MIC1555BM5 TR Micrel Inc, MIC1555BM5 TR Datasheet - Page 9

• Manufacturer Part Number: MIC1555BM5 TR
• Description: IC RC TIMER/OSCILLATOR SOT23-5
• Manufacturer: Micrel Inc
• Type: 555 Type, Timer/Oscillator (Single)r
• Series: IttyBitty®r

Specifications of MIC1555BM5 TR

• Frequency: 5MHz
• Voltage - Supply: 2.7 V ~ 18 V
• Current - Supply: 350µA
• Operating Temperature: -40°C ~ 85°C
• Package / Case: SOT-23-5, SC-74A, SOT-25
• # Internal Timers: 1
• Operating Supply Voltage (min): 2.7V
• Operating Supply Voltage (typ): 3.3/5/9/12/15V
• Operating Supply Voltage (max): 18V
• Package Type: SOT-23
• High Level Output Current: -20mA
• Low Level Output Current: 20mA
• Pin Count: 5
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Count: -
• Lead Free Status / RoHS Status: Not Compliant, Contains lead / RoHS non-compliant
• Other names: MIC1555BM5TR; MIC1555BM5TR

MOSFET may be driven by a second MIC1555/7,
powered by 12V to 15V, to level-shift the input.
Charge-Pump Low-Side MOSFET Drivers
A standard MOSFET requires approximately 15V to fully
enhance the gate for minimum R
logic-level MOSFET reduces the required gate voltage,
allowing an MIC1557 to be used as an inverting Schmitt
Trigger, described above. An MIC1557 may be
configured as a voltage quadrupler to boost a 5V input to
over 15V to fully enhance an N-channel MOSFET which
may have its drain connected to a higher voltage,
through a high-side load. ATTL high signal applied to CS
enables a 10kHz oscillator, which quickly develops 15V
at the gate of the MOSFET, clamped by a zener diode. A
resistor from the gate to ground ensures that the FET
will turn off quickly when the MIC1557 is turned off.
Micrel, Inc.
May 2010
OFF 3.3V
ON 1.6V
Figure 7. Schmitter Trigger
5
4
2
THR
TRG
GND
MIC1555
DS(on)
OUT
VS
. Substituting a
+5V +12V
1
3
R
L
9
to 10µF
Audible Voltmeter
If an additional charge or discharge source is connected
to the timing capacitor, the frequency may be shifted by
turning the source on or off. An MIC1555 oscillator,
powered by the circuit under test, may be used to drive a
small loud speaker or piezo-electric transducer to
provide a medium frequency for an open or high
impedance state at the probe. A high tone is generated
for a high level, and a lower frequency for a logic low on
the probe.
100pF
C1
1N914
10k
0.01µF
C
47k
T
+5V
43
1
2
Figure 9. Audible Voltmeter
T/T
GND
VS
R
Figure 8. Charge-Pump
T
MIC1557
1k to 1M
5
4
2
OUT
CS
THR
TRG
GND
TTL High = ON
MIC1555
R
5
T
10k
R
100k
OUT
E
VS
3
1
M9999-052610-D
MIC1555/1557
0.001µF
10k
+5V to +18V
15V
N-Channel
MOSFET
(IRF540)
100
+12V
R
L