Linear LT3063 Precision dual output, high current, low noise, voltage reference Datasheet

LT6658
Precision Dual Output,
High Current, Low Noise,
Voltage Reference
Description
Features
Dual Output Tracking Reference
nn Each Output Configurable: 2.5V to 6V
nn Output 1: 150mA Source/20mA Sink
nn Output 2: 50mA Source/20mA Sink
nn Low Drift:
nn A-Grade: 10ppm/°C Max
nn B-Grade: 20ppm/°C Max
nn High Accuracy:
nn A-Grade: ±0.05% Max
nn B-Grade: ±0.1% Max
nn Low Noise: 1.5ppm
P-P (0.1Hz to 10Hz)
nn Wide Operating Voltage Range to 36V
nn Load Regulation: 0.1ppm/mA
nn AC PSRR: 96dB at 10kHz
nn Kelvin Sense Connection on Outputs
nn Thermal Shutdown
nn Separate Supply Pins for Each Output
nn Available in Exposed Pad Package MSE16
The LT®6658 precision 2.5V dual output reference combines the performance of a low drift low noise reference
and a linear regulator. Both outputs are ideal for driving
the precision reference inputs of high resolution ADCs and
DACs, even with heavy loading while simultaneously acting
as output supplies powering microcontrollers and other
supporting devices. Both outputs have the same precision
specifications and track each other over temperature and
load. Both outputs are nominally 2.5V, however each can
be configured with external resistors to give an output
voltage up to 6V.
nn
Using Kelvin connections, the LT6658 typically has
0.1ppm/mA load regulation with up to 150mA load current.
A noise reduction pin is available to band-limit and lower
the total integrated noise.
Dual outputs provide flexibility for powering reference
and regulator applications and localizing PCB routing. The
outputs have excellent supply rejection and are stable with
1µF to 50µF capacitors.
Applications
Short circuit and thermal protection help maintain stability
and prevent thermal overstress. The LT6658 is offered in
the MSE16 exposed pad package.
Microcontroller with ADC/DAC Applications
nn Data Acquisition Systems
nn Automotive Control and Monitoring
nn Precision Low Noise Regulators
nn Instrumentation and Process Control
nn
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners.
Typical Application
Output Voltage Temperature Drift Both Outputs
2.502
VIN
5V TO 36V
VIN1
VOUT2_F
VIN2
VOUT2_S
RLOAD2
VIN
OD
VOUT2
2.5V
50mA
LT6658-2.5
0.1µF
VOUT1
2.5V
150mA
VOUT1_F
BYPASS
1µF
1µF
VOUT1_S
GND
RLOAD1
OUTPUT VOLTAGE (V)
Precision Dual Output 2.5V Reference and Supply
2.501
2.500
2.499
ILOAD1 = 150mA
VOUT1
VOUT2
1µF
6658 TA01a
2.498
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
6658 TA01b
6658f
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1
LT6658
Absolute Maximum Ratings
Pin Configuration
(Note 1)
Supply Voltages
VIN, VIN1, VIN2 to GND............................. –0.3V to 38V
Input Voltages
OD to GND.............................................. –0.3V to 38V
VOUT1_S , VOUT2_S, NR, BYPASS to GND... –0.3V to 6V
Output Voltages
VOUT1_F, VOUT2_F to GND.......................... –0.3V to 6V
Input Current
BYPASS............................................................ ±10mA
Output Short-Circuit Duration........................... Indefinite
Specified Temperature Range
I-Grade.................................................–40°C to 85°C
H-Grade.............................................. –40°C to 125°C
Operating Junction Temperature Range.. –55°C to 150°C
Storage Temperature Range (Note 2)...... –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
(Note 3)............................................................. 300°C
TOP VIEW
GND
GND
BYPASS
DNC
NR
GND
VOUT2_S
VOUT2_F
1
2
3
4
5
6
7
8
17
GND
16
15
14
13
12
11
10
9
DNC
NC
VIN
VOUT1_S
VOUT1_F
VIN1
VIN2
OD
MSE PACKAGE
16-LEAD PLASTIC MSOP
TJMAX = 150°C, θJC = 10°C/W, θJA = 35°C/W
DNC: CONNECTED INTERNALLY
DO NOT CONNECT EXTERNAL CIRCUITRY TO THESE PINS
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
Order Information
http://www.linear.com/product/LT6658#orderinfo
TUBE
TAPE AND REEL
PART MARKING* PACKAGE DESCRIPTION
SPECIFIED JUNCTION
TEMPERATURE RANGE
LT6658AIMSE-2.5#PBF
LT6658AIMSE-2.5#TRPBF
665825
–40°C to 85°C
16-Lead Plastic MSOP
LT6658BIMSE-2.5#PBF
LT6658BIMSE-2.5#TRPBF
665825
16-Lead Plastic MSOP
–40°C to 85°C
LT6658AHMSE-2.5#PBF
LT6658AHMSE-2.5#TRPBF
665825
16-Lead Plastic MSOP
–40°C to 125°C
LT6658BHMSE-2.5#PBF
LT6658BHMSE-2.5#TRPBF
665825
16-Lead Plastic MSOP
–40°C to 125°C
*The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges. Parts ending with PBF are RoHS and WEEE compliant.
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/
6658f
2
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LT6658
Available Options
OUTPUT VOLTAGE
INITIAL ACCURACY
TEMPERATURE COEFFICIENT
SPECIFIED JUNCTION TEMPERATURE RANGE
2.500V
0.05%
10ppm/°C
–40°C to 85°C
0.1%
20ppm/°C
–40°C to 85°C
0.05%
10ppm/°C
–40°C to 125°C
0.1%
20ppm/°C
–40°C to 125°C
Electrical Characteristics
The l denotes the specifications which apply over the full specified temperature
range, otherwise specifications are at TA = 25°C. VIN = VIN1 = VIN2 = VOUT1,2_F + 2.5V, COUT1,2 = 1µF, ILOAD = 0, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
Output Voltage Accuracy
LT6658A
LT6658B
LT6658AI
LT6658BI
LT6658AH
LT6658BH
l
l
l
l
Output Voltage Temperature
Coefficient (Note 4)
LT6658A
LT6658B
l
l
Line Regulation (Note 5)
VOUT + 2.5V ≤ VIN ≤ 36V, VIN = VIN1 = VIN2
TYP
–0.05
–0.1
–0.175
–0.35
–0.215
–0.43
Output 1 Sourcing, ΔILOAD = 0mA to 150mA
1.4
4.5
5
ppm/V
ppm/V
0.1
0.5
0.8
ppm/mA
ppm/mA
0.1
1.3
1.5
ppm/mA
ppm/mA
0.1
2.2
2.5
ppm/mA
ppm/mA
0.1
2.2
2.5
ppm/mA
ppm/mA
3.5
3.9
4.25
V
V
l
Output 2 Sinking, ΔILOAD = 0mA to 20mA
l
VIN Minimum Voltage
ΔVOUT = 0.1%, IOUT = 0mA, VIN1 = VIN2 = VOUT + 2.5V
l
VIN1 Dropout Voltage
%
%
%
%
%
%
ppm/°C
ppm/°C
l
Output 1 Sinking, ΔILOAD = 0mA to 20mA
0.05
0.1
0.175
0.35
0.215
0.43
10
20
l
Output 2 Sourcing, ΔILOAD = 0mA to 50mA (Note 6)
UNITS
3
10
l
Load Regulation (Note 5)
MAX
ΔVOUT = 0.1%, IOUT = 0mA, VIN = VIN2 = VOUT + 2.5V
ΔVOUT = 0.1%,IOUT = 150mA,VIN = VIN2 = VOUT + 2.5V
l
2.0
2.2
2.3
2.5
V
V
ΔVOUT = 0.1%, IOUT = 0mA, VIN = VIN1 = VOUT + 2.5V
ΔVOUT = 0.1%, IOUT = 50mA, VIN = VIN1 = VOUT + 2.5V
l
1.8
2
2.2
2.5
V
V
Supply Current
VOD = 5V, No Load
VOD = 0.8V, No Load
l
l
1.9
1.0
3.0
1.2
mA
mA
Output Short-Circuit Current
Short VOUT1_F to GND
Short VOUT2_F to GND
l
l
VIN2 Dropout Voltage
170
65
Output Noise Voltage (Note 7) 0.1Hz ≤ f ≤ 10Hz
10Hz ≤ f ≤ 1kHz, COUT = 1µF, CNR = 10µF, ILOAD = Full Current (Note 9)
Frequency = 1kHz, COUT1 = 1µF, CNR = 10µF, ILOAD = Full Current (Note 9)
Output Voltage Tracking
Tracking = Output 1 – Output 2
VOUT1_S, VOUT2_S Pin Current
Unity Gain
OD Threshold Voltage
Logic High Input Voltage
Logic Low Input Voltage
l
l
OD Pin Current
VOD = 0V
VOD = 36V
l
l
270
120
mA
mA
1.5
ppmP–P
2
8
ppmRMS
nV/√Hz
0.9
µV/°C
135
nA
2
30
0.3
0.8
V
V
45
1.5
μA
μA
6658f
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LT6658
Electrical Characteristics
The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. VIN = VIN1 = VIN2 = VOUT1,2_F + 2.5V, COUT1,2 = 1µF, ILOAD = 0, unless otherwise noted.
