MIC5321-3.0/2.6YML [MICROCHIP]
DUAL OUTPUT, FIXED POSITIVE LDO REGULATOR, DSO6;
| 型号： | MIC5321-3.0/2.6YML |
| 厂家： | 
MICROCHIP |
| 描述： | DUAL OUTPUT, FIXED POSITIVE LDO REGULATOR, DSO6 输出元件 |
| 文件： | 总12页 (文件大小：422K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC5321
Dual, High Performance 150mA µCap ULDO™
General Description
Features
The MIC5321 is a tiny Dual Ultra Low-Dropout
(ULDO™) linear regulator ideally suited for those
applications that require high PSRR because it
provides a bypass pin for those noise sensitive
portable electronics. The MIC5321 integrates two
high-performance; 150mA ULDOs into a very compact
1.6mm x 1.6mm leadless MLF ® package that
provides exceptional thermal package characteristics.
•
•
2.3V to 5.5V input voltage range
Ultra-low dropout voltage ULDO™ 35mV @
150mA
Tiny 6-pin 1.6mm x 1.6mm MLF® leadless
package
•
•
•
Low cost TSOT-23-6 package
Bypass pin for improved noise performance
High PSRR – >75dB on each LDO
Ultra low noise output - > 30µVrms
Dual 150mA outputs
The MIC5321 is a µCap design which enables
operation with very small ceramic output capacitors
for stability, thereby reducing required board space
and component cost. The combination of extremely
low-drop-out voltage, very high power supply
rejection, very low output noise and exceptional
thermal package characteristics makes it ideal for
powering RF application, cellular phone camera
modules, imaging sensors for digital still cameras,
PDAs, MP3 players and WebCam applications.
•
•
•
•
•
•
•
µCap stable with 1µF ceramic capacitor
Low quiescent current – 150µA
Fast turn-on time – 45µs
Thermal shutdown protection
Current Limit protection
The MIC5321 ULDO™ is available in fixed-output
voltages in the tiny 6-pin 1.6mm x 1.6mm leadless
MLF ® package which is only 2.56mm2 in area, less
than 30% the area of the SOT-23, TSOP and MLF
3x3 packages. It’s also available in the thin SOT-23-6
lead package. Additional voltage options are
available. For more information, contact Micrel
marketing department.
Applications
•
•
•
•
•
•
Mobile phones
PDAs
GPS receivers
Portable electronics
Portable media players
Digital still and video cameras
Data sheets and support documentation can be found
on Micrel’s web site at www.micrel.com.
Typical Application
MIC5321-x.xYML
Rx/Synth
Tx
VIN
VOUT 1
VOUT 2
EN
1µF
RF
Transceiver
BYP
GND
1µF
1µF
0.01µF
RF Power Supply Circuit
ULDO is a trademark of Micrel, Inc.
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
M9999-073106
July 2006
Micrel, Inc.
