Fairchild FAN5601 Regulated step-down charge pump dc/dc converter Datasheet

www.fairchildsemi.com
FAN5601
Regulated Step-Down Charge Pump DC/DC Converter
Features
Description
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The FAN5601 is an advanced third generation switched
capacitor step down DC/DC converter utilizing Fairchild’s
proprietary ScalarPump™ technology. This innovative architecture utilizes scalar switch re-configuration and fractional
switching techniques to produce low output ripple, low ESR
spikes and improve efficiency over a wide load range.
> 85% Peak Efficiency
Low EMI
Low Ripple
Output Voltage 1.3V/1.8V
Input Voltage Range: 2.2V to 5.5V
Output Current: Up to 250mA
±2.5% Output Voltage Accuracy
30µA Operating Current
ICC < 1µA in Shutdown Mode
2MHz Operating Frequency
Shutdown Isolates Output from Input
Soft-Start Limits Inrush Current
Short Circuit and Over Temperature Protection
Minimum External Component Count
6-Lead 3x3mm MLP Package
The FAN5601 produces a fixed regulated output from 2.2V
to 5V input voltage. Customized output voltages are available in 100mV increments from 1V to 1.8V. Contact marketing for customized outputs.
In order to maximize efficiency, the FAN5601 achieves
regulation by skipping pulses. Depending upon load current,
the size of the switches is scaled dynamically, consequently,
current spikes and EMI are minimized. An internal soft start
circuitry prevents excessive current drawn from the supply.
The device is internally protected against short circuit and
over temperature conditions.
Applications
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Cell Phones
Handheld Computers
Portable Electronic Equipment
Core Supply to Next Generation Processors
Low Voltage DC Bus
Digital Cameras
DSP Supplies
The FAN5601 is available in 6-lead 3x3mm MLP.
ScalarPump™ is a registered trademark of Fairchild Semiconductor Corporation.
Typical Application
CB = 1µF
C+
VIN
CIN = 10µF
FAN5601
INPUT 2.2V to 5.5V
CVOUT
ENABLE GND
OUTPUT 1.0V t o 1.8V
COUT = 10µF
REV. 1.0.4 4/4/05
PRODUCT SPECIFICATION
FAN5601
Pin Assignment
FAN5601
Top-View
C+
1
6
VIN
C-
2
5
VOUT
ENABLE
3
4
GND
6-Lead 3x3mm MLP
Pin Description
Pin Name
2
Pin No.
6-Lead 3x3mm MLP
1
C+
Bucket Capacitor Positive Connection
Pin Function Description
2
C-
Bucket Capacitor Negative Connection
3
ENABLE
4
GND
No Connection
5
VOUT
No Connection
6
VIN
Enable Pin
Ground
REV. 1.0.4 4/4/05
FAN5601
PRODUCT SPECIFICATION
Absolute Maximum Ratings (Note1)
Parameter
Min
Max
Unit
VIN,VOUT, ENABLE to GND
-0.3
6.0
V
C+, C-, to GND
-0.3
VIN + 0.3
V
VOUT Short Circuit Duration
INDEFINITE
Lead Soldering Temperature (10 seconds)
Operating Temperature Range
-40
Junction Temperature
Storage Temperature
-55
Electrostatic Discharge (ESD) Protection (Note2)
HBM
4
CDM
1
300
°C
+85
°C
150
°C
150
°C
kV
Recommended Operating Conditions
Parameter
Package
Input Voltage
Min
Typ
Operating Ambient Temperature
Thermal Resistance Junction to Ambient
Unit
5.5
V
250
mA
85
°C
2.2
Output Current
Thermal Resistance Junction to Tab
Max
-40
6-lead 3x3mm MLP
8
°C/W
6-lead 3x3mm MLP (Note 3)
90
°C/W
Notes:
1. Operation beyond the absolute maximum rating may cause permanent damage to device.
2. Using Mil Std. 883E, method 3015.7(Human Body Model) and EIA/JESD22C101-A (Charge Device Model).
3. One square inch, 1oz bottom side GND plane connected to top side GND plane by field of via.
REV. 1.0.4 4/4/05
3
PRODUCT SPECIFICATION
FAN5601
Electrical Characteristics
VIN = 2.2V to 5.5V, IOUT = 1mA, CB = 1µF, CIN = 10µF, COUT = 10µF, TA = -40°C to +85°C, typical values measured
at TA = 25°C, unless otherwise noted.
