MIC2660 [MICREL]
IttyBitty Charge Pump; IttyBitty电荷泵
| 型号： | MIC2660 |
| 厂家： | 
MICREL SEMICONDUCTOR |
| 描述： | IttyBitty Charge Pump |
| 文件： | 总8页 (文件大小：97K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC2660
IttyBitty™ Charge Pump
Not Recommended for New Designs
General Description
Features
The MIC2660 IttyBitty™ charge pump functions as a low-
current,step-upconverterwhereconventionalinductorbased,
dc-to-dc converters are too complex and expensive. This
device features a complete, self-contained charge pump in a
tiny 5-lead SOT-23-5 package.
• 3V input produces approx. 5V unregulated output*
3.8mA with 1µF external output capacitor
2.5mA without external capacitor
• 5V input produces approx. 9V unregulated output*
4.5mA output without external capacitor
• CMOS-logic compatible enable
The MIC2660 is powered from a 3V to 5V nominal supply and
produces nominally 5V to 9V as a function of the input
voltage. The output is unregulated and follows a load-line
type function.
• ESD protected
Applications
• Squib firing
• Refresh
• Burst/dump
• Low duty cycle load
• LCD bias generator
• Local 5V logic supply
• MOSFET driver
• Battery or solarcell boost
The MIC2660 can be used with or without external compo-
nents. When used with two noncritical external capacitors, a
3V input will produce 5V at 3.8mA. With no external compo-
nents, a 3V input will produce 5V at 2.5mA.
The MIC2660 charge pump consists of an approximately
18MHz oscillator and a voltage tripler.
The MIC2660 is available in the SOT-23-5 package and
is rated for –40°C to +85°C ambient temperature range.
Ordering Information
Part Number
Temperature Range
Package
MIC2660BM5
–40°C to +85°C
SOT-23-5
Typical Application
+3V Input
MIC2660
1
5
3
0.01µF
+5V, 2.5mA*
Output
0.01µF
IN
OUT
2
EN
GND
* The output is unregulated and
follows a load-line type function
Enable
Disable
Low-Current Unregulated Step-Up Supply
Timing Diagram
2V
0V
EN
0.2
µs
1.3
µs
5V
OUT
1V
0V
Output vs. Enable Input
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
August 1999
1
MIC2660
MIC2660
Micrel
Pin Configuration
OUT GND IN
3
2
1
Part
Identification
C10
4
5
NC
EN
SOT-23-5 (M5)
Pin Description
Pin Number
Pin Name
IN
Pin Function
1
2
3
4
5
Supply (Input): +3V to +5V supply.
Ground: Power return.
GND
OUT
NC
Output: Charge pump output. Connect to load.
Not internally connected.
EN
Enable (Input): CMOS compatible input. EN high (VEN = VIN) enables the
charge pump . EN low (VIN = 0V) disables the charge pump.
Absolute Maximum Ratings
Input Voltage (V ) .....................................................+5.5V
Lead Temperature, Soldering 10sec. ........................ 300°C
IN
Enable Voltage (V ) ......................................... V + 1.3V
Package Thermal Resistance
EN
IN
SOT-23-5 θ ....................................................220°C/W
Ambient Temperature Range (T ) ............. –40°C to +85°C
JA
A
SOT-23-5 θ ....................................................130°C/W
JC
Electrical Characteristics
Parameter
Condition (Note 1)
Min
4.5
8.1
.9
Typ
5
Max
Units
V
Output Voltage, Enabled
VIN = 3V, VEN = VIN, COUT = 1000pF, RL = 2kΩ
VIN = 5V, VEN = VIN, COUT = 1000pF, RL = 2kΩ
VIN = 3V, VEN = GND, COUT = 1000pF, RL = 2kΩ
VIN = 5V, VEN = GND, COUT = 1000pF, RL = 2kΩ
VIN = 3V, VEN = VIN, RL = 2kΩ
VIN = 5V, VEN = VIN, RL = 2kΩ
VIN = 3V, VEN < 0.4V
9
V
Output Voltage, Disabled
Input Current
1.0
3.0
14.5
28.5
1.3
3.3
19.5
38.5
3
V
2.9
V
mA
mA
µA
µA
mA
mA
V
Quiescent Current
Output Current
1.5
3.5
1.9
3.4
VIN = 5V, VEN < 0.4V
5
VIN = 3V, VEN = VIN, VOUT = VOUT min
VIN = 5V, VEN = VIN, VOUT = VOUT min
VIN = 3V
2.5
4.5
1.5
2.5
Enable Threshold
VIN = 5V
V
Enable Current
Turn-On Time
Turn-Off Time
VIN = 5V, VEN = VIN
10
µA
ns
µs
VIN = 3V
VIN = 3V
Load = 2kΩ, COUT = 1000pF, Note 2
Load = 2kΩ, COUT = 1000pF, Note 3
200
1.3
General Note: Devices are ESD protected, however handling precautions are recommended.
Note 1: Typicals values at T = 25°C. Minimum and maximum values at –40°C ≤ T ≤ +85°C.