PARAMETER
CONDITIONS
Ripple Rejection
VIN1 = VOUT1 + 3V, VRIPPLE = 0.5VP–P, fRIPPLE = 120Hz, ILOAD = 150mA,
COUT1 = 1µF, CNR = 10µF
VIN2 = VOUT2 + 3V, VRIPPLE = 0.5VP–P, fRIPPLE = 120Hz, ILOAD = 50mA,
COUT2 = 1µF, CNR = 10µF
107
dB
107
dB
0.1% Settling, CLOAD = 1μF
160
μs
120
ppm/√kHr
30
45
ppm
ppm
Turn-On Time
MIN
Long Term Drift (Note 8)
Thermal Hysteresis (Note 9)
∆T = –40°C to 85°C
∆T = –40°C to 125°C
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: Thermal hysteresis can occur during storage at extreme
temperatures.
Note 3: The stated temperature is typical for soldering of the leads during
manual rework. For detailed IR reflow recommendations, refer to the
Applications Information section.
Note 4: Temperature coefficient is measured by dividing the maximum
change in output voltage by the specified temperature range.
Note 5: Line and load regulation are measured on a pulse basis for
specified input voltage or load current ranges. Output changes due to die
temperature change must be taken into account separately.
Note 6: VOUT2 load regulation specification is limited by practical
automated test resolution. Please refer to the Typical Performance
Characteristics section for more information regarding actual typical
performance.
Note 7: Peak-to-peak noise is measured with a 1-pole highpass filter at
0.1Hz and 2-pole lowpass filter at 10Hz. The unit is enclosed in a still-air
environment to eliminate thermocouple effects on the leads. The test
TYP
MAX
UNITS
time is 10 seconds. RMS noise is measured on a spectrum analyzer in
a shielded environment where the intrinsic noise of the instrument is
removed to determine the actual noise of the device.
Note 8: Long-term stability typically has a logarithmic characteristic
and therefore, changes after 1000 hours tend to be much smaller than
before that time. Total drift in the second thousand hours is normally less
than one third that of the first thousand hours with a continuing trend
toward reduced drift with time. Long-term stability will also be affected by
differential stresses between the IC and the board material created during
board assembly.
Note 9: Hysteresis in output voltage is created by package stress that
differs depending on whether the IC was previously at a higher or
lower temperature. Output voltage is always measured at 25°C, but
the IC is cycled to the hot or cold temperature limit before successive
measurements. Hysteresis measures the maximum output change for the
averages of three hot or cold temperature cycles. For instruments that
are stored at well controlled temperatures (within 20 or 30 degrees of
operational temperature), it’s usually not a dominant error source. Typical
hysteresis is the worst-case of 25°C to cold to 25°C or 25°C to hot to
25°C, preconditioned by one thermal cycle.
Note 10: The full current for ILOAD is 150mA and 50mA for Output 1 and
Output 2, respectively.
6658f
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LT6658
Typical Performance Characteristics
TA = 25°C, VIN = VIN1 = VIN2 = VOUT1_F + 2.5V =
VOUT2_F + 2.5V, COUT1 = COUT2 = 1µF, ILOAD = 0mA, unless otherwise noted.
2.5V VOUT1 Output Voltage
Temperature Drift
2.502
2.501
2.500
2.499
2.498
–50 –25
0
2.501
2.500
2.499
2.498
–50 –25
25 50 75 100 125 150
TEMPERATURE (°C)
2.502
THREE TYPICAL PARTS
OUTPUT VOLTAGE (V)
THREE TYPICAL PARTS
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
2.502
2.5V VOUT1 and VOUT2 Output
Voltage vs Temperature with
150mA Load on VOUT1
2.5V VOUT2 Output Voltage
Temperature Drift
0
–20
–30
–40
–50
–60
–70
–100
0.1
125°C
25°C
–40°C
1
10
100
OUTPUT CURRENT (mA)
5
24
0
20
–5
–10
–15
125°C
25°C
–40°C
–20
–25
0.1
500
1
10
OUTPUT CURRENT (mA)
2.5V VOUT2 Load Regulation,
Sinking
6
3
0
0.1
8
100
6658 G07
125°C
25°C
–40°C
4
1
10
OUTPUT CURRENT (mA)
2.5V Line Regulation VOUT2
2.502
2.501
2.501
2.500
2.499
2.498
2.496
125°C
25°C
–40°C
0
5
10
15 20 25 30
INPUT VOLTAGE (V)
100
6658 G06
2.502
2.497
1
10
OUTPUT CURRENT (mA)
12
0
100
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE CHANGE (ppm)
125°C
25°C
–40°C
9
25 50 75 100 125 150
TEMPERATURE (°C)
16
2.5V Line Regulation VOUT1
18
12
0
6658 G05
6658 G04
15
VOUT1
VOUT2
2.5V VOUT1 Load Regulation,
Sinking
OUTPUT VOLTAGE CHANGE (ppm)
OUTPUT VOLTAGE CHANGE (ppm)
OUTPUT VOLTAGE CHANGE (ppm)
–10
ILOAD1 = 150mA
6658 G03
2.5V VOUT2 Load Regulation,
Sourcing
0
–90
2.499
6658 G02
2.5V VOUT1 Load Regulation,
Sourcing
–80
2.500
2.498
–50 –25
25 50 75 100 125 150
TEMPERATURE (°C)
6658 G01
2.501
35
40
6658 G08
2.500
2.499
2.498
2.497
2.496
125°C
25°C
–40°C
0
5
10
15 20 25 30
INPUT VOLTAGE (V)
35
40
6658 G09
6658f
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LT6658
Typical Performance Characteristics
TA = 25°C, VIN = VIN1 = VIN2 = VOUT1_F + 2.5V =
VOUT2_F + 2.5V, COUT1 = COUT2 = 1µF, ILOAD = 0mA, unless otherwise noted.
2.5V Supply Current vs Input
Voltage
2.5V Output Accuracy Histogram
40
2.5V Output Disable (OD) Low
Supply Current vs Input Voltage
1.4
2.5
35
25
20
15
10
1.2
2.0
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
NUMBER OF UNITS
30
1.5
1.0
0.5
125°C
25°C
–40°C
5
0
2.4985 2.4990 2.4995 2.5000 2.5005 2.5010 2.5015
VOUT1 (V)
0
0
4
8
1.0
0.8
0.6
0.4
0
12 16 20 24 28 32 36 40
INPUT VOLTAGE (V)
6658 G10
125°C
25°C
–40°C
0.2
0
4
8
6658 G11
2.5V Minimum VIN to VOUT1
Differential, Sourcing
6658 G12
2.5V Minimum VIN to VOUT2
Differential, Sourcing
200
12 16 20 24 28 32 36 40
INPUT VOLTAGE (V)
2.5V VOUT1 Power Supply
Rejection Ratio vs Frequency
120
100
VIN = VIN1 = VIN2 = 6V
100
10
1
0.1
1.1
125°C
25°C
–40°C
1.4
1.6
1.9
INPUT–OUTPUT VOLTAGE (V)
80
10
PSRR (dB)
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
100
40
1
0.1
1.1
2.1
1.3
1.5
1.7
1.9
INPUT–OUTPUT VOLTAGE (V)
0
0.01
2.1
120
120
VIN = VIN1 = VIN2 = 6V
80
80
0
0.01
CNR = 1µF
CNR = 10µF
0.1
1
10
FREQUENCY (kHz)
100
1000
6658 G16
PSRR (dB)
80
PSRR (dB)
100
PSRR (dB)
100
20
1
10
FREQUENCY (kHz)
100
60
40
CNR = 10µF
COUT1 = 1µF
20
0
0.01
ILOAD1 = 0A
ILOAD1 = 150mA
0.1
1
10
FREQUENCY (kHz)
100
1000
2.5V VOUT2 Power Supply
Rejection Ratio vs Frequency
100
COUT2 = 1µF
ILOAD = 0A
0.1
6658 G15
2.5V VOUT1 Power Supply
Rejection Ratio vs Frequency
VIN = VIN1 = VIN2 = 6V
40
CNR = 1µF
CNR = 10µF
6658 G14
2.5V VOUT2 Power Supply
Rejection Ratio vs Frequency
60
COUT1 = 1µF
ILOAD = 0A
20
125°C
25°C
–40°C
6658 G13
120
60
1000
6658 G17
VIN = VIN1 = VIN2 = 6V
60
40
CNR = 10µF
COUT1 = 1µF
20
0
0.01
ILOAD = 0A
ILOAD = 50mA
0.1
1
10
FREQUENCY (kHz)
100
1000
6658 G18
6658f
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LT6658
Typical Performance Characteristics
VOUT2_F + 2.5V, COUT1 = COUT2 = 1µF, ILOAD = 0mA, unless otherwise noted.
