MAXIM MAX834EUK

19-1157; Rev 0; 12/96
Micropower, Latching Voltage Monitors
in SOT23-5
The MAX834/MAX835 micropower voltage monitors
contain a 1.204V precision bandgap reference, comparator, and latched output in a 5-pin SOT23 package.
Using the latched output prevents deep discharge of
batteries. The MAX834 has an open-drain, N-channel
output driver, while the MAX835 has a push/pull output
driver. Two external resistors set the trip-threshold
voltage.
The MAX834/MAX835 feature a level-sensitive latch,
eliminating the need to add hysteresis to prevent oscillations in battery-load-disconnect applications.
____________________________Features
♦ Prevents Deep Discharge of Batteries
♦ Precision ±1.25% Voltage Threshold
♦ Latched Output (once low, stays low
until cleared)
♦ SOT23-5 Package
♦ Low Cost
♦ Wide Operating Voltage Range, +2.5V to +11V
♦ <2µA Typical Supply Current
♦ Open-Drain Output (MAX834)
Push/Pull Output (MAX835)
________________________Applications
______________Ordering Information
Precision Battery Monitor
PART
TEMP.
RANGE
PINPACKAGE
SOT
TOP MARK
Battery-Powered Systems
MAX834EUK-T
-40°C to +85°C
5 SOT23-5
AAAX
Threshold Detectors
MAX835EUK-T
-40°C to +85°C
5 SOT23-5
AAAY
Load Switching
__________Typical Operating Circuit
VCC
RL
CLEAR LATCH
OUT
CLEAR
(MAX834
ONLY)
__________________Pin Configuration
OUT
TOP VIEW
MAX834
MAX835
CLEAR 1
GND
VCC
GND 2
IN
VCC
5
OUT
4
IN
MAX834
MAX835
VCC 3
R1
0.1µF
R2
SOT23-5
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
MAX834/MAX835
_______________General Description
MAX834/MAX835
Micropower, Latching Voltage Monitors
in SOT23-5
ABSOLUTE MAXIMUM RATINGS
VCC, OUT (MAX834), CLEAR to GND ......................-0.3V to 12V
IN, OUT (MAX835), to GND........................-0.3V to (VCC + 0.3V)
INPUT Current
VCC .................................................................................20mA
IN.....................................................................................10mA
OUT Current.......................................................................-20mA
VCC Rate of Rise .............................................................100V/µs
Continuous Power Dissipation
SOT23-5 (derate 7.1mW/°C above +70°C)..................571mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC = +2.5V to +11V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
Operating Voltage
Range (Note 1)
Supply Current
(Note 2)
SYMBOL
MIN
VCC
ICC
Threshold Voltage
VTH
Threshold Voltage
Hysteresis
VHYST
TYP
2.5
VIN = 1.16V,
OUT = low,
VCLEAR ≥ VCC - 0.25V
or VCLEAR ≤ 0.25V
VIN = 1.25V,
OUT = high,
VCLEAR ≥ VCC - 0.25V
or VCLEAR ≤ 0.25V
VIN falling
VCC = 3.6V
TA = +25°C
2.4
TA = TMIN to TMAX
UNITS
11
V
5
10
VCC = full operating range
VCC = 3.6V
MAX
15
µA
TA = +25°C
1.1
TA = TMIN to TMAX
4
8
VCC = full operating range
13
TA = +25°C
1.185
1.204
1.215
TA = 0°C to +70°C
1.169
1.204
1.231
VCC = 5V, IN = low to high
6
V
mV
IN Operating Voltage
Range (Note 1)
VIN
IN Leakage Current
(Note 3)
IIN
VIN = VTH
±3
Propagation Delay
tPL
VCC = 5V, 50mV overdrive
80
µs
VCC = 5V, 100mV overdrive
35
µs
Glitch Immunity
0
VCC - 1
±12
V
nA
OUT Rise Time
tRT
VCC = 5V, no load (MAX835 only)
200
µs
OUT Fall Time
tFT
VCC = 5V, no load (MAX834 pull-up = 10kΩ)
480
µs
Output Leakage
Current (Note 4)
2
CONDITIONS
ILOUT
VIN > VTH(MAX) (MAX834 only)
Output Voltage High
VOH
VIN > VTH(MAX), ISOURCE = 500µA (MAX835 only)
Output Voltage Low
VOL
VIN < VTH(MIN), ISINK = 500µA
±1
VCC - 0.5
_______________________________________________________________________________________
µA
V
0.4
V
Micropower, Latching Voltage Monitors
in SOT23-5
MAX834/MAX835
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +2.5V to +11V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CLEAR Input
High Voltage
VCIH
CLEAR Input
Low Voltage
VCIL
CLEAR Input
Leakage Current
MIN
TYP
MAX
UNITS
2
V
ICLEAR
CLEAR Input
Pulse Width
Note 1:
Note 2:
Note 3:
Note 4:
CONDITIONS
±1
tCLR
0.4
V
±100
nA
1
µs
The voltage-detector output remains in the correct state for VCC down to 1.2V when VIN ≤ VCC / 2.
