LTC1696
1
, LTC and LT are registered trademarks of Linear Technology Corporation.
■
±2% Overvoltage Threshold Accuracy
■
Low Profile (1mm) ThinSOT
TM
Package
■
Gate Drive for SCR Crowbar or External N-Channel
Disconnect MOSFET
■
Monitors Two Output Voltages
■
Senses Output Voltages from 0.8V to 24V
■
Wide Supply Range: 2.7V to 27V
■
Multifunction TIMER/RESET Pin
Overvoltage Protection
Controller
■
Telecommunication Systems
■
Computer Systems
■
Industrial Control Systems
■
Notebook Computers
SCR Crowbar
DESCRIPTIO
U
FEATURES
APPLICATIO S
U
TYPICAL APPLICATIO
U
The LTC
®
1696 is a standalone power supply overvoltage
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 condi-
tion 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 pro-
grammed. 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 overvolt-
age 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.
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
I
OUT
20mA/DIV
ThinSOT is a trademark of Linear Technology Corporation.
100µs/DIV 1696 TA02
Overvoltage Response
C1 = 1nF
LTC1696
2
Supply Voltage (V
CC
) ............................................... 28V
Input Voltage
FB1, FB2 ............................................... –0.3V to 17V
TIMER/RESET .......................................–0.3V to 17V
Operating Temperature Range (Note 2) .. –40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
ORDER PART NUMBER
T
JMAX
= 125°C, θ
JA
= 256°C/W
LTC1696ES6
(Note 1)
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. 2.7V ≤ VCC ≤ 27V (Notes 3, 4) unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
CC
Supply Voltage Range Operating Range ●2.7 27 V
I
VCC
Standby Supply Current FB1, FB2 < V
FB
●170 540 µA
Active Supply Current FB1, FB2 > V
FB
, C
OUT
= 1000pF ●1.1 3.5 mA
V
FB
FB1, FB2 Feedback Threshold Voltage Going Positive T
A
≥ 0°C●0.862 0.880 0.898 V
T
A
< 0°C●0.853 0.880 0.907 V
I
FB
FB1, FB2 Input Current ●–1 –0.05 µA
V
FBHST
FB1, FB2 Feedback Hysteresis High-to-Low Transition 12 mV
V
LKO
V
CC
Undervoltage Lockout FB1, FB2 > V
FB
Low-to-High Transition ●1.75 2.05 2.35 V
High-to-Low Transition ●1.64 1.94 2.24 V
V
LKH
V
CC
Undervoltage Lockout Hysteresis FB1, FB2 > V
FB
110 mV
V
RST
TIMER/RESET Reset Low Threshold FB1, FB2 > V
FB
●0.78 0.865 0.95 V
V
TIM
TIMER/RESET Timer High Threshold FB1, FB2 > V
FB
●1.11 1.185 1.26 V
V
TRIG
TIMER/RESET External Trigger High FB1, FB2 < V
FB
●1.35 1.50 1.65 V
Threshold
I
TRIG
TIMER/RESET External Trigger High FB1, FB2 < V
FB
, TIMER/RESET = V
TRIG
●260 650 µA
Current
I
TIM
TIMER/RESET Timer Current FB1 = (V
FB
+ 30mV), FB2 < V
FB
●41022 µA
FB1 = (V
FB
+ 200mV), FB2 < V
FB
●51226 µA
FB2 = (V
FB
+ 30mV), FB1 < V
FB
●41022 µA
FB2 = (V
FB
+ 200mV), FB1 < V
FB
●51226 µA
FB1, FB2 = (V
FB
+ 200mV) ●81840 µA
V
OUTH
OUT High Voltage 12V ≤ V
CC
≤ 27V, FB1, FB2 > V
FB
, C
OUT
= 1000pF ●4.8 6.3 8.0 V
V
CC
= 3.3V, FB1, FB2 > V
FB
, C
OUT
= 1000pF ●2.7 3.2 3.3 V
V
OUTL
OUT Low Voltage FB1, FB2 < V
FB
, I
SINK
= 1mA, V
CC
= 3.3V ●0.45 V
t
OVPD1
OUT Propagation Delay for FB1 FB1 > V
FB
, FB2 < V
FB
, TIMER/RESET = Open, ●728 µs
C
OUT
= 1000pF
t
OVPD2
OUT Propagation Delay for FB2 FB2 > V
FB
, FB1 < V
FB
, TIMER/RESET = Open, ●728 µs
C
OUT
= 1000pF
S6 PART MARKING
LTLT
Consult LTC Marketing for parts specified with wider operating temperature
ranges.
