LTC1696
1
1696fb
For more information www.linear.com/LTC1696
TYPICAL APPLICATION
FEATURES DESCRIPTION
Overvoltage Protection
Controller
The LT C
®
1696 is a standalone power supply overvolt-
age monitor and protection device designed to protect a
power supply load in the event of an overvoltage fault. It
monitors two adjustable output voltages. If an overvoltage
condition is detected, the output drives either an external
SCR crowbar or turns off external back-to-back N-channel
MOSFETs, thereby, disconnecting the input voltage from
the power supply.
Pin 6 offers three functions. By connecting a capacitor
to this pin, the internal glitch filter time delay can be
programmed. Without the capacitor, the default time
delay is determined by an internal capacitor. This pin also
serves as a reset input to clear the internal latch after an
overvoltage fault condition. By pulling it high, the OUT
pin is activated if the FB1 and FB2 voltages remain below
the trip threshold.
The LTC1696 is available in the low profile (1mm)
ThinSOT package.
APPLICATIONS
n ±2% Overvoltage Threshold Accuracy
n Low Profile (1mm) ThinSOT
™
Package
n Gate Drive for SCR Crowbar or External N-Channel
Disconnect MOSFET
n Monitors Two Output Voltages
n Senses Output Voltages from 0.8V to 24V
n Wide Supply Range: 2.7V to 27V
n Multifunction TIMER/RESET Pin
n Telecommunication Systems
n Computer Systems
n Industrial Control Systems
n Notebook Computers
L, LT , LT C , LT M , Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation.All other
trademarks are the property of their respective owners. .
SCR Crowbar
C1
1nF
6
V
OUT2
5V
V
OUT1
3.3V
5
4
1696 TA01
1
2
3
SCR
2N6507
LTC1696
RESET
Q1
2N7002
FB1
GND
V
CC
FB2
OUT
TIMER/
RESET
R1
44.2k
1%
V
CC
12V
R2
137k
1%
R3
44.2k
1%
R4
232k
1%
C2
0.1µF
POWER
SUPPLY
FB1
0.5V/DIV
TIMER/RESET
2V/DIV
IOUT
20mA/DIV
100µs/DIV 1696 TA02
Overvoltage Response
C1 = 1nF
LTC1696
2
1696fb
For more information www.linear.com/LTC1696
PIN CONFIGURATIONABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC) ................................................28V
Input Voltage
FB1, FB2 ............................................... – 0.3V to 17V
TIMER/RESET ........................................ –0.3V to 17V
Operating Junction Temperature Range (Note 2)
LTC1696E ........................................... –40°C to 125°C
LTC1696I............................................ –40°C to 125°C
LTC1696H .......................................... –40°C to 150°C
Storage Temperature Range ................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
(Note 1)
ORDER INFORMATION
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VCC Supply Voltage Range Operating Range ●2.7 27 V
IVCC Standby Supply Current FB1, FB2 < VFB ●170 540 µA
Active Supply Current FB1, FB2 > VFB, COUT = 1000pF ●1.1 3.5 mA
VFB FB1, FB2 Feedback Threshold Voltage Going Positive TA ≥ 0°C and TA ≤ 85°C
TA ≥ 0°C and TA ≤ 125°C
TA ≥ 0°C and TA ≤ 150°C
TA < 0°C
●
●
●
●
0.862
0.858
0.853
0.853
0.880
0.880
0.880
0.880
0.898
0.898
0.898
0.907
V
V
V
V
IFB FB1, FB2 Input Current ●–1 –0.05 µA
VFBHST FB1, FB2 Feedback Hysteresis High-to-Low Transition 12 mV
VLKO VCC Undervoltage Lockout
Low-to-High Transition
High-to-Low Transition
FB1, FB2 > VFB
●
●
1.75
1.64
2.05
1.94
2.35
2.24
V
V
VLKH VCC Undervoltage Lockout Hysteresis FB1, FB2 > VFB 110 mV
VRST TIMER/RESET Reset Low Threshold FB1, FB2 > VFB ●0.78 0.865 0.95 V
VTIM TIMER/RESET Timer High Threshold FB1, FB2 > VFB, TA ≤ 85°C
TA ≤ 125°C
TA ≤ 150°C
●
●
●
1.11
1.08
1.07
1.185
1.185
1.185
1.26
1.26
1.26
V
V
V
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at TA = 25°C. 2.7V ≤ VCC ≤ 27V (Notes 2, 3, 4) unless otherwise noted.