Supply current has a monotonic dependence on VCC (see Typical Operating Characteristics).
IN leakage current has a monotonic dependence on VCC (see Typical Operating Characteristics).
The MAX834 open-drain output can be pulled up to a voltage greater than VCC, but may not exceed 11V.
__________________________________________Typical Operating Characteristics
(VCC = +5V, Typical Operating Circuit, TA = +25°C, unless otherwise noted.)
3.5
3.0
2.5
2.0
50
40
40
60
TA = -40°C
80 100
MAXMAX834/835-10
VIN = 1.25V
3.5
TA = +85°C
3.0
2.5
TA = +25°C
2.0
TA = -40°C
1.5
1.0
0.5
TA = +85°C
0
0
1 2
3
4 5
6
7
8
9 10 11 12
0
1 2
4 5
3
6
7
9 10 11 12
8
TEMPERATURE (°C)
VIN (V)
VCC (V)
SUPPLY CURRENT
vs. INPUT VOLTAGE
SUPPLY CURRENT
vs. INPUT VOLTAGE
PROGRAMMED TRIP VOLTAGE
vs. TEMPERATURE
2
1
8
7
6
5
4
3
0
0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6
VIN (V)
4.8
VTRIP ≈ 4.5V
(FIGURE 2, R1 = 270kΩ,
R2 = 100kΩ)
4.4
4.0
3.6
3.2
VTRIP ≈ 3.3V
(FIGURE 2, R1 = 180kΩ,
R2 = 100kΩ)
2.4
1
0
5.2
2.8
2
MAXMAX834/835-13
9
6.0
5.6
TRIP VOLTAGE (V)
4
VCC = 11.0V
10
SUPPLY CURRENT (µA)
5
12
11
MAXMAX834/835-12
VCC = 3.6V
0
4.5
4.0
20
0
20
TA = +25°C
30
1.0
0
MAXMAX834/835-08
60
10
6
SUPPLY CURRENT (µA)
70
1.5
-60 -40 -20
VCC = 11.0V
80
SUPPLY CURRENT (µA)
4.0
90
INPUT LEAKAGE CURRENT (nA)
VCC = 5.0V
VIN = 1.2V
MAX834/835-11
INPUT LEAKAGE CURRENT (nA)
5.0
4.5
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
INPUT LEAKAGE CURRENT
vs. INPUT VOLTAGE
MAXMAX834/835-07
INPUT LEAKAGE CURRENT
vs. TEMPERATURE
2.0
0
1 2
3
4 5
6
7
VIN (V)
8
9 10 11 12
-60 -40 -20
0
20
40
60
80
100
TEMPERATURE (°C)
_______________________________________________________________________________________
3
_____________________________Typical Operating Characteristics (continued)
(VCC = +5V, Typical Operating Circuit, TA = +25°C, unless otherwise noted.)
MAX835
OUTPUT HIGH VOLTAGE
vs. SUPPLY VOLTAGE
150
100
TA = +25°C
TA = +85°C
350
300
250
200
TA = +25°C
150
100
0
15
TA = -40°C
1 2
3 4 5
6
7
9 10 11 12
8
TA = +25°C
10
TA = +85°C
5
0
0
0
0
1 2
3
4 5
6
9 10 11 12
8
7
0
1 2
3
4 5
6
7
8
9 10 11 12
VCC (V)
VCC (V)
VCC (V)
MAX835
OUTPUT SHORT-CIRCUIT
SOURCE CURRENT vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE FALLING TO OUT
PROPAGATION DELAY vs. TEMPERATURE
MAX835
OUTPUT RISE TIME vs. SUPPLY VOLTAGE
TA = +25°C
10
5
TA = +85°C
3 4 5
6
7
110
100
90
80
MAXMAX834/835-20
600
500
TA = +25°C
400
300
70
10mV/µs
200
50
100
40
0
-60 -40 -20
0
20
40
60
80 100
TA = -40°C
0
1 2
3
4 5
6
7
8
9 10 11 12
TEMPERATURE (°C)
VCC (V)
OUTPUT FALL TIME
vs. SUPPLY VOLTAGE
OUTPUT LOW VOLTAGE
vs. OUTPUT SINK CURRENT
MAX835
OUTPUT HIGH VOLTAGE
vs. OUTPUT SOURCE CURRENT
100k
MAXMAX834/835-21
2.0
VCC = 11V
10k
TA = +25°C
VOL (mV)
TA = +85°C
1.5
1.0
1k
TA = +85°C
100
TA = +25°C
10
0.5
TA = -40°C
3
TA = -40°C
4 5
6
7
VCC (V)
8
9 10 11 12
100k
VCC = 11V
TA = +25°C
10k
TA = +85°C
1k
TA = -40°C
100
10
1
0
1 2
TA = +85°C
700
VCC (V)
2.5
0
800
1mV/µs
120