2.5V VOUT1 AC Output Impedance
150mA Load
1
0.1
0.1
0.001
IOUT1 = 10mA
0.0001
0.01
COUT1 = 1µF
COUT1 = 50µF
0.1
1
10
FREQUENCY (kHz)
100
1000
10
0.01
0.001
IOUT1 = 150mA
COUT1 = 1µF
COUT1 = 50µF
0.0001
0.01
0.1
6658 G19
1
10
FREQUENCY (kHz)
100
1000
OUTPUT IMPEDANCE (Ω)
0.1
VBYPASS
2V/DIV
2V/DIV
VOUT1
2V/DIV
VOUT2
IOUT2 = 50mA
1
10
FREQUENCY (kHz)
100
CNR = OPEN
COUT1 = 1µF
COUT2 = 1µF
50µs/DIV
COUT2 = 1µF
COUT2 = 50µF
0.1
0.001
IOUT2 = 1mA
0.0001
0.01
COUT2 =1µF
COUT2 = 50µF
0.1
1
10
FREQUENCY (kHz)
6658 G23
1000
160
140
120
COUT1 = 1µF / CNR = OPEN
100
COUT1 = 50µF / CNR = 10µF
80
COUT1 = 10µF / CNR =10µF
60
40
VIN = VIN1 = 7V
20 VIN2 = 6VDC + 700mVRMS
ILOAD1 = ILOAD2 = 0A, TA = 25°C
0
0.01
0.1
1
10
FREQUENCY (kHz)
2.5V Channel to Channel Load
Regulation (Effects of Heating
Removed)
80
COUT2 = 50µF / CNR = 10µF
COUT2 = 1µF / CNR = OPEN
60
40
VIN = VIN2 = 7V
20 V = 6VDC + 700mV
IN1
RMS
ILOAD1 = ILOAD2 = 0A, TA = 25°C
0
0.01
0.1
1
10
FREQUENCY (kHz)
2.5V Channel to Channel
Isolation, Time Domain
20
COUT2 = 10µF / CNR=10µF
18
VOUT2 VOLTAGE CHANGE (ppm)
VOUT2 CHANNEL TO CHANNEL ISOLATION (dB)
100
150mA
16
IOUT1
14
10mA
12
10
VOUT2
8
100µV/DIV
6
4
2
100
6658 G25
100
6658 G24
2.5V Channel to Channel
Isolation VIN1 to VOUT2
120
1000
6658 G21
6658 G22
140
100
2.5V Channel to Channel
Isolation VIN2 to VOUT1
VIN
5V/DIV
0.0001
0.01
0.01
2.5V Turn-On Characteristic
1
0.001
0.1
6658 G20
2.5V VOUT2 AC Output Impedance
50mA Load
0.01
1
VOUT1 CHANNEL TO CHANNEL ISOLATION (dB)
0.01
2.5V VOUT2 AC Output Impedance
1mA Load
OUTPUT IMPEDANCE (Ω)
1
OUTPUT IMPEDANCE (Ω)
OUTPUT IMPEDANCE (Ω)
2.5V VOUT1 AC Output Impedance
10mA Load
TA = 25°C, VIN = VIN1 = VIN2 = VOUT1_F + 2.5V =
0
1
10
100
VOUT1 LOAD CURRENT (mA)
500
CNR = 0.1µF
COUT1 = 1µF
COUT2 = 1µF
10µs/DIV
6658 G27
6658 G26
6658f
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LT6658
Typical Performance Characteristics
TA = 25°C, VIN = VIN1 = VIN2 = VOUT1_F + 2.5V =
VOUT2_F + 2.5V, COUT1 = COUT2 = 1µF, ILOAD = 0mA, unless otherwise noted.
2.5V VOUT1_S Pin Input Current
vs Temperature
200
200
OD PIN INPUT CURRENT (µA)
VOUT1_S PIN CURRENT (nA)
250
100
THREE TYPICAL PARTS
225
175
150
125
100
75
50
10
1
25 50 75 100 125 150
TEMPERATURE (°C)
0
1
2
3
OD PIN INPUT VOLTAGE (V)
6658 G28
160
90
120
60
80
VOUT1 – VOUT2 (µV)
VOUT1 – VOUT2 (µV)
200
THREE TYPICAL PARTS
120
30
0
–30
–60
16
20 24
VIN (V)
28
32
36
OUTPUT
NOISE
(2µV/DIV)
NOISE VOLTAGE (nV/√Hz)
300
6658 G34
6658 G33
1s/DIV
–200
0.01
2.5V VOUT2 Output Noise
0.1Hz to 10Hz
1s/DIV
2.5V VOUT1 Output Noise
0.1Hz to 10Hz
THREE TYPICAL PARTS
6658 G31
OUTPUT
NOISE
(2µV/DIV)
6658 G30
–80
–160
12
–250
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
2.5V Tracking (VOUT1 – VOUT2)
vs VOUT1 Load Current
0
–120
8
4
–40
–90
4
–100
–200
40
–120
–150
0
–50
6658 G29
2.5V Tracking (VOUT1 – VOUT2)
vs Input Voltage
150
50
0.1
1
10
100
VOUT1 LOAD CURRENT (mA)
1k
6658 G32
2.5V VOUT1 Output Voltage Noise
Spectrum ILOAD = 0mA
240
CNR = OPEN
180
120
60
0
0.01
300
COUT1 = 1µF
NOISE VOLTAGE (nV/√Hz)
0
0.1
100
–150
125°C
25°C
–40°C
25
0
–50 –25
THREE TYPICAL PARTS
150
VOUT1 – VOUT2 (µV)
250
2.5V Tracking (VOUT1 – VOUT2)
vs Temperature
2.5V OD Pin Current vs OD Pin
Input Voltage
CNR = 10µF
0.1
1
10
FREQUENCY (kHz)
100
1000
6658 G35
2.5V VOUT2 Output Voltage Noise
Spectrum ILOAD = 0mA
COUT2 = 1µF
240
CNR = OPEN
180
120
60
0
0.01
CNR = 10µF
0.1
1
10
FREQUENCY (kHz)
100
1000
6658 G36
6658f
8
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LT6658
Typical Performance Characteristics
VOUT2_F + 2.5V, COUT1 = COUT2 = 1µF, ILOAD = 0mA, unless otherwise noted.
300
COUT1 = 1µF
CNR = OPEN
150
100
CNR = 10µF
50
0
0.01
0.1
200
CNR = OPEN
150
100
CNR = 10µF
50
1
10
FREQUENCY (kHz)
100
0
0.01
1000
0.1
6658 G37
INTEGRATED NOISE (µVRMS)
INTEGRATED NOISE (µVRMS)
60
COUT2 = 1µF
50 ILOAD = 0mA
40
30
20
10
0
0.01
0.1
1
10
FREQUENCY (kHz)
100
1000
50
40
2mV/DIV
2mV/DIV
100
20
0
0.01
1000
VBYPASS
COUT1 = 1µF
ILOAD = 150mA
0
0.01
2mV/DIV
VIN = 5V to 5.5V
ILOAD = 0mA
6658 G43
100
0.1
1
10
FREQUENCY (kHz)
100
1000
50
40
COUT2 = 1µF
ILOAD = 50mA
30
20
10
0
0.01
0.1
1
10
FREQUENCY (kHz)
100
6658 G42
500mV/DIV
VBYPASS
2mV/DIV
VOUT1
2mV/DIV
VOUT2
2mV/DIV
50µs/DIV
1000
2.5V Line Transient Response
VIN
CNR = 1µF
COUT1 = COUT2 = 1µF
1000
CNR = OPEN
CNR = 10µF
6658 G41
2mV/DIV
VOUT2
1
10
FREQUENCY (kHz)
6658 G39
60
10
2mV/DIV
VOUT1
0.1
2.5V VOUT2 Integrated Noise
ILOAD = 50mA
20
500mV/DIV
50µs/DIV
30
2.5V Line Transient Response
VIN
CNR = OPEN
COUT1 = COUT2 = 1µF
1
10
FREQUENCY (kHz)
30
2.5V Line Transient Response
2mV/DIV
40
10
CNR = OPEN
CNR = 10µF
6658 G40
500mV/DIV
COUT1 = 1µF
50 ILOAD = 0mA
2.5V VOUT1 Integrated Noise
ILOAD = 150mA
CNR = OPEN
CNR =10µF
60
CNR = 0PEN
CNR = 10µF
6658 G38
2.5V VOUT2 Integrated Noise
ILOAD = 0mA
70
2.5V VOUT1 Integrated Noise
ILOAD = 0mA
60
INTEGRATED NOISE (µVRMS)
200
70
COUT2 = 1µF
250
NOISE VOLTAGE (nV/√Hz)
NOISE VOLTAGE (nV/√Hz)
250
2.5V VOUT2 Output Voltage Noise
Spectrum ILOAD = 50mA
INTEGRATED NOISE (µVRMS)
300
2.5V VOUT1 Output Voltage Noise
Spectrum ILOAD = 150mA
TA = 25°C, VIN = VIN1 = VIN2 = VOUT1_F + 2.5V =
VIN = 5V to 5.5V
ILOAD = 0mA
6658 G44
VIN
VBYPASS
VOUT1
VOUT2
CNR = 1µF
COUT1 = COUT2 = 1µF
50µs/DIV
VIN = 5V to 5.5V
ILOAD = 50mA
6658 G45
6658f
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9
LT6658
Typical Performance Characteristics
VOUT2_F + 2.5V, COUT1 = COUT2 = 1µF, ILOAD = 0mA, unless otherwise noted.
