Load-driving capability – Rainbow Electronics MAX4244 User Manual
Page 12
MAX4240–MAX4244
GND). When using dual supplies, pull SHDN to V
EE
to
enter shutdown mode.
Load-Driving Capability
The MAX4240–MAX4244 are fully guaranteed over tem-
perature and supply voltage to drive a maximum resis-
tive load of 10k
Ω
to V
CC
/ 2, although heavier loads can
be driven in many applications. The rail-to-rail output
stage of the amplifier can be modeled as a current
source when driving the load toward V
CC
, and as a cur-
rent sink when driving the load toward V
EE
. The magni-
tude of this current source/sink varies with supply
voltage, ambient temperature, and lot-to-lot variations
of the units.
Figures 7a and 7b show the typical current source and
sink capability of the MAX4240–MAX4244 family as a
function of supply voltage and ambient temperature.
The contours on the graph depict the output current
Single/Dual/Quad, +1.8V/10µA, SOT23,
Beyond-the-Rails Op Amps
12
______________________________________________________________________________________
MAX4240-44 fig06
200
µ
s/div
5V/div
1V/div
SHDN
OUT
V
IN
= 2V
R
L
= 100k
Ω
TIED TO V
EE
Figure 6. Shutdown Enable/Disable Output Voltage
1200
0
-60
-40
-20
100
200
400
1000
MAX4240-44 fig07a
TEMPERATURE (°C)
OUTPUT SOURCE CURRENT (
µ
A)
0
40
20
600
800
80
60
V
CC
= 5.5V, V
OH
= 200mV
V
CC
= 5.5V, V
OH
= 100mV
V
CC
= 1.8V, V
OH
= 50mV
V
CC
= 5.5V, V
OH
= 50mV
V
CC
= 1.8V,
V
OH
= 200mV
V
CC
= 1.8V,
V
OH
= 100mV
Figure 7a. Output Source Current vs. Temperature
3000
0
-60
-40
-20
100
500
1000
2500
MAX4240-44 fig07b
TEMPERATURE (°C)
OUTPUT SINK CURRENT (
µ
A)
0
40
20
1500
2000
80
60
V
CC
= 5.5V, V
OL
= 200mV
V
CC
= 1.8V, V
OL
= 200mV
V
CC
= 5.5V,
V
OL
= 100mV
V
CC
= 1.8V, V
OL
= 50mV
V
CC
= 5.5V, V
OL
= 50mV
V
CC
= 1.8V, V
OL
= 100mV
Figure 7b. Output Sink Current vs. Temperature
Table 1. MAX4240/MAX4241 Characteristics with Typical Battery Systems
RECHARGEABLE
V
END-OF-LIFE
(V)
Alkaline (2 Cells)
No
3.0
Nickel-
Cadmium (2 Cells)
Yes
1.8
BATTERY TYPE
Lithium-Ion (1 Cell)
Yes
2.4
Nickel-Metal-
Hydride (2 Cells)
Yes
1.8
V
FRESH
(V)
3.5
2.7
2.4
1.8
CAPACITY,
AA SIZE
(mA-h)
2000
750
1000
1000
MAX4240/MAX4241
OPERATING TIME
IN NORMAL MODE
(Hours)
200,000
75,000
100,000
100,000
MAX4241
OPERATING TIME
IN SHUTDOWN
MODE (Hours)
2 x 10
6
0.75 x 10
6
10
6
10
6