ETC1 HWD20012 High-efficiency, low-supply-current, compact, step-up dc-dc converter Datasheet

High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
____________________________Features
________________________Applications
Pagers
Wireless Phones
Medical Devices
Hand-Held Computers
♦ 94% Efficient at 200mA Output Current
♦ 16µA Quiescent Supply Current
♦ Internal Synchronous Rectifier (no external diode)
♦ 0.1µA Logic-Controlled Shutdown
♦ LBI/LBO Low-Battery Detector
♦ Selectable Current Limit for Reduced Ripple
♦ Low-Noise, Anti-Ringing Feature (HWD20012)
♦ 8-Pin and 10-Pin MSOP Packages
♦ Preassembled Evaluation Kit (HWD20012EVKIT)
_______________Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
HWD20011EUA
HWD2001EUA
HWD20012EUB
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
8 MSOP
8 MSOP
10 MSOP
PDAs
RF Tags
Pin Configurations
1 to 3-Cell Hand-Held Devices
TOP VIEW
Typical Operating Circuit
FB 1
INPUT
0.7V TO VOUT
LBI
2
LBO
3
HWD20011
HWD2001
REF 4
ON
SHDN
OFF
LX
HWD20011OUT
HWD2001
OUTPUT
3.3V, 5V, OR
ADJ (2V TO 5.5V)
UP TO 300mA
FB 1
LBI
REF
LBO
FB
OUT
7
LX
6
GND
5
SHDN
MSOP
10 OUT
LBI 2
LOW-BATTERY
DETECT IN
8
LOW-BATTERY
DETECT OUT
LBO 3
GND
0.1µF
HWD20012
LX
8
GND
CLSEL 4
7
BATT
REF 5
6
SHDN
MSOP
1
9
HWD20011/HWD2001/HWD20012
General Description
The HWD20011/HWD2001/HWD20012 compact, high
effIciency, step-up DC-DC converters fit in small MSOP
packages. They feature a built-in synchronous rectifier,
which improves efficiency and reduces size and cost
by eliminating the need for an external Schottky diode.
Quiescent supply current is only 16µA.
The input voltage ranges from 0.7V to VOUT, where
VOUT can be set from 2V to 5.5V. Start-up is guaranteed from 1.1V inputs. The HWD20011/HWD2001/
HWD20012 have a preset, pin-selectable output for 5V or
3.3V. The outputs can also be adjusted to other voltages using two external resistors.
All three devices have a 0.3Ω N-channel MOSFET
power switch. The HWD20011 has a 1A current limit. The
HWD2001 has a 0.5A current limit, which permits the
use of a smaller inductor. The HWD20012 comes in a
10-pin MSOP package and features an adjustable current limit and circuitry to reduce inductor ringing.
HWD20011/HWD2001/HWD20012
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (OUT to GND) ..............................-0.3V to +6.0V
Switch Voltage (LX to GND) .....................-0.3V to (VOUT + 0.3V)
Battery Voltage (BATT to GND).............................-0.3V to +6.0V
SHDN, LBO to GND ..............................................-0.3V to +6.0V
LBI, REF, FB, CLSEL to GND ...................-0.3V to (VOUT + 0.3V)
Switch Current (LX) ...............................................-1.5A to +1.5A
Output Current (OUT) ...........................................-1.5A to +1.5A
Continuous Power Dissipation (TA = +70°C)
8-Pin MSOP (derate 4.1mW/°C above +70°C) ....... .330mW
10-Pin MSOP (derate 5.6mW/°C above +70°C) ..... ..444mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +165°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(VBATT = 2V, FB = OUT (VOUT = 3.3V), RL = ˙∞, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
Operating Voltage
VIN
Start-Up Voltage
1.1
TA = +25°C
VOUT
3.17