VOUT1 Current Limit
450
VIN = 5V
VIN = 7.5V
VIN = 10V
350
140
CURRENT LIMIT (mA)
CURRENT LIMIT (mA)
400
VOUT2 Current Limit
160
300
250
200
150
100
Current Limit vs Supply Voltage
VIN = 5V
VIN = 10V
0
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
6658 G46
IOUT1
IOUT2
450
400
120
100
80
60
40
350
300
250
200
150
100
20
50
500
CURRENT LIMIT (mA)
500
TA = 25°C, VIN = VIN1 = VIN2 = VOUT1_F + 2.5V =
50
0
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
6658 G47
0
0
5
10 15 20 25 30
SUPPLY VOLTAGE (V)
35
40
6658 G48
6658f
10
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LT6658
Pin Functions
GND (Pins 1, 2, 6, Exposed Pad Pin 17): These pins are
the main ground connections and should be connected into
a star ground or ground plane. The exposed pad must be
soldered to ground for good electrical contact and rated
thermal performance.
BYPASS (Pin 3): Bypass Pin. This requires a 1μF capacitor
for bandgap stability.
DNC (Pin 4, 16): Do Not Connect. Keep leakage current
from these pins to a minimum.
NR (Pin 5): Noise Reduction Pin. To band limit the noise
of the reference, connect a capacitor between this pin and
ground. See Applications Information section.
VOUT2_S (Pin 7): VOUT2 Sense Pin. Connect this Kelvin
sense pin at the load.
VOUT2_F (Pin 8): VOUT2 Output Voltage. A 1μF to 50μF
output capacitor is required for stable operation. This
output can source up to 50mA.
OD (Pin 9): Output Disable. This active low input disables
both outputs.
VIN2 (Pin 10): Input Voltage Supply for Channel 2. Bypass
VIN2 with 0.1μF capacitor to ground. This pin supplies
power to buffer amplifier 2.
VIN1 (Pin 11): Input Voltage Supply for Channel 1. Bypass
VIN1 with 0.1μF capacitor to ground. This pin supplies
power to buffer amplifier 1.
VOUT1_F (Pin 12): VOUT1 Output Voltage. A 1μF to 50μF
output capacitor is required for stable operation. This
output can source up to 150mA.
VOUT1_S (Pin 13): VOUT1 Sense Pin. Connect this Kelvin
sense pin at the load.
VIN (Pin 14): Input Voltage Supply. Bypass VIN with 0.1μF
capacitor to ground.
NC (Pin 15): No Connect.
6658f
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11
LT6658
Block Diagram
14
9
VIN
OD
VIN2
4 DNC
VOUT2_F
16 DNC
15 NC
800Ω
THERMAL
SHUTDOWN
VOUT2_S
VIN1
1
2
6
17
GND
10
8
7
11
400Ω
BANDGAP
VOUT1_F
GND
12
GND
800Ω
GND
3
BYPASS
5
VOUT1_S
13
NR
6658 BD
6658f
12
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LT6658
Applications Information
The LT6658 combines the low noise and accuracy of a
high performance reference and the high current drive of
a regulator. The LT6658 is a high performance regulator providing two precise low noise outputs with Kelvin
sense pins. The isolated outputs maintain their precision
even when large voltage or current transients exist on the
adjacent channel.
The LT6658 architecture consists of a low drift bandgap
reference followed by an optional noise reduction stage
and two independent buffers. The bandgap reference and
the buffers are trimmed for low drift and high accuracy.
The high gain buffers ensure outstanding line and load
regulation.
The guidance that follows describes how to reduce noise,
lower power consumption, generate different output
voltages, and maintain low drift. Also included are notes
on internal protection circuits, PCB layout, and expected
performance.
To minimize power consumption each supply pin can
be operated with its minimum voltage. For example, if
Buffer 1 has a 2.5V output, VIN1 can be operated at 5V. If
Buffer 2’s output is run at 3V, run VIN2 at 5.5V. The power
savings gained by minimizing each supply voltage can be
considerable.
Excessive ground current and parasitic resistance in ground
lines can degrade load regulation. Unlike an LDO, the ground
current of the LT6658 is designed such that ground current
does not increase substantially when sourcing a large load
current. All three ground pins and exposed pad should be
connected together on the PCB, through a ground plane
or through a separate trace terminating at a star ground.
The supply pins can be powered up in any order without
an adverse response. However, all three supplies pins
need the minimum specified voltage for proper operation.
INDICATES CURRENT FLOW
14
Supply Pins and Ground
The LT6658 can operate with a supply voltage from
VOUT + 2.5V, to 36V. To provide design flexibility, the LT6658
includes 3 supply pins. The VIN pin supplies power to the
bandgap voltage reference. The VIN1 and VIN2 pins supply
power to buffer amplifiers 1 and 2, respectively. Figure 1
illustrates how current flows independently through each
of the output buffers. The simplest configuration is to
connect all three supply pins together. To reduce power
consumption or isolate the buffer amplifiers, separate the
supply pins and drive them with independent supplies.
Separate VIN,VIN1 and VIN2 supply pins isolate the bandgap
reference and the two outputs VOUT1_F and VOUT2_F from
each other. For example, a load current surge through
VIN1 to VOUT1_F is isolated from VOUT2_F and the bandgap
voltage reference. In Figure 2 a 140mA load current pulse
on buffer 1 and the resulting output waveforms are shown.
Despite the large current step on buffer 1, there is only a
small transient at the output of buffer 2. When providing
a stable voltage reference to quiet circuits like an ADC or
DAC, it is important the two buffer outputs are isolated.
11
10
VIN1 VIN2
VIN
+
–
LT6658-2.5
+
–
+
–
BANDGAP
+
–
THERMAL
SHUTDOWN
+
–
GND
1,2
VOUT2_F
VOUT1_F
8
12
LOAD2
LOAD1
GND GND
17
6
6658 F01
Figure 1. LT6658 Current Flow through the Supply Pins
LOAD CURRENT
100mA/DIV
20mV/DIV
100µV/DIV
VOUT1
VOUT2
COUT1 = 10µF
COUT2 = 10µF
50µs/DIV
6658 F02
Figure 2. 10mA to 150mA Load Step on VOUT1
6658f
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13
LT6658
Applications Information
Input Bypass Capacitance
Each input voltage pin requires a 0.1µF capacitor located
as close to the supply pin as possible. A 10µF capacitor
is recommended for each supply where the supply enters
the board. When the supply pins are connected together,
a single 0.1µF and single 10µF capacitor can be used.
The BYPASS pin requires a 1µF capacitor for stability.
Stability and Output Capacitance
The LT6658 is designed to be stable for any output capacitance between 1µF and 50µF, under any load condition, specified input voltage, or specified temperature.
Choosing a suitable capacitor is important in maintaining
stability. Preferably a low ESR and ESL capacitor should
be chosen. The value of the output capacitor will affect
the settling response.
Care should be exercised in choosing an output capacitor,
as some capacitors tend to deviate from their specified
value as operating conditions change.
1.2
X5R
X7R
CAPACITANCE (µF)
1.0
Film capacitors do not vary much over temperature and
DC bias as much as X5R and X7R capacitors, but generally they are only rated to 105°C. Film capacitors are also
physically larger.
Effective series resistance (ESR) in the output capacitor
can add a zero to the loop response of the output buffers
creating an instability or excessive ringing. For the best
results keep the ESR at or below 0.2Ω.
One measure of stability is the closed loop response of
the output buffer. By driving the NR pin, a closed loop
response can be obtained. In Figure 4 the closed loop
response of the output buffer with three different output
capacitance values is shown. In the Figure 5 the same plot
is repeated with a 150mA load.
A large value electrolytic capacitor with a 1µF to 50µF ceramic capacitor in parallel can be used on the output pins.
The buffers will be stable, and the bandwidth will be lower.
20
10
GAIN (dB)
Although ceramic capacitors are small and inexpensive,
they can vary considerably over the DC bias voltage. For
example, the capacitance value of X5R and X7R capacitors
will change significantly over their rated voltage range as
shown in Figure 3. In this example the 1µF X5R capacitor
loses almost 75% of its value at its rated voltage of 10V.
X5R and X7R capacitors will also vary up to 20% or more
over a temperature range of –55°C to 125°C. This change
in capacitance will be combined with any DC bias voltage
variation.
COUT1 = 1µF
0
COUT1 = 50µF
–10
0.8
COUT1 = 10µF
0.6
–20
0.01
0.4
1
10
FREQUENCY (kHz)
100
1k
6658 F04
0.2
0.0
0.1
0
1
2
3
4 5 6
DC BIAS (V)
7
8
9
10
Figure 4. LT6658 Closed Loop Response of the
Channel 1 Output Buffer for 3 Values of Output
Capacitance and No Load
6658 F03
Figure 3. Capacitance Value of a 1µF X7R Over Its Full Rated Voltage
6658f
14
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LT6658
Applications Information
20
11
15
12
GAIN (dB)
10
VIN
5V
COUT1 = 1µF
5
0
14
9
VIN1
VOUT2_F
VIN2
VOUT2_S
OD
1µF
LT6658-2.5
–10
VOUT1_F
3
COUT1 = 50µF
BYPASS
1µF
COUT1 = 10µF
–15
7
VIN
0.1µF
–5
10Ω
8
VOUT1_S
GND
1, 2, 6, 17
IGEN
12
13
1µF
6658 F07
–20
0.01
0.1
1
10
FREQUENCY (kHz)
100
1k
Figure 7. Load Current Response Time Test Circuit
6658 F05
Figure 5. LT6658 Closed Loop Response of the
Channel 1 Output Buffer for 3 Values of Output
Capacitance and 150mA Load
The Channel 2 output buffer has a similar response.
