The ILC6360 step-up/step-down DC-DC converter is a
switch mode converter, capable of supplying up to 500mA
output current, at a fixed or user selectable output voltage.
The range of input, and output voltage options makes the
ILC6360 ideal for Lithium-ion (Li-ion) , or any other battery
application, where the input voltage range spans above and
below the regulated output voltage. When ILC6360’s input
voltage exceeds the output voltage by more than 800mV,
the output will begin to track the input linearly.
Configured as a 300kHz, fixed frequency PWM boost con-
verter, the ILC6360 performs the buck operation by seam-
lessly switching to PFM, when the output voltage rises near
the positive range of regulation. However, since the transition
point between PWM and PFM mode is dependent upon both
line, and load regulation, under certain conditions, regulation
will remain in PWM mode even in the buck mode of operation.
The ILC6360 is unconditionally stable with no external com-
pensation; the sizes of the input and output capacitors influ-
ence the ripple on the input, and output voltages. Since the
ILC6360 has an internal synchronous rectifier, the standard
fixed voltage version requires minimal external components:
an inductor, an input capacitor, and an output capacitor. An
additional 10µF ceramic output capacitor will help reduce
output ripple voltage.
Other features include an external sync input for synchro-
nizing the PWM frequency, low battery input detector with
100ms transient rejection delay built-in, and, a power good
indicator useful as a system power on reset.
Features
• ILC6360CIR-36: Fixed 3.6V output; custom
voltages possible
• ILC6360CIR-ADJ: Adjustable output to 6V maximum
• Capable of 500mA output current
• Peak efficiency: > 90% at V
OUT
= .6V,I
OUT
= 300mA,
V
IN =
3.6V
• No external diode is required (synchronous rectification)
• Battery input current of 250mA at no load
• True load disconnect from battery input in shutdown (1mA)
• OSC freq: 300kHz ±15%
• External freq synchronization from 150kHz to 500kHz
• Low battery detector with 100ms transient rejection delay
• Power good output flag when V
OUT
is in regulation
• MSOP-8 package
Applications
• Cellular phones
• Palmtops, PDAs and portable electronics
• Equipment using single Lithium-Ion batteries
Patent Pending
Optimized to Maximize Battery Life
ILC6360 Efficiency (%)
ILC6360 Efficiency @ I
OUT
= 300mA
IN
100µF
C
ILC6360CIR-ADJ
L
1
15µH
2
R5
3
LBI/SD
SYNC
LBO
V
FB
6
5
R6
4
Low Battery
Detector Output
Power Good Output
C
OUT
10µF
100µF
Battery Voltage (V)
90
4.2
+
V
IN
2.7V to 4.2V
L
X
V
IN
V
OUT
GND
8
+
7
+
V
OUT
3.6V/500mA
80
Typical Li-ion Battery Discharge Curve
3.6
ON
OFF
70
Time
3.0
Ext Sync
(Connect to GND if unused)
MSOP-8
Typical Performance Characteristics for 1-cell Li-ion
Typical Step-up/Step-down Application Circuit
(Note: R5 and R6 are required only if LBI feature is used)
Impala Linear Corporation
ILC6360 1.1
(408) 574-3939
www.impalalinear.com
Jan 1999
1
Step-Up/Step-Down DC-DC Converter for 1-Cell Lithium-Ion Batteries
Pin Functions ILC6360CIR-36
Pin Number
1
2
3
4
SYNC
5
POK
(ILC6382CIR-XX)
V
FB
(ILC6382CIR-ADJ)
LBO
GND
V
OUT
Pin Name
L
x
V
IN
LBI/SD
Pin Description
Inductor input. Inductor L connected between this pin and the battery
Connect directly to battery
Low battery detect input and shutdown. Low battery detect threshold is set with this pin
using a potential divider. If this pin is pulled to logic low then the device will shutdown.
A logic level signal referenced to V
IN
, at a frequency between 150kHz and 500kHz on
this pin will over-ride the internal 300kHz oscillator. If the SYNC function is unused, pin
4 should be connected to ground
This open drain output pin will go high when output voltage is within regulation,
0.92*V
OUT (NOM)
< V
OUT
< 0.98*V
OUT (NOM)
This pin sets the adjustable output voltage via an external resistor divider network. The
formula for choosing the resistors is shown in the “Applications Information“ section.