3.30
3.43
4.80
5
5.20
IOUT
VREF
300
420
HWD2001,
HWD20012 (CLSEL = GND)
150
220
V
V
V
mA
FB = GND
(VOUT = 5V)
Reference Voltage Tempco
5.5
HWD20011,
HWD20012 (CLSEL = OUT)
V
mV/°C
FB = GND
FB = OUT
(VOUT = 3.3V)
Reference Voltage
1.1
FB = OUT
2
UNITS
V
-2
Output Voltage Range
Steady-State Output Current
(Note 2)
MAX
5.5
0.9
TA = +25°C, RL = 3kΩ (Note 1)
Start-Up Voltage Tempco
Output Voltage
TYP
0.7
Minimum Input Voltage
HWD20011,
HWD20012 (CLSEL = OUT)
180
285
HWD2001,
HWD20012 (CLSEL = GND)
90
130
1.274
IREF = 0
1.30
1.326
0.024
TEMPCO
V
mV/°C
Reference Voltage Load
Regulation
VREF_LOAD
IREF = 0 to 100µA
3
15
mV
Reference Voltage Line
Regulation
VREF_LINE
VOUT = 2V to 5.5V
0.08
2.5
mV/V
1.30
1.326
V
0.3
0.6
Ω
1.274
FB, LBI Input Threshold
Internal NFET, PFET
On-Resistance
LX Switch Current
Limit (NFET)
LX Leakage Current
RDS(ON)
ILIM
ILEAK
ILX = 100mA
HWD20011, HWD20012 (CLSEL = OUT)
0.80
1
1.20
HWD2001, HWD20012 (CLSEL = GND)
0.4
0.5
0.65
0.05
1
VLX = 0, 5.5V; VOUT = 5.5V
2
A
µA
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
(VBATT = 2V, FB = OUT (VOUT = 3.3V), RL = ˙∞, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
Operating Current into OUT
(Note 3)
Shutdown Current into OUT
SYMBOL
Efficiency
CONDITIONS
MIN
TYP
MAX
UNITS
VFB = 1.4V, VOUT = 3.3V
16
35
µA
SHDN = GND
0.1
1
µA
VOUT = 3.3V, ILOAD = 200mA
90
VOUT = 2V, ILOAD = 1mA
85
LX Switch On-Time
tON
VFB = 1V, VOUT = 3.3V
3
LX Switch Off-Time
tOFF
VFB = 1V, VOUT = 3.3V
0.8
FB Input Current
IFB
VFB = 1.4V
ILBI
VLBI = 1.4V
%
4
7
µs
1
1.2
µs
0.03
50
nA
1
50
nA
CLSEL Input Current
ICLSEL
HWD20012, CLSEL = OUT
1.4
3
µA
SHDN Input Current
I SHDN
V SHDN = 0 or VOUT
0.07
50
nA
VLBI = 0, ISINK = 1mA
0.2
0.4
V
V LBO = 5.5V, VLBI = 5.5V
0.07
1
µA
150
Ω
LBI Input Current
LBO Low Output Voltage
LBO Off Leakage Current
I LBO
Damping Switch Resistance
SHDN Input Voltage
CLSEL Input Voltage
HWD20012, VBATT = 2V
88
VIL
0.2VOUT
VIH
0.8VOUT
VIL
0.2VOUT
VIH
0.8VOUT
V
V
ELECTRICAL CHARACTERISTICS
(VBATT = 2V, FB = OUT, RL = ∞, TA = -40°C to +85°C, unless otherwise noted.) (Note 4)
PARAMETER
Output Voltage
SYMBOL
VOUT
MIN
MAX
FB = OUT
CONDITIONS
3.13
3.47
FB = GND
4.75
5.25
Output Voltage Range
Reference Voltage
VREF
IREF = 0
FB, LBI Thresholds
Internal NFET, PFET
On-Resistance
2.20
5.5
V
1.3325
V
1.2675
1.3325
V
0.6
Ω
40
µA
VFB = 1.4V, VOUT = 3.3V
SHDN = GND
Shutdown Current into OUT
V
1.2675
RDS(ON)
Operating Current into OUT
(Note 3)
UNITS
1
µA
LX Switch On-Time
tON
VFB = 1V, VOUT = 3.3V
2.7
7.0
µs
LX Switch Off-Time
tOFF
VFB = 1V, VOUT = 3.3V
0.75
1.25
µs
HWD20012, HWD20012 (CLSEL = OUT)
0.75
1.25
HWD2001, HWD20012 (CLSEL = GND)
0.36
0.69
LX Switch Current
Limit (NFET)
ILIM
3
A
HWD20011/HWD2001/HWD20012
ELECTRICAL CHARACTERISTICS (continued)
ELECTRICAL CHARACTERISTICS (continued)
(VBATT = 2V, FB = OUT, RL = ∞, TA = -40°C to +85°C, unless otherwise noted.) (Note 4)
MAX
UNITS
CLSEL Input Current
PARAMETER
ICLSEL
HWD20012, CLSEL = OUT
3
µA
SHDN Input Current
SYMBOL
I SHDN
VSHDN = 0 or VOUT
75
nA
V LBO = 5.5V, VLBI = 5.5V
1
µA
LBO Off Leakage Current
I LBO
CONDITIONS
MIN
Note 1: Start-up voltage operation is guaranteed with the addition of a Schottky MBR0520 external diode between the input and
output.