Parameter
Conditions
Input Undervoltage Lockout
Min.
1.9
Output Voltage
Output Voltage Accuracy
Output Voltage Temperature Coefficient
Max.
2.0
2.17
Vnom
Units
V
V
TA = 25°C, VIN = 3.3V
-2
+2
%
VIN = 3.3V
-2.5
+2.5
%
VIN = 3.3V
25
Load Regulation
Line Regulation
Typ.
ppm
0.133
mV/mA
TA = 25°C
1.35
2
mV/V
IOUT = 0mA,
VIN = 2.2V
30
60
µA
ENABLE =GND.
VOUT = 0
0.1
1
µA
VOUT = GND.
25
mA
VIN = 2.35 × VOUT
IOUT =150mA
85
%
From 2:1 to 1:1 mode
2.22 x
Vnom
V
Oscillator Frequency
2.0
MHz
Thermal Shutdown Threshold
150
°C
Thermal Shutdown Threshold Hysteresis
15
°C
No load Supply Current (Note 4)
Shutdown Supply Current
Output Short-circuit Current (Note 5)
Efficiency
VIN at Configuration Change
ENABLE Logic Input High Voltage, VIH
VIN = 2.2V to 5.5V
ENABLE Logic Input Low Voltage, VIL
VIN = 2.2V to 5.5V
ENABLE Logic Input Current
ENABLE = VIN or GND
VOUT Turn On Time
VIN = 3.6V, IOUT = 0mA,
10% to 90%
1.3
V
0.4
-1
1
1
V
µA
mS
Notes:
4. No load supply current is measured when the oscillator is off.
5. The short circuit protection is designed to protect against pre-existing short circuit conditions, i.e. assembly shorts that exist
prior to device power-up. The short circuit current limit is 25mAAverage. Short circuit currents in normal operation are inherently
limited by the ON-resistance of internal device. Since this resistance is in the range of 1Ω, in some cases thermal shutdown
may occur. However, immediately following the first thermal shutdown event, the short circuit condition will be treated as preexisting, and the load current will reduce to 25mAAverage.
4
REV. 1.0.4 4/4/05
FAN5601
PRODUCT SPECIFICATION
Typical Performance Characteristics
TA = 25°C, CIN = COUT =10µF, CB = 1µF, VOUT = 1.3V, unless otherwise noted.
Load Transient Response
(20mV/div)
Output Voltage
V IN = 2 V to 4.4V
IOUT = 10mA
V IN = 2V
VIN = 3.3V
IOUT = 100mA
Load Current
(100mA/div)
(50mV/div)
V IN = 4.4V
(1V/div)
Input Voltage
Output Voltage
Line Transient Response
IOUT = 1mA
Time (10µs/div)
Time (1ms/div)
Shutdown Current vs Input Voltage
Input Current vs Input Voltage
70
46
Shutdown Current (nA)
Input Current (µA)
VOUT = 0V
IOUT = 0mA
44
42
40
38
36
34
32
60
50
40
30
20
30
10
28
2.0
2.5
2.5
3.0
3.5
4.0
4.5
5.0
3.0
3.5
5.5
4.0
4.5
5.0
5.5
Input Voltage (V)
Input Voltage (V)
Mode Change Threshold and Hysteresis
vs Load Current
1.31
Output Voltage (V)
1.30
VIN = 4V
IOUT = 10mA
1.29
1.28
1.27
1.26
-60
-40
-20
0
20
40
60
80
100 120 140
Ambient Temperature (°C)
REV. 1.0.4 4/4/05
Threshold and Hysteresis (V)
Output Voltage vs Ambient Temperature
3.5
3.0
2.5
High Threshold
Low Threshold
2.0
1.5
Hysteresis
1.0
0.5
0.0
0
20
40
60
80
100
120
140
160
Load Current (mA)
5
PRODUCT SPECIFICATION
FAN5601
Typical Performance Characteristics (cont.)
TA = 25°C, CIN = COUT =10µF, CB = 1µF, VOUT = 1.3V, unless otherwise noted.