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC1696ES6#PBF LTC1696ES6#TRPBF LT LT 6-Lead Plastic TSOT-23 –40°C to 125°C
LTC1696IS6#PBF LTC1696IS6#TRPBF LT LT 6-Lead Plastic TSOT-23 –40°C to 125°C
LTC1696HS6#PBF LTC1696HS6#TRPBF LT LT 6-Lead Plastic TSOT-23 –40°C to 150°C
Consult LT C Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LT C Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
FB1 1
GND 2
VCC 3
6
5 FB2
4 OUT
TOP VIEW
TIMER/
RESET
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
TJMAX = 150°C, θJA = 192°C/W
LTC1696
3
1696fb
For more information www.linear.com/LTC1696
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VTRIG TIMER/RESET External Trigger High
Threshold
FB1, FB2 < VFB ●1.35 1.50 1.65 V
ITRIG TIMER/RESET External Trigger High
Current
FB1, FB2 < VFB, TIMER/RESET = VTRIG ●260 650 µA
ITIM TIMER/RESET Timer Current FB1 = (VFB + 30mV), FB2 < VFB
FB1 = (VFB + 200mV), FB2 < VFB
FB2 = (VFB + 30mV), FB1 < VFB
FB2 = (VFB + 200mV), FB1 < VFB
FB1, FB2 = (VFB + 200mV)
●
●
●
●
●
4
5
4
5
8
10
12
10
12
18
22
26
22
26
40
µA
µA
µA
µA
µA
VOUTH OUT High Voltage 12V ≤ VCC ≤ 27V, FB1, FB2 > VFB, COUT = 1000pF
VCC = 3.3V, FB1, FB2 > VFB, COUT = 1000pF
●
●
4.8
2.7
6.3
3.2
8.0
3.3
V
V
VOUTL OUT Low Voltage FB1, FB2 < VFB, ISINK = 1mA, VCC = 3.3V ●0.45 V
tOVPD1 OUT Propagation Delay for FB1 FB1 > VFB, FB2 < VFB, TIMER/RESET = Open,
COUT = 1000pF
●7 28 µs
tOVPD2 OUT Propagation Delay for FB2 FB2 > VFB, FB1 < VFB, TIMER/RESET = Open,
COUT = 1000pF
●7 28 µs
tOVPD1,2 OUT Propagation Delay for FB1, FB2 FB1, FB2 > VFB, TIMER/RESET = Open
COUT = 1000pF
●6 24 µs
trOUT Rise Time FB1, FB2 > VFB, COUT = 1000pF ●0.4 3 µs
IOUTSC OUT Short-Circuit Current 12V ≤ VCC ≤ 27V, FB1, FB2 > VFB,
VOUT Shorted to GND
●35 80 160 mA
VCC = 2.7V, FB1, FB2 > VFB, VOUT Shorted to GND ●2 9 18 mA
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at TA = 25°C. 2.7V ≤ VCC ≤27V (Notes 2, 3, 4) unless otherwise noted.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: The 1696E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the -40°C to 125°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LTC1696I is guaranteed
from -40°C to 125°C, and the LTC1696H is guaranteed over the -40°C to
150°C operating junction temperature range. High junction temperatures
degrade operating lifetime; operating lifetime is derated for temperatures
greater than 125°C. The maximum ambient temperature consistent with
these specifications is determined by specific operating conditions in
conjunction with board layout, the package thermal impedance and other
environmental factors. TJ is calculated from the ambient temperature, TA ,
and power dissipation, PD , according to the following formula:
LTC1696S6: TJ = TA + (PD • 192°C/W)
Note 3: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to device ground unless
otherwise specified.
Note 4: All typical numbers are given for VCC = 12V and TA = 25°C.
