LTC2906/LTC2907
Precision Dual Supply Monitors
with One Pin-Selectable Threshold
and One Adjustable Input
FEATURES
s
s
DESCRIPTIO
s
s
s
s
s
s
s
s
s
s
Monitors Two Inputs Simultaneously
Three Threshold Selections for 5V, 3.3V or 2.5V
Supplies
Low Voltage Adjustable Input (0.5V)
Three Supply Tolerances (5%, 7.5%, 10%)
Guaranteed Threshold Accuracy:
±1.5%
of
Monitored Voltage Over Temperature
Internal V
CC
Auto Select
Power Supply Glitch Immunity
200ms Reset Time Delay (LTC2906 Only)
Adjustable Reset Time Delay (LTC2907 Only)
Open Drain RST Output
Guaranteed RST for V1
≥
1V or V
CC
≥
1V
Low Profile (1mm) SOT-23 (ThinSOT
TM
) and
Plastic (3mm
×
2mm) DFN Packages
Desktop and Notebook Computers
Handheld Devices
Network Servers
Core, I/O Monitor
, LTC and LT are registered trademarks of Linear Technology Corporation.
The LTC
®
2906/LTC2907 are dual supply monitors in-
tended for systems with multiple supply voltages. The
dual supply monitors have a common reset output with
delay (200ms for the LTC2906 and adjustable using an
external capacitor for the LTC2907). These products pro-
vide a precise, space-conscious and micropower solution
for supply monitoring.
The LTC2906/LTC2907 feature a tight 1.5% threshold
accuracy over the whole operating temperature range
and glitch immunity to ensure reliable reset operation
without false triggering. The open drain RST output state
is guaranteed to be in the correct state for V1 and/or V
CC
down to 1V.
The LTC2906/LTC2907 also feature one adjustable input
with a nominal threshold level at 0.5V, another input with
three possible input threshold levels, and three supply
tolerances for possible margining. These features provide
versatility for any kind of system requiring dual supply
monitors. Two three-state input pins program the thresh-
old and tolerance level without requiring any external
components.
APPLICATIO S
s
s
s
s
TYPICAL APPLICATIO
Dual Supply Monitor with Adjustable Tolerance (2.5V, 0.8V)
DC/DC
CONVERTER
2.5V
0.8V
49.9k
V1
LTC2907
0.1µF
V
CC
S1
TOL
TMR
22nF
GND
RST
V
ADJ
0.1µF
100k
SYSTEM
LOGIC
Supply Selection Programming
V1
5.0
3.3
2.5
S1
V1
OPEN
GND
Tolerance Programming
TOLERANCE
5%
7.5%
29067 TA01
TOLERANCE = 10%
10%
U
TOL
V1
OPEN
GND
29067f
U
U
1
LTC2906/LTC2907
ABSOLUTE
AXI U RATI GS
Terminal Voltages
V1, V
CC
........................................................ –0.3V to 7V
S1, V
ADJ
, TOL ............................ –0.3V to (V
MAX
+ 0.3V)
RST ............................................................. –0.3V to 7V
RST (LTC2906) ............................................ –0.3V to 7V
TMR (LTC2907) ........................................... –0.3V to 7V
PACKAGE/ORDER I FOR ATIO
TOP VIEW
GND 1
RST 2
RST/TMR* 3
V
CC
4
9
8 TOL
7 S1
6 V
ADJ
5 V1
ORDER PART
NUMBER
LTC2906CDDB
LTC2906IDDB
LTC2907CDDB
LTC2907IDDB
DDB8 PART MARKING
LBDC
LBDD
LBDF
LBDG
DDB8 PACKAGE
8-LEAD (3mm
×
2mm) PLASTIC DFN
EXPOSED PAD IS GND (PIN 9),
MUST BE SOLDERED TO PCB
*RST FOR LTC2906
TMR FOR LTC2907
T
JMAX
= 125°C,
θ
JA
= 250°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= V1 = 2.5V, V
ADJ
= 0.55V, S1 = TOL = 0V, unless otherwise noted.
