LTC2903-1
Precision Quad Supply
Monitor in 6-Lead SOT-23
FEATURES
s
s
DESCRIPTIO
s
s
s
s
s
s
s
Ultralow Voltage Reset: V
CC
= 0.5V Guaranteed
Monitor Four Inputs Simultaneously
3.3V, 2.5V, 1.8V, ADJ (LTC2903-A1)
5V, 3.3V, 2.5V, 1.8V (LTC2903-B1)
5V, 3.3V, 1.8V, –5.2V (LTC2903-C1)
Guaranteed Threshold Accuracy:
±1.5%
of
Monitored Voltage over Temperature
10% Undervoltage Monitoring
Low Supply Current: 20µA Typical
200ms Reset Time Delay
Active Low Open-Drain RST Output
Power Supply Glitch Immunity
Low Profile (1mm) SOT-23 (ThinSOT
TM
) Package
The LTC
®
2903-1 monitors up to four supply voltages. The
common reset output remains low until all four inputs
have been in compliance for 200ms. Voltage thresholds
maintain
±1.5%
accuracy over temperature (with respect
to the monitored voltage). The LTC2903-1 features an
open-drain RST output with a weak internal pullup.
Internal supply voltage (V
CC
) is generated from the greater
voltage on the V1, V2 inputs. The RST output is guaranteed
to sink at least 5µA (V
OL
= 0.15V) for V1, V2 or V3 down
to 0.5V and will typically conduct current down to 0V.
Quiescent current is 20µA typical, making the LTC2903-1
ideal for power conscious systems. The LTC2903-1 is
available in a 6-lead low profile (1mm) SOT-23 package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
APPLICATIO S
s
s
s
s
Multivoltage Systems
Optical Networking Systems
Cell Phone Base Stations
Network Servers
TYPICAL APPLICATIO
Low Voltage Reset Pull-Down Performance
vs External Pull-Up Current and Input Supply Voltage
0.10
5V
0.09
3.3V
DC/DC
2.5V
CONVERTER
1.8V
LTC2903-B1
RST
V1
GND
V2
V4
V3
2903 TA01
RESET PIN VOLTAGE (V)
SYSTEM
LOGIC
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0
1µA
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
V
IN
, INPUT SUPPLY VOLTAGE (V)
1
2µA
5µA
20µA
10µA
C1
0.1µF
C2
0.1µF
U
V
IN
= V1 = V2 = V3
2903 TA01b
U
U
29031f
1
LTC2903-1
ABSOLUTE
MAXIMUM
RATINGS
(Notes 1, 2, 3)
PACKAGE/ORDER INFORMATION
TOP VIEW
V1 1
GND 2
V2 3
6 RST
5 V4
4 V3
V1, V2 ...................................................... – 0.3V to 6.5V
V3 ................................................. 2.7V or (V
CC
+ 0.3V)
V4 (LTC2903-A1, LTC2903-B1) ................– 0.3V to 6.5V
V4 (LTC2903-C1) .................................... – 6.5V to 0.3V
RST ........................................................ – 0.3V to 6.5V
Operating Temperature Range
LTC2903C-X1 .......................................... 0°C to 70°C
LTC2903I-X1 ...................................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T
JMAX
= 125°C,
θ
JA
= 230°C/W
ORDER PART NUMBER
LTC2903CS6-A1
LTC2903CS6-B1
LTC2903CS6-C1
LTC2903IS6-A1
LTC2903IS6-B1
LTC2903IS6-C1
S6 PART MARKING
LTAFV
LTAJN
LTAJQ
LTAFW
LTAJP
LTAJR
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
SYMBOL
V
RT33
V
RT25
V
RT18
V
RTA
PARAMETER
3.3V, 10% Reset Threshold
2.5V, 10% Reset Threshold
1.8V, 10% Reset Threshold
Adjustable Reset Threshold
(LTC2903-A1) The
q
denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 3.3V unless otherwise noted.
CONDITIONS
V1 Input Threshold
V2 Input Threshold
V3 Input Threshold
V4 Input Threshold
q
q
q
q
MIN
2.871
2.175
1.566
0.492
TYP
2.921
2.213
1.593
0.500
MAX
2.970
2.250
1.620
0.508
UNITS
V
V
V
V
(LTC2903-B1) The
q
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at
T
A
= 25°C. V
CC
= 5V unless otherwise noted.