9 10 11 12
8
900
VCC - VOH (mV)
1 2
130
MAXMAX834/835-23
0
140
60
0
1000
MAXMAX834/835-25
TA = -40°C
15
150
RISE TIME (ns)
20
160
MAXMAX834/835-19
MAXMAX834/835-18
VIN = 1.3V
PROPAGATION DELAY (µs)
25
4
VIN = 1.1V
TA = -40°C
50
TA = -40°C
20
MAXMAX834/835-17
400
50
SHORT-CIRCUIT CURRENT (mA)
ISOURCE = 500µA
450
VCC - VOH (mV)
VOL (mV)
TA = +85°C
MAXMAX834/835-15
ISINK = 500µA
200
500
MAXMAX834/835-14
250
OUTPUT SHORT-CIRCUIT
SINK CURRENT vs. SUPPLY VOLTAGE
SHORT-CIRCUIT CURRENT (mA)
OUTPUT LOW VOLTAGE
vs. SUPPLY VOLTAGE
FALL TIME (µs)
MAX834/MAX835
Micropower, Latching Voltage Monitors
in SOT23-5
1
0.1
1
10
OUTPUT SINK CURRENT (mA)
100
0.1
1
10
OUTPUT SOURCE CURRENT (mA)
_______________________________________________________________________________________
100
Micropower, Latching Voltage Monitors
in SOT23-5
MAX835
OUTPUT HIGH VOLTAGE
vs. OUTPUT SOURCE CURRENT
TA = -40°C
TA = +25°C
10
100
TA = -40°C
TA = +25°C
10
1.5
MAXMAX834/835-30
TA = +85°C
1k
VCC - VOH (mV)
VOL (mV)
VCC = 3.6V
TA = +85°C
100
MAXMAX834/835-29
VCC = 3.6V
1k
10k
MAXMAX834/835-27
10k
CLEAR TO OUT PROPAGATION DELAY
vs. TEMPERATURE
VIN > VTH
1.3
PROPAGATION DELAY (µs)
OUTPUT LOW VOLTAGE
vs. OUTPUT SINK CURRENT
VCC = 3.6V
1.1
0.9
VCC = 5.0V
0.7
0.5
VCC = 11.0V
0.3
1
1
0.1
1
10
OUTPUT SINK CURRENT (mA)
100
0.1
0.1
1
OUTPUT SOURCE CURRENT (mA)
-60 -40 -20
10
0
20
40
60
80
100
TEMPERATURE (°C)
______________________________________________________________Pin Description
PIN
NAME
1
CLEAR
2
GND
System Ground
3
VCC
System Supply Input
4
IN
5
OUT
FUNCTION
Clear Input resets the latched output. With VIN > VTH, pulse CLEAR high for a minimum of 1µs to reset the
output latch. Connect to VCC to make the latch transparent.
Noninverting Input to the Comparator. The inverting input connects to the internal 1.204V bandgap reference.
Open-Drain (MAX834) or Push/Pull (MAX835) Latched Output. OUT is active low.
VCC
CLEAR
RL (MAX834 ONLY)
CLEAR
LATCH
GND
MAX834
MAX835
LATCH
CLEAR
GND
OUT
OUT
IN
VCC
VCC
MAX834
MAX835
IN
1.204V
OUT
VCC
0.1µF
VTRIP = (1.204)
R1
( R1R2+ R2 )
R2
(UNITS ARE OHMS AND VOLTS)
Figure 1. Functional Diagram
Figure 2. Programming the Trip Voltage (VTRIP)
_______________________________________________________________________________________
5
MAX834/MAX835
_____________________________Typical Operating Characteristics (continued)
(VCC = +5V, Typical Operating Circuit, TA = +25°C, unless otherwise noted.)
MAX834/MAX835
Micropower, Latching Voltage Monitors
in SOT23-5
_______________Detailed Description
The MAX834/MAX835 micropower voltage monitors contain a 1.204V precision bandgap reference and a comparator with an output latch (Figure 1). The difference
between the two parts is the structure of the comparator
output driver. The MAX834 has an open-drain, N-channel
output driver that can be pulled up to a voltage higher
than VCC, but less than 11V. The MAX835’s output is
push/pull and can both source and sink current.