(Notes 2, 3, 4)
SYMBOL
V
RT50
PARAMETER
5V, 5% Reset Threshold
5V, 7.5% Reset Threshold
5V, 10% Reset Threshold
3.3V, 5% Reset Threshold
3.3V, 7.5% Reset Threshold
3.3V, 10% Reset Threshold
2.5V, 5% Reset Threshold
2.5V, 7.5% Reset Threshold
2.5V, 10% Reset Threshold
ADJ, 5% Reset Threshold
ADJ, 7.5% Reset Threshold
ADJ, 10% Reset Threshold
V
CC
Input Current
V1 Input Current
V
ADJ
Input Current
CONDITIONS
V1 Input Threshold
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
ELECTRICAL CHARACTERISTICS
V
RT33
V1 Input Threshold
V
RT25
V1 Input Threshold
V
RTADJ
V
ADJ
Input Threshold
V
MAX(MIN)
I
VCC
I
V1
I
VADJ
Minimum V
MAX
Operating Voltage (Note 2) RST, RST in Correct Logic State
V
CC
> V1
V1 > V
CC
V
CC
> V1
V1 > V
CC
2
U
U
W
W W
U
W
(Notes 1, 2)
Operating Temperature Range
LTC2906C/LTC2907C .............................. 0°C to 70°C
LTC2906I/LTC2907I ............................–40°C to 85°C
Storage Temperature Range ..................–65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
TOP VIEW
V
CC
1
RST/TMR* 2
RST 3
GND 4
8 V1
7 V
ADJ
6 S1
5 TOL
ORDER PART
NUMBER
LTC2906CTS8
LTC2906ITS8
LTC2907CTS8
LTC2907ITS8
TS8 PART MARKING
LTBCM
LTBCN
LTBCP
LTBCQ
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
*RST FOR LTC2906
TMR FOR LTC2907
T
JMAX
= 125°C,
θ
JA
= 250°C/W
MIN
4.600
4.475
4.350
3.036
2.954
2.871
2.300
2.238
2.175
0.492
0.479
0.465
TYP
4.675
4.550
4.425
3.086
3.003
2.921
2.338
2.275
2.213
0.500
0.487
0.473
54
1
55
MAX
4.750
4.625
4.500
3.135
3.053
2.970
2.375
2.313
2.250
0.508
0.495
0.481
1
100
±1
3
100
±15
UNITS
V
V
V
V
V
V
V
V
V
V
V
V
V
µA
µA
µA
µA
nA
29067f
LTC2906/LTC2907
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= V1 = 2.5V, V
ADJ
= 0.55V, S1 = TOL = 0V, unless otherwise noted.
(Notes 2, 3, 4)
SYMBOL
I
TMR(UP)
I
TMR(DOWN)
t
RST
t
RST
t
UV
V
OL
V
OH
PARAMETER
TMR Pull-Up Current
TMR Pull-Down Current
Reset Time-Out Period
Reset Time-Out Period
V
X
Undervoltage Detect to
RST or RST
Output Voltage Low RST, RST
Output Voltage High RST, RST
(Notes 2, 5)
Low Level Input Voltage
High Level Input Voltage
Pin Voltage when Left in Hi-Z State
I = –10µA
I = 0µA
I = 10µA
(LTC2907)
(LTC2907)
(LTC2906)
(LTC2907)
C
TMR
= 22nF
V
X
Less Than Reset Threshold V
RTX
by More than 1%
I = 2.5mA
I = 100µA; V1 and/or V
CC
= 1V (RST Only)
I = –1µA
q
q
q
V
MAX
– 1
ELECTRICAL CHARACTERISTICS
CONDITIONS
V
TMR
= 0V
V
TMR
= 1.4V
q
q
q
q
MIN
–1.5
1.5
140
140
TYP
–2.1
2.1
200
200
150
0.15
0.05
MAX
–2.7
2.7
260
260
UNITS
µA
µA
ms
ms
µs
0.4
0.3
V
V
V
Three-State Inputs S1, TOL
V
IL
V
IH
V
Z
q
q
q
q
q
0.4
1.4
0.7
0.9
1.1
±25
V
V
V
V
V
µA
I
VPG
Programming Input Current (Note 6)
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
The greater of V1, V
CC
is the internal supply voltage (V
MAX
).
