Micrel MIC834 Comparator with reference advance information Datasheet

MIC834
Micrel
MIC834
Comparator with Reference
Final Information
General Description
Features
The MIC834 is a micropower, precision voltage comparator
with an on-chip voltage reference.
• Optimized for PDAs, cellular telephones, pagers,
and other battery-powered devices
• Input and output can be pulled up to 6V
regardless of supply voltage
• High ±1.5% voltage threshold accuracy
• Built in hysteresis for noise suppression
• Extremely low 1.5µA typical supply current
• Immune to brief input transients
• 5-lead SOT-23 package
The threshold is adjusted by the choice of two external
resistors. Voltage detection threshold is accurate to 1.5%.
Supply current is extremely low (1.5µA, typical), making it
ideal for portable applications.
The MIC834 is supplied in Micrel’s IttyBitty™ 5-lead SOT-235 package.
Applications
•
•
•
•
•
•
PDAs
Pagers
Cordless phones
Consumer electronics
Embedded controllers
Personal electronics
Ordering Information
Part Number
Marking
Accuracy
Temperature Range
Package
MIC834BM5
B12
1.5%
–40°C to +85°C
SOT-23-5
Typical Application
VIN VDD
VPULL-UP
MIC834
R1
5
1
VDD
OUT
INP
GND
R2
RPU
4
2
VOUT
VREF = 1.24V
VINP(max) = 6V
VPULL-UP(max) = 6V
1.5V ≤ VDD ≤ 5.5V
IttyBitty™ is a trademark of Micrel, Inc.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
September 2001
1
MIC834
MIC834
Micrel
Pin Configuration
NC GND INP
3
2
1
4
5
OUT
VDD
SOT-23-5 (M5)
Pin Description
Pin Number
Pin Name
1
INP
Input: Analog input to the comparator. When VINP > VREF + VHYST, VOUT is
asserted to a logic-high level output.
2
GND
Ground
3
NC
4
OUT
Output: Active-high, open-drain output. This output is de-asserted when
VINP < VREF, indicating a low voltage input. The output is asserted when
VINP > VREF + VHYST.
5
VDD
Power Supply (Input): Independent supply input for internal circuitry.
MIC834
Pin Function
No Connect
2
September 2001
MIC834
Micrel
Absolute Maximum Ratings (Note 1)
Operating Ratings (Note 2)
Supply Voltage (VDD) ..................................... –0.3V to +7V
Input Voltage (VINP) ...................................................... +7V
Output Current (IOUT) ................................................. 20mA
Storage Temperature (TS) ....................... –65°C to +150°C
ESD Rating, Note 3 ...................................................... 2kV
Supply Voltage (VDD) .................................. +1.5V to +5.5V
Input Voltage (VINP) ......................................... –0.3V to 6V
Ambient Temperature Range (TA) ............. –40°C to +85°C
Junction Temperature (TJ) ....................... Internally Limited
Package Thermal Resistance (θJA) ...................... 260°C/W
Electrical Characteristics
1.5V ≤ VDD ≤ 5.5V; TA = +25°C, bold values indicate –40°C ≤ TA ≤ +85°C; unless noted
Symbol
Parameter
Condition
IDD
Supply Current
output not asserted
IINP
Input Leakage Current
VREF
Reference Voltage
VHYST
Hysteresis Voltage, Note 4
tD
Propagation Delay
VOUT
Output Voltage-Low, Note 5
Min
Typ
Max
Units
1.5
3
µA
0.005
10
nA
1.221
1.240
1.259
V
10
23
35
mV
VINP = 1.352V to 1.128V
12
µs
VINP = 1.143V to 1.367V
8
µs
OUT de-asserted, ISINK = 1.6mA, VDD ≥ 1.6V
0.05
0.3
V
OUT de-asserted, ISINK = 100µA, VDD ≥ 1.2V,
0.005
0.4
V
Note 1.
Exceeding the absolute maximum rating may damage the device.
Note 2.
The device is not guaranteed to function outside its operating rating.
Note 3.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Note 4.
VHTH = VREF + VHYST.
Note 5.
VDD operating range is 1.5V to 5.5V. Output is guaranteed to be held low down to VDD = 1.2V.
Functional Diagram
VIN
(Note A)
VHTH
VREF
Note B
Note B
0V
VPULL-UP
tD
tD
VOUT
0V
Note A. VIN here represents the attenuated input voltage, as applied to the INP pin; i.e., VINP.
