MIC845
Micro-Power Comparator /
Battery Monitor
TeenyTM is a trademark of Micrel, Inc.
Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 http://www.micrel.com
July 2005
M9999-070505
(408) 955-1690
General Description
The MIC845 is a precision micro-power voltage
comparator with an on-chip 2.55V reference voltage
source.
Intended for voltage monitoring applications, the
MIC845 can be used with an external resistor divider
to detect a wide range of voltages, or without
external resistors to directly monitor voltages with its
high input impedance CMOS input.
The MIC845 incorporates a voltage reference and
comparator with fixed internal hysteresis. When the
2.55V internal threshold is crossed, the output
switches polarity.
MIC845 is available with a push-pull or open-drain
output stage. The push-pull output stage is
configured for both active high or active low output;
the open-drain output stage is only configured active
high.
Supply current is extremely low (typically 1A),
making it ideal for portable applications.
MIC845 is supplied in Micrel's TeenyTM 5-lead SC-
70 package.
Data sheets and support documentation can be
found on Micrel's web site at www.micrel.com.
TeenyTM
Features
Extremely low 1A supply current (typical)
2.55V on chip reference
2% voltage threshold accuracy
Optimized for PDAs, cellular telephones, pagers,
and other battery-powered devices
Open-drain output can be pulled up to 6V
regardless of supply voltage
5-lead SC-70 package
Applications
PDAs
Pagers
Cordless phones
Portable electronics
Motherboards
Bladed servers
____________________________________________________________________________________________________
Typical Applications
R1
INP
GND
OUT
V
DD
V
REF
= 2.55V
MIC845
Internal Fixed Hysteresis
R2
V
DD
V
IN
V
OUT
2.75V < V
DD
< 5.5V
Threshold Detector with
3.3V
INP
GND
OUT
V
DD
to Host
Memory
power
Lithium
Coin Cell
MIC845
Nano-Power Battery Monitor
Micrel, Inc.
MIC845
July 2005
2
M9999-070505
(408) 955-1690
Ordering Information
Part Number
Standard Marking
Pb-Free Marking*
Temperature Range
Package
MIC845HBC5 B19
MIC845HYC5 B19
40 to +85C
SC-70
MIC845LBC5 B20
MIC845LYC5 B20
40 to +85C
SC-70
MIC845NBC5 B21
MIC845NYC5 B21
40 to +85C
SC-70
*
Note:
Underscore on device marking indicates Pb-Free packaging.
Pin Configuration
INP GND
OUT
VDD
NIC
3
1
5
2
4
SC-70-5 (C5)
(TOP VIEW)
Pin Description
Pin Number
Pin Name
Pin Function
1
NIC
No Internal Connection. A signal applied to this pin will have no effect
on device operation.
2 GND
Ground
3 INP
Input: Analog input to the comparator. When V
INP
> V
REF
+ V
HYST
, V
OUT
is
asserted, and the condition is held until V
INP
< V
REF
.
OUT
("N" Version)
Output: Active-high, open-drain output. This output is low when
V
INP
< V
REF
, indicating a low voltage input. The output is high when
V
INP
> V
REF
+ V
HYST
.
OUT
("H" Version)
Output: Active-high, Push-pull output. This output is low when
V
INP
< V
REF
, indicating a low voltage condition. The output is high when
V
INP
> V
REF
+ V
HYST
.
4
OUT
("L" Version)
Output: Active-low, Push-pull output. This output is high when
V
INP
< V
REF
, indicating a low voltage condition. The output is low when
V
INP
> V
REF
+ V
HYST
.
5
VDD
Power Supply (Input): Independent supply input for internal circuitry.
Micrel, Inc.