Note 2: Steady-state output current indicates that the device maintains output voltage regulation under load. See Figures 5 and 6.
Note 3: Device is bootstrapped (power to the IC comes from OUT). This correlates directly with the actual battery supply.
Note 4: Specifications to -40°C are guaranteed by design, not production tested.
Typical Operating Characteristics
(L = 22µH, CIN = 47µF, COUT = 47µF 0.1µF, CREF = 0.1µF, TA = +25°C, unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT
90
80
EFFICIENCY (%)
VIN = 2.4V
70
VIN = 1.2V
60
50
40
50
40
30
20
20
VOUT = 5V
ILIMIT = 500mA
10
0
0.1
1
10
100
0
0.01
50
40
0.1
1
10
100
VOUT = 3.3V
ILIMIT = 500mA
0
1000
0.01
0.1
HWD20011 toc04
VIN = 2.4V
60
50
40
30
20
VOUT = 3.3V
ILIMIT = 1A
10
0
1
10
100
10
100
HWD20011 toc05
1.300
REFERENCE OUTPUT VOLTAGE (V)
80
VIN = 1.2V
1
LOAD CURRENT (mA)
REFERENCE OUTPUT VOLTAGE
vs. TEMPERATURE
90
0.1
60
LOAD CURRENT (mA)
100
0.01
VIN = 1.2V
10
EFFICIENCY vs. LOAD CURRENT
70
VIN = 2.4V
70
20
VOUT = 5V
ILIMIT = 1A
10
1000
80
30
LOAD CURRENT (mA)
EFFICIENCY (%)
0.01
VIN = 3.6V
VIN = 1.2V
60
30
90
VIN = 2.4V
70
HWD20011 toc03
VIN = 3.6V
80
100
HWD20011 toc02
90
EFFICIENCY vs. LOAD CURRENT
100
EFFICIENCY (%)
HWD20011 toc01
EFFICIENCY vs. LOAD CURRENT
100
EFFICIENCY (%)
HWD20011/HWD2001/HWD20012
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
1.298
IREF = 0
1.296
1.294
IREF = 100µA
1.292
1.290
-40
1000
-20
0
20
40
60
TEMPERATURE (°C)
LOAD CURRENT (mA)
4
80
100
1000
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
NO-LOAD BATTERY CURRENT
vs. INPUT BATTERY VOLTAGE
100
80
ILIMIT = 0.5A, 5.0V
60
ILIMIT = 0.5A, 3.3V
ILIMIT = 1A, 3.3V
0
WITHOUT DIODE
1.0
0.8
0.6
WITH 1N5817
0.1
1
10
LOAD CURRENT (mA)
1
100
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE (VOUT = 3.3V)
0.4
0.2
HWD20011 toc11
1A CURRENT LIMIT
600
500
400
300
200
0.5A CURRENT LIMIT
800
MAXIMUM OUTPUT CURRENT (mA)
0.6
800
700
100
0
1.0
1.5
2.0
2.5
3.0
3.5
4.0
200
0.5A CURRENT LIMIT
100
1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
LX CURRENT LIMIT
vs. OUTPUT VOLTAGE
P-CHANNEL
0.35
1.2
HWD20011, HWD20012 (CLSEL = OUT)
1.0
0.8
0.30
ILIM (A)
RESISTANCE (Ω)
300
SWITCH RESISTANCE vs. TEMPERATURE
0.40
VOUT
AC COUPLED
100mV/div
400
INPUT VOLTAGE (V)
0.45
VLX
5V/div
ILX
0.5A/div
1A CURRENT LIMIT
500
4.5
HWD20011 toc13.5
HWD20011 TOC13
600
INPUT VOLTAGE (V)
SUPPLY VOLTAGE (V)
HEAVY-LOAD SWITCHING WAVEFORMS
700
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
900
MAXIMUM OUTPUT CURRENT (mA)
