
8
0.004 – 0.010
(0.101 – 0.254)
0° – 8° TYP
0.016 – 0.050
0.406 – 1.270
7
0.050
(1.270)
TYP
S16 0695
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
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.
15
LT1398/LT1399/LT1399HV
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Single Supply RGB Video Amplifier
input. Assuming a 75Ω source impedance for the signal
driving VIN, the Thevenin equivalent signal arriving at
A1’s positive input is 3V + 0.4VIN, with a source impedance of 714Ω. The combination of these two inputs gives
an output at the cathode of D2 of 2 • VIN with no additional
DC offset. The 75Ω back termination resistor R9 halves
the signal again such that VOUT equals a buffered version
of VIN.
The LT1399 can be used with a single supply voltage of
6V or more to drive ground-referenced RGB video. In
Figure 10, two 1N4148 diodes D1 and D2 have been
placed in series with the output of the LT1399 amplifier
A1 but within the feedback loop formed by resistor R8.
These diodes effectively level-shift A1’s output downward by 2 diodes, allowing the circuit output to swing to
ground.
It is important to note that the 4.7µF capacitor C1 has
been added to provide enough current to maintain the
voltage drop across diodes D1 and D2 when the circuit
output drops low enough that the diodes might otherwise
reverse bias. This means that this circuit works fine for
continuous video input, but will require that C1 charge up
after a period of inactivity at the input.
Amplifier A1 is used in a positive gain configuration. The
feedback resistor R8 is 324Ω. The gain resistor is created
from the parallel combination of R6 and R7, giving a
Thevenin equivalent 80.4Ω connected to 3.75V. This
gives an AC gain of + 5 from the noninverting input of
amplifier A1 to the cathode of D2. However, the video
input is also attenuated before arriving at A1’s positive
5V
R1
1000Ω
R6
107Ω
+
A1
1/3 LT1399
R2
1300Ω
–
R3
160Ω
VIN
R4
75Ω
R5
2.32Ω
C1
4.7µF
VS
6V TO 12V
D2
D1
1N4148 1N4148
R9
75Ω
VOUT
R8
324Ω
1398/99 F10
R7
324Ω
Figure 10. Single Supply RGB Video Amplifier (1 of 3 Channels)
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1203/LT1205
150MHz Video Multiplexers
2:1 and Dual 2:1 MUXs with 25ns Switch Time
LT1204
4-Input Video MUX with Current Feedback Amplifier
Cascadable Enable 64:1 Multiplexing
LT1227
140MHz Current Feedback Amplifier
1100V/µs Slew Rate, Shutdown Mode
LT1252/LT1253/LT1254
Low Cost Video Amplifiers
Single, Dual and Quad Current Feedback Amplifiers
LT1259/LT1260
Dual/Triple Current Feedback Amplifier
130MHz Bandwidth, 0.1dB Flatness > 30MHz
LT1675
Triple 2:1 Buffered Video Mulitplexer
2.5ns Switching Time, 250MHz Bandwidth
16
Linear Technology Corporation
13989f LT/TP 0699 4K • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
 LINEAR TECHNOLOGY CORPORATION 1998