This open drain output will go low if the battery voltage is below the low battery
threshold set at pin 3
Connect this pin to the battery and system ground
This is the regulated output voltage
6
7
8
PIN-PACKAGE CONFIGURATIONS
Ordering Information (T
A
= -40°C to +85°C)
ILC6360CIR-36
ILC6360CIR-ADJ
3.6V output, MSOP-8 package
Adjustable output, MSOP-8 package
L
X
1
V
IN
2
8 V
OUT
7 GND
6 LBO
5 POK
MSOP-8
(TOP VIEW)
L
X
1
V
IN
2
8 V
OUT
7 GND
6 LBO
5 V
FB
MSOP-8
(TOP VIEW)
LBI/SD 3
SYNC
4
LBI/SD 3
SYNC
4
ILC6360CIR-36
ILC6360CIR-ADJ
Impala Linear Corporation
ILC6360 1.1
(408) 574-3939
www.impalalinear.com
Jan 1999
2
Step-Up/Step-Down DC-DC Converter for 1-Cell Lithium-Ion Batteries
Absolute Maximum Ratings (Note 1)
Parameter
Voltage on V
OUT
pin
Voltage on LBI, Sync, LBO, POK, LBI/SD, V
FB
, L
X
and V
IN
pins
Peak switch current on L
X
pin
Current on LBO pin
Continuous total power dissipation at 85°C
Short circuit duration
Operating ambient temperature
Maximum junction temperature
Storage temperature
Lead temperature (soldering 10 sec)
Package thermal resistance
Symbol
V
OUT
-
I
L
X
I
sink(LBO)
P
d
I
SC
T
A
T
J (max)
T
stg
θ
JA
Ratings
-0.3 to 7
-0.3 to 7
1
5
400
1
-40 to 85
170
-40 to 125
300
206
Units
V
V
A
mA
mW
sec
°C
°C
°C
°C
°C/W
Electrical Characteristics ILC6360CIR-36 and ILC6360CIR-ADJ
Unless otherwise specified all limits are at T
A
= 25°C, V
IN
= 3.6V, V
OUT
= 3.6V, V
LBI
= 1.5V, I
OUT
= 1mA, F
OSC
= 300kHz.
Test circuit of figure 2 for ILC6360-36 and test circuit of figure 9 for ILC6360-ADJ.
BOLDFACE
type indicates limits that
apply over the full operating temperature range.
Note 2.
Parameter
Input Voltage
Output Voltage
Feedback Voltage
(ILC6360-ADJ only)
Output Voltage
Adjustment Range
ILC6360CIR-ADJ only
Output Current
Load Regulation
Symbol
V
IN
V
OUT
V
FB
V
OUT (adj) min
V
OUT (adj) max
I
OUT
∆V
OUT
V
OUT (no
λοαδ)
Efficiency
No Load Battery Input
Current
η
I
IN (no load)
Conditions
V
OUT
= V
OUT(nominal)
± 4%
(Note 3)
2.8V < V
IN
< 4.2V, I
OUT
= 0mA
Min
2.7
3.528
1.225
1.212
Typ
Max
V
OUT (nom)
+0.8
3.600
1.250
2.5
6
500
4
1
1
93
250
3.672
1.275
1.288
Units
V
V
V
V
V
IN
= 3.3V, I
OUT
= 50mA
V
IN
= 3.6V, V
OUT
= V
OUT(nom)
± 4%
(Note 3)
0mA < I
OUT
< 500mA
0mA < I
OUT
< 300mA
0mA < I
OUT
< 200mA
I
OUT
= 300mA
I
OUT
= 0mA
mA
%
%
µA
Impala Linear Corporation
ILC6360 1.1
(408) 574-3939
www.impalalinear.com
Jan 1999
3
Step-Up/Step-Down DC-DC Converter for 1-Cell Lithium-Ion Batteries
Electrical Characteristics ILC6360CIR-36 and ILC6360CIR-ADJ (Continued)
Unless otherwise specified all limits are at TA = 25°C, V
IN
= 3.6V, V
OUT
= 3.6V, V
LBI
= 1.5V, I
OUT
= 1mA, FOSC = 300kHz. Test circuit
of figure 2 for ILC6360-36 and test circuit of figure 9 for ILC6360-ADJ.
BOLDFACE
type indicates limits that apply over the full oper-
ating temperature range.
Note 2.
Parameter
Battery input current in shutdown
Symbol
I
IN(SD)
(short circuit)
True load disconnect
Switch on resistance
Oscillator frequency
External clock frequency range (sync)
External clock pulse width
External clock rise/fall time
LBI input threshold
Input leakage current
LBI hold time
LBO output voltage low
LBO output leakage current
Shutdown input voltage low
Shutdown input voltage high
Sync input voltage low
Sync input voltage high
POK output voltage low
POK output voltage high
POK output leakage current
POK threshold
POK hysteresis
R
ds(on)
f
osc
f
sync
t
W
(sync)
t
r
/ t
f
V
REF
I
LEAK
t
hold
(LBI)
V
LBO (low)
I
LBO (hi)
V
SD (low)
V
SD (hi)
V
SYNC (low)
V
SD (hi)
V
POK (low)
V
POK (hi)
I
L (POK)
V
TH (POK)
V
HYST
Force 6V at pin 5
1
50
I
SINK
= 2mA, open drain output
1
V
LBO
= 5V
1
Pins LBI/SD, Sync and V
FB
,
Note 4
Note 5
I
SINK
= 20mA, open drain output
V
LBO
= 5V
1
120
100
0.4
2
0.4
6
0.4
6
0.4
6
2
0.92xV
OUT
0.95xV
OUT
0.98xV
OUT
Note 4
Note 4
1.175
1.150
1.250
N-Channel MOSFET
P-Channel MOSFET
255
150
200
100
1.325
1.350
200
V
nA
ms
V
µA
V
V
V
V
V
V
µA
V
mV
400
750
300
345
500
mΩ
kHz
kHz
ns
ns
Conditions
V
LBI/SD
< 0.4V, V
OUT
= 0V
Min
Typ
1
Max
2
Units
µA
Note 1. Absolute maximum ratings indicate limits which, when exceeded, may result in damage to the component. Electrical specifications do not apply when operating the
device outside its rated operating conditions.