A
A
Note 2: Turn-on time is the time between V = 0.5 × V and V
= 0.9 (V
– V
) for a rising EN input.
EN
IN
OUT
OUTmax
OUTmin
Note 3: Turn-off time is the time between V = 0.5 × V and V
= V – 1.9V for a falling EN input.
EN
IN
OUT
IN
MIC2660
2
August 1999
MIC2660
Micrel
Typical Characteristics
Output Voltage
vs. Supply Voltage
Output Voltage
vs. Supply Voltage
Output Voltage
vs. Supply Voltage
20
20
15
10
5
20
15
10
5
COUT = NONE
TA = -55° C
COUT = NONE
TA = 25° C
COUT = NONE
TA = 125° C
15
NO LOAD
NO LOAD
NO LOAD
10
3mA
3mA
3mA
2mA
2mA
5
2mA
1mA
1mA
1mA
0
0
0
2.0 2.5 3.0 3.5 4.0 4.5 5.0
2.0 2.5 3.0 3.5 4.0 4.5 5.0
SUPPLY VOLTAGE (V)
2.0 2.5 3.0 3.5 4.0 4.5 5.0
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Output Voltage
vs. Supply Voltage
Output Voltage
vs. Supply Voltage
Output Voltage
vs. Supply Voltage
20
20
20
COUT = 1µF
TA = 125° C
COUT = 1µF
TA = -55° C
COUT = 1µF
TA = 25° C
15
15
10
5
15
10
5
NO LOAD
NO LOAD
10
NO LOAD
3mA
3mA
3mA
5
0
2mA
2mA
2mA
1mA
1mA
1mA
0
0
2.0 2.5 3.0 3.5 4.0 4.5 5.0
SUPPLY VOLTAGE (V)
2.0 2.5 3.0 3.5 4.0 4.5 5.0
SUPPLY VOLTAGE (V)
2.0 2.5 3.0 3.5 4.0 4.5 5.0
SUPPLY VOLTAGE (V)
Efficiency
vs. Output Voltage
Efficiency
vs. Output Voltage
Efficiency
vs. Output Voltage
35
35
35
30
25
20
15
10
5
30
25
20
15
10
5
30
25
20
15
10
5
3mA
3mA
3mA
2mA
2mA
1mA
2mA
1mA
1mA
COUT = NONE
TA = -55° C
COUT = NONE
TA = 25° C
COUT = NONE
TA = 125° C
0
0
0
0
2
4
6
8
10 12 14
0
2
4
6
8
10 12 14
0
2
4
6
8
10 12 14
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
Efficiency
vs. Output Voltage
Efficiency
vs. Output Voltage
Efficiency
vs. Output Voltage
35
30
25
20
15
10
5
40
35
30
25
20
15
10
5
40
35
30
25
20
15
10
5
3mA
3mA
3mA
2mA
2mA
2mA
1mA
1mA
1mA
COUT = 1µF
TA = -55° C
COUT = 1µF
TA = 25° C
COUT = NONE
TA = 125° C
0
0
0
0
2
4
6
8
10 12 14
0
2
4
6
8
10 12 14
0
2
4
6
8
10 12 14
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
August 1999
3
MIC2660
MIC2660
Micrel
Block Diagram
MIC2660
2×
3×
IN
D1
OUT
D2
D3
Q1
Q2
Q3
EN
XLO
XLO
C1
C2
OSC
Q4
GND
Functional Description
Refer to the block diagram.
All formulas are simplified. Refer to the last paragraph of this
subsection about the actual output voltage.
The MIC2660 charge pump consists of an oscillator and a
voltage tripler. A logic-high applied to EN activates the
charge pump. The charge pump produces an output voltage
that is higher than the input voltage.
The following sequence describes the basic operation of the
tripler by showing how the voltage at the “2×” and “3×” nodes,
V
and V , increases.
2×
3×
Supply Input
Q2 turns on, completing the ground path to charge C1 (and
the 2× node) to the supply voltage, less a diode voltage drop.
IN (supply input) is rated for +2.7V to +5.5V.
V
= V – V
IN D1
Ouput
2× (charging)
After Q2 turns off, Q1 turns on. The Q1-Q2 side of C1 is
OUT is connected to IN, less 3 diode drops, at all times.
switched (offset upward) from ground to V . The 2× node,
IN
Enable
that was nominally at the supply voltage, becomes nominally
twice the supply voltage.
EN (enable) is a CMOS input. A logic low turns the oscillator
off. The threshold is approximately half the supply voltage. A
floating EN input may cause unpredictable operation.
V
= V – V + V
IN D1 IN
2×
While Q1 is on, Q4 is also on. When Q4 is on, the nominally
doubled voltage at the 2× node is applied across C2, through
D2.
Oscillator
The oscillator produces a square wave at approximately
18MHz. It has a noninverting and an inverting output.