HWD20011 TOC10
SHUTDOWN THRESHOLD (V)
0.8
N-CHANNEL
0.25
0.20
0.6
0.4
0.15
HWD2001,HWD20012 (CLSEL = GND)
0.10
0.2
0.05
0
0
1µs/div
HWD20011 toc09
-1.0
0.01
MAXIMUM OUTPUT CURRENT
vs. INPUT VOLTAGE (VOUT = 5V)
1.0
VIN = 2.4V
VOUT = 5.0V
-0.4
-0.8
SHUTDOWN THRESHOLD
vs. SUPPLY VOLTAGE
0
0
-0.2
-0.6
INPUT BATTERY VOLTAGE (V)
1.2
0.2
0.2
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
1.4
0.4
0.4
0
0
0.6
HWD20011 toc12
20
1.4
1.2
0.8
HWD20011 toc14
ILIMIT = 1A, 5.0V
40
1.6
SHUTDOWN CURRENT (µA)
120
1.8
START-UP VOLTAGE (V)
INPUT BATTERY CURRENT (µA)
140
1.0
HWD20011 toc08
HWD20011 toc07
160
SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE
START-UP VOLTAGE
vs. LOAD CURRENT
-60 -40
-20
0
20
40
TEMPERATURE (°C)
5
60
80
100
2.0
2.5
3.0
3.5
4.0
OUTPUT VOLTAGE (V)
4.5
5.0
HWD20011/HWD2001/HWD20012
Typical Operating Characteristics (continued)
(L = 22µH, CIN = 47µF, COUT = 47µF 0.1µF, CREF = 0.1µF, TA = +25°C, unless otherwise noted.)
HWD20011/HWD2001/HWD20012
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
Typical Operating Characteristics (continued)
(L = 22µH, CIN = 47µF, COUT = 47µF 0.1µF, CREF = 0.1µF, TA = +25°C, unless otherwise noted.)
LOAD-TRANSIENT RESPONSE
LINE-TRANSIENT RESPONSE
HWD20011 TOC17
VIN = 2.4V
VOUT = 3.3V
VIN
2V TO 3V
1V/div
VOUT
2V/div
IOUT
200mA/div
VSHDN
2V/div
VOUT
50mV/div
AC
COUPLED
VOUT
AC COUPLED
100mV/div
ILOAD
100mA
EXITING SHUTDOWN
HWD20011 TOC16
HWD20011 TOC15
5µs/div
10µs/div
500µs/div
Pin Description
PIN
HWD20011
HWD2001
HWD20012
NAME
FUNCTION
1
1
FB
Dual-Mode™ Feedback Input. Connect to GND for +5.0V output.
Connect to OUT for +3.3V output. Use a resistor network to set the
output voltage from +2.0V to +5.5V.
2
2
LBI
Low-Battery Comparator Input. Internally set to trip at +1.30V.
3
3
LBO
Open-Drain Low-Battery Comparator Output. Connect LBO to OUT
through a 100kΩ resistor. Output is low when VLBI is <1.3V. LBO is
high impedance during shutdown.
—
4
CLSEL
4
5
REF
5
6
SHDN
Shutdown Input. Drive high (>80% of VOUT) for operating mode.
Drive low (<20% of VOUT) for shutdown mode. Connect to OUT for
normal operation.
—
7
BATT
Battery Input and Damping Switch Connection. If damping switch is
unused, leave BATT unconnected.
6
8
GND
Ground
7
9
LX
8
10
OUT
Current-Limit Select Input. CLSEL = OUT sets the current limit to 1A.
CLSEL = GND sets the current limit to 0.5A.
1.3V Reference Voltage. Bypass with a 0.1µF capacitor.
N-Channel and P-Channel Power MOSFET Drain
Power Output. OUT provides bootstrap power to the IC.