MIC5321
Ordering Information
Part number
Manufacturing
Part Number
Voltage
Junction
Temperature Range
Package
MIC5321-1.8/1.5YML
MIC5321-1.8/1.6YML
MIC5321-2.5/1.8YML
MIC5321-2.5/2.5YML
MIC5321-2.6/1.85YML
MIC5321-2.6/1.8YML
MIC5321-2.7/2.7YML
MIC5321-2.8/1.5YML
MIC5321-2.8/1.8YML
MIC5321-2.8/2.6YML
MIC5321-2.8/2.8YML
MIC5321-2.8/2.85YML
MIC5321-2.85/1.85YML
MIC5321-2.85/2.6YML
MIC5321-2.85/2.85YML
MIC5321-2.85/2.85YML
MIC5321-2.9/1.5YML
MIC5321-2.9/1.8YML
MIC5321-2.9/2.9YML
MIC5321-3.0/1.8YML
MIC5321-3.0/2.5YML
MIC5321-3.0/2.6YML
MIC5321-3.0/2.8YML
MIC5321-3.0/2.85YML
MIC5321-3.0/3.0YML
MIC5321-3.3/1.5YML
MIC5321-3.3/1.8YML
MIC5321-3.3/2.5YML
MIC5321-3.3/2.6YML
MIC5321-3.3/2.7YML
MIC5321-3.3/2.8YML
MIC5321-3.3/2.85YML
MIC5321-3.3/2.9YML
MIC5321-3.3/3.0YML
MIC5321-3.3/3.2YML
MIC5321-3.3/3.3YML
MIC5321-1.8/1.5YD6
MIC5321-1.8/1.6YD6
MIC5321-2.5/1.8YD6
MIC5321-2.5/2.5YD6
MIC5321-2.6/1.85YD6
MIC5321-2.6/1.8YD6
MIC5321-2.7/2.7YD6
MIC5321-2.8/1.5YD6
MIC5321-2.8/1.8YD6
MIC5321-2.8/2.6YD6
MIC5321-GFYML
MIC5321-GWYML
MIC5321-JGYML
MIC5321-JJYML
MIC5321-KDYML
MIC5321-KGYML
MIC5321-LLYML
MIC5321-MFYML
MIC5321-MGYML
MIC5321-MKYML
MIC5321-MMYML
MIC5321-MNYML
MIC5321-NDYML
MIC5321-NKYML
MIC5321-NNYML
MIC5321-NNYML
MIC5321-OFYML
MIC5321-OGYML
MIC5321-OOYML
MIC5321-PGYML
MIC5321-PJYML
MIC5321-PKYML
MIC5321-PMYML
MIC5321-PNYML
MIC5321-PPYML
MIC5321-SFYML
MIC5321-SGYML
MIC5321-SJYML
MIC5321-SKYML
MIC5321-SLYML
MIC5321-SMYML
MIC5321-SNYML
MIC5321-SOYML
MIC5321-SPYML
MIC5321-SRYML
MIC5321-SSYML
MIC5321-GFYD6
MIC5321-GWYD6
MIC5321-JGYD6
MIC5321-JJYD6
MIC5321-KDYD6
MIC5321-KGYD6
MIC5321-LLYD6
MIC5321-MFYD6
MIC5321-MGYD6
MIC5321-MKYD6
1.8V/1.5V
1.8V/1.6V
2.5V/1.8V
2.5V/2.5V
2.6V/1.85
2.6V/1.8V
2.7V/2.7V
2.8V/1.5V
2.8V/1.8V
2.8V/2.6V
2.8V/2.8V
2.8V/2.85V
2.85V/1.85V
2.85V/2.6V
2.85V/2.85V
2.85V/2.85V
2.9V/1.5V
2.9V/1.8V
2.9V/2.9V
3.0V/1.8V
3.0V/2.5V
3.0V/2.6V
3.0V/2.8V
3.0V/2.85V
3.0V/3.0V
3.3V/1.5V
3.3V/1.8V
3.3V/2.5V
3.3V/2.6V
3.3V/2.7V
3.3V/2.8V
3.3V/2.85V
3.3V/2.9V
3.3V/3.0V
3.3V/3.2V
3.3V/3.3V
1.8V/1.5V
1.8V/1.6V
2.5V/1.8V
2.5V/2.5V
2.6V/1.85
2.6V/1.8V
2.7V/2.7V
2.8V/1.5V
2.8V/1.8V
2.8V/2.6V
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin 1.6x1.6 MLF®
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
2
M9999-073106
July 2006
Micrel, Inc.