SYMBOL
V
RT50
V
RT33
V
RT25
V
RT18
PARAMETER
5V, 10% Reset Threshold
3.3V, 10% Reset Threshold
2.5V, 10% Reset Threshold
1.8V, 10% Reset Threshold
CONDITIONS
V1 Input Threshold
V2 Input Threshold
V3 Input Threshold
V4 Input Threshold
q
q
q
q
MIN
4.350
2.871
2.175
1.566
TYP
4.425
2.921
2.213
1.593
MAX
4.500
2.970
2.250
1.620
UNITS
V
V
V
V
(LTC2903-C1) The
q
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at
T
A
= 25°C. V
CC
= 5V unless otherwise noted.
SYMBOL
V
RT50
V
RT33
V
RT18
V
RT52N
PARAMETER
5V, 10% Reset Threshold
3.3V, 10% Reset Threshold
1.8V, 10% Reset Threshold
–5.2V, 10% Reset Threshold
CONDITIONS
V1 Input Threshold
V2 Input Threshold
V3 Input Threshold
V4 Input Threshold
q
q
q
q
MIN
4.350
2.871
1.566
TYP
4.425
2.921
1.593
MAX
4.500
2.970
1.620
UNITS
V
V
V
V
–4.524 –4.602 –4.680
2
U
W
U
U
W W
W
29031f
LTC2903-1
ELECTRICAL CHARACTERISTICS
SYMBOL
I
V1
I
V2
I
V3
I
V4
PARAMETER
V1 Input Current (Note 4)
V2 Input Current (Note 4)
V3 Input Current
V4 Input Current
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 3.3V unless otherwise noted.
CONDITIONS
V1 = 3.3V (LTC2903-A1)
V1 = 5V (LTC2903-B1, LTC2903-C1)
V2 = 2.5V (LTC2903-A1)
V2 = 3.3V (LTC2903-B1, LTC2903-C1)
V3 = 1.8V (LTC2903-A1, LTC2903-C1)
V3 = 2.5V (LTC2903-B1)
V4 = 0.55V (LTC2903-A1)
V4 = 1.8V (LTC2903-B1)
V4 = –5.2V (LTC2903-C1)
V
X
Less Than Threshold V
RTX
by
More Than 1%
I
RST(DN)
= –1µA
V
CC
= 0.2V, I
RST
= 0.1µA
V
CC
= 0.5V, I
RST
= 5µA
V
CC
= 1V, I
RST
= 200µA
V
CC
= 3V, I
RST
= 2500µA
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
MIN
TYP
20
25
8
10
6
8
2
–3
MAX
80
80
30
30
30
30
±15
4
–6
260
UNITS
µA
µA
µA
µA
µA
µA
nA
µA
µA
ms
µs
V
t
RST
t
UV
V
OH
V
OL
Reset Time-Out Period
V
X
Undervoltage Detect to RST
Output Voltage High RST (LTC2903-1) (Note 5)
Output Voltage Low RST (Note 6)
140
200
150
V2 – 1
5
10
25
100
60
150
300
300
mV
mV
mV
mV
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2:
All currents into pins are positive, all voltages are referenced to
GND unless otherwise noted.
Note 3:
The internal supply voltage (V
CC
) is generated from the greater
voltage on the V1, V2 inputs.
Note 4:
Under typical operating conditions, quiescent current is drawn
from the V1 input. When V2 exceeds V1, V2 supplies the quiescent
current.
Note 5:
The RST output pin on the LTC2903-1 has an internal pull-up to
V2 of typically 10µA. However, for faster rise times or for V
OH
voltages
greater than V2, use an external pull-up resistor.
Note 6:
At input voltages below 1V on V1 and V2, voltage on V3 assists
pulling down the RST output.