V
= V – V + V – V
IN D1 IN D2
3× (charging)
Crossover Lockout
After Q4 turns off, Q3 turns on. The Q3-Q4 side of C2 is
The charge pump contains two crossover lockout (XLO)
circuits. Each crossover lockout circuit drives a totem pole,
consisting of a P-channel MOSFET and an N-channel MOS-
FET. The crossover lockout alternately switches the MOS-
FETs with no significant transition current (shoot-through
current from supply to ground).
switched from ground to V . The 3× node, that was nomi-
nally twice the supply voltage, becomes nominally three
times the supply voltage.
IN
V
= V – V + V – V + V
IN D1 IN D2 IN
3×
The tripled voltage is available at the output through D3.
= V – V + V – V + V – V
V
Tripler
OUT
IN
D1
IN
D2
IN
D3
The output is nominally 3 times the supply voltage less the
voltage drop across three diodes.
Voltage stepup is performed by charging an internal capaci-
tor then switching the charged capacitor in series with the
supply voltage to produce a higher voltage. A description of
the nominal voltage tripler output is:
The actual output is lower. These simplified formulas do not
show that the voltage across the capacitors decreases when
charge flows to the following stage or output. An actual
device also has some internal loss.
V
= 3V – 3V .
IN D
OUT
where:
ESD Protection
V
V
= output voltage
= supply voltage
OUT
Zener diodes are provided at IN, EN, and OUT to limit ESD
voltage.
IN
V = voltage drop across forward biased diode
D
MIC2660
4
August 1999
MIC2660
Micrel
Charge-Pump/Dump
Applications Information
A large capacitor can be charged to the unloaded tripled
voltage output after a time based on the maximum current
provided by the MIC2660. A 1000µF Capacitor can be
charged from 2V to approximately 12V in less than 3 seconds
by a 5V powered MIC2660. (i = C dv/dt).
Electromagnetic Interference
The 18MHz oscillator may cause interference to radio cir-
cuits. 0.01µF bypass capacitors should be mounted close to
the IN and OUT terminals.
Low-Side MOSFET Charge-Pump Driver
Once charged, a maximum current of 3mA may be drawn
continuously at the 12V level. A high value bleeder resistor
(100k) is not needed to prevent spikes from exceeding the
capacitor voltage rating, since the MIC2660’s internal 15V
ESD zener limits maximum output. A 68Ω resistor in series
with the output limits short-circuit current to 30mA.
A standard MOSFET requires approximately 15V to fully
enhance the gate for minimum RDS(on). Substituting a logic-
level MOSFET reduces the required gate voltage, allowing
an MIC2660 to be used as an low-side FET driver.
A 3V powered MIC2660 will fully enhance a logic-level
N-channel MOSFET low-side switch, with a 5k gate pull-
down resistor, in less than 1ms after the enable pin rises
above 1.5V. The 1nF MOSFET gate capacitance will be
discharged to turn-off in less than 10ms after the enable pin
goes below 1.5V.
+5V
MIC2660
68Ω
1
5
3
2
100k
+12V
IN
OUT
1000µF
EN
GND
Load
Supply
+3V to +5V
0.1µF
RLOAD
MIC2660
OUT
1
3
2
100k
IN
Figure 2. Charge-Pump/Dump
5-Volt Lamp Flasher
5
Enable
Disable
EN
GND
1µF
0.1µF
An IttyBitty MIC1557 oscillator provides a short pulse once
per second, enabling the CS pin of an MIC2660, which
charges the gate-to-drain capacitance of a logic-level
N-channel MOSFET to approximately 9V, which turns on a
lamp. When the CS pin is low, a 2k resistor discharges the
Figure 1. Charge-Pump Driver
An MIC2660 boosts a 5V input to 9V–12V to fully enhance an
N-channel MOSFET, which may have its drain connected to
a higher voltage, through a high-side load. A TTL high signal
applied to CS enables the internal oscillator, which quickly
develops 9V–12V 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 MIC2660 is turned off.
gate capacitance, turning off the lamp. A resistor (R ) in
series with a diode determines the “on” time to approximately
S
R ||R ×C ,while R and C set the “off” time to 1.1R ×C .
S
T
T
T
T
T
T
+5V
RS 470k
RT1MΩ
MIC1557
5V lamp
2k
4
1
3
5
VS
CS
MIC2660
IRL3103
N-channel
FET
1
5
3
2
0.1µF
T/T
IN
OUT
GND
CT
0.68µF
2
GND
OUT
EN
Figure 3. 5-Volt Lamp Flasher
August 1999
5
MIC2660
MIC2660
Micrel
Package Information
1.90 (0.075) REF
0.95 (0.037) REF
1.75 (0.069) 3.00 (0.118)
1.50 (0.059) 2.60 (0.102)
DIMENSIONS:
MM (INCH)
1.30 (0.051)
0.90 (0.035)
3.02 (0.119)
2.80 (0.110)
0.20 (0.008)
0.09 (0.004)
10°
0°
0.15 (0.006)
0.00 (0.000)
0.50 (0.020)
0.35 (0.014)
0.60 (0.024)
0.10 (0.004)
SOT-23-5 (M5)
MIC2660
6
August 1999
MIC2660
Micrel
August 1999
7
MIC2660
MIC2660
Micrel
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 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.
© 1999 Micrel Incorporated
MIC2660
8
August 1999
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