6
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
combines the high output power and efficiency of a
pulse-width-modulation (PWM) device with the ultra-low
The HWD20011/HWD2001/HWD20012 compact, step-up
quiescent current of a traditional PFM (Figure 1). There
DC-DC converters start up with voltages as low as 0.9V
is no oscillator; a constant-peak-current limit in the
and operate with an input voltage down to 0.7V.
switch allows the inductor current to vary between this
Consuming only 16µA of quiescent current, these
peak limit and some lesser value. At light loads, the
devices offer a built-in synchronous rectifier that
switching frequency is governed by a pair of one-shots
reduces cost by eliminating the need for an external
that set a typical minimum off-time (1µs) and a typical
diode and improves overall efficiency by minimizing
maximum on-time (4µs). The switching frequency
losses in the circuit (see Synchronous Rectification secdepends upon the load and the input voltage, and can
tion for details). The internal MOSFET resistance is typirange up to 500kHz. The peak current of the internal Ncally 0.3Ω, which minimizes losses. The current limit of
channel MOSFET power switch is fixed at 1A
the HWD20011 and HWD2001 are 1A and 0.5A, respec(HWD20011), at 0.5A (HWD2001), or is selectable
tively. The HWD2001's lower current limit allows the use
(HWD20012). Unlike conventional pulse-skipping DC-DC
of a physically smaller inductor in space-sensitive
converters (where ripple amplitude varies with input
applications. The HWD20012 features a circuit that elimivoltage), ripple in these devices does not exceed the
nates noise due to inductor ringing. In addition, the
product of the switch current limit and the filter-capaciHWD20012 offers a selectable current limit (0.5A or 1A)
tor equivalent series resistance (ESR).
for design flexibility.
Synchronous Rectification
PFM Control Scheme
The internal synchronous rectifier eliminates the need
A unique minimum-off-time, current-limited, pulse-frefor an external Schottky diode, thus reducing cost and
quency-modulation (PFM) control scheme is a key feaboard space. During the cycle off-time, the P-channel
ture of the HWD20011/HWD2001/HWD20012. This scheme
MOSFET turns on and shunts the MOSFET body diode.
OUT
MINIMUM
OFF-TIME
ONE-SHOT
SHDN
EN
TRIG
Q
ONE-SHOT
0.1µF 47µF
ZERO
CROSSING
AMPLIFIER
P
VIN
LX
22µH
F/F
S
R
CLSEL
(HWD20012)
GND
HWD20011
HWD2001
HWD20012
BATT
CURRENT-LIMIT
AMPLIFIER
TRIG
Q
ONE-SHOT
VOUT
DAMPING
SWITCH
FB
ERROR
AMPLIFIER
R4
LOW-BATTERY
COMPARATOR
R5
R6
REFERENCE
LBO
R1
200Ω
(HWD20012)
R3
R2
100k
47µF
N
Q
MAXIMUM
ON-TIME
ONE-SHOT
VIN
VOUT
REF
0.1µF
LBI
Figure 1. Simplified Functional Diagram
7
HWD20011/HWD2001/HWD20012
Detailed Description
HWD20011/HWD2001/HWD20012
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
As a result, the synchronous rectifier significantly
improves efficiency without the addition of an external
component. Conversion efficiency can be as high as
94%, as shown in the Typical Operating Characteristics.
For low-voltage inputs from single cells (Alkaline, NiCd,
or NiMH), use an external Schottky diode such as the
1N5817 to ensure start-up.
VIN
R1
200Ω
BATT
22µH
HWD20012
Voltage Reference
The voltage at REF is nominally +1.30V. REF can
source up to 100µA to external circuits. The reference
maintains excellent load regulation (see Typical Operating Characteristics). A bypass capacitor of 0.1µF is
required for proper operation.
DAMPING
SWITCH
LX
VOUT
OUT
0.1µF
Shutdown
The device enters shutdown when V SHDN is low
(V SHDN <20% of VOUT). For normal operation, drive
SHDN high (V SHDN >80% of VOUT) or connect SHDN
to OUT. During shutdown, the body diode of the Pchannel MOSFET allows current flow from the battery to
the output. VOUT falls to approximately VIN - 0.6V and
LX remains high impedance. The capacitance and load
at OUT determine the rate at which V OUT decays.