MIC5321
MIC5321-2.8/2.8YD6
MIC5321-MMYD6
MIC5321-MNYD6
MIC5321-NDYD6
MIC5321-NKYD6
MIC5321-NNYD6
MIC5321-OFYD6
MIC5321-OGYD6
MIC5321-OOYD6
MIC5321-PGYD6
MIC5321-PJYD6
MIC5321-PKYD6
MIC5321-PMYD6
MIC5321-PNYD6
MIC5321-PPYD6
MIC5321-SFYD6
MIC5321-SGYD6
MIC5321-SJYD6
MIC5321-SKYD6
MIC5321-SLYD6
MIC5321-SMYD6
MIC5321-SNYD6
MIC5321-SOYD6
MIC5321-SPYD6
MIC5321-SRYD6
MIC5321-SSYD6
2.8V/2.8V
2.8V/2.85V
2.85V/1.85V
2.85V/2.6V
2.85V/2.85V
2.9V/1.5V
2.9V/1.8V
2.9V/2.9V
3.0V/1.8V
3.0V/2.5V
3.0V/2.6V
3.0V/2.8V
3.0V/2.85V
3.0V/3.0V
3.3V/1.5V
3.3V/1.8V
3.3V/2.5V
3.3V/2.6V
3.3V/2.7V
3.3V/2.8V
3.3V/2.85V
3.3V/2.9V
3.3V/3.0V
3.3V/3.2V
3.3V/3.3V
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
6-Pin TSOT-23
MIC5321-2.8/2.85YD6
MIC5321-2.85/1.85YD6
MIC5321-2.85/2.6YD6
MIC5321-2.85/2.85YD6
MIC5321-2.9/1.5YD6
MIC5321-2.9/1.8YD6
MIC5321-2.9/2.9YD6
MIC5321-3.0/1.8YD6
MIC5321-3.0/2.5YD6
MIC5321-3.0/2.6YD6
MIC5321-3.0/2.8YD6
MIC5321-3.0/2.85YD6
MIC5321-3.0/3.0YD6
MIC5321-3.3/1.5YD6
MIC5321-3.3/1.8YD6
MIC5321-3.3/2.5YD6
MIC5321-3.3/2.6YD6
MIC5321-3.3/2.7YD6
MIC5321-3.3/2.8YD6
MIC5321-3.3/2.85YD6
MIC5321-3.3/2.9YD6
MIC5321-3.3/3.0YD6
MIC5321-3.3/3.2YD6
MIC5321-3.3/3.3YD6
Note:
1. Other Voltages available. Contact Micrel for details.
3
M9999-073106
July 2006
Micrel, Inc.
MIC5321
Pin Configuration
GND
2
VIN
3
BYP
1
VIN
GND
BYP
1
2
3
6
5
4
VOUT1
VOUT2
EN
4
5
6
VOUT2
VOUT1
EN
6-Pin 1.6mm x 1.6mm MLF (ML)
Top View
TSOT-23-6 (D6)
Top View
Pin Description
Pin Number
MLF-6
Pin Number
TSOT-23-6
Pin Name
Pin Function
1
2
3
3
2
1
VIN
GND
BYP
Supply Input.
Ground
Reference Bypass: Connect external 0.01µF to GND to reduce output noise.
May be left open.
4
6
EN
Enable Input (both regulators): Active High Input. Logic High = On; Logic
Low = Off; Do not leave floating.
5
6
5
4
VOUT2
VOUT1
Regulator Output – LDO2
Regulator Output – LDO1
4
M9999-073106
July 2006
Micrel, Inc.
MIC5321
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN).....................................0V to +6V
Enable Input Voltage (VEN)...........................0V to +6V
Power Dissipation………………….Internally Limited(3)
Lead Temperature (soldering, 3sec)..................260°C
Storage Temperature (TS)................ –65°C to +150°C
ESD Rating(4) .........................................................2kV
Supply Voltage (VIN).............................. +2.3V to +5.5V
Enable Input Voltage (VEN).............................. 0V to VIN
Junction Temperature (TJ) ................. –40°C to +125°C
Junction Thermal Resistance
MLF-6 (θJA) .............................................100°C/W
TSOT-6 (θJA) ...........................................235°C/W
Electrical Characteristics(5)
VIN = EN = VOUT + 1.0V; higher of the two regulator outputs, IOUTLDO1 = IOUTLDO2 = 100µA; COUT1 = COUT2 = 1µF;
CBYP = 0.01µF; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted.