In Figure 8 and Figure 9, a 75mA and 140mA load step is
applied to Channel 1, respectively. In Figure 10, a 40mA
load step is applied to Channel 2. The settling time is determined by the size and edge rate of the load step, and
the size of the output capacitor.
Start-Up and Transient Response
When the LT6658 is powered up, the bandgap reference
charges the capacitor on the BYPASS pin. The output
buffer follows the voltage on the BYPASS pin charging the
output capacitor. Figure 6 shows the start-up response on
the BYPASS and VOUT1_F pins for three different output
capacitor values. The start-up response is limited by the
current limit in the bandgap charging the BYPASS capacitor. The turn-on time is also restricted by the current limit
in the output buffer and the size of the output capacitor. A
larger output capacitor will take longer to charge. Adding a
capacitor to the NR pin will also affect turn-on time.
5V/DIV
VIN
20mV/DIV
VOUT1
VOUT2
50µV/DIV
CNR = 0.1µF
COUT1 = 1µF
COUT2 = 1µF
COUT1 = 1µF
2V/DIV
VOUT1
COUT1 = 10µF
6658 F08
Figure 8. LT6658-2.5 Output 1 Response to 75mA Load Step
IOUT1
2V/DIV
VOUT1
COUT1 = 50µF
20mV/DIV
100µs/DIV
10µs/DIV
10mA
VOUT1
2V/DIV
IOUT1
10mA
150mA
VBYPASS
2V/DIV
85mA
VOUT1
VOUT2
100µV/DIV
6658 F06
Figure 6. Start-Up Response on the BYPASS and VOUT1_F Pins
The test circuit for the transient response test is shown
in Figure 7. The transient response due to load current
steps are shown in Figures 8, 9, and 10.
CNR = 0.1µF
COUT1 = 1µF
COUT2 = 1µF
10µs/DIV
6658 F09
Figure 9. LT6658-2.5 Output 1 Response to 140mA Load Step
6658f
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15
LT6658
Applications Information
Referring to the 2.5V VOUT1_S Pin Input Current vs Temperature plot in the Typical Performance Characteristics
section, the input sense current varies about 50nA between
–40°C and 125°C. This 50nA variation may cause a 0.5mV
voltage change across the 10kΩ feedback resistor affecting the output voltage.
50mA
IOUT2
10mA
5mV/DIV
50µV/DIV
VOUT2
VOUT1
CNR = 0.1µF
COUT1 = 1µF
COUT2 = 1µF
10µs/DIV
14
6658 F10
VIN
Figure 10. LT6658-2.5 Output 2 Response to 40mA Load Step
Each output can be configured with external resistors to
gain up VOUT, enabling the output to be set from 2.5V to
6V. Unity gain is configured by tying the sense and force
pins together.
In Figure 11, Channel 2 is configured with a gain of 2 (see
Typical Applications Section for more examples). This can
be done to one or both of the channels. When configuring
a gain >1 make sure that the associated supply pin is 2.5V
higher than the VOUT_F pin. Also note that the absolute
maximum voltage on the output pins (both force and sense)
is 6V. Place the gain resistors close to the part keeping
the traces short. Since this is part of the feedback path,
the feedback resistor should be connected near the load,
avoiding any resistive parasitic in the high current path.
Another source of error is having some resistance in the
feedback network to ground. If possible the resistor should
be connected as close as possible to the chip ground.
When using non-unity gain configurations, VOS drift errors
are possible. There is an 800Ω resistor in the Kelvin sense
line which is designed to cancel base current variation on
the input of the buffer amplifier. Matching the impedances
on the positive and negative inputs reduces base current
error and minimizes VOS drift. A feedback network will
have a small base current flowing through the feedback
resistor possibly causing a small VOS drift.
+
–
BANDGAP
+
–
Output Voltage Scaling
11
10
VIN1 VIN2
LT6658-2.5
VOUT2_F
VOUT2_S
THERMAL
SHUTDOWN
+
–
VOUT1_F
VOUT1_S
GND
1,2
GND GND
17
6
8
10k
7
10k
12
13
1µF
1µF
6658 F11
Figure 11. The LT6658-2.5 with Output 2 Configured for a 5V Output
Kelvin Sense Pins
To ensure the LT6658 maintains good load regulation,
the Kelvin sense pins should be connected close to the
load to avoid any voltage drop in the copper trace on the
force pin. It only takes 10mΩ of resistance to develop a
1.5mV drop with 150mA. This would cause an ideal 2.5V
output voltage to exceed the 0.05% specification at the
load. The circuit in Figure 12a illustrates how an incorrect
Kelvin sense connection can lead to errors. The parasitic
resistance of the copper trace will cause the output voltage
to change as the load current changes. As a result, the
voltage at the load will be lower than the voltage at the
sense line. The circuit in Figure 12b shows the proper way
to make a Kelvin connection with the sense line as close
to the load as possible. The voltage at the load will now
be well regulated. The VOUT1_S current is typically 135nA,
and a low resistance in series with the Kelvin sense input
is unlikely to cause a significant error or drift.
6658f
16
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LT6658
Applications Information
LT6658-2.5
+
–
Table 1. NR Capacitor Values and the Corresponding 3dB Frequency
VPAR
+
–
RPAR
VOUT2_F 12
NR Capacitor (µF)
NR 3dB Frequency (Hz)
0.1
3979
0.22
1809
0.47
847
ILOAD
RLOAD
VOUT2_S 13
a)
LT6658-2.5
+
–
VPAR
+
VOUT2_F 12
–
RPAR
VOUT2_S 13
ILOAD
1
398
2.2
181
4.7
85
10
40
22
18
RLOAD
6658 F12
b)
Figure 12. How to Make a Proper Kelvin Sense Connection
Output Noise and Noise Reduction (NR)
The LT6658 noise characteristic is similar to that of a high
performance reference. The total noise is a combination
of the bandgap noise and the noise of the buffer amplifier.
The bandgap noise can be measured at the NR pin and
is shown in Figure 13 with a 1μF capacitor, 10µF capacitor and no capacitor on the NR pin. The bandgap can be
bandlimited by connecting a capacitor between the NR
pin and ground. The RC product sets the low pass 3dB
corner attenuating the out-of-band noise of the bandgap.
An internal 400Ω ±15% resistor combines with the external
capacitor to create a single-pole low pass filter. Table 1
lists capacitor values and the corresponding 3dB cutoff
frequency.
The primary trade-off for including an RC filter on the
NR pin is a slower turn-on time. The effective resistance
seen by the NR capacitor is 400Ω. The RC time constant
(τ) for charging the NR capacitor is τ = R • C. To reach
the initial accuracy specification for the LT6658, 0.05%,
it will take 7.6τ of settling time. Example settling time
constants are shown in Table 2. An example of the NR
pin charging and the relationship to the output voltage
is shown in Figure 14. The appropriate trade-off between
settling time and noise limiting is specific to the demands
of each unique application.
Table 2. Settling Times for Different NR Capacitor Values
Output Voltage
(V)
NR Pin Resistance
(Ω)
C
(μF)
7.6τ
(ms)
2.5
400
0.01
0.030
0.1
0.30
1
3.04
250
CNR = 0µF
5V/DIV
NOISE (nV/√Hz)
200
1V/DIV
150
100
CNR = 1µF
1V/DIV
50
CNR = 10µF
0
0.01
0.1
VIN
VNR
VOUT1
CNR = 1µF
COUT1 = 1µF
500µs/DIV
1
10
FREQUENCY (kHz)
100
1000
6658 F14
Figure 14. Start-up Response on the NR pin and VOUT_F
6658 F13
Figure 13. LT6658 Bandgap Output Voltage Noise
6658f
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17
LT6658
Applications Information
INTEGRATED NOISE (µVRMS)
5
4
COUT2 = 1µF
COUT2 = 50µF
COUT2 = 100µF
4
CNR = 22µF
3
2
1
0
0.01
COUT1 = 1µF
COUT1 = 50µF
COUT1 = 100µF
0.1
1
10
100
FREQUENCY (kHz)
1000 10000
6658 F16
CNR = 22µF
Figure 16. LT6658-2.5 VOUT2 Integrated Noise with CNR = 22µF
and COUT2 = 1µF, 50µF and 100µF
3
The output voltage noise does not change appreciably as
load current increases.
2
1
0
0.01
5
INTEGRATED NOISE (µVRMS)
The LT6658’s two low noise buffer amplifiers measure
8nV/√Hz. The combined bandgap and buffer noise results
for Buffer 1 and Buffer 2 are shown in the Typical Performance Characteristics section. Note that beyond the
NR pin cutoff frequency, the noise is primarily due to the
buffer amplifiers. As shown, the buffer can be bandlimited
by increasing the size of the output capacitors. Figure 15
and Figure 16 show the total integrated noise of Buffer 1
and Buffer 2, respectively.
0.1
1
10
100
FREQUENCY (kHz)
1000 10000
6658 F15
Figure 15. LT6658-2.5 Total Integrated Output Voltage Noise
with CNR = 22µF and COUT1 = 1µF, 50µF and 100µF Output
Capacitors
The wide range of output capacitance capability and the NR
pin capacitance allows the LT6658 noise density spectrum
to be customized for specific applications. Table 3 lists
the output noise for different conditions.
The output and NR capacitances also affect the AC PSRR
response as shown in Table 3. See the Typical Performance
Characteristics section for more information.