ABSOLUTE AXI U RATI GS
WWWU
PACKAGE/ORDER I FOR ATIO
UU
W
ELECTRICAL CHARACTERISTICS
FB1 1
GND 2
V
CC
3
6
5 FB2
4 OUT
TOP VIEW
TIMER/
RESET
S6 PACKAGE
6-LEAD PLASTIC SOT-23
LTC1696
3
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. 2.7V ≤ VCC ≤ 27V (Notes 3, 4) unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
OVPD1,2
OUT Propagation Delay for FB1, FB2 FB1, FB2 > V
FB
, TIMER/RESET = Open ●624 µs
C
OUT
= 1000pF
t
r
OUT Rise Time FB1, FB2 > V
FB
, C
OUT
= 1000pF ●0.4 3 µs
I
OUTSC
OUT Short-Circuit Current 12V ≤ V
CC
≤ 27V, FB1, FB2 > V
FB
,●35 80 160 mA
V
OUT
Shorted to GND
V
CC
= 2.7V, FB1, FB2 > V
FB
, V
OUT
Shorted to GND ●2918 mA
ELECTRICAL CHARACTERISTICS
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: The LTC1696E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
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 V
CC
= 12V and T
A
= 25°C.
LTC1696
4
TYPICAL PERFOR A CE CHARACTERISTICS
UW
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)
–55
SUPPLY CURRENT (µA)
160
170
180
105
1696 G02
150
140
120 –15 25 65
–35 125
545 85
130
200
190
V
CC
= 12V
SUPPLY VOLTAGE (V)
0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
015 25
1696 G03
510 20 30
SUPPLY CURRENT (mA)
T
A
= 25°C
C
OUT
= 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)
–55
0.95
SUPPLY CURRENT (mA)
1.00
1.10
1.15
1.20
–15 25 45 125
1696 G04
1.05
–35 5 65 85 105
V
CC
= 12V
C
OUT
= 1000pF
SUPPLY VOLTAGE (V)
FB1, FB2 FEEDBACK THRESHOLD VOLTAGE (V)
0.8814
0.8811
0.8808
0.8805
0.8802
0.8799
0.8796 6121824
1696 G05
3030 9 15 21 27
T
A
= 25°C
FB1, FB2 Feedback Threshold
Voltage vs Temperature
TEMPERATURE (°C)
–55
0.85
FB1, FB2 FEEDBACK THRESHOLD VOLTAGE (V)
0.86
0.88
0.89
0.90
–15 25 45 125
1696 G06
0.87
–35 5 65 85 105
V
CC
= 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
1.160 510 20
1.190
1.195
1.200
30
T
A
= 25°C
TIMER Threshold Voltage
vs Temperature
TEMPERATURE (°C)
–55
1.14
TIMER THRESHOLD VOLTAGE (V)
1.16
1.20
1.22
1.24
–15 25 45 125
1696 G08
1.18
–35 5 65 85 105
V
CC
= 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
TYPICAL PERFOR A CE CHARACTERISTICS
UW
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)
–55
8
TIMER CURRENT (µA)
10
12
14
65 85 105
22
1696 G10
–35 –15 5 25 45 125
16
18
20
V
CC
= 12V
FB1 AND 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
V
CC
= 12V
T
A
= 25°CFB1 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
V
CC
= 3.3V
T
A
= 25°CFB1 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
V
CC
= 3.3V
T
A
= 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
V
CC
= 12V
T
A
= 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
510 20 30
EXTERNAL TRIGGER TRESHOLD VOLTAGE (V)
T
A
= 25°C
TEMPERATURE (°C)
–55
1.475
EXTERNAL TRIGGER THRESHOLD VOLTAGE (V)
1.480
1.490
1.495
1.500
–15 25 45 125
1696 G16
1.485
–35 5 65 85 105
1.505 VCC = 12V
SUPPLY VOLTAGE (V)
0
RESET THRESHOLD VOLTAGE (V)
0.858
0.860
0.862
15 25
1696 G17
0.856
0.854
0.852 510 20
0.864
0.866
0.868
30
T
A
= 25°C
RESET Threshold Voltage
vs Temperature
TEMPERATURE (°C)
–55
RESET TRHESHOLD VOLTAGE (V)
0.860
0.865
0.870
105
1696 G18
0.855
0.850
0.840 –15 25 65
–35 125
545 85
0.845
0.880
0.875
V
CC
= 12V
TIMER Current
vs Feedback Overdrive
LTC1696
6
TYPICAL PERFOR A CE CHARACTERISTICS
UW
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
0510 20
6
7
8
30
T
A
= 25°C
C
OUT
= 1000pF
OUT Pin Active Output Voltage
vs Temperature
TEMPERATURE (°C)
–55
OUT PIN ACTIVE OUTPUT VOLTAGE (V)
6.2
6.3
6.4
105
1696 G20
6.1
6.0
5.8 –15 25 65
–35 125
545 85
5.9
6.6
6.5
V
CC
= 12V
C
OUT
= 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)
–55
0
OUT PIN SHORT-CIRCUIT CURRENT (mA)
20
60
80
100
–15 25 45 125
1696 G22
40
–35 5 65 85 105
120 V
OUT
SHORTED TO GND
V
CC
= 27V
V
CC
= 12V
V
CC
= 5V
V
CC
= 2.7V
OUTPUT VOLTAGE (V)
0
ACTIVE OUTPUT CURRENT (mA)
10
20
30
5
15
25
1234
1696 G23
50.50 1.5 2.5 3.5 4.5
T
A
= 25°C
V
CC
= 5V
V
CC
= 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
T
A
= 25°C
V
CC
= 27V
V
CC
= 12V
LTC1696
7
UU
U
PI FU CTIO S
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 thresh-
old 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.