Parameter
Conditions
Min
-2.0
-3.0
Typ
Max
+2.0
+3.0
Units
%
Output Voltage Accuracy
Variation from nominal VOUT
Variation from nominal VOUT; –40°C to +125°C
VIN = VOUT + 1V to 5.5V; IOUT = 100µA
%
Line Regulation
0.02
0.3
0.6
%/V
%/V
Load Regulation
Dropout Voltage (6)
IOUT = 100µA to 150mA
IOUT = 100µA
0.5
0.1
12
2.0
%
mV
mV
mV
mV
µA
µA
dB
I
I
I
OUT = 50mA
OUT = 100mA
OUT = 150mA
50
75
25
35
100
190
2
Ground Current
EN = High; IOUT1 = 150mA, IOUT2 = 150mA
EN1 ≤ 0.2V
150
0.01
75
Ground Current in Shutdown
Ripple Rejection
f = 1kHz; COUT = 1.0µF; CBYP = 0.1µF
f = 20kHz; COUT = 1.0µF; CBYP = 0.1µF
45
dB
Current Limit
VOUT = 0V
300
1.1
550
30
950
0.2
mA
Output Voltage Noise
Enable Inputs (EN)
Enable Input Voltage
COUT = 1.0µF; CBYP = 0.01µF; 10Hz to 100kHz
µVRMS
Logic Low
Logic High
VIL ≤ 0.2V
VIH ≥ 1.0V
V
V
Enable Input Current
0.01
0.01
1
1
µA
µA
Turn-on Time (See Timing Diagram)
Turn-on Time (LDO1 and 2)
COUT = 1.0µF; No CBYP
OUT = 1.0µF; CBYP = 0.01µF
40
45
100
100
µs
µs
C
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max) – TA) / θJA. Exceeding the maximum allowable
power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.
4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
5. Specification for packaged product only.
6. Dropout voltage is defined as the input-to-output differential at which the output voltage drops 2% below it’s nominal VOUT. For outputs below 2.3V,
the dropout voltage is the input-to-output differential with the minimum input voltage 2.3V
5
M9999-073106
July 2006
Micrel, Inc.
MIC5321
Functional Diagram
VOUT 1
VOUT 2
VIN
EN
LDO1
LDO2
Enable
Reference
BYP
GND
MIC5321 Block Diagram
6
M9999-073106
July 2006
Micrel, Inc.
MIC5321
Typical Characteristics
Power Supply
Rejection Ratio
Dropout Voltage
vs. Output Current
Output Voltage
vs. Temperature
-90
40
35
30
25
20
15
10
5
3.00
2.95
2.90
2.85
2.80
2.75
2.70
2.65
2.60
2.55
2.50
-80
-70
-60
-50
50mA
-40
-30
V
V
= V
+ 1V
V
V
= V + 1V
OUT
V
V
C
C
= V
+1V
150mA
IN
OUT
IN
IN
OUT
-20
-10
0
= 2.8V
= 1µF
= 2.8V
= 1µF
= 2.8V
= 1µF
= 0.1µF
OUT
OUT
OUT
OUT
OUT
OUT
BYP
C
C
EN = V
EN = V
IN
IN
0
0.1
1
10
100
1,000
0
25 50 75 100 125 150
OUTPUT CURRENT (mA)
20 40 60 80
TEMPERATURE (°C)
FREQUENCY (kHz)
Ground Current
vs. Temperature
Ground Current
vs. Temperature
Output Voltage
vs. Input Voltage
160
155
150
145
140
135
130
125
120
160
155
150
145
140
135
130
125
120
3.0
2.5
2.0
1.5
1.0
0.5
0.0
2.8V
100µA
150mA
1.5V
V
V
= V
+ 1V
V
V
= V
+ 1V
IN
OUT
IN
OUT
= 3V
= 3V
OUT
OUT
OUT
OUT
C
= 1µF
C
= 1µF
I
= 100µA
= 1µF
OUT
OUT
EN = V
EN = V
IN
C
IN
20 40 60 80
20 40 60 80
0
1
2
3
4
5
6
INPUT VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
Dropout Voltage
vs. Temperature