LTC1696
4
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For more information www.linear.com/LTC1696
TYPICAL PERFORMANCE CHARACTERISTICS
Standby Supply Current
vs Supply Voltage
SUPPLY VOLTAGE (V)
0
0
SUPPLY CURRENT (µA)
40
80
120
510 15 20
1696 G01
25
160
200
20
60
100
140
180
30
TA = 25°C
TEMPERATURE (°C)
–50
SUPPLY CURRENT (µA)
160
170
180
190
150
1696 G02
150
140
120 050 100
–25 25 75 125
130
210
200
VCC = 12V
SUPPLY VOLTAGE (V)
0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
015 25
1696 G03
5 10 20 30
SUPPLY CURRENT (mA)
TA = 25°C
COUT = 1000pF
Standby Supply Current
vs Temperature
Active Supply Current
vs Supply Voltage
Active Supply Current
vs Temperature
FB1, FB2 Feedback Threshold
Voltage vs Supply Voltage
TEMPERATURE (°C)
–50
SUPPLY CURRENT (mA)
1
1.05
1.1
1.15
150
1696 G04
0.95 050 100
–25 25 75 125
1.25
1.2
VCC = 12V
COUT = 1000pF
SUPPLY VOLTAGE (V)
FB1, FB2 FEEDBACK THRESHOLD VOLTAGE (V)
0.8814
0.8811
0.8808
0.8805
0.8802
0.8799
0.8796
6 12 18 24
1696 G05
3030 9 15 21 27
TA = 25°C
FB1, FB2 Feedback Threshold
Voltage vs Temperature
TEMPERATURE (°C)
–50
FB1/FB2 FEEDBACK THRESHOLD VOLTAGE (V)
0.86
0.87
0.88
150
1696 G06
0.85 050 100
–25 25 75 125
0.9
0.89
VCC = 12V
TIMER Threshold Voltage
vs Supply Voltage TIMER Current vs Supply Voltage
SUPPLY VOLTAGE (V)
0
TIMER THRESHOLD VOLTAGE (V)
1.175
1.180
1.185
15 25
1696 G07
1.170
1.165
1.160 5 10 20
1.190
1.195
1.200
30
TA = 25°C
TIMER Threshold Voltage
vs Temperature
TEMPERATURE (°C)
–50
TIMER THRESHOLD VOLTAGE (V)
1.16
1.18
1.2
150
1696 G08
1.14 050 100
–25 25 75 125
1.24
1.22
VCC = 12V
SUPPLY VOLTAGE (V)
0
8
TIMER CURRENT (µA)
10
12
14
16
20
510 15 20
1696 G09
25 30
18
TA = 25°C
FB1 AND FB2 OVERDRIVE = 200mV
FB1 OR FB2 OVERDRIVE = 200mV
LTC1696
5
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For more information www.linear.com/LTC1696
TYPICAL PERFORMANCE CHARACTERISTICS
TIMER Current vs Temperature
TIMER Current
vs Feedback Overdrive
Glitch Filter Timer
vs Feedback Overdrive
Glitch Filter Timer
vs Feedback Overdrive
External Trigger Threshold
Voltage vs Supply Voltage
External Trigger Threshold
Voltage vs Temperature
RESET Threshold Voltage
vs Supply Voltage
TEMPERATURE (°C)
–50
12
14
16
18
150
1696 G10
10
8050 100
–25 25 75 125
22
20
VCC = 12V
TIMER CURRENT (µA)
FB1 + FB2 OVERDRIVE 200mV
FB1 OR FB2 OVERDRIVE 200mV
FEEDBACK OVERDRIVE (mV)
0
TIMER CURRENT (µA)
12
16
20
200
1696 G11
8
4
050 100 150 250
VCC = 12V
TA = 25°C
FB1 AND FB2 OVERDRIVE
FB1 OR FB2 OVERDRIVE
FEEDBACK OVERDRIVE (mV)
0
4
TIMER CURRENT (µA)
6
8
10
12
14
16
50 100 150 200
1696 G12
250
VCC = 3.3V
TA = 25°C FB1 AND FB2 OVERDRIVE
FB1 OR FB2 OVERDRIVE
FEEDBACK OVERDRIVE (mV)
0
GLITCH FILTER TIMER (µs)
15
20
25
200
1696 G13
10
5
050 100 150 250
VCC = 3.3V
TA = 25°C
FB1 AND FB2 OVERDRIVE