Table 3. Output Noise and Ripple Rejection Typical Values
PARAMETER
CONDITIONS
TYP
UNITS
Output Noise Voltage
(VOUT1 and VOUT2)
Frequency = 10Hz, COUT = 1µF, CNR = 0F, ILOAD = Full Current*
Frequency = 10Hz, COUT = 1µF, CNR = 10µF, ILOAD = Full Current*
Frequency = 1kHz, COUT = 1µF, CNR = 0F, ILOAD = Full Current*
Frequency = 1kHz, COUT = 1µF, CNR = 10F, ILOAD = Full Current*
176
164
157
9
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
Output RMS Noise
10Hz to 100kHz, COUT1 = 1µF, CNR = 0F
10Hz to 100kHz, COUT1 = 1µF, CNR = 10µF
10Hz to 100kHz, COUT1 = 50µF, CNR = 22µF
10Hz to 100kHz, COUT2 = 1µF, CNR = 0F
10Hz to 100kHz, COUT2 = 1µF, CNR = 10µF
10Hz to 100kHz, COUT2 = 50µF, CNR = 22µF
26.2
1.5
0.7
21.8
1.1
0.9
ppmRMS
ppmRMS
ppmRMS
ppmRMS
ppmRMS
ppmRMS
Power Supply Rejection
(VIN1 = VOUT1 + 3V,
VIN2 = VOUT2 + 3V)
VRIPPLE = 500mVP-P, fRIPPLE = 120Hz, ILOAD1 = 150mA, COUT1 = 1µF, CNR = 1µF
VRIPPLE = 150mVP-P, fRIPPLE = 10kHz, ILOAD1 = 150mA, COUT1 = 1µF, CNR = 1µF
VRIPPLE = 150mVP-P, fRIPPLE = 100kHz, ILOAD1 = 150mA, COUT1 = 1µF, CNR = 1µF
VRIPPLE = 150mVP-P, fRIPPLE = 1MHz, ILOAD1 = 150mA, COUT1 = 1µF, CNR = 1µF
VRIPPLE = 500mVP-P, fRIPPLE = 120Hz, ILOAD2 = 50mA, COUT2 = 1µF, CNR = 1µF
VRIPPLE = 150mVP-P, fRIPPLE = 10kHz, ILOAD2 = 50mA, COUT2 = 1µF, CNR = 1µF
VRIPPLE = 150mVP-P, fRIPPLE = 100kHz, ILOAD2 = 50mA, COUT2 = 1µF, CNR = 1µF
VRIPPLE = 150mVP-P, fRIPPLE = 1MHz, ILOAD2 = 50mA, COUT2 = 1µF, CNR = 1µF
107
96
65
64
104
96
66
65
dB
dB
dB
dB
dB
dB
dB
dB
* The full current for ILOAD is 150mA and 50mA for output 1 and output 2, respectively.
6658f
18
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LT6658
Applications Information
Power Supply Rejection
The three supply pins provide flexibility depending on
the demands of the application. The LT6658 provides
excellent AC power supply rejection with all three supply
pins connected together. Superior performance can be
achieved when the supply pins are independently powered.
For example, use a quiet supply for the VIN pin. This will
isolate the bandgap circuit from the outputs. Further, each
buffer can be supplied independently providing >140dB of
isolation across some frequencies. Table 3 summarizes
several conditions of power supply rejection.
Output Disable
The OD pin disables the output stage of both output buffers. This pin is useful for disabling the buffers when fault
conditions exist. For example, if external circuitry senses
that the load is too hot or there is a short circuit condition, asserting this pin will remove the output current.
This active low pin will disable the output buffers when
the voltage on the pin is less than 0.8V. When the input
voltage is greater than 2V the LT6658 is enabled.
The start-up time when the LT6658 enables is determined
by the size of the output capacitor. Figure 17 is an example
of the LT6658-2.5 being enabled and disabled. The OD pin
has an internal pull-up current that will keep the output
buffers enabled when the OD pin floats. In noisy environments, it is recommended that OD be tied high explicitly.
5V/DIV
1V/DIV
1V/DIV
COUT1 = 1µF
COUT2 = 1µF
OD
VOUT1
The output stage of each output buffer is disabled when
the internal die temperature is greater than 165°C. There
is 11°C of hysteresis allowing the part to return to normal
operation once the die temperature drops below 154°C.
In addition, a short circuit protection feature prevents the
output from supplying an unlimited load current. A fault
or short on either output force pin will cause the output
stage to limit the current and the output voltage will drop
accordingly to the output fault condition. For example,
if a 1Ω fault to ground occurs on Channel 1, the circuit
protection will limit both outputs. A load fault on either
channel will affect the output of both channels.
Power Dissipation
To maintain reliable precise and accurate performance
the LT6658 junction temperature should never exceed
TJMAX = 150°C. If the part is operated at the absolute
maximum input voltage and maximum output currents, the
MSE package will need to dissipate over 7 watts of power.
The LT6658 is packaged in an MSE package with an exposed pad. The thermal resistance junction to case, θJC,
of the MSE package is 10°C/W. The thermal resistance
junction to ambient, θJA, is determined by the amount of
copper on the PCB that is soldered to the exposed pad.
When following established layout guidelines the θJA can
be as low as 35°C/W for the MSE package.
As a simple example, if 2 watts is dissipated in the MSE
package, the die temperature would rise 70°C above the
ambient temperature. The following expression describes
the rise in temperature (θJA • PTOTAL), and the increase of
junction temperature over ambient temperature as
TJ = TA + θJA • PTOTAL
VOUT2
500µs/DIV
6658 F17
Figure 17. The Output Disable Function
Internal Protection
There are two internal protection circuits for monitoring
output current and die temperature.
where TJ is the junction temperature, TA is the ambient
temperature, θJA is the thermal resistance junction to ambient, and PTOTAL is the total power dissipated in the LT6658.
Further, if the package was initially at room temperature
(25°C), the die would increase to 95°C. At 3 watts the die
would exceed the specified H-grade temperature of 125°C.
The derating curve for the MSE package is shown in
Figure 18. Three different θJA curves are shown. θJA
is dependent on the amount of copper soldered to the
6658f
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19
LT6658
Applications Information
exposed pad. Multiple layers of copper with multiple vias
is recommended.
MAX. POWER DISSIPATION (W)
3
output, use a 5V supply and maximum output current on
each channel, the total power can be calculated as
P1 = (5V – 2.5V) • 0.15A = 0.375W
θJA = 35°C/W
θJA = 60°C/W
θJA = 85°C/W
P2 = (5V – 2.5V) • 0.05A = 0.125W
PSTATIC = 5V • 0.001A = 0.005W
2
PTOTAL = 0.375W + 0.125W + 0.005W = 0.505W
which is an operating condition that can be tolerated above
100°C when proper heat sinking is used.
1
0
0
25
50
75
100
TEMPERATURE (°C)
125
6658 F18
Figure 18. MSE Derating Curve
The power dissipated by the LT6658 can be calculated
as three components. There is the power dissipated in
the two output devices (one for each channel) and the
power dissipated within the remaining internal circuits.
Calculate the power in the remaining circuits using the
following expressions
PSTATIC = VIN • ISTATIC
where PSTATIC is the power dissipated in the LT6658 minus
the output devices, VIN is the supply voltage, and ISTATIC
is the current flowing through the LT6658. To calculate
the power dissipated by the output devices use
In Figure 19, the output current in both channels is increased
linearly for three values of VIN where all three supply pins
are connected together. As VIN and IOUT increases, the
total power increases proportionally. When the supply
voltage is 30V and the total output current is 200mA, the
power exceeds 5W, representing a junction temperature
increase of over 175°C using a best case scenario when
using a MSE with a θJA = 35°C/W. Figure 20, illustrates
how rapidly power increases when the supply voltage
increases, especially with 200mA of total load current. If
possible, reduce the voltage on VIN1 and VIN2, which in turn
will reduce the power dissipated in the LT6658 package.
The LT6658 is a high performance reference and extreme
thermal cycling will cause thermal hysteresis and should
be avoided if possible. See the Thermal Hysteresis section.
6
5
P2 = (VIN2 – VOUT2) • IOUT2
where P1 and P2 are the power dissipated in the Channel 1 and Channel 2 output devices, VIN1 and VIN2 are the
supply voltages for each channel, and VOUT1 and VOUT2
are the output voltages. Finally,
POWER (W)
P1 = (VIN1 – VOUT1) • IOUT1
4
3
2
1
0
PTOTAL = P1 + P2 + PSTATIC
where PTOTAL is the total power dissipated in the package.
PSTATIC tends to be much smaller than P1 or P2.
To lower the power in the output devices, the supply voltage for each of the output buffers can be reduced to only
2.5V above the output voltage. For example, with a 2.5V
VIN = 5V
VIN = 15V
VIN = 30V
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2
OUTPUT CURRENT (A)
6658 F19
Figure 19. Power Dissipation vs Output Current
When the supply voltage, VIN1 or VIN2, is greater than
30V, a hard short from either output to ground can result
in more than 3 to 6 watts of instantaneous power which
can damage the output devices.
6658f
20
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LT6658
Applications Information
7
There are three regions in the SOA plot. The top left region
is the maximum rated current of the LT6658. The diagonal
lines in the middle are where both the load current and
supply voltage must be reduced as not to exceed TJMAX.