Output Voltage
vs. Output Current
Output Voltage
vs. Output Current
50
45
40
35
30
25
20
15
10
5
2.90
2.85
2.80
2.75
2.70
1.60
1.55
1.50
1.45
1.40
V
= V
+ 1V
IN
OUT
V
= 2.8V
= 1µF
150mA
OUT
OUT
C
100mA
50mA
V
V
= V
+ 1V
V
V
= V
+ 1V
IN
OUT
C
OUT
= 1.5V
IN
OUT
OUT
= 2.8V
= C
100µA
= C
= 1µF
OUT2
C
= 1µF
OUT2
OUT1
10mA
20 40 60 80
OUT1
EN = V
EN = V
IN
IN
0
0
25 50 75 100 125 150
OUTPUT CURRENT (mA)
0
25 50 75 100 125 150
OUTPUT CURRENT (mA)
TEMPERATURE (°C)
Ground Current
Current Limit
Output Noise
vs. Output Current
vs. Input Voltage
Spectral Density
162
158
154
150
146
142
138
610
600
590
580
570
560
550
540
530
520
510
10
1
0.1
V
V
= V
OUT
+ 1V
IN
OUT
V
V
C
C
= 3.8V
IN
OUT
OUT
BYP
0.01
= 2.85V
= 2.8V
= 1µF
EN = V
OUT1
EN = V
IN
IN
= C
C
= 1µF
C
OUT
= 1µF
OUT2
= 0.01µF
0.001
0
25 50 75 100 125 150
OUTPUT CURRENT (mA)
3
3.5
4
4.5
5
5.5
0.01 0.1
1
10 100 1,000 10,000
INPUT VOLTAGE (V)
FREQUENCY (kHz)
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MIC5321
Functional Characteristics
Enable Turn-On
Load Transient
V
V
= V
+ 1V
OUT
IN
150mA
= 2.8V
= 1µF
OUT
C
OUT
C
= 0.1µF
BYP
V
V
= V
+ 1V
OUT
IN
10mA
= V
= 3.0V
OUT1
OUT2
C
= 1µF
OUT
C
= 0.1µF
BYP
Time (10µs/div)
Time (40µs/div)
Line Transient
5.5V
4V
V
V
= V
+ 1V
OUT
IN
= 2.8V
= 1µF
OUT
C
OUT
I
= 10mA
OUT
Time (40µs/div)
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MIC5321
Applications Information
Enable/Shutdown
increased, further reducing noise and improving
PSRR. Turn-on time increases slightly with respect to
bypass capacitance. A unique, quick-start circuit
allows the MIC5321 to drive a large capacitor on the
bypass pin without significantly slowing turn-on time.
Refer to the Typical Characteristics section for
performance with different bypass capacitors.
The MIC5321 comes with a single active-high enable
pin that allows both regulators to be disabled
simultaneously. Forcing the enable pin low disables
the regulator and sends it into a “zero” off-mode-
current state. In this state, current consumed by the
regulator goes nearly to zero. Forcing the enable pin
high enables the output voltage. The active-high
enable pin uses CMOS technology and the enable pin
cannot be left floating; a floating enable pin may
cause an indeterminate state on the output.
No-Load Stability
Unlike many other voltage regulators, the MIC5321
will remain stable and in regulation with no load. This
is especially important in CMOS RAM keep-alive
applications.
Input Capacitor
The MIC5321 is a high-performance, high bandwidth
device. Therefore, it requires a well-bypassed input
supply for optimal performance. A 1µF capacitor is
required from the input to ground to provide stability.
