MAX919EUK+T Maxim Integrated Products, MAX919EUK+T Datasheet - Page 11

• Manufacturer Part Number: MAX919EUK+T
• Description: IC COMPARATOR BTR SOT23-5
• Manufacturer: Maxim Integrated Products
• Series: Beyond-the-Rails™r
• Type: General Purposer

Specifications of MAX919EUK+T

• Number Of Elements: 1
• Output Type: CMOS, Push-Pull, Rail-to-Rail, TTL
• Voltage - Supply: 1.8 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: SC-74A, SOT-753
• Number Of Channels: 1 Channel
• Product: Analog Comparators
• Offset Voltage (max): 10 mV
• Input Bias Current (max): 2 nA
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 1.8 V
• Supply Current (max): 0.8 uA
• Maximum Power Dissipation: 571 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Comparator Type: General Purpose
• No. Of Comparators: 1
• Response Time: 22µs
• Ic Output Type: CMOS, Push Pull
• Supply Current: 450nA
• Supply Voltage Range: 1.8V To 5.5V
• Amplifier Case Style: SOT-23
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MAX919EUK+T; MAX919EUK+TTR

The MAX917/MAX919 have a 4mV internal hysteresis
band (V
with three resistors using positive feedback (Figure 3).
Unfortunately, this method also slows hysteresis re-
sponse time. Use the following procedure to calculate
resistor values.
1) Select R3. Leakage current at IN is under 2nA, so
2) Choose the hysteresis band required (V
3) Calculate R1 according to the following equation:
4) Choose the trip point for V
5) Calculate R2 as follows:
Figure 2. Threshold Hysteresis Band
OUT
IN+
IN-
the current through R3 should be at least 0.2µA to
minimize errors caused by leakage current. The cur-
rent through R3 at the trip point is (V
Considering the two possible output states in solving
for R3 yields two formulas: R3 = V
(V
resistor values. For example, when using the
MAX917 (V
choose I
1.2MΩ and 3.8MΩ. Choose a 1.2MΩ standard value
for R3.
example, choose 50mV.
For this example, insert the values
V
V
comparator switches its output from low to high as
V
choose 3V.
R2 = 1/[V
Additional Hysteresis (MAX917/MAX919)
THR
IN
IN
V
V
CC
THR
THF
falling). This is the threshold voltage at which the
rises above the trip point. For this example,
HB
- V
> V
). Additional hysteresis can be generated
REF
R3
R1 = 1.2MΩ (50mV/5V) = 12kΩ
REF
THR
SOT23, 1.8V, Nanopower, Beyond-the-Rails
V
REF
)/I
HB
= 1µA, then the two resistor values are
/(V
· (R1 + R3)/R3 (V
R3
R1 = R3 (V
______________________________________________________________________________________
= 1.245V) and V
REF
. Use the smaller of the two resulting
· R1) - (1 / R1) - (1 / R3)]
THRESHOLDS
HYSTERESIS
Comparators With/Without Reference
BAND
HB
IN
/ V
rising (V
THF
CC
CC
)
is the trip point for
REF
= 5V, and if we
REF
THR
/I
HB
- V
R3
) such that
). For this
OUT
or R3 =
)/R3.
For this example, choose an 8.2kΩ standard value.
6) Verify the trip voltages and hysteresis as follows:
The MAX918/MAX920 have a 4mV internal hysteresis
band. They have open-drain outputs and require an
external pullup resistor (Figure 4). Additional hysteresis
can be generated using positive feedback, but the for-
mulas differ slightly from those of the MAX917/
MAX919. Use the following procedure to calculate
resistor values.
1) Select R3 according to the formulas R3 = V
2) Choose the hysteresis band required (V
3) Calculate R1 according to the following equation:
4) Choose the trip point for V
5) Calculate R2 as follows:
Figure 3. MAX917/MAX919 Additional Hysteresis
R2 = 1/[3.0V/(1.2V · 12kΩ) - (1 / 12kΩ) -
V
V
Hysteresis = V
or R3 = (V
the two resulting resistor values.
the trip point for V
voltage at which the comparator switches its output
from low to high as V
Additional Hysteresis (MAX918/MAX920)
V
IN
IN
IN
R2
rising: V
falling: V
(1/1.2MΩ)] = 8.05kΩ
=
R1
1/ V
+ (1 / R3)]
CC
⎡
⎢
⎢
⎣
R1 = (R3 + R4) (V
THR
THF
R2
THR
THR
- V
= V
= V
/ V
REF
(
- V
IN
V
REF
REF
THR
REF
IN
)/1µA - R4. Use the smaller of
THF
falling). This is the threshold
rises above the trip point.
⋅
· R1 [(1 / R1) + (1 / R2)
- (R1 · V
R3
R1
IN
)
V
V
−
V
HB
CC
CC
EE
rising (V
⎛
⎜
⎝
R1
/V
CC
1
CC
⎞
⎟ −
⎠
/ R3)
OUT
MAX917
MAX919
)
R3
1
THR
HB
⎤
⎥
⎥
⎦
).
) (V
REF
THF
/ 1µA
11
is