Shutdown can be pulled as high as 6V, regardless of
the voltage at OUT.
47µF
Figure 2. Simplified Diagram of Inductor Damping Switch
Current Limit Select Pin (HWD20012)
VLX
1V/div
The HWD20012 allows a selectable inductor current limit
of either 0.5A or 1A. This allows flexibility in designing
for higher current applications or for smaller, compact
designs. Connect CLSEL to OUT for 1A or to GND for
0.5A. CLSEL draws 1.4µA when connected to OUT.
BATT/Damping Switch (HWD20012)
2µs/div
The HWD20012 is designed with an internal damping
switch to minimize ringing at LX. The damping switch
connects an external resistor (R1) across the inductor
when the inductor’s energy is depleted (Figure 2).
Normally, when the energy in the inductor is insufficient
to supply current to the output, the capacitance and
inductance at LX form a resonant circuit that causes
ringing. The ringing continues until the energy is dissipated through the series resistance of the inductor. The
damping switch supplies a path to quickly dissipate this
energy, minimizing the ringing at LX. Damping LX ringing does not reduce VOUT ripple, but does reduce EMI.
R1 = 200Ω works well for most applications while reducing efficiency by only 1%. Larger R1 values provide less
damping, but have less impact on efficiency. Generally,
lower values of R1 are needed to fully damp LX when
the VOUT/VIN ratio is high (Figures 2, 3, and 4).
Figure 3. LX Ringing Without Damping Switch
VLX
1V/div
2µs/div
Figure 4. LX Waveform with Damping Switch (with 200Ω
external resistor)
8
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
where VREF = +1.3V and VOUT may range from 2V to
5V. The input bias current of FB has a maximum value
of 50nA which allows large-value resistors (R6 ≤ 260kΩ)
to be used.
Low-Battery Detection
The HWD20011/HWD2001/HWD20012 contain an on-chip
comparator for low-battery detection. If the voltage at
LBI falls below the internal reference voltage (1.30V),
LBO (an open-drain output) sinks current to GND. The
low-battery monitor threshold is set by two resistors, R3
and R4 (Figures 5, 6, and 7). Since the LBI current is
less than 50nA, large resistor values (R4 ≤ 260kΩ) can
be used to minimize loading of the input supply.
Calculate R3 using the following equation:
R3 = R4 [(VTRIP / VREF) - 1]
R5 = R6 [(VOUT / VREF ) - 1]
VIN
47µF
22µH
R1
200Ω
BATT
(HWD20012)
VOUT
OUT
CLSEL
(HWD20012)
LBI
for VTRIP ≥ 1.3V. VTRIP is the level where the low-battery
detector output goes low, and V REF is the internal
1.30V reference. Connect a pull-up resistor of 100kΩ or
greater from LBO to OUT when driving CMOS circuits.
LBO is an open-drain output, and can be pulled as
high as 6V regardless of the voltage at OUT. When LBI
is above the threshold, the LBO output is high impedance. If the low-battery comparator is not used, ground
LX
R3
0.1µF
OUTPUT
+3.3V
47µF
FB
R4
SHDN
REF
HWD20011
HWD2001
HWD20012
R2
100k
LOW-BATTERY
OUTPUT
LBO
VIN
GND
0.1µF
Figure 5. Preset Output Voltage of +3.3V
47µF
22µH
VIN
R1
200Ω
47µF
R1
200Ω
R3
22µH
OUTPUT
5.0V
OUT
CLSEL
(HWD20012)
0.1µF
REF
0.1µF
LBO
0.1µF
R2
100k
REF
LOWBATTERY
OUTPUT
FB
GND
LOWBATTERY
OUTPUT
0.1µF
FB
GND
Figure 6. Preset Output Voltage of +5V
Figure 7. Setting an Adjustable Output
9
47µF
R5
HWD20011
HWD2001 LBO
HWD20012
47µF
R2
100k
HWD20011
HWD2001
HWD20012
OUTPUT
2V to 5.5V
SHDN
CLSEL
(HWD20012)
R4
SHDN
R4
LX
OUT
LX
R3
LBI
BATT
(HWD20012)
LBI
BATT
(HWD20012)
HWD20011/HWD2001/HWD20012
Selecting the Output Voltage
VOUT can be set to 3.3V or 5.0V by connecting the FB
pin to GND (5V) or OUT (3.3V) (Figures 5 and 6).