29031f
3
LTC2903-1
TYPICAL PERFOR A CE CHARACTERISTICS
5V Threshold Voltage
vs Temperature
4.500
2.975
THRESHOLD VOLTAGE, V
RT50
(V)
THRESHOLD VOLTAGE, V
RT33
(V)
4.475
4.450
4.425
4.400
4.375
4.350
–50
THRESHOLD VOLTAGE, V
RT25
(V)
–25
0
25
50
TEMPERATURE (°C)
1.8V Threshold Voltage
vs Temperature
1.625
0.510
THRESHOLD VOLTAGE, V
RTA
(V)
1.615
1.605
1.595
1.585
1.575
1.565
–50
THRESHOLD VOLTAGE, V
RT52N
(V)
THRESHOLD VOLTAGE, V
RT18
(V)
–25
0
25
50
TEMPERATURE (°C)
Supply Currents
vs Temperature (LTC2903A)
30
25
20
I
VX
(µA)
I
VX
(µA)
I
V1
15
10
I
V2
5
I
V3
0
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
5
V1 = 3.3V
V2 = 2.5V
V3 = 1.8V
30
25
20
15
10
I
VX
(µA)
4
U W
75
75
29031 G07
3.3V Threshold Voltage
vs Temperature
2.250
2.5V Threshold Voltage
vs Temperature
2.950
2.235
2.220
2.925
2.205
2.900
2.190
100
2.875
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
2.175
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
28031 G01
28031 G02
28031 G03
ADJ Threshold Voltage
vs Temperature
–4.530
–4.555
–4.580
–4.605
–4.630
–4.655
–5.2V Threshold Voltage
vs Temperature
0.505
0.500
0.495
100
0.490
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
–4.680
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
28031 G04
28031 G05
28031 G06
Supply Currents
vs Temperature (LTC2903B)
V1 = 5V
V2 = 3.3V
V3 = 2.5V
V4 = 1.8V
I
V1
Supply Currents
vs Temperature (LTC2903C)
30
25
20
I
V1
15
10
I
V2
5
V1 = 5V
V2 = 3.3V
V3 = 1.8V
V4 = –5.2V
I
V2
I
V4
0
–50
–25
I
V3
I
V3
0
–5
–50
I
V4
–25
50
25
0
TEMPERATURE (°C)
75
100
29031 G09
0
25
50
TEMPERATURE (°C)
75
100
29031 G08
29031f
LTC2903-1
TYPICAL PERFOR A CE CHARACTERISTICS
Transient Duration
vs Comparator Overdrive
400
TYPICAL TRANSIENT DURATION (µs)
350
300
250
200
150
100
50
0
1
10
100
0.1
RESET COMPARATOR OVERDRIVE (% OF V
RTX
)
29031 G10
RESET TIME-OUT PERIOD, t
RST
(ms)
RST OUTPUT VOLTAGE (V)
RESET OCCURS
ABOVE CURVE
RST Output Voltage with
10k Pull-Up to V1
0.30
0.25
0.10
0.09
RST OUTPUT VOLTAGE (V)
RESET PIN VOLTAGE (V)
0.20
0.15
0.10
0.05
V1 = V2 = V3
0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
V1 (V)
29301 G13
10µA
0.05
0.04
0.03
0.02
0.01
0
1µA
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
V
IN
, INPUT SUPPLY VOLTAGE (V)
1
2µA
5µA
I
RST
(mA)
V1 ONLY
RST Voltage Output Low
vs RST Sink Current
1.5
LTC2903A
V1 = 3.3V
V2 = 2.1V
1.5
85°C
25°C
1.2
–45°C
1.2
V
OL
(V)
0.6
V
OL
(V)
0.9
0.3
0
0
5
10
15
25 30
I
RST
(mA)
20
35
40
45
U W
Reset Time-Out Period
vs Temperature
260
240
220
200
180
160
140
–50
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
RST Output Voltage with 10k
Pull-Up to V1
V1 = V2 = V3
LTC2903B, C
–25
0
25
50
TEMPERATURE (°C)
75
100
0
0
0.5
1
1.5
2
2.5 3
V1 (V)
3.5
4
4.5
5
29301 G11
29031 G12
Low Voltage Reset Pull-Down
Performance vs External Pull-Up
Current and Input Supply Voltage
V
IN
= V1 = V2 = V3
15
RST Current Sink Capability
vs V
CC
0.08
0.07
0.06
20µA
12
V
OL
= 0.4V
9
V
OL
= 0.2V
6
3
0
0
0.5
1
1.5
2
2.5 3
V
CC
(V)
3.5
4
4.5
5
29031 G14
29031 G15
RST Voltage Output Low
vs RST Sink Current
LTC2903B, C
V1 = 5V
V2 = 2.7V
85°C
0.9
25°C
–45°C
0.6
0.3
0
0
10
20
40
30
I
RST
(mA)
50
60
29031 G16
29031 G16
29031f
5
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