Note 2. Specified min/max limits are production tested or guaranteed through correlation based on statistical control methods. Measurements are taken at constant junction
temperature as close to ambient as possible using low duty pulse testing.
Note 3. V
OUT(nom)
is the nominal output voltage at I
OUT
= 0mA.
Note 4. Guaranteed by design.
Note 5. In order to get a valid low-battery-output (LBO) signal, the input voltage must be lower than the low-battery-input (LBI) threshold for a duration greater than the low
battery hold time (t
hold(LBI)
). This feature eliminates false triggering due to voltage transients at the battery terminal.
Impala Linear Corporation
ILC6360 1.1
(408) 574-3939
www.impalalinear.com
Jan 1999
4
Step-Up/Step-Down DC-DC Converter for 1-Cell Lithium-Ion Batteries
APPLICATIONS INFORMATION
The ILC6360 performs both buck and boost DC-DC con-
version by controlling the switch element as shown in the
simplified circuit in figure 1 below.
Fig. 1: Basic Circuit
When the switch is closed, current is built up through the
inductor. When the switch opens, this current is forced
through the diode to the output capacitor and load. As this
on and off switching continues, the output capacitor voltage
builds up due to the charge it is storing from the inductor
current. The output voltage is therefore boosted relative to
the input.
In general, the switching characteristic is determined by the
output voltage desired and the current required by the load.
Specifically the energy transfer is determined by the power
stored in the coil during each switching cycle.
P
L
= ƒ(t
ON
, V
IN
)
Synchronous Rectification
The ILC6360 also uses a technique called “synchronous
rectification” which removes the need for the external diode
used in other circuits. The diode is replaced with a second
switch (SW2) or in the case of the ILC6360, a FET as
shown in figure 2 below.
V
IN
L
X
SW1
SW2
-
+
Modes of Operation
There are four modes of operation for the ILC6360
buck/boost DC-DC converter. These four modes are inter-
nally selected by the regulator depending on external con-
ditions such as line voltage, output voltage, load current,
inductor size, output capacitor size and resistive losses.
The first mode is the discontinuous mode. If the load is light
and the inductor value is small enough, the inductor will
transfer all of its energy to the output capacitor before a
cycle is completed. The input current waveform instead of
being continuous with a triangle ripple, will be a series of
discrete triangle shaped pulses as the inductor charges
from the input and discharges into the capacitor. The ripple
on the output capacitor becomes larger than expected com-
pared to continuous mode calculation because of the cur-
rent spikes from the input.
Boost (Step-up) Operation
The second mode is the conventional boost (step-up) mode
of operation. The input current is a smooth waveform with a
triangular ripple current. The output waveform exhibits rip-
ple caused by the charging and discharging of the output
capacitor and the current flowing through the capacitor’s
equivalent series resistance (ESR).
The third mode is the PFM mode. If the output voltage
exceeds an upper limit, for whatever reason, the regulator
enters the PFM mode. The regulator shuts down for one or
more cycles until the output voltage drops below a pre-set
threshold and one cycle is initiated. The inductor current falls
to zero during the off time. The basic cycle is the 3.3mS
PWM cycle but one or more cycles are dropped from the
pulse train (also called pulse skipping). This may be in
response to a light load condition or from a fast transient
load condition where the output capacitor charges too high
during load turn-off. In light load conditions, PFM mode
offers high efficiency due to significantly lower quiescent cur-
rent for the regulator. The output voltage will be a few tens
of millivolts higher in the PFM mode than in the PWM mode.
The fourth mode of operation is the buck (step-down) mode
and is described below.
Buck (Step-down) Operation
The “buck” mode is not a true switching regulator mode but
allows the regulator to operate when the input voltage
exceeds the output voltage. Once the input voltage exceeds
the output voltage, the regulator is not capable of limiting
the current in a non-dissipative fashion.
ILC6360
V
OUT
PWM/PFM
CONTROLLER
POK
GND
SHUTDOWN
CONTROL
+
V
REF
DELAY
LBO
-
SYNC
LB/SD
Fig. 2: Simplified ILC6360 block diagram
The two switches now open and close in opposition to each
other, directing the flow of current to either charge the
inductor or to feed the load. The ILC6360 monitors the volt-
age on the output capacitor to determine how much and