To adjust the output voltage, connect a resistor-divider
from VOUT to FB to GND (Figure 7). Choose a value
less than 260kΩ for R6. Use the following equation to
calculate R5:
R6
HWD20011/HWD2001/HWD20012
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
VIN
VTRIP (VH, VL)
HWD20011
HWD2001
HWD20012
R3
47µF
22µH
R1
200Ω
VOUT
OUT
0.1µF
47µF
LBI
BATT
(HWD20012)
LX
OUT
R3
CLSEL
(HWD20012)
LBI
R2
100k
R4
VOUT
LBO
47µF
0.1µF
FB
GND
R7
SHDN
HWD20011
HWD2001
REF HWD20012
GND
LBO
R2
100k
LOWBATTERY
OUTPUT
R4

VH = 1.3V 1 +


VL = 1.3V 1 +

0.1µF
(
)
(
)
R3
R3 
+

R7
R4 
(VOUT − 1.3V) R 3 
R3
−

R4
(1.3V) (R2 + R7) 
WHERE VH IS THE UPPER TRIP LEVEL
VL IS THE LOWER TRIP LEVEL
Figure 8. Setting Resistor Values for the Low-Battery Indicator
when VIN < 1.3V
LBI and LBO. For VTRIP less than 1.3V, configure the
comparator as shown in Figure 8. Calculate the value of
the external resistors R3 and R4 as follows:
R3 = R4(VREF - VTRIP) / (VOUT - VREF)
Since the low-battery comparator is noninverting, external hysteresis can be added by connecting a resistor
between LBO and LBI as shown in Figure 9. When LBO
is high, the series combination of R2 and R7 source
current into the LBI summing junction.
Figure 9. Adding External Hysteresis to the Low-Battery
Indicator
HWD20011, 500mA for the HWD2001, and 1A or 0.5A for
the HWD20012. However, it is generally acceptable to
bias the inductor into saturation by as much as 20%,
although this will slightly reduce efficiency. Table 1 lists
suggested components.
The inductor’s DC resistance significantly affects efficiency. See Table 2 for a comparison of inductor specifications. Calculate the maximum output current as
follows:
Applications Information
( )
Inductor Selection
IOUT MAX
=
V
VIN 
– VIN  
ILIM – t OFF  OUT
 η
VOUT 
2 x L

 
An inductor value of 22µH performs well in most applications. The HWD20011/HWD2001/HWD20012 will
also work with inductors in the 10µH to 47µH range. Smaller
inductance values typically offer a smaller physical size
for a given series resistance, allowing the smallest
where IOUT(MAX) = maximum output current in amps
overall circuit dimensions. However, due to higher peak
VIN = input voltage
inductor currents, the output voltage ripple (IPEAK x
L = inductor value in µH
output filter capacitor ESR) also tends to be higher.
