Datasheet MIC834BM5 Datasheet (MICREL)

MIC834 Micrel

MIC834

Comparator with Reference

Advance Information

General Description

The MIC834 is a micropower, precision voltage comparator
with an on-chip voltage reference.

The threshold is adjusted by the choice of two external
resistors. Voltage detection threshold is accurate to 1%.

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.

Ordering Information

Part Number Marking Accuracy Temperature Range Package

MIC834BM5 B12 1% –40°C to +85°C SOT-23-5

Features

• 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% 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

Applications

•PDAs

• Pagers

• Cordless phones

• Consumer electronics

• Embedded controllers

• Personal electronics

Typical Application

V

V

IN

DD

MIC834

R1

R2

IttyBitty™ is a trademark of Micrel, Inc.

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com

5

INP

April 2000 1 MIC834

OUTVDD

GND

V

PULL-UP

4

21

R

PU

V
V
V

1.5V ≤ V

V

OUT

= 1.24V

REF

= 6V

INP(max)
PULL-UP(max)

DD

= 6V

≤ 5.5V

MIC834 Micrel

Pin Configuration

GND

2

INP

13

VDDOUT

NC

45

SOT-23-5 (M5)

Pin Description

Pin Number Pin Name Pin Function

1 INP Input: Analog input to the comparator. When V

2 GND Ground
3 NC No Connect
4 OUT Output: Active-high, open-drain output. This output is de-asserted when

5 VDD Power Supply (Input): Independent supply input for internal circuitry.

asserted to a logic-high level output.

V

INP<VREF

V

INP>VREF+VHYST.

, indicating a low voltage input. The output is asserted when

INP>VREF+VHYST

, V

OUT

is

MIC834 2 April 2000

MIC834 Micrel

Absolute Maximum Ratings (Note 1)

Supply Voltage (V
Input Voltage (V
Output Current (I

Storage Temperature (TS) ....................... –65°C to +150°C

ESD Rating, Note 3 ......................................................2kV

) ..................................... –0.3V to +7V

DD

) ......................................................+7V

INP

).................................................20mA

OUT

Operating Ratings (Note 2)

Supply Voltage (V
Input Voltage (V
Ambient Temperature Range (T

Junction Temperature (TJ) ....................... Internally Limited

Package Thermal Resistance (θ

) .................................. +1.5V to +5.5V

DD

) ......................................... –0.3V to 6V

INP

) .............–40°C to +85°C

A

) ......................260°C/W

JA

Electrical Characteristics

1.5V ≤ VDD ≤ 5.5V; TA = +25°C, bold values indicate –40°C ≤ TA ≤ +85°C; unless noted
Symbol Parameter Condition Min Typ Max Units

I

DD

I

INP

V

REF

V

HYST

t

D

V

OUT

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. V
Note 5. VDD operating range is 1.5V to 5.5V. Output is guaranteed to be held low down to VDD = 1.2V.

Supply Current output not asserted 1.5 3 µA
Input Leakage Current 0.005 10 nA
Reference Voltage 1.228 1.240 1.252 V
Hysteresis Voltage, Note 4 10 23 35 mV
Propagation Delay V

Output Voltage-Low, Note 5 OUT de-asserted, I

= V

HTH

REF

+ V

HYST

.

= 1.352V to 1.128V 12 µs

INP

V

= 1.143V to 1.367V 8 µs

INP

= 1.6mA, VDD ≥ 1.6V 0.05 0.3 V

SINK

OUT de-asserted, I

= 100µA, VDD ≥ 1.2V, 0.005 0.4 V

SINK

Functional Diagram

V

HTH

V

V

IN

REF

(Note A)

0V

V

PULL-UP

V

OUT

0V

Note A. VIN here represents the attenuated input voltage, as applied to the INP pin; i.e., V
Note B. Brief transients are ignored by the MIC834. See “Applications Information.”

Note B

Note B

t

D

INP

t

D

.

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MIC834 Micrel

Block Diagram

V

V

IN

INP

TH

1

1.24V
Bandgap
Reference

2

GND

DD

VDD

5

High-Voltage

Detect

MIC834

OUT

4

Functional Description

The MIC834 monitors the input voltage and detects when it
is higher than a programmed level (plus V
tion 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 (V
the output stage is on.

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.

). This condi-

HYST

INP<VREF

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 V
output is pulled high by an external resistor.

),

V

is typically 23mV, and is added to the programmed

HYST

threshold voltage for positive-going inputs. Decreasing in­puts trip at the user-programmed threshold voltage.

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
tolerance of the hysteresis voltage.

HYST

plus

), the

the

MIC834 4 April 2000

MIC834 Micrel

V

R1

IN

5

MIC834

OUTVDD

470k

V

4

OUT

Applications Information

Output

Since the MIC834 output is an open-drain MOSFET, most
applications will require a pull-up resistor. The value of the

INP

resistor should not be too large or leakage effects may
dominate. 470kΩ is the maximum recommended value. Note

R2

GND

21

that the output may be pulled up as high as 6V regardless of
the IC’s supply voltage. See “Electrical Characteristics.”

Programming the Threshold

The voltage threshold is calculated using:

R1 R2

+

VV

=

IN(lo) REF






R2






where:

V 1.240V

=

REF

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 = R
value such as 1MΩ for R

is a reasonable value because

TOTAL

TOTAL

. A

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 V
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

Input Transients

The MIC834 is inherently immune to very short negative­going “glitches.” Very brief transients may exceed the V
threshold without tripping the output.

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.

IN

Figure 1. Example Circuit

Input Transient

140
120
100

80
60
40
20

0

MAX. TRANSIENT DURATION (µs)

1 10 100 1000

RESET COMP. OVERDRIVE, V

Response

REF–VLTH

(mV)

Figure 2. Input Transient Response

IN(lo)

“Electrical Characteristics.”

April 2000 5 MIC834

MIC834 Micrel

Package Information

1.90 (0.075) REF

0.95 (0.037) REF

3.02 (0.119)

2.80 (0.110)

0.50 (0.020)

0.35 (0.014)

1.75 (0.069)

1.50 (0.059)

1.30 (0.051)

0.90 (0.035)

0.15 (0.006)

0.00 (0.000)

5-Pin SOT (M)

3.00 (0.118)

2.60 (0.102)

10°

0°

DIMENSIONS:

MM (INCH)

0.20 (0.008)

0.09 (0.004)

0.60 (0.024)

0.10 (0.004)

MIC834 6 April 2000

MIC834 Micrel

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MIC834 Micrel

MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL + 1 [phone] FAX + 1 [phone] WEB 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.

© 2000 Micrel Incorporated

MIC834 8 April 2000