FB1 OR FB2 OVERDRIVE
FEEDBACK OVERDRIVE (mV)
0
0
GLITCH FILTER TIMER (µs)
5
10
15
20
25
30
50 100 150 200
1696 G14
250
VCC = 12V
TA = 25°C
FB1 AND FB2 OVERDRIVE
FB1 OR FB2 OVERDRIVE
SUPPLY VOLTAGE (V)
0
1.51
1.50
1.49
1.48
1.47
1.46
1.45
1.44 15 25
1696 G15
5 10 20 30
EXTERNAL TRIGGER TRESHOLD VOLTAGE (V)
TA = 25°C
TEMPERATURE (°C)
–50
EXTERNAL TRIGGER THRESHOLD VOLTAGE (V)
1.48
1.485
1.49
1.495
150
1696 G16
1.475 050 100
–25 25 75 125
1.505
1.5
VCC = 12V
SUPPLY VOLTAGE (V)
0
RESET THRESHOLD VOLTAGE (V)
0.858
0.860
0.862
15 25
1696 G17
0.856
0.854
0.852 5 10 20
0.864
0.866
0.868
30
TA = 25°C
RESET Threshold Voltage
vs Temperature
TEMPERATURE (°C)
–50
RESET THRESHOLD (V)
0.855
0.86
0.865
0.87
150
1696 G18
0.85
0.845
0.84 050 100
–25 25 75 125
0.88
0.875
VCC = 12V
TIMER Current
vs Feedback Overdrive
LTC1696
6
1696fb
For more information www.linear.com/LTC1696
TYPICAL PERFORMANCE CHARACTERISTICS
OUT Pin Active Output Voltage
vs Supply Voltage
SUPPLY VOLTAGE (V)
0
OUT PIN ACTIVE OUTPUT VOLTAGE (V)
3
4
5
15 25
1696 G19
2
1
05 10 20
6
7
8
30
TA = 25°C
COUT = 1000pF
OUT Pin Active Output Voltage
vs Temperature
TEMPERATURE (°C)
–50
OUT PIN ACTIVE OUTPUT VOLTAGE (V)
6.1
6.2
6.3
6.4
150
1696 G20
6
5.9
5.7 050 100
–25 25 75 125
5.8
6.6
6.5
VCC = 12V
COUT = 1000pF
OUT Pin Short-Circuit Current
vs Supply Voltage
SUPPLY VOLTAGE (V)
0
0
OUT PIN SHORT-CIRCUIT CURRENT (mA)
20
40
60
510 15 20
1696 G21
25
80
100
10
30
50
70
90
30
TA = 25°C
VOUT SHORTED TO GND
OUT Pin Short-Circuit Current
vs Temperature
OUT Pin Active Output Current
vs Output Voltage
TEMPERATURE (°C)
–50
20
40
60
80
150
1696 G10
8050 100
–25 25 75 125
120
100
VOUT SHORTED TO GND
VCC = 27V
VCC = 12V
VCC = 5V
VCC = 2.7V
OUT PIN SHORT-CIRCUIT CURRENT (mA)
OUTPUT VOLTAGE (V)
0
ACTIVE OUTPUT CURRENT (mA)
10
20
30
5
15
25
1 2 3 4
1696 G23
50.50 1.5 2.5 3.5 4.5
TA = 25°C
VCC = 5V
VCC = 2.7V
OUT Pin Active Output Current
vs Output Voltage
OUTPUT VOLTAGE (V)
0
0
ACTIVE OUTPUT CURRENT (mA)
10
30
40
50
100
70
245
1696 G24
20
80
90
60
1367
TA = 25°C
VCC = 27V
VCC = 12V
LTC1696
7
1696fb
For more information www.linear.com/LTC1696
PIN FUNCTIONS
FB1 (Pin 1): First Feedback Input. FB1 monitors and senses
the first supply output voltage through an external resistor
divider. This voltage is then compared with an internal
reference voltage of 0.88V, which sets the threshold for
an overvoltage fault detection. If the sense voltage exceeds
the threshold level, the output response time at the OUT
pin is dependent on the feedback overdrive above the
threshold level. The higher the feedback overdrive, the
faster will be the response time.
GND (Pin 2): Power Ground. Return path for all device
currents.
VCC (Pin 3): Power Supply. The pin is connected separately
from the power supply output that the chip is monitoring.