Enable Delay
Enable Threshold vs Input Voltage
Output Voltage
(500m V/div)
1.3
IOUT = 10mA
TA = 25°C
1.1
IOUT = 10mA
VIN = 2.2V
1.0
0.9
0.8
0.7
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Enable Voltage
(5V/div)
V En able (V)
1.2
V IN (V)
Time (400 s/div)
IOUT = 1.3µA
VIN = 2.7V
VOUT = 1.3V
VOUT = 1.3V
Output Ripple
(10mV/div)
IOUT = 1.3µA
VIN = 2.2V
Time (40ms/div)
Time (40ms/div)
Output Ripple
Output Ripple
IOUT = 1.3µA
IOUT = 1.3µA
VIN = 3.6V
VIN = 4.2V
VOUT = 1.3V
VOUT = 1.3V
Time (20ms/div)
6
Output Ripple
Output Ripple
(10mV/div)
Output Ripple
(2mV/div)
Output Ripple
(10mV/div)
Output Ripple
Time (20ms/div)
REV. 1.0.4 4/4/05
FAN5601
PRODUCT SPECIFICATION
Typical Performance Characteristics (cont.)
TA = 25°C, CIN = COUT =10µF, CB = 1µF, VOUT = 1.3V, unless otherwise noted.
Output Ripple
VOUT = 1.3V
VOUT = 1.3V
(10mV/div)
IOUT = 10mA
VIN = 2.2V
Output Ripple
IOUT = 1.3µA
VIN = 5.5V
(10mV/div)
Time (20ms/div)
Time (100µs/div)
Output Ripple
Output Ripple
IOUT = 10mA
VIN = 3.6V
Output Ripple
VOUT = 1.3V
(10mV/div)
IOUT = 10mA
VIN = 2.7V
VOUT = 1.3V
Time (100µs/div)
Time (100µs/div)
Output Ripple
Output Ripple
IOUT = 10mA
VIN = 5.5V
VOUT = 1.3V
Time (100µs/div)
REV. 1.0.4 4/4/05
(10mV/div)
IOUT = 10mA
VIN = 4.2V
Output Ripple
(10mV/div)
Output Ripple
Output Ripple
(10mV/div)
Output Ripple
Output Ripple
VOUT = 1.3V
Time (100µs/div)
7
PRODUCT SPECIFICATION
FAN5601
Typical Performance Characteristics (cont.)
TA = 25°C, CIN= COUT =10µF, CB = 1µF, VOUT = 1.3V, unless otherwise noted.
Output Ripple
IOUT = 150mA
VIN = 2.7V
VOUT = 1.3V
VOUT = 1.3V
Output Ripple
(20mV/div)
IOUT = 150mA
VIN = 2.2V
Time (10µs/div)
Time (10µs/div)
Output Ripple
Output Ripple
IOUT = 150mA
IOUT = 150mA
VIN = 3.6V
VIN = 4.2V
VOUT = 1.3V
VOUT = 1.3V
Output Ripple
(20mV/div)
Output Ripple
(20mV/div)
Output Ripple
(20mV/div)
Output Ripple
Time (10µs/div)
Time (1µs/div)
Output Ripple
IOUT = 150mA
Output Ripple
(20mV/div)
VIN = 5.5V
VOUT = 1.3V
Time (1µs/div)
8
REV. 1.0.4 4/4/05
FAN5601
PRODUCT SPECIFICATION
Typical Performance Characteristics (cont.)
TA = 25°C, CIN= COUT =10µF, CB = 1µF, VOUT = 1.3V, unless otherwise noted.
Output Voltage vs Input Voltage
Efficiency vs Input Voltage
100
1.35
90
1.30
VOUT = 1.3V
Efficiency (%)
Ouput Voltage (V)
80
1.25
1.20
1.15
Load Current = 1mA
Load Current = 10mA
Load Current = 50mA
Load Current = 100mA
Load Current = 150mA
Load Current = 250mA
1.10
1.05
1.00
TA = 25°C
70
60
50
40
Load
Load
Load
Load
Load
Load
30
20
10
Current
Current
Current
Current
Current
Current
=
=
=
=
=
=
0
0.95
1
2
3
4
5
1
6
2
3
4
5
6
Input Voltage (V)
Input Voltage (V)
Output Voltage vs Load Current
Peak Efficiency vs Load Current
88
1.32
VIN = 4.5V
VIN = 2.95V
Peak Efficiency (%)
1.30
Ouput Voltage (V)
1mA
10mA
50mA
100mA
150mA
250mA
1.28
1.26
TA
TA
TA
TA
1.24
1.22
=
=
=
=
-40°C
0°C
80°C
125°C
TA = 25°C
86
84
82
80
1.20
78
0
50
100
150
200
Load Current (mA)
REV. 1.0.4 4/4/05
250
300
0
50
100
150
200
250
300
Load Current (mA)
9
PRODUCT SPECIFICATION
FAN5601
Block Diagram
V IN
0.25SW1
0.25SW1 0.5SW1
OSCILLATOR
(2MHz)
IN
VOLTAGE
REF.