Note B. Brief transients are ignored by the MIC834. See “Applications Information.”
September 2001
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MIC834
MIC834
Micrel
Block Diagram
VDD
VIN
5
High-Voltage
Detect
INP
VTH
VDD
OUT
1
4
1.24V
Bandgap
Reference
MIC834
2
GND
Trip Points
Input voltage is monitored by a comparator via a voltage
divider network. The divided voltage is compared to an
internal reference voltage. When the voltage at the input pin
INP exceeds the internal reference voltage (plus VHYST), the
output is pulled high by an external resistor.
Functional Description
The MIC834 monitors the input voltage and detects when it
is higher than a programmed level (plus VHYST). This condition asserts the active-high output. An external pull-up resistor is used to produce a logic-one output. When the input
voltage falls below the programmed threshold (VINP < VREF),
the output stage is on.
VHYST is typically 23mV, and is added to the programmed
threshold voltage for positive-going inputs. Decreasing inputs trip at the user-programmed threshold voltage.
Voltage Low Output
The voltage-low output (OUT) is an active-high, open-drain
output which sinks current when the MIC834 detects a low
input voltage.
MIC834
The tolerance of the switching threshold on the falling edge
is equal to the tolerance of just the voltage reference. The
tolerance of the switching threshold on the rising edge is
equal to the tolerance of the voltage reference plus the
tolerance of the hysteresis voltage.
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September 2001
MIC834
Micrel
VIN
Applications Information
Output
Since the MIC834 output is an open-drain MOSFET, most
applications will require a pull-up resistor. The value of the
resistor should not be too large or leakage effects may
dominate. 470kΩ is the maximum recommended value. Note
that the output may be pulled up as high as 6V regardless of
the IC’s supply voltage. See “Electrical Characteristics.”
MIC834
R1
5
1
INP
GND
4
VOUT
2
Figure 1. Example Circuit
Input Transients
The MIC834 is inherently immune to very short negativegoing “glitches.” Very brief transients may exceed the VIN(lo)
threshold without tripping the output.
 R1 + R2 
= VREF 

 R2 
where:
As shown in Figure 2, the narrower the transient, the deeper
the threshold overdrive that will be ignored by the MIC834.
The graph represents the typical allowable transient duration
for a given amount of threshold overdrive that will not generate an output.
VREF = 1.240V
MAX. TRANSIENT DURATION (µs)
In order to provide the additional criteria needed to solve for
the resistor values, the resistors can be selected such that
they have a given total value, that is, R1 + R2 = RTOTAL. A
value such as 1MΩ for RTOTAL is a reasonable value because
it draws minimum current but has no significant effect on
accuracy.
When working with large resistors, a small amount of leakage
current can cause voltage offsets that degrade system accuracy. The maximum recommended total resistance from VIN
to ground is 3MΩ. The accuracy of the resistors can be
chosen based upon the accuracy required by the system. The
inputs may be subjected to voltages as high as 6V steadystate without adverse effects of any kind regardless of the
IC’s supply voltage. This applies even if the supply voltage is
zero. This permits the situation in which the IC’s supply is
turned off, but voltage is still present on the inputs. See
“Electrical Characteristics.”
September 2001
OUT
R2
Programming the Threshold
The voltage threshold is calculated using:
VIN(lo)
470k
VDD
Input Transient
Response
140
120
100
80
60
40
20
0
1
10
100
1000
RESET COMP. OVERDRIVE, VREF–VLTH (mV)
Figure 2. Input Transient Response
5
MIC834
MIC834
Micrel
Package Information
1.90 (0.075) REF
0.95 (0.037) REF
1.75 (0.069)
1.50 (0.059)
3.00 (0.118)
2.60 (0.102)
DIMENSIONS:
MM (INCH)
3.02 (0.119)
2.80 (0.110)
0.50 (0.020)
0.35 (0.014)
1.30 (0.051)
0.90 (0.035)
0.20 (0.008)
0.09 (0.004)
10°
0°
0.15 (0.006)
0.00 (0.000)
0.60 (0.024)
0.10 (0.004)
5-Pin SOT (M)
MIC834
6
September 2001
MIC834
September 2001
Micrel
7
MIC834
MIC834
Micrel
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
+ 1 (408) 944-0800
FAX
+ 1 (408) 944-0970
WEB
USA
http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or
other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.
© 2001 Micrel Incorporated
MIC834
8
September 2001
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