Its input range is from 2.7V to 27V. The quiescent current
is typically 100µA in standby mode when the device is
operating at 5V. The quiescent current increases to 170µA
when operating at 12V.
OUT (Pin 4): Output Current Limit Driver. Capable of deliv-
ering continuous current, typically 80mA, at high supplies.
The output current decreases with lower supply voltage.
This pin directly drives the SCR crowbar at high supply
voltage. It can also provide gate drive for an N-channel
MOSFET or the base of an NPN transistor, which drives
the gate of an external SCR at low supply voltage. It is
normally in the inactive low state in the standby mode. In
the event of an overvoltage fault condition, the OUT pin is
latched into the active high state. The latched active high
state is reset by pulling the TIMER/RESET pin low through
an N-channel MOSFET switch or if the supply voltage at
the VCC pin goes below the undervoltage lockout threshold
voltage of 1.94V.
FB2 (Pin 5): Second Feedback Input. FB2 monitors and
senses the second supply output voltage through an
external resistor divider. This voltage is then compared
with an internal reference voltage of 0.88V, which sets the
threshold for an overvoltage fault detection. If the sense
voltage exceeds the threshold level, the output response
time at the OUT pin is dependent on the feedback over-
drive above the threshold level. The higher the feedback
overdrive, the faster will be the response time.
TIMER/RESET (Pin 6): Glitch Filter Timer Capacitor,
Reset and External Trigger Input. The external capacitor
connected to this pin programs the internal glitch filter
time delay. The internal current source used to charge the
timer capacitor is typically 10µA with feedback overdrive
of less than 20mV above the feedback trip threshold from
one feedback input. The current source increases to 12µA
when the feedback overdrive increases to more than
100mV. It further increases to 18µA if larger overdrive
occurs from both feedback inputs. The default glitch filter
time delay without an external timer capacitor is fixed by
an internal capacitor of 5pF with the internal reference
voltage of 1.185V. The delay reduces with increases in
first and second feedback input overdrive. This pin also
serves as a reset input to clear the internal latch during
an overvoltage fault condition. If pulled low, it resets the
active high state of the internal latch. The reset signal to
this pin should be an open drain type. This pin can also be
driven high externally to activate the OUT pin active high
if the FB1 and FB2 voltages remain below the feedback
trip threshold.
LTC1696
9
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For more information www.linear.com/LTC1696
APPLICATIONS INFORMATION
Feedback Inputs
The LTC1696 has two feedback inputs that allow monitor-
ing of two output voltages. The trip point of the internal
comparator is set by an internal reference of 0.88V with
±2% accuracy. The output voltage, VS, is sensed through
an external resistor divider network (Figure 1). The resis-
tors R1 and R2 values are calculated with the typical trip
point of 0.88V.
R1
R1+R2
• VS=0.88
R2 =
(V
S
−0.88) •R1
0.88
As an example, let’s calculate values for R1 and R2 for a
3.3V supply in which an overvoltage indication is required
at +10% (3.63V). First, a value for R1 is chosen based on
the allowable resistor divider string current. This is de-
termined by power dissipation requirements and possible
sensitivity to noise coupling into the resistor divider. In
this exercise, assume the resistor divider current is 20µA.
R1 is calculated from:
R1=
V
FB
I
DIVIDER
=
0.88V
20µA =44k
The nearest 1% value for R1 is 44.2k. Now, calculating
for R2 yields:
R2 =
44.2k •(3.63v −0.88V)
0.88V
=138.1k
Choosing the nearest 1% value yields 137k.
VREF = 0.88V
FB1
R2
VS
R1
LTC1696
+
–
–
+
Figure 1
The chosen values for R1 and R2 yield an overvoltage
threshold of 3.608V (+ 9.3%). With worst-case tolerances
applied, the minimum overvoltage threshold is 3.481V
(+5.5%) and the maximum overvoltage threshold is
3.738V (+13.3%).
Reset Function
In the event of an overvoltage condition, the OUT pin of
the LTC1696 is latched into an active high state. The in-
ternal latch is reset by pulling the TIMER/RESET pin low
through an external N-channel MOSFET switch or pulling
VCC voltage below the UVLO trip point of 1.94V.
