LTC1727/LTC1728
All except LTC1728-1.8. The
q
denotes specifications which apply over the
full operating temperature range, otherwise specifications are at T
A
= 25°C. V
CC3
= 3.3V, V
CC5
= 5V, V
CC25
= 2.5V, V
CCA
= V
CC3
unless
otherwise noted.
SYMBOL
t
UV
V
OL
PARAMETER
V
CC
Undervoltage Detect to RST
or COMPX
Output Voltage Low, RST, COMPX
CONDITIONS
V
CC5
, V
CC25
, V
CC3
or V
CCA
Less Than Reset
Threshold V
RT
by More Than 1% (Note 5)
I
SINK
= 2.5mA, V
CC3
= 3V, V
CC5
/V
CC25
= 0V
I
SINK
= 100µA, V
CC3
= 1V, V
CC5
/V
CC25
= 0V
I
SINK
= 100µA, V
CC3
= 0V, V
CC5
/V
CC25
= 1V
I
SINK
= 100µA, V
CC3
= 1V, V
CC5
/V
CC25
= 1V
I
SOURCE
= 1µA
Override V
CC5
Ability to Assert RST
q
q
q
q
q
V
CC3
– 1
ELECTRICAL CHARACTERISTICS
MIN
TYP
110
0.15
0.05
0.05
0.05
MAX
UNITS
µs
0.4
0.3
0.3
0.3
V
V
V
V
V
V
OH
V
OVR
Output Voltage High, RST, COMPX (Note 6)
V
CC5
Reset Override Voltage (Note 7)
LTC1727-5/LTC1728-5 Only
V
CC3
±0.025
V
LTC1728-1.8 The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are at
T
A
= 25°C. V
CC3
= 3V, V
CC18
= 1.8V, V
CCA
= V
CC3
unless otherwise noted.
SYMBOL
V
RT3
V
RT18
V
RTA
V
CCOP
I
VCC3
I
VCC18
I
VCCA
t
RST
t
UV
V
OL
PARAMETER
Reset Threshold V
CC3
Reset Threshold V
CC18
Reset Threshold V
CCA
V
CC3
, V
CC18
Operating Voltage
V
CC3
Supply Current
V
CC18
Supply Current
V
CCA
Input Current
Reset Pulse Width
V
CC
Undervoltage Detect to RST
Output Voltage Low, RST
CONDITIONS
V
CC3
Input Threshold
V
CC18
Input Threshold
V
CCA
Input Threshold
RST in Correct Logic State
V
CC18
> V
CC3
V
CC18
< V
CC3
, V
CC3
= 3V (Note 4)
V
CC18
< V
CC3
, V
CC18
= 1.8V (Note 4)
V
CCA
= 1V
RST Low (Note 5)
V
CC18
, V
CC3
or V
CCA
Less Than Reset (Note 5)
Threshold V
RT
by More Than 1%
I
SINK
= 2.5mA, V
CC3
= 3V, V
CC18
= 0V
I
SINK
= 100µA, V
CC3
= 1V, V
CC18
= 0V
I
SINK
= 100µA, V
CC3
= 0V, V
CC18
= 1V
I
SINK
= 100µA, V
CC3
= 1V, V
CC18
= 1V
I
SOURCE
= 1µA (Note 6)
q
q
q
q
q
V
CC3
– 1
q
q
q
q
q
q
q
q
q
MIN
2.760
1.656
0.985
1
TYP
2.805
1.683
1.000
1
10
1
MAX
2.850
1.710
1.015
7
2
20
2
15
280
UNITS
V
V
V
V
µA
µA
µA
nA
ms
µs
– 15
140
0
200
110
0.15
0.05
0.05
0.05
0.4
0.3
0.3
0.3
V
V
V
V
V
V
OH
Output Voltage High, RST
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2:
All voltage values are with respect to GND.
Note 3:
The LTC1727E/LTC1728E are guaranteed to meet specified
performance from 0°C to 70°C and are designed, characterized and
assured to meet the extended temperature limits of – 40°C to 85°C
but are not tested at these temperatures.
Note 4:
Both V
CC3
and V
CC5
/V
CC25
/V
CC18
can act as the supply depending
on which pin has the greatest potential.
Note 5:
Measured from when input passes through the input threshold
(V
RTX
) until RST or COMPX passes through 1.5V.
Note 6:
The output pins RST and COMPX have internal pull-ups to V
CC3
of
typically 6µA. However, external pull-up resistors may be used when faster
rise times are required or for V
OH
voltages greater than V
CC3
.
Note 7:
The V
CC5
reset override voltage is valid for an operating range less
than approximately 4.15V. Above this point the override is turned off and
the V
CC5
pin functions normally.
3
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