Circuits using larger inductance values exhibit higher
η = efficiency (typically 0.9)
output current capability and larger physical dimentOFF = LX switch’s off-time in µs
sions for a given series resistance. The inductor’s increILIM = 0.5A or 1.0A
mental saturation current rating should be greater than
the peak switch-current limit, which is 1A for the
10
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
PRODUCTION
METHOD
INDUCTORS
RECTIFIERS
(OPTIONAL)
CAPACITORS
Surface Mount
Sumida CD43 series
Sumida CD54 series
Coilcraft DT1608C
Coilcraft DO1608C
Coiltronics Uni-PAC
Murata LQH4 series
Sprague 593D series
Sprague 595D series
AVX TPS series
ceramic
Miniature Through-Hole
Sumida RCH654-220
Sanyo OS-CON series
Table 2. Surface-Mount Inductor
Specifications
MANUFACTURER
PART NUMBER
µH
Ω (max) IPEAK (A)
Motorola MBR0530
Nihon EC 15QS02L
—
Table 3. Component Suppliers
COMPANY
HEIGHT
(mm)
Coilcraft DT1608C-103
10
0.095
0.7
2.92
Coilcraft DO1608C-153
15
0.200
0.9
2.92
Coilcraft DO1608C-223
22
0.320
0.7
2.92
Coiltronics UP1B-100
10
0.111
1.9
5.0
Coiltronics UP1B-150
15
0.175
1.5
5.0
Coiltronics UP1B-220
22
0.254
1.2
5.0
Murata LQH4N100
10
0.560
0.4
2.6
Murata LQH4N220
22
0.560
0.4
2.6
Sumida CD43-8R2
8.2
0.132
1.26
3.2
Sumida CD43-100
10
0.182
1.15
3.2
Sumida CD54-100
10
0.100
1.44
4.5
Sumida CD54-180
18
0.150
1.23
4.5
Sumida CD54-220
22
0.180
1.11
4.5
PHONE
FAX
AVX
USA (803) 946-0690
USA (803) 626-3123
Coilcraft
USA (847) 639-6400
USA (847) 639-1469
Coiltronics
USA (561) 241-7876
USA (561) 241-9339
Motorola
USA (303) 675-2140
(800) 521-6274
USA (303) 675-2150
Murata
USA (814) 237-1431
(800) 831-9172
USA (814) 238-0490
Nihon
USA (805) 867-2555 USA (805) 867-2556
Japan 81-3-3494-7411 Japan 81-3-3494-7414
Sanyo
USA (619) 661-6835
USA (619) 661-1055
Japan 81-7-2070-6306 Japan 81-7-2070-1174
Sprague
Sumida
Taiyo Yuden
USA (603) 224-1961
USA (603) 224-1430
USA (647) 956-0666
USA (647) 956-0702
Japan 81-3-3607-5111 Japan 81-3-3607-5144
USA (408) 573-4150
USA (408) 573-4159
inductor current and the output capacitor ESR. Use
low-ESR capacitors for best performance, or connect
two or more filter capacitors in parallel. Low-ESR, SMT
tantalum capacitors are currently available from
Sprague (595D series) AVX (TPS series) and other
sources. Ceramic surface-mount and Sanyo OS-CON
organic-semiconductor through-hole capacitors also
exhibit very low ESR, and are especially useful for operation at cold temperatures. See Table 3 for a list of suggested component suppliers.
Capacitor Selection
A 47µF, 10V surface-mount tantalum (SMT) output filter
capacitor provides 80mV output ripple when stepping
up from 2V to 5V. Smaller capacitors (down to 10µF
with higher ESRs) are acceptable for light loads or in
applications that can tolerate higher output ripple.
Values in the 10µF to 100µF range are recommended.
The equivalent series resistance (ESR) of both bypass
and filter capacitors affects efficiency and output ripple. Output voltage ripple is the product of the peak
11
HWD20011/HWD2001/HWD20012
Table 1. Suggested Components
Optional External Rectifier
VIN
Although not required, a Schottky diode (such as the
MBR0520) connected between LX and OUT allows
lower start-up voltages (Figure 10) and is recommended when operating at input voltages below 1.3V. Note
that adding this diode provides no significant efficiency
improvement.
47µF
22µH
R1
200Ω
PC Board Layout and Grounding
Careful printed circuit layout is important for minimizing
ground bounce and noise. Keep the IC’s GND pin and
the ground leads of the input and output filter capacitors less than 0.2in (5mm) apart. In addition, keep all
connections to the FB and LX pins as short as possible. In particular, when using external feedback resistors, locate them as close to the FB as possible. To
maximize output power and efficiency and minimize
output ripple voltage, use a ground plane and solder
the IC’s GND directly to the ground plane.
BATT
(HWD20012)
LX
MBR0520
OUT
R3
LBI
HWD20011
FB
HWD2001
HWD20012 SHDN
R4
0.1µF
47µF
R2
100k
CLSEL
(HWD20012)
LBO
LOW-BATTERY
OUTPUT
REF
0.1µF
GND
Figure 10. Adding a Schottky Diode for Low Input Voltage
Operation
Chip Information
TRANSISTOR COUNT: 751
Package Information
10LUMAX.EPS
HWD20011/HWD2001/HWD20012
High-Efficiency, Low-Supply-Current,
Compact, Step-Up DC-DC Converters
__
_12
Chengdu Sino Microelectronics System Co.,Ltd
13