LTC1696
10
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For more information www.linear.com/LTC1696
APPLICATIONS INFORMATION
Glitch Filter Timer
The LTC1696 has a programmable glitch filter to prevent
the output from entering its active high latched condition
if transients occur on the FB1 or FB2 pins. The filter time
delay is programmed externally by an external capacitor
C1 connected to the TIMER/RESET pin.
The time delay is given by:
tD=
C1• V
INT
I
CHG
where VINT is the internal reference voltage of 1.185V and
ICHG is the internal current source charging the external
capacitor C1. The current source ICHG charging the external
timer capacitor is 10µA for small feedback transients and
increases to 12µA for large feedback transients (greater
than 100mV) from one feedback input. The charging
current increases to 18µA for large feedback transients
from both feedback inputs.
SCR Crowbar
The LTC1696 can deliver continuous output current typi-
cally 80mA at high supply voltage to trigger an external
SCR crowbar in the event of an overvoltage condition as
shown in the typical application on the front page of the
data sheet. The output current decreases when the supply
voltage reduces. It delivers 25mA at a supply voltage of
5V. At a low supply voltage of 3.3V, the output current
reduces to 10mA and an external NPN emitter follower
is needed to boost the current in order to drive the SCR
crowbar as shown in Figure 2. The power dissipation
due to the high output current at high supply voltage can
potentially exceed the thermal limit of the package. This is
avoided by resetting the device rapidly when the external
SCR crowbar has been triggered, so that the device is not
kept in the active high state for too long.
C1
1nF
6
VOUT2
2.5V
VOUT1
1.8 V
5
4
1696 F02
1
2
3
LTC1696
RESET
Q2
2N7002
FB1
GND
VCC
FB2
OUT
TIMER/
RESET
R1
44.2k
1%
VCC
3.3V
R2
54.9k
1%
Q1
2N3904
SCR
2N6507
R5
470Ω
5%
R6
22Ω
5%
R3
44.2k
1%
R4
93.1k
1%
C2
0.1µF
POWER
SUPPLY
Figure 2. External SCR with NPN Emitter Follower with Low Voltage Supplies
LTC1696
11
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For more information www.linear.com/LTC1696
Back-to-Back N-Channel MOSFET
A power management circuit that uses the LTC1696 to
control external back-to-back N-channel MOSFET at low
supply voltage is shown in Figure 3. In standby mode, the
drain of the external N-channel MOSFET, Q1, is pulled high
APPLICATIONS INFORMATION
by the power management controller when the LTC1696
OUT pin is in the low state. The LTC1696 drives the gate
of Q1 high during an overvoltage fault condition. This
pulls the drain of Q1 low and turns off the back-to-back
N-channel MOSFETs.
C1
1nF
6
5
4
1696 F03
1
2
3
LTC1696
RESET
1.8V
Q2
2N7002
FB1
GND
V
CC
FB2
OUT
TIMER/
RESET
R1
44.2k
1%
1.5V
V
CC
3.3V
R2
38.3k
1%
R3
44.2k
1%
Q1
2N7002
N-CHANNEL
×2
PRIMARY
INPUT
SUPPLY
R4
54.9k
1%
C2
0.1µF
POWER MANAGEMENT
CONTOLLER
Figure 3. Back-to-Back N-Channel MOSFETs for Low Supply Application
LTC1696
12
1696fb
For more information www.linear.com/LTC1696
PACKAGE DESCRIPTION
S6 Package
6-Lead Plastic SOT-23
(LTC DWG # 05-08-1634)
(LTC DWG # 05-08-1636)
1.50 – 1.75
(.059 – .069)
(NOTE 3)
2.60 – 3.00
(.102 – .118)
.25 – .50
(.010 – .020)
(6PLCS, NOTE 2)
L
DATUM ‘A’
.09 – .20