The bottom right is the maximum voltage of the LT6658.
200mA
NO LOAD
6
POWER (W)
5
4
It is important to realize the SOA limit is an absolute maximum rating at TJMAX. It is not recommended to operate
at this limit for extended periods of time.
3
2
1
0
0
5
10 15 20 25 30
SUPPLY VOLTAGE (V)
35
40
6658 F20
Figure 20. Power Dissipation vs Supply Voltage
Safe Operating Area
The safe operating area, or SOA, describes the operating
region where the junction temperature does not exceed
TJMAX. In Figure 21, the SOA for the LT6658 is plotted. In
this plot, the output voltage is 2.5V and the output current
is the combined current of both channels. The SOA is plotted for three values of θJA. This illustrates how a lower θJA
value will remove more heat and allow more power to be
dissipated through the package without damaging the part.
LOAD CURRENT (mA)
1000
100
10
1
TA = 25°C
θJA = 35°C/W
θJA = 60°C/W
θJA = 85°C/W
1
10
100
SUPPLY VOLTAGE – LOAD VOLTAGE (V)
6658 F21
Figure 21. SOA for the LT6658
PCB Layout
The LT6658 is a high performance reference and therefore, requires good layout practices. Each supply pin
should have 0.1µF capacitor placed close to the package.
The output capacitors should also be close to the part to
keep the equivalent series resistance to a minimum. As
mentioned earlier, avoid parasitic resistance between the
sense line and the load. Any error here will directly affect
the output voltage.
All three ground pins (1, 2, 6) , and exposed pad should
be connected together, preferably in a star ground configuration or ground plane. The exposed pad, Pin 17, is
electrically connected to the die and must be connected to
ground. It is also necessary for good thermal conductivity
to use plenty of copper and multiple vias.
If the design requires the part to dissipate significant
power, consider using 2oz copper and/or a multilayer
board with a large area of copper connected to the exposed
pad. Note that θJA is proportional to the amount of copper
soldered to the exposed pad. Preferably the copper should
be on the outermost layers of the board for good thermal
dissipation. A sample layout is shown in Figure 22a. The
sense lines, VOUT1_S and VOUT2_S should connect as close
as possible to the top of the load. In Figure 22b, a star
ground is shown where the LT6658 ground is directly
connected to the bottom of the load. Connect all other
grounds in the system to this same point. Minimize the
resistance between GND side of the load and the LT6658
GND pins, especially for applications where the LT6658
is sinking current. This minimizes load regulation errors.
6658f
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21
LT6658
Applications Information
LONG TERM DRIFT (ppm)
200
150
100
50
0
–50
0
500
1000 1500 2000
TIME (HOURS)
2500
3000
6658 F23
Figure 23. LT6658 Long Term Drift
(a) LT6658 Sample PCB Layout
IR Reflow Shift
10, 11, 14
LT6658-2.5
VIN, VIN1, VIN2
+
–
5V
TO
36V
VOUT2_F 12
VOUT2_S 13
RLOAD
GND
1, 2, 6, 17
STAR-GROUND
(b) Bring Out Ground to the Load and Make a Star Connection
6658 F22
Figure 22.
As with many precision devices, the LT6658 will experience an output shift when soldered to a PCB. This shift
is caused by uneven contraction and expansion of the
plastic mold compound against the die and the copper
pad underneath the die. Critical devices in the circuit will
experience a change of physical force or pressure, which
in turn changes its electrical characteristics, resulting in
subtle changes in circuit behavior. Lead free solder reflow
profiles reach over 250°C, which is considerably higher
than lead based solder. A typical lead free IR reflow profile
is shown in Figure 24. The experimental results simulating
this shift are shown in Figure 25. In this experiment, LT6658
is run through an IR reflow oven once and three times.
Long Term Drift
Long term drift is a settling of the output voltage while the
part is powered up. The output slowly drifts at levels of parts
per million (ppm). The first 1000 hours of being powered
up sees the most shift. By the end of 3000 hours, most
parts have settled and will not shift appreciably. The plot in
Figure 23 is representative of the LT6658 long term drift.
TEMPERATURE (°C)
300
380s
TP = 260°C
TL = 217°C
TS(MAX) = 200°C
TS = 190°C
225
RAMP
DOWN
tP
30s
T = 150°C
150
tL
130s
RAMP TO
150°C
75
40s
120s
0
0
2
4
6
MINUTES
10
8
6658 F24
Figure 24. Lead Free Reflow Profile
6658f
22
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LT6658
Applications Information
14
MSE–16
10
MAX AVG HOT CYCLE
12 25°C TO 125°C TO 25°C
NUMBER OF UNITS
NUMBER OF UNITS
12
14
1 CYCLE
3 CYCLES
8
6
4
2
10
MAX AVG COLD CYCLE
25°C TO –40°C TO 25°C
8
6
4
2
0
–300 –250 –200 –150 –100 –50
0
CHANGE IN OUTPUT VOLTAGE (ppm)
0
–100 –75 –50 –25 0
25 50 75
CHANGE IN OUTPUT VOLTAGE (ppm)
50
6658 F25
100
6658 F26a
Figure 25. ∆VOUT1 Due to IR Reflow Shift
(a) H-Grade
Thermal Hysteresis
24
18
NUMBER OF UNITS
Thermal hysteresis is caused by the same effect as IR
reflow shift. However, in the case of thermal hysteresis,
the temperature is cycled between its specified operating
extremes to simulate how the part will behave as it experiences extreme temperature excursions and then returns
to room temperature. For example, an H-grade part is
repeatedly cycled between 125°C and –40°C. Each time
the temperature passes through 25°C, the output voltage
is recorded. The plots in Figure 26 illustrate the change in
output voltage from the initial output voltage after a cold
and hot excursion.
22 MAX AVG HOT CYCLE
25°C TO 85°C TO 25°C
20
16
14
MAX AVG COLD CYCLE
25°C TO –40°C TO 25°C
12
10
8
6
4
2
0
–100 –75 –50 –25 0
25 50 75
CHANGE IN OUTPUT VOLTAGE (ppm)
100
6658 F26b
(b) I-Grade
Figure 26. Thermal Hysteresis
6658f
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23
LT6658
Typical Applications
200mA Reference
11
10
14
5.15V < VIN < 36V
9
VIN1
VOUT2_F
VIN2
VOUT2_S
8
7
VIN
OD
LT6658-2.5
0.1µF
1µF
13
VOUT1_S
BYPASS
RLOAD
12 0.01Ω
VOUT1_F
3
0.03Ω
2µF
GND
1, 2, 6, 17
6658 TA02
Single Supply Precision Data Acquisition Circuit
11
10
14
6.6V
9
0.1µF
12
13.7k
13
4.096V
1k
OD
VOUT1_F
1k
V+
8
4
+
LTC6362
1k
VCM
3
1
VOUT1_S
5
V–
1k
0.41V
IN+
35.7Ω
6
7
1µF
REF
VDD
10µF
LTC2378-20
IN
35.7Ω
3.69V
BYPASS
GND
1, 2, 6, 17
8
2.5V
6800pF
3300pF
–
2
3.69V
VOUT2_F
VOUT2_S
47µF
1k
1k
3.28V
0V
–3.28V
VIN LT6658-2.5
21.5k
VCM
10µF
VIN1
VIN2
6800pF
–
REF/DGC
6658 TA03
0.41V
6658f
24
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LT6658
Typical Applications
LT6658 Driving the LTC2323-16 Dual ADC with Independent Voltage References
5V TO 36V
REFINT
14
V
11 IN
VIN1
12
VOUT1_F
13
VOUT1_S
0.1µF
2.5V
REFOUT1
LTC2323-16
10µF
REFRTN1
1µF
LT6658-2.5
REFRTN2
7.5V TO 36V
10µF
10
8
VOUT2_F
VOUT2_S 7
VIN2
0.1µF
BYPASS
1µF
GND
1, 2, 6, 17
5V
10k
REFOUT2
GND
6658 TA04
1µF
10k
LT6658 Driving Two Code Dependent DAC Reference Inputs. Separate DAC
Reference Biasing Eliminates Code Dependent Reference Current Interaction
14
11
10
5V < VIN < 36V
0.1µF
12
13
VIN
VIN1
LT6658-2.5
VIN2
VOUT1_F
VOUT2_F
VOUT1_S
VOUT2_S
8
7
BYPASS
1µF
VREF
5V
0.1µF
RPAR*
GND
1, 2, 6, 17
4.7µF
7
REF
VDD
VDD
LTC2641-16
CS
3
SCLK
4
DIN
5
CLR
0.1µF
1
7
2
VREF
5V
2.5V
RPAR*
2.5V
4.7µF
1
REF
LTC2641-16
16-BIT DAC
VOUT 6
GND
2
CS
3
SCLK
4
DIN
5
CLR
8
VOUT 6
16-BIT DAC
GND
8
6658 TA05
*RPAR IS THE PARASITIC RESISTANCE OF THE BOARD TRACE AND SHOULD BE > 0.048Ω TO MAINTAIN GOOD INL
6658f
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25
LT6658
Typical Applications
Common Errors for Non-Unity Gain Applications
Load Voltage Error Due to Parasitic Resistance
LOAD VOLTAGE ERROR (mV)
100
7.5V TO 36V
14 V
IN
10 V
11 V
IN2
IN1
LT6658-2.5
+
–
1µF
BANDGAP
0.1µF
3
VOUT1_S
BYPASS
THERMAL
SHUTDOWN
1µF
2
GND
VOUT1_F
1
GND
+
–
VOUT2_F
VOUT2_S
17
GND
6
GND
10
1
0.1
-10
12
R1
10k
13
R2 ILOAD
10k
8
0.1Ω
0.05Ω
0.01Ω
10
30 50 70 90 110 130 150
LOAD CURRENT (mA)
VERROR = ILOAD • RPAR
RPAR
VIDEAL = 5V
7
1µF
1µF
RLOAD
6658 TA06
KELVIN SENSE ERROR: RPAR WILL CAUSE AN ERROR VERROR = ILOAD • RPAR.