SOFT START
Vref RAMP
OUT
Vref RAMP
FB
OUTPUT
150mV
0.5* INPUT
1V
C+
- CONFIGURATION
0.25SW2 0.25SW2 0.5SW2
+
-
PULSE_SKIP
CONTROL
LOGIC
+
-
SHORT_CKT.
D
R
I
V
E
R
S
0.25SW3
0.25SW3 0.5SW3
0.25SW4
0.25SW4 0.5SW4
C-
+
-
VOUT
UVLO
SHUTDOWN
+
THERMAL
SHUTDOWN
FB
ENABLE
Detailed Description
The FAN5601 switched capacitor DC/DC converter automatically configures switches to achieve a high efficiency
and provides a regulated output voltage by means of pulse
skipping, pulse frequency modulation (PFM). An internal
soft start circuit prevents excessive inrush current drawn
from the supply. Each switch is split into three segments.
Based on the values of VIN, VOUT and IOUT, an internal circuitry determines the number of segments to be used to
reduce current spikes.
Step-Down Charge Pump Operation
When VIN ≥ 2.22 × VOUT, a 2:1 configuration shown in
Fig.1(A) is enabled. The factor 0.9 is used instead of 1 in
order to account for the effect of resistive losses across the
switches and to accommodate hysteresis in the voltage detector comparator. Two phase non-overlapping clock signals are
generated to drive four switches. When switches 1 and 3 are
ON, switches 2 and 4 are OFF and CB is charged. When
switches 2 and 4 are ON, switches 1 and 3 are OFF, charge is
transferred from CB to COUT.
10
GND.
When VIN <2.22 × VOUT , a 1:1 configuration shown in
Fig. 1(B) is enabled. In the 1:1 configuration switch 3 is
always OFF and the switch 4 is always ON. At 1.6V output
setting the configuration changes from 2:1 to 1:1 at VIN =
3.56V. At 1.3V output setting the change occurs at VIN =
3.06V
.
Pulse-skipping PFM and Fractional Switch
Operation
When the regulated output voltage reaches its upper limit,
the switches are turned off the output voltage reaches its
lower limit. Considering a step-down 2:1 mode of operation,
1.6V output as an example, when the output reaches about
1.62V(upper limit), the control logic turns off all switches.
Switching stops completely. This is pulse-skipping mode.
Since the supply is isolated from the output, the output voltage will drop. Once the output is dropped to about
1.58V(lower limit), the device will return to regular switching mode with one quarter of each switch turning on first.
Another quarter of each switch will be turned on if VOUT
cannot reach regulation by the time of arrival of the third
REV. 1.0.4 4/4/05
FAN5601
PRODUCT SPECIFICATION
Switch Configuration
VIN
VIN
S1
S1
C+
C+
S2
S2
C
B
VOUT
VOUT
C
B
S3
S3
C-
CC
OUT
S4
C
OUT
S4
GND
GND
Figure 1. (A)
2:1 configuration
Switches in charging phase
Reverse all switches for pumping phase
charge cycle. Full switch operation occurs only during startup or under heavy load condition, when half switch operation cannot achieve regulation within seven charge cycles.
Soft Start
The soft-start feature limits inrush current when the device is
initially powered up and enabled. The reference voltage is
used to control the rate of the output voltage ramp-up to its
final value. Typical start-up time is 1ms. Since the rate of the
output voltage ramp-up is controlled by an internally generated slow ramp, pulse-skipping occurs and inrush current is
automatically limited.
REV. 1.0.4 4/4/05
Figure 1. (B)
1:1 configuration
Switch 3 is always off and
Switch 4 is always on
Switches 1 and 2 are in phase 1
Reverse the position of switches 1&2
for phase 2
Shutdown, UVLO, Short Circuit Current Limit
and Thermal Shutdown
The device has an active-low shutdown pin to decrease supply current to less than 1µA. In shutdown mode the supply is
disconnected from the output. UVLO triggers when supply
voltage drops below 2V. When the output voltage is lower
than 150mV, a short circuit protection is triggered. In this
mode 15 out of 16 pulses during the switching will be
skipped and the supply current is limited. Thermal shutdown
triggers at 150ºC.