Note 3:
All currents into pins are positive; all voltages are referenced to
GND unless otherwise noted.
Note 4:
For reset thresholds test conditions refer to the voltage threshold
programming table in the Applications Information section.
Note 5:
The output pins RST and RST have an internal pull-up to V
MAX
of
typically –6µA. However, an external pull-up resistor may be used when
faster rise time is required or for V
OH
voltages greater than V
MAX
.
Note 6:
The input current to the three-state input pins are the pull-up and
the pull-down current when the pins are either set to V1 or GND
respectively. In the open state, the maximum leakage current to V1 or GND
permissible is 10µA.
TYPICAL PERFOR A CE CHARACTERISTICS
Specifications are at T
A
= 25°C unless otherwise noted.
5V Threshold Voltage vs
Temperature
4.75
3.12
5%
THRESHOLD VOLTAGE, V
RT50
(V)
THRESHOLD VOLTAGE, V
RT33
(V)
4.65
4.60
4.55
4.50
4.45
4.40
4.35
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
29067 G01
3.07
THRESHOLD VOLTAGE, V
RT25
(V)
4.70
5%
7.5%
10%
U W
3.3V Threshold Voltage vs
Temperature
2.375
2.5V Threshold Voltage vs
Temperature
5%
2.325
7.5%
2.275
3.02
7.5%
2.97
10%
2.92
2.225
10%
2.87
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
29067 G02
2.175
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
29067 G03
29067f
3
LTC2906/LTC2907
TYPICAL PERFOR A CE CHARACTERISTICS
Specifications are at T
A
= 25°C unless otherwise noted.
ADJ Threshold Voltage vs
Temperature
0.505
5%
THRESHOLD VOLTAGE, V
RTADJ
(V)
0.500
19.0
0.495
I
V1
(µA)
0.490
0.485
0.480
17.5
0.475
0.470
–50
10%
17.0
–50
I
VCC
(µA)
18.5
19.5
7.5%
–25
25
50
0
TEMPERATURE (°C)
Typical Transient Duration vs
Comparator Overdrive (V1, V
ADJ
)
700
TYPICAL TRANSIENT DURATION (µs)
600
500
400
300
200
100
0
1
10
100
0.1
COMPARATOR OVERDRIVE VOLTAGE (% OF V
RTX
)
29067 G07
RESET TIME OUT PERIOD, t
RST
(ms)
1000
RESET TIME OUT PERIOD, t
RST
(ms)
RESET OCCURS
ABOVE CURVE
RST Output Voltage vs V1
5
4
RST OUTPUT VOLTAGE (V)
3
2
1
0
–1
S1 = TOL = V
CC
= V1
V
ADJ
= 0.55V
10k PULL-UP RESISTOR
RST OUTPUT VOLTAGE (V)
5
4
3
2
1
0
–1
RST OUTPUT VOLTAGE (V)
0
1
2
V1 (V)
3
4
U W
75
29067 G04
I
V1
vs Temperature
V1 = 5V
V
CC
= 3.3V
V
ADJ
=0.55V
S1 =TOL = 1.4V
15.8
15.6
15.4
15.2
15.0
14.8
14.6
14.4
14.2
14.0
–25
25
50
0
TEMPERATURE (°C)
75
100
100
I
VCC
vs Temperature
V1 = 2.5V
V
CC
= 3.3V
V
ADJ
=0.55V
S1 =TOL = 1.4V
18.0
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
29067 G05
29067 G06
Reset Time Out Period (t
RST
)
vs Capacitance (C
TMR
)
10000
235
Reset Time Out Period (t
RST
)
vs Temperature
CRT = 22nF
230 (FILM)
225
220
215
210
205
200
195
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
100
10
1
0.1
10p
100p
10n
C
TMR
(FARAD)
1n
100n
1µ
29067 G08
29067 G09
RST Output Voltage vs V1
5
S1 = TOL = V
CC
= V1
V
ADJ
= 0.55V
10k PULL-UP RESISTOR
4
3
2
1
0
–1
RST Output Voltage vs V1
S1 = TOL = V
CC
= V1
V
ADJ
= 0.55V
10pF CAPACITOR AT RST
4
29067 G10
5
0
1
2
V1 (V)
3
4
5
29067 G11
0
1
2
V1 (V)
3
4
29067 G12
5
29067f
LTC2906/LTC2907
TYPICAL PERFOR A CE CHARACTERISTICS
Specifications are at T
A
= 25°C unless otherwise noted.