Programming the Trip Voltage (VTRIP)
Two external resistors set the trip voltage, VTRIP (Figure
2). VTRIP is the point at which the falling monitored voltage (typically VCC) causes OUT to go low. IN’s high
input impedance allows the use of large-value
resistors without compromising trip voltage accuracy. To
minimize current consumption, choose a value for R2
between 500kΩ and 1MΩ, then calculate R1 as follows:
where VTRIP is the desired trip voltage and VTH is the
threshold voltage (1.204V). The voltage at IN must be at
least 1V less than VCC.
Latched-Output Operation
The MAX834/MAX835 feature a level-sensitive latch
input (CLEAR), designed to eliminate the need for hysteresis in battery undervoltage-detection applications.
When the monitored voltage (VMON) is above the programmed trip voltage (VTRIP) (as when the system battery is recharged or a fresh battery is installed), pulse
CLEAR low-high-low for at least 1µs to reset the output
latch (OUT goes high). When VMON falls below VTRIP,
OUT goes low and remains low (even if VMON rises
above VTRIP), until CLEAR is pulsed high again with
VMON > VTRIP. Figure 3 shows the timing relationship
between VMON, OUT, and CLEAR.
R1 = R2 [(VTRIP / VTH) - 1]
> VTRIP
VMON
< VTRIP
> 1µs
> 1µs
> 1µs
VCC
CLEAR
0V
VCC
OUT
0V
Figure 3a. Timing Diagram
> VTRIP
VMON
< VTRIP
VCC
OUT
0V
Figure 3b. Timing Diagram, CLEAR = VCC
6
_______________________________________________________________________________________
Micropower, Latching Voltage Monitors
in SOT23-5
CLEAR
LATCH
VMON
RL*
R1
OUT
CLEAR
VMON(MAX) = (VCC - 1)(R1 + R2) / R2
IN
GND
VCC
OUT
Load-Disconnect Switch
VCC
R2
MAX834
MAX835
0.1µF
R1 + R2
R2
(UNITS ARE OHMS AND VOLTS)
VTRIP = (1.204)
*MAX834 ONLY
Figure 4. Monitoring Voltages Other than VCC
P
___________________Chip Information
Q1
CLEAR
LATCH
VBATT
The circuit in Figure 5 is designed to prevent a leadacid battery or a secondary battery such as an NiCd,
from sustaining damage through deep discharge. As
the battery reaches critical undervoltage, OUT switches
low. Q1 and Q2 turn off, disconnecting the battery from
the load. The MAX835’s latched output prevents Q1 and
Q2 from turning on again as the battery voltage relaxes
to its open-circuit voltage when the load disconnects.
CLEAR can be connected to a pushbutton switch, an
RC network, or a logic gate to reset the latch when the
battery is recharged or replaced.
TRANSISTOR COUNT: 74
1M
RLOAD
R1
Q2
CLEAR
N
OUT
GND
VCC
IN
R2
MAX835
VCC
0.1µF
Figure 5. Load-Disconnect Switch
_______________________________________________________________________________________
7
MAX834/MAX835
VCC
Monitoring Voltages Other than VCC
The typical operating circuit for the MAX834/MAX835
monitors VCC. Voltages other than VCC can easily be
monitored, as shown in Figure 4. Calculate VTRIP as
in the section Programming the Trip Voltage. When
monitoring voltages other than VCC, ensure that the
maximum value for VMON is not exceeded:
__________________________________________________Tape-and-Reel Information
E
D
P0
W
P2
B0
t
D1
F
P
NOTE: DIMENSIONS ARE IN MM.
AND FOLLOW EIA481-1 STANDARD.
K0
A0
A0
3.200
±0.102
E
1.753
±0.102
P0
B0
3.099
±0.102
F
3.505
±0.051
P010
D
1.499
+0.102
+0.000
K0
1.397
±0.102
P2
P
3.988
±0.102
t
D1
0.991
+0.254
+0.000
3.988
±0.102
40.005±0.203
2.007±0.051
0.254±0.127
+0.305
-0.102
W 8.001
5 SOT23-5
MAX834/MAX835
Micropower, Latching Voltage Monitors
in SOT23-5
________________________________________________________________Package Information
b
DIM
e
E
e1
D
α
A
A1
A2
b
C
D
E
E1
L
e
e1
α
MILLIMETERS
MIN
MAX
0.90
1.45
0.00
0.15
0.90
1.30
0.35
0.50
0.08
0.20
2.80
3.00
2.60
3.00
1.50
1.75
0.35
0.55
0.95ref
1.90ref
0°
10°
21-0057B
E1
A A2
C
L
5-PIN SOT23-5
SMALL-OUTLINE
TRANSISTOR PACKAGE
A1
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
8 ___________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600
© 1996 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.