11
PRODUCT SPECIFICATION
FAN5601
One of the key benefits of the ScalarPump™ architecture is
that the dynamically scaled on-resistance of the switches
effectively reduces the peak current in the bucket capacitor
and therefore input and output ripple current is also reduced.
Nevertheless, due to the ESR of the input and output bypass
capacitors, these current spikes generate voltage spikes at the
input and output pins. However, these ESR spikes can be
easily filtered because their frequency lie at up to 12 times
the clock frequency.
In applications where conductive and radiated EMI/RFI
interference has to be kept as low as possible, the user may
consider the use of additional input and output filtering. For
example, adding an L-C filter to the standard output bypass
configuration is very effective in reducing both the output
ripple and the voltage spikes. Figure 2 shows an L-C filter
using a 100nH chip inductor and a 1µF capacitor. The channel 1 of Figure 3 shows the ripple voltage at the output of the
device while Channel 2 shows the ripple voltage at the output of the filter at VIN = 3.3V,
(10mV/div)
Output Ripple
The value of the bucket capacitor is dependent on load current requirements. A 1µF bucket capacitor will work well in
all applications at all load currents, while a 0.1µF capacitor
will support most applications under 100mA of load current.
The choice of bucket capacitor values should be verified in
the actual application at the lowest input voltage and highest
load current. A 30% margin of safety is recommended in
order to account for the tolerance of the bucket capacitor and
the variations in the on-resistance of the internal switches.
IOUT = 100mA
VIN = 3.3V
VOUT = 1.3V
(10mV/div)
Proper operation of the FAN5601 requires one ceramic
bucket capacitor in the 0.1µF to 1µF range; one 10µF output
bypass capacitor and one 10µF input bypass capacitor. In
order to obtain optimum output ripple and noise performance, use of low ESR (<0.05Ω) ceramic input and output
bypass capacitors is recommended. The X5R and X7R
rated capacitors provide adequate performance over the
-40ºC to 85ºC temperature range.
VOUT = 1.3V and IOUT = 100mA. Similar filtering method
will greatly reduce the current spikes at the input. The user
should be mindful of considering resistive voltage drops in
the inductors connected serially in the input and output
leads.
Ripple at CF
Applications Information
Time (10µs/div)
Figure 3. Effect of L-C Filter on output ripple
While evaluating the FAN5601 (or any other switched
capacitor DC-DC converter) the user should be careful to
keep the power supply source impedance low; use of long
wires causing high lead inductances and resistive losses
should be avoided. A carefully laid out ground plane is
essential because current spikes are generated as the bucket
capacitor is charged and discharged. The input and output
bypass capacitors should be placed as close to the device
pins as possible.
CB = 1µF
C+
VIN
CIN = 10µF
C–
FAN5601
INPUT 2.2V to 5.5V
LF = 100nH Output 1.0V to 1.8V
VOUT
CF = 1µF
COUT = 10µF
ENABLE GND
Figure 2. Optional L-C Filter
12
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FAN5601
PRODUCT SPECIFICATION
Mechanical Dimensions
6-Lead 3x3mm MLP Package
2.45
0.15
3.0
C
2X
1.65
2.10
3.50
3.0
(0.70)
0.15
C
0.95 TYP
0.65 TYP
2X
TOP VIEW
RECOMMENDED LAND PATTERN
0.8 MAX
0.10
C
(0.20)
0.08
C
0.05
0.00
SIDE VIEW
SEATING
PLANE
2.25
PIN #1 IDENT
3
1
0.45
0.20
1.65
0.2 MIN
4
6
0.95
1.90
0.30~0.45
0.10
0.05
C A B
C
BOTTOM VIEW
NOTES:
A. CONFORMS TO JEDEC REGISTRATION MO-229,
VARIATION WEEA, DATED 11/2001
B. DIMENSIONS ARE IN MILLIMETERS.
C. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994
REV. 1.0.4 4/4/05
13
PRODUCT SPECIFICATION
FAN5601
Ordering Information
Product Number
FAN5601
Package Type
Voltage Option [Vnom]
Order Code
6-Lead 3x3mm MLP
1.3V
FAN5601MP13X
6-Lead 3x3mm MLP
1.8V
FAN5601MP18X
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ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME
ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN;
NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
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when properly used in accordance with instructions for use
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