MIC845
July 2005
3
M9999-070505
(408) 955-1690
Absolute Maximum Ratings
(1)
Supply Voltage (V
DD
) ..............................-0.3V to +6V
Input Voltage (V
INP
).................................-0.3V to +6V
Output Current (I
OUT
)......................................... 20mA
Junction Temperature (T
J
).............. 40C to +125C
Storage Temperature (T
s
)............... 65C to +150C
Lead Temperature (soldering, 5 sec.) ..............260C
ESD Rating
(3)
........................................................3kV
Operating Ratings
(2)
Supply voltage (V
DD
) ........................ +2.75V to +5.5V
Input Voltage............................................... -0.3 to 6V
Ambient Temperature (T
A
)................ 40C to +85C
Junction to Ambient Thermal Resistance:
SC-70
(
JA
)............................................ 450C/W
Electrical Characteristics
2.75V < V
DD
< 5.5V; T
A
= 25C,
Bold
values indicate 40C< T
A
< +85C, unless noted.
Parameter Parameter
Conditions
Min Typ. Max Units
I
DD
Supply Current
No load on output
1
3
A
I
INP
Input Leakage Current
V
DD
= 5.5V, V
INP
= 0V
.005
10
nA
I
INP_PD
Input Leakage Current in power down
V
DD
= 0V
(note 4)
,
V
INP
= 5.5V
.005
10
nA
V
REF
V
REF
40C to 85C
2.50
2.55
2.60
V
V
HYST
Comparator
Hysteresis
8
25
40
mV
V
OUT
Output Voltage, `N'
I
SINK
= 1.6mA, VDD 2.75V
0.3
V
I
SINK
= 1.6mA, VDD 2.75V
0.3
V
V
OUT
Output Voltage, `L' and `H'
I
SOURCE
= 500A,
VDD 2.75V
0.95
V
DD
0.99
V
DD
V
V
INP
= 2.7V to 2.4V
12
39
s
t
D
Propagation
Delay
V
INP
= 2.4V to 2.7V
8
26
s
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model: 1.5k in series with 100pF.
4. VDD is tied to Gnd, not left floating.
Micrel, Inc.
MIC845
July 2005
4
M9999-070505
(408) 955-1690
Typical Characteristics
-200
0
200
400
600
800
-40 -20
0
20
40
60
80
I
DD
(nA
)
TEMPERATURE (C)
I
DD
vs. Temperature
V
DD
= 4.5V
V
IN
= 0V
V
DD
= 0V
V
IN
= 4.5V
-2000
-1500
-1000
-500
0
500
1000
1500
-40 -20
0
20
40
60
80
TEMPERATURE (C)
I
IN
vs. Temperature
V
DD
= 0V
V
IN
= 4.5V
V
DD
= 4.5V
V
IN
= 0V
-200
0
200
400
600
800
1000
1200
-40 -20
0
20
40
60
80
I
DD
(nA
)
TEMPERATURE (C)
I
DD
vs. Temperature
V
DD
= 3V
V
IN
= 4.2V
V
DD
= 0V
V
IN
= 4.2V
-200
0
200
400
600
800
-40 -20
0
20
40
60
80
TEMPERATURE (C)
I
IN
vs. Temperature
V
DD
= 0V
V
IN
= 4.2V
V
DD
= 3V
V
IN
= 4.2V
Micrel, Inc.
MIC845
July 2005
5
M9999-070505
(408) 955-1690
Block Diagrams
GND
V
DD
OUT
2.55V
Bandgap
Reference
High-Voltage
Detect
INP
V
TH
MIC845H
V
DD
V
IN
3
2
4
5
GND
V
DD
OUT
2.55V
Bandgap
Reference
High-Voltage
Detect
INP
V
TH
MIC845L
V
DD
V
IN
3
2
4
5
GND
V
DD
OUT
2.55V
Bandgap
Reference
High-Voltage
Detect
INP
V
TH
MIC845N
V
DD
V
IN
3
2
4
5
V
OUT
V
IN
V
REF
Type H and N
V
REF
+ Hysteresis
V
OUT
V
IN
V
REF
Type L
V
REF
+ Hysteresis
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