RST Pull-Down Current (I
RST
)
vs V
MAX
RST PULL-DOWN CURRENT, I
RST
(mA)
RST PULL-DOWN CURRENT, I
RST
(mA)
RST OUTPUT VOLTAGE LOW, V
OL
(V)
5
4
S1 = TOL = V
CC
= V1
V
ADJ
= 0.55V
NO PULL-UP R
RST AT 150mV
3
2
1
0
0
1
2
3
V
MAX
(V)
4
5
29067 G13
RST AT 50mV
RST Output Voltage Low (V
OL
)
vs RST Pull-Down Current (I
RST
)
1.8
RST OUTPUT VOLTAGE LOW, V
OL
(V)
RST PULL-UP CURRENT, I
RST
(µA)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
–14
–12
–10
–8
–6
–4
–2
V
RT25
0
V
RT33
3.0
3.5
4.0
V
MAX
(V)
V
RT50
4.5
5.0
29067G17
RST PULL-UP CURRENT, I
RST
(µA)
1.6
V1 = V
CC
= 5V
V
ADJ
= 0.55V
S1 = TOL = V1
NO PULL-UP R
85°C
10
30
40
50
60
20
RST PULL-DOWN CURRENT, I
RST
(mA)
29067 G16
RST Output Voltage High (V
OH
)
vs RST Output Source Current (I
RST
)
3.0
RST OUTPUT VOLTAGE HIGH, V
OH
(V)
RST OUTPUT VOLTAGE HIGH, V
OH
(V)
2.5
TOL = V1 = 3.3V
V
ADJ
= 0.55V
S1 = OPEN
NO PULL-UP R
I
S1
, I
TOL
(µA)
2.0
1.5
85°C
–40°C
25°C
1.0
0.5
–12
–8
–6
–4
–2
–10
OUTPUT SOURCE CURRENT, I
RST
(µA)
U W
25°C
–40°C
0
29067 G19
RST Pull-Down Current (I
RST
)
vs V
MAX
5
4
3
2
1
0
0
1
2
3
V
MAX
(V)
4
5
29067 G14
RST Output Voltage Low (V
OL
)
vs RST Pull-Down Current (I
RST
)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
10
30
40
50
60
20
RST PULL-DOWN CURRENT, I
RST
(mA)
29067G15
V
CC
= V1
S1 = TOL = GND
V
ADJ
= 0.55V
NO PULL-UP R
RST AT 150mV
V1 = V
CC
= 5V
V
ADJ
= 0.45V
S1 = TOL = V1
NO PULL-UP R
85°C
25°C
–40°C
RST AT 50mV
RST Pull-Up Current (I
RST
)
vs V
MAX
–18
TOL = GND
–16
–14
–12
–10
–8
–6
–4
–2
0
–16
RST Pull-Up Current (I
RST
)
vs V
MAX
TOL = V1
V
RT25
2.0
2.5
3.0
V
RT33
3.5
4.0
V
MAX
(V)
V
RT50
4.5
5.0
2.0
2.5
29067 G18
RST Output Voltage High (V
OH
) vs
RST Output Source Current (I
RST
)
3.5
TOL = V1 = 3.3V
V
ADJ
= 0.45V
3.0 S1 = OPEN
NO PULL-UP R
2.5
2.0
–40°C
1.5
1.0
0.5
–8
–7 –6 –5 –4 –3 –2
–1
OUTPUT SOURCE CURRENT, I
RST
(µA)
0
85°C
25°C
20
19
18
17
16
15
14
13
12
11
I
S1
, I
TOL
vs Temperature
S1 = TOL = V1 = 3.3V
10
–50
–25
0
25
50
75
100
TEMPERATURE (°C)
29067 G21
290467 G20
29067f
5
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