V
CC
(Pin 3): Power Supply. The pin is connected sepa-
rately 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
delivering 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 condi-
tion, 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 V
CC
pin goes below the undervolt-
age 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 overdrive
above the threshold level. The higher the feedback over-
drive, the faster will be the response time.
TIMER/RESET (Pin 6): Glitch Filter Timer Capacitor, Reset
and External Trigger Input. The external capacitor con-
nected 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
8
BLOCK DIAGRA
W
–
+
+
1.185V
0.865V
1696 BD
TIMER/
RESET
10µA +
FUNCTION
OF FB1 AND FB2
OVERDRIVE
INTERNAL 5V SUPPLY
BANDGAP
REFERENCE
0.88V
–
+
–
+
–
+
6
OUT
4
FB2
FB1
5
1
GND
LOGIC
GLITCH
FILTER
2V
UVLO
R1
+
–
+
–
2
V
CC
3
R2
INTERNAL 5V SUPPLY
V
REF
R3R4
APPLICATIO S I FOR ATIO
WUUU
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, V
S
, 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.
R
RRVS
1
12 088
+=•.
RVR
S
2088 1
088
=
()
–. •
.
As an example, let’s calculate values for R1 and R2 for a
3.3V supply in which an overvoltage indication is required
V
REF
= 0.88V
FB1
R2
V
S
R1
LTC1696
+
–
–
+
Figure 1
at +10% (3.63V). First, a value for R1 is chosen based on
the allowable resistor divider string current. This is deter-
mined 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:
LTC1696
9
APPLICATIO S I FOR ATIO
WUUU
RV
I
V
Ak
FB
DIVIDER
1088
20 44==
µ=
.
The nearest 1% value for R1 is 44.2k. Now, calculating for
R2 yields:
RkVV
Vk2 44 2 3 63 0 88
088 138 1=
()
=
.•. –.
..
Choosing the nearest 1% value yields 137k.
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 internal
latch is reset by pulling the TIMER/RESET pin low through
an external N-channel MOSFET switch or pulling V
CC
voltage below the UVLO trip point of 1.94V.
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:
tCV
I
DINT
CHG
=1•
where V
INT
is the internal reference voltage of 1.185V and
I
CHG
is the internal current source charging the external
capacitor C1. The current source I
CHG
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 crow-
bar has been triggered, so that the device is not kept in the
active high state for too long.
C1
1nF
6
V
OUT2
2.5V
V
OUT1
1.8 V
5
4
1696 F02
1
2
3
LTC1696
RESET
Q1
2N7002
FB1
GND
V
CC
FB2
OUT
TIMER/
RESET
R1
44.2k
1%
V
CC
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
10
APPLICATIO S I FOR ATIO
WUUU
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
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
11
PACKAGE DESCRIPTIO
U
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 represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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
12
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
C1
1nF
6
5
4
1696 F04
1
2
3
LTC1696
RESET
5V
1.8V
Q2
2N7002 TRIGGER
Q3
2N7002
D1
1N4148
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%
R5
6.8k
5%
Q1
2N7002
N-CHANNEL
×2
PRIMARY
INPUT
SUPPLY
R4
54.9k
1%
C2
0.1µF
POWER MANAGEMENT
CONTOLLER
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com
LINEAR TECHNOLOGY CORPORATION 2001
1696f LT/TP 0701 2K • PRINTED IN USA
Figure 4. External Triggering
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APPLICATIO S I FOR ATIO
WUUU
FB1 and FB2 pins are below the trip threshold of the
internal 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.