(.004 – .008)
(NOTE 2)
A1
S6 SOT-23 0401
2.80 – 3.10
(.110 – .118)
(NOTE 3)
.95
(.037)
REF
AA2
1.90
(.074)
REF
.20
(.008)
.90 – 1.45
(.035 – .057)
.00 – 0.15
(.00 – .006)
.90 – 1.30
(.035 – .051)
.35 – .55
(.014 – .021)
1.00 MAX
(.039 MAX)
A
A1
A2
L
.01 – .10
(.0004 – .004)
.80 – .90
(.031 – .035)
.30 – .50 REF
(.012 – .019 REF)
PIN ONE ID
MILLIMETERS
(INCHES)
NOTE:
1. CONTROLLING DIMENSION: MILLIMETERS
2. DIMENSIONS ARE IN
3. DRAWING NOT TO SCALE
4. DIMENSIONS ARE INCLUSIVE OF PLATING
5. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
6. MOLD FLASH SHALL NOT EXCEED .254mm
7. PACKAGE EIAJ REFERENCE IS:
SC-74A (EIAJ) FOR ORIGINAL
JEDEC MO-193 FOR THIN
SOT-23
(Original)
SOT-23
(ThinSOT)
LTC1696
13
1696fb
For more information www.linear.com/LTC1696
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
REVISION HISTORY
REV DATE DESCRIPTION PAGE NUMBER
A 06/14 Added "I” and "H” Grade 2 – 6
B 12/14 Changed Equation
from R1
R1+R1• VS=0.88 to R1
R1+R2 • VS=0.88
Changed Figure 2 schematic from Q1 to Q2
9
10
LTC1696
14
1696fb
For more information www.linear.com/LTC1696
LINEAR TECHNOLOGY CORPORATION 2001
LT 1214 REV B • PRINTED IN USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LTC1696
RELATED PARTS
TYPICAL APPLICATION
PART NUMBER DESCRIPTION COMMENTS
LTC3890 60V, Low IQ, Dual 2-Phase Synchronous Step-Down DC/DC
Controller
Phase-Lockable Fixed Frequency 50kHz to 900kHz
4V ≤ VIN ≤ 60V, 0.8V ≤ VOUT ≤ 24V, IQ = 50μA
LTC3855 Dual, Multiphase, Synchronous Step-Down DC/DC Controller
with Diff Amp and DCR Temperature Compensation
PLL Fixed Frequency 250kHz to 770kHz,
4.5V≤ VIN ≤ 38V, 0.8V ≤ VOUT ≤ 12V
LTC3861 Dual, Multiphase, Synchronous Step-Down Controller with Diff
Amp and Tr i -State Output Drive
Operates with Power Blocks, DR MOS Devices or External MOSFETs,
3V≤ VIN ≤ 24V, Up to 2.25MHz Operating Frequency
LTC3875 Dual, 2-Phase, Synchronous Current Mode Controller with Low
Value DCR Sensing and Temperature Compensation
PLL Fixed Frequency 250kHz to 720kHz, 4.5V≤ VIN ≤ 38V
0.6V ≤ VOUT ≤ 5V, 4mm x 4mm QFN-24, TSSOP-24E
LTC3866 Sub Milli Ohm Current Mode Synchronous Step-Down
Controller with Remote Sense
PLL Fixed Frequency 250kHz to 750kHz, 4V≤ VIN ≤ 38V
0.6V ≤ VOUT ≤ 5V, 6mm x 6mm QFN-40
LTC3765/
LTC3766
Forward No Opto Synchronous Controller Chip Set
with Active Clamp Reset
Direct Flux Limit, Supports Self Starting Secondary Forward Control
LTC3722/
LTC3722-2
Synchronous Full Bridge Controllers Adaptive or Manual Delay Control for Zero Voltage Switching,
Adjustable Synchronous Rectification Timing
External Triggering
The LTC1696 has a feature which allows the output to
be latched into an active high state by pulling the TIMER/
RESET pin high even if both the feedback voltages at the
FB1 and FB2 pins are below the trip threshold of the in-
ternal comparator. The output is then reset by pulling the
TIMER/RESET pin low. Figure 4 shows a circuit that uses
the external triggering function of the LTC1696
C1
1nF
6
5
4
1696 F04
1
2
3
LTC1696
RESET
5V
1.8V
Q2
2N7002 TRIGGER
Q3
2N7002
D1
1N4148
FB1
GND
VCC
FB2
OUT
TIMER/
RESET
R1
44.2k
1%
1.5V
VCC
3.3V
R2
38.3k
1%
R3
44.2k
1%
R5
6.8k
5%
Q1
2N7002
N-CHANNEL
×2
PRIMARY
INPUT
SUPPLY
R4
54.9k
1%
C2
0.1µF
POWER MANAGEMENT
CONTOLLER
Figure 4. External Triggering