CONNECT THE TOP OF R1 DIRECTLY TO THE TOP OF RLOAD.
RESISTOR TOLERANCE ERROR: GAIN NETWORK ERROR CAN BE REDUCED BY
USING A MATCHED RESISTOR NETWORK SUCH AS THE LT5400.
R1 AND R2 TOLERANCE
(%)
RPAR
(Ω)
ILOAD
(mA)
± ERROR
(mV)
1
0.05
0
35.4
1
0.05
150
42.9
0.1
0.05
0
3.5
0.1
0.05
150
11.0
0.1
0.02
150
6.5
0.1
0.01
150
5.0
R1 AND R2 TOLERANCE ERRORS ADDED ROOT-SUM-SQUARE
6658f
26
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LT6658
Typical Applications
Automotive Reference and Supply Voltage Application
14
11
10
12V BATTERY
9
VIN
VOUT2_F
VIN1
VOUT2_S
1µF
LT6658-2.5
0.1µF
VOUT1_F
1µF
3
7
VIN2
OD
2.5V 50mA
REFERENCE
VOLTAGE
8
VOUT1_S
BYPASS
1µF
GND
1, 2, 6, 17
12
13
10k
5V 150mA
SUPPLY
VOLTAGE
1µF
10k
6658 TA07
LT6658 Biasing Multiple Strain Gauges
10µF
0.1µF
1µF
1µF
VCC
7.5V
TO 36V
11
10
14
10µF
VIN1
VOUT2_F
VIN2
VOUT2_S
8
2.5V
1µF
7
VREF+
VIN+
VREF–
VIN–
335Ω
LTC2440
1µF
335Ω
GND
VIN
VCC
335Ω
LTC2440
VREF+
VIN+
VREF–
VIN–
335Ω
335Ω
GND
335Ω
LT6658-2.5
9
3
1µF
OD
VOUT1_F
BYPASS
VOUT1_S
5V
12
13
GND
GND (PAD)
1, 2, 6
17
10k
10µF
10k
1µF
0.1µF
1µF
VCC
1µF
+
VIN+
–
VIN–
VREF
VREF
LTC2440 AND STRAIN GAUGE BIAS
GND
VCC
335Ω
LTC2440
1µF
335Ω
335Ω
335Ω
LTC2440
+
VREF
VIN+
VREF–
VIN–
GND
335Ω
335Ω
6658 TA08
6658f
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27
LT6658
Typical Applications
Recursive Reference Application (VOUT1 Supplies Power to VIN and VIN2)
7.5V TO 36V
1.5k
1W
140
1N4148
1N4148
14
10µF
11
VIN
LT6658-2.5
10
VIN1
VIN2
VOUT2_F
400Ω
BANDGAP
1µF
VOUT2_S
VOUT1_F
VOUT1_S
VOUT2
2.5V
8
7
POWER SUPPLY REJECTION RATIO (dB)
4.7V
1N5230
Recursive Reference
Power Supply Rejection Ratio
10µF
10k
100
80
60
40
20
0
0.001
VOUT1
5V
12
120
0.01
0.1
1
FREQUENCY (kHz)
10
100
6658 TA09b
1µF
13
10k
3
BYPASS
5
1µF
NR
GND
1, 2, 6, 17
1µF
6658 TA09a
Low Drift Regulator Application
5V TO 13.2V
11
VIN
LT6658-2.5
VIN1
10
Precision Low Drift Application
Drift = 1.5ppm/°C; –40°C to 125°C
VIN2
8
400Ω
BANDGAP
7
1µF
12
13
LTC6655-2.5
IN
SHDN
BYPASS
3
5
NR
VOUT2_S
VOUT1_F
VOUT1_S
1µF
VOUT1
2.5V
1µF
OUTS
1µF
2.502
VOUT2
2.5V
GND
1,2,6,17
OUTF
GND
VOUT2_F
OUTPUT VOLTAGE (V)
14
2.501
2.500
2.499
2.498
–40 –20
1µF
NR
VOUT1
VOUT2
0
20 40 60 80 100 120 140
TEMPERATURE (°C)
6658 TA10b
6658 TA10a
6658f
28
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LT6658
Package Description
Please refer to http://www.linear.com/product/LT6658#packaging for the most recent package drawings.
MSE Package
16-Lead Plastic MSOP, Exposed Die Pad
(Reference LTC DWG # 05-08-1667 Rev F)
BOTTOM VIEW OF
EXPOSED PAD OPTION
2.845 ±0.102
(.112 ±.004)
5.10
(.201)
MIN
2.845 ±0.102
(.112 ±.004)
0.889 ±0.127
(.035 ±.005)
8
1
1.651 ±0.102
(.065 ±.004)
1.651 ±0.102 3.20 – 3.45
(.065 ±.004) (.126 – .136)
0.305 ±0.038
(.0120 ±.0015)
TYP
16
0.50
(.0197)
BSC
4.039 ±0.102
(.159 ±.004)
(NOTE 3)
RECOMMENDED SOLDER PAD LAYOUT
0.254
(.010)
0.35
REF
0.12 REF
DETAIL “B”
CORNER TAIL IS PART OF
DETAIL “B” THE LEADFRAME FEATURE.
FOR REFERENCE ONLY
9
NO MEASUREMENT PURPOSE
0.280 ±0.076
(.011 ±.003)
REF
16151413121110 9
DETAIL “A”
0° – 6° TYP
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
4.90 ±0.152
(.193 ±.006)
GAUGE PLANE
0.53 ±0.152
(.021 ±.006)
DETAIL “A”
1.10
(.043)
MAX
0.18
(.007)
SEATING
PLANE
0.17 – 0.27
(.007 – .011)
TYP
1234567 8
0.50
NOTE:
(.0197)
1. DIMENSIONS IN MILLIMETER/(INCH)
BSC
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
6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD SHALL
NOT EXCEED 0.254mm (.010") PER SIDE.
0.86
(.034)
REF
0.1016 ±0.0508
(.004 ±.002)
MSOP (MSE16) 0213 REV F
6658f
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.
For more
information
www.linear.com/LT6658
29
LT6658
Typical Application
7.5V TO 36V
14
11
VIN
VIN1
10
VIN2
LT6658-2.5
8
1µF
400Ω
BANDGAP
7
12
VOUT2_F
4.096V
13.7k
VOUT2_S
VOUT1_F
5V
10k
13
BYPASS
3
5
1µF
10µF
1µF
464Ω
10k
GND
1,2,6,17
1µF
TO OTHER
ANALOG CIRCUITS
1k
10µF
NR
VOUT1_S
21k
47µF
(X7R, 1210 SIZE)
2.5V
1k
1k
3.28V
0V
–3.28V
1k
35.7Ω
– +
1k
VOCM
+
1k
–
S
35.7Ω
LTC6362
6800pF
IN+
3300pF
VDD
LTC2379-18
IN–
6800pF
REF
REF/DGC
GND
LT5400-4
6658 TA11
Related Parts
PART NUMBER
DESCRIPTION
COMMENTS
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LT1461
Precision Low Dropout Series References
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LT6654
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LTC6655
Precision Low Noise Series References
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(0.1Hz to 10Hz), –40°C to 125°C
LT6660
Tiny Micropower Series References
20mA Output Drive, 0.2% Accuracy, 20ppm/°C Drift, 2mm × 2mm DFN Package
LT1761
Low Noise Low Dropout Linear Regulator
100mA Output Drive, 300mV Dropout, VIN = 1.8V to 20V, 20µVRMS Noise
(10Hz to 100kHz), ThinSOT™ package
LT3042
Ultralow Noise, Ultrahigh PSRR Linear Regulator
200mA Output Drive, 350mV Dropout, VIN = 1.8V to 20V 0.8µVRMS Noise (10Hz
to 100kHz), 79dB PSRR (1MHz)
LT3050
Low Noise Linear Regulator with Current Limit and
Diagnostic Functions
100mA Output Drive, 300mV Dropout, VIN = 2V to 45V, 30μVRMS Noise
(10Hz to 100kHz), 50μA Supply Current, Adj. Output
LT3060
Micropower, Low Noise, Low Dropout Linear
Regulator
100mA Output Drive, 300mV Dropout, VIN =1.7V to 45V, 30μVRMS Noise
(10Hz to 100kHz), 40μA Supply Current, Adj. Output
LT3063
Micropower, Low Noise, Low Dropout Linear
Regulator with Output Discharge
200mA Output Drive, 300mV Dropout, VIN =1.6V to 45V, 30μVRMS Noise
(10Hz to 100kHz), 40μA Supply Current
6658f
30 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LT6658
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LT6658
LT 0816 • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2016