Low-ESR ceramic capacitors provide optimal
performance at a minimum of space. Additional high-
frequency capacitors, such as small-valued NPO
dielectric-type capacitors, help filter out high-
frequency noise and are good practice in any RF-
based circuit.
Thermal Considerations
The MIC5321 is designed to provide 150mA of
continuous current for both outputs in a very small
package. Maximum ambient operating temperature
can be calculated based on the output current and the
voltage drop across the part. Given that the input
voltage is 3.3V, the output voltage is 2.8V for VOUT1
,
2.5V for VOUT2 and the output current = 150mA. The
actual power dissipation of the regulator circuit can be
determined using the equation:
Output Capacitor
PD = (VIN – VOUT1) IOUT1 + (VIN – VOUT2) IOUT2+ VIN IGND
The MIC5321 requires an output capacitor of 1µF or
greater to maintain stability. The design is optimized
for use with low-ESR ceramic chip capacitors. High
ESR capacitors may cause high frequency oscillation.
The output capacitor can be increased, but
performance has been optimized for a 1µF ceramic
output capacitor and does not improve significantly
with larger capacitance.
Because this device is CMOS and the ground current
is typically <150µA over the load range, the power
dissipation contributed by the ground current is < 1%
and can be ignored for this calculation.
PD = (3.3V – 2.8V) × 150mA + (3.3V -1.5) × 150mA
PD = 0.345W
X7R/X5R dielectric-type ceramic capacitors are
recommended because of their temperature
To determine the maximum ambient operating
temperature of the package, use the junction-to-
ambient thermal resistance of the device and the
following basic equation:
performance.
X7R-type
capacitors
change
capacitance by 15% over their operating temperature
range and are the most stable type of ceramic
capacitors. Z5U and Y5V dielectric capacitors change
value by as much as 50% and 60%, respectively, over
their operating temperature ranges. To use a ceramic
chip capacitor with Y5V dielectric, the value must be
much higher than an X7R ceramic capacitor to ensure
the same minimum capacitance over the equivalent
operating temperature range.
T
J(MAX) - TA
⎛
⎝
PD(MAX)
=
JA
TJ(max) = 125°C, the maximum junction temperature of
the die θJA thermal resistance = 100°C/W.
The table below shows junction-to-ambient thermal
resistance for the MIC5321 in the MLF® package.
Bypass Capacitor
A capacitor can be placed from the noise bypass pin
to ground to reduce output voltage noise. The
capacitor bypasses the internal reference. A 0.1µF
capacitor is recommended for applications that require
low-noise outputs. The bypass capacitor can be
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MIC5321
For example, when operating the MIC5321-MFYML at
an input voltage of 3.3V and 150mA loads at each
output with a minimum footprint layout, the maximum
ambient operating temperature TA can be determined
as follows:
θJA
Recommended
Minimum
Package
θJC
Footprint
6-Pin 1.6x1.6 MLF®
100°C/W
2°C/W
0.345W = (125°C – TA)/(100°C/W)
TA=90.5°C
Thermal Resistance
Substituting PD for PD(max) and solving for the ambient
operating temperature will give the maximum
operating conditions for the regulator circuit. The
junction-to-ambient thermal resistance for the
minimum footprint is 100°C/W.
Therefore, a 2.8V/1.5V application with 150mA at
each output current can accept an ambient operating
temperature of 90.5°C in a 1.6mm x 1.6mm MLF®
package. For a full discussion of heat sinking and
thermal effects on voltage regulators, refer to the
“Regulator Thermals” section of Micrel’s Designing
with Low-Dropout Voltage Regulators handbook. This
information can be found on Micrel's website at:
The maximum power dissipation must not be
exceeded for proper operation.
http://www.micrel.com/_PDF/other/LDOBk_ds.pdf
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MIC5321
Package Information
6-Pin 1.6mm x 1.5mm MLF (ML)
6-Pin TSOT-23 (D6)
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MIC5321
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for
its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a
product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for
surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant
injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk
and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale.
© 2005 Micrel, Inc.
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