Control IC. MIC2184 Datasheet

MIC2184 IC. Datasheet pdf. Equivalent

MIC2184 Datasheet
Recommendation MIC2184 Datasheet
Part MIC2184
Description Low Voltage Buck PWM Control IC
Feature MIC2184; MIC2184 Micrel, Inc. MIC2184 Low Voltage Buck PWM Control IC General Description Micrel’s MIC2184 .
Manufacture Micrel Semiconductor
Datasheet
Download MIC2184 Datasheet




Micrel Semiconductor MIC2184
MIC2184
Micrel, Inc.
MIC2184
Low Voltage Buck PWM Control IC
General Description
Micrel’s MIC2184 is a high efficiency PWM buck control IC.
With its wide input voltage range of 2.9V to 14V, the MIC2184
can be used to efficiently step voltages down in 1- or 2-cell Li
Ion battery powered applications, as well as in fixed 3.3V, 5V,
or 12V systems.
Efficiencies over 90% are achievable over a wide range of
load conditions with the MIC2184’s PWM control scheme.
The operating frequency can be divided by two by raising the
FREQ/2 pin to VDD. This allows the user to optimize efficiency
versus board space. It also allows the MIC2184 to be exter-
nally synchronized to frequencies below its nominal 400KHz.
The MIC2184 features an oscillator output, FreqOut, which
can be used to implement a simple charge pump in low
voltage applications. The output of the charge pump can be
fed into the gate drive power circuitry via the VINP pin,
allowing enhanced gate drive, hence higher efficiencies,
despite low input voltages.
MIC2184 features a 1µA shutdown mode, and a program-
mable undervoltage lockout, making it well suited for portable
applications.
The MIC2184 is available in 16 pin SOP and QSOP package
options with a junction temperture range range from –40°C
to +125°C.
Features
• Input voltage range: 2.9V to 14V
• >90% efficiency
• Oscillator frequency of 400kHz
• Frequency divide-by-two pin
• Frequency sync to 600kHz
• FrequOut oscillator output allows simple charge pump
implementation in low voltage systems
• 1.245V reference output
• Front edge blanking
• 5output driver
• Soft start
• PWM current mode control
• 1µA shutdown current
• Cycle-by-cycle current limiting
• Frequency foldback short circuit protection
• Adjustable under-voltage lockout
• 16 pin narrow-body SOIC and QSOP package options
Applications
• 3.3V to 2.5V/1.8V/1.5V conversion
• DC power distribution systems
• Wireless Modems
• ADSL line cards
• 1-and 2-cell Li Ion battery operated equipment
• Satellite Phones
Typical Application
VIN = 3.3V
120µF (x2)
6.3V
1
VINA
16
VINP
7 EN/UVLO
2
FreqOut
16
FREQ/2
10
VDD
MIC2184
4
COMP
3
SS
13 VREF
SYNC SGND
11 5
9
CSH
CSL 8
14
OUTP
12
PGND
6
FB
15m
Q3
Si9803DY(x2)
4.7µH
VOUT
2.5V @5A
220µF(x2)
6.3V
100
95
90
85
80
75
70
65
60
55
500
MIC2184 EFFICIENCY
VIN = 3.3V
VOUT = 2.5V
fS = 200kHz
12345
OUTPUT CURRENT (A)
Adjustable Output Buck Converter
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
April 2005
1 M9999-042205



Micrel Semiconductor MIC2184
MIC2184
Ordering Information
Part Number
Standard
Pb-Free
MIC2184BM MIC2184YM
MIC2184BQS MIC2184YQS
Output
Voltage
Adj.
Adj.
Frequency
400KHz
400KHz
Micrel, Inc.
Junction
Temp. Range
–40°C to +125°C
–40°C to +125°C
Package
16-lead SOP
16-lead QSOP
Pin Configuration
VINA 1
FreqOut 2
SS 3
COMP 4
SGND 5
FB 6
EN/UVLO 7
CSL 8
16 VINP
15 FREQ/2
14 OUTP
13 VREF
12 PGND
11 SYNC
10 VDD
9 CSH
16 Lead SOIC
(M)
M9999-042205
2
April 2005



Micrel Semiconductor MIC2184
MIC2184
Pin Description
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Pin Name
VINA
FreqOut
SS
COMP
SGND
FB
EN/UVLO
CSL
CSH
VDD
SYNC
PGND
VREF
OUTP
FREQ/2
VINP
Micrel, Inc.
Pin Function
Analog voltage input voltage to the circuit. This powers up the analog
sections of the die and does not need to be the same voltage as Pin 16
(VINP).
This provides a digital signal output signal at half the switching frequency.
This signal swings from 0 to 3V, and can be used to drive an external
capacitive doubler to provide a higher voltage to the VINP input.
Soft start reduces the inrush current and delays and slows the output voltage
rise time. A 5µA current source will charge the capacitor up to VDD. A 1µF
capacitor will soft start the switching regulator in 1.5ms.
Compensation (Output): Internal error amplifier output. Connect to a
capacitor or series RC network to compensate the regulator’s control loop.
Small signal ground: must be routed separately from other grounds to the (-)
terminal of COUT.
Feedback Input - the circuit regulates this pin to 1.245V.
Enable/UnderVoltage Lockout (input): A low level on this pin will power down
the device, reducing the quiescent current to under 5uA. This pin has two
separate thresholds, below 1.5V the output switching is disabled, and below
0.9V the part is forced into a complete micropower shutdown. The 1.5V
threshold functions as an accurate undervoltage lockout (UVLO) with 140mV
hysteresis.
The (-) input to the current limit comparator. A built in offset of 100mV
between CSH and CSL in conjunction with the current sense resistor sets
the current limit threshold level. This is also the (-) input to the current
amplifier.
The (+) input to the current limit comparator. A built in offset of 100mV
between CSH and CSL in conjunction with the current sense resistor sets
the current limit threshold level. This is also the (+) input to the current
amplifier.
3V internal linear-regulator output. VDD is also the supply voltage bus for the
chip. Bypass to SGND with 1µF.
Frequency Synchronization (Input): Connect an external clock signal to
synchronize the oscillator. Leading edge of signal above 1.5V starts the
switching cycle. Connect to SGND if not used.
MOSFET driver power ground, connects to source of synchronous MOSFET
and the (-) terminal of CIN.
The 1.245V voltage reference is available on this pin. A 0.1µF capacitor
should be connected from this pin to ground.
High current drive for high side P channel MOSFET. Voltage swing is from
ground to VINP. On-resistance is typically 2.5.
When this is low, the oscillator frequency is 400KHz. When this pin is raised
to VDD, the oscillator frequency is 200KHz.
Power Input voltage to the circuit. The output gate drivers are powered from
this supply. The current sense resistor RCS should be connected as close as
possible to this pin.
April 2005
3 M9999-042205







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