Anpec APW7008 1x/1.5x/2x charge pump white led driver Datasheet

APW7008
1X/1.5X/2x Charge Pump White LED Driver
General Description
Features
±1.5% LED Current Matching
The APW7008 is a high efficiency charge pump white
High Efficiency Up to 90% Over Li-ion Battery
LED driver; the device drives up four white LEDs with
regulated constant current for uniform intensity. The sup-
Discharge
Output Current Up to 30mA per LED
1.5x, and 2x charge pump modes and automatically
switches the charge pump modes depend on the input
2.7V to 5.5V Operating Voltage
Allow to Turn On or Off a Combination of LEDs
voltage to maintain the required power for high power
efficiency. The APW7008 provides up to 30mA per LED
1x/1.5x/2x Charge Pump Modes
for a total of 120mA and allows several methods, such as
a PWM signal on the CTRL0 pin for LED dimming. Three
Low Shutdown Current: 2µA Maximum
Low Input Ripple and EMI
control logic pins allow to disable or enable a combination of LEDs. The supply current is only 2mA in 2x mode,
Internal Soft-Start Limits Inrush Current
and the EN pin allows the device to enter shutdown mode
with 2µA quiescent current. The APW7008 switches at
Short Circuit Current-Limit
Thermal Shutdown Protection
1MHz frequency and only requires four 1µF ceramic capacitors and one resistor, and ensures low input current
Output Over-Voltage Protection
ripple and EMI.
The APW7008 is available in a 16-pin QFN package.
3mmx3mm 16-pin QFN (QFN3X3-16) Package
Lead Free and Green Devices Available
(RoHS Compliant)
Cellular Phone White LED Back Light
16 15
EN
1
PDA and Handheld Computer
CTRL0
2
DSC
CTRL1
3
CTRL2
4
ILED4
12 GND
11 C1-
Metal
GND Pad
(Bottom)
10 C1+
9
ISET
5
6
7
8
C2+
Portable Device
14 13
VIN
•
•
•
•
ILED1
Applications
ILED3
Pin Configuration
ILED2
•
•
•
•
•
•
•
•
•
•
•
•
ply voltage ranges from 2.7V to 5.5V and it is optimized for
a Li-ion battery application. The APW7008 operates in 1x,
VOUT
•
•
C2-
APW7008
QFN3x3-16 Top View
ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and
advise customers to obtain the latest version of relevant information to verify before placing orders.
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
1
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APW7008
Ordering and Marking Information
Package Code
QA : QFN3x3-16
Operating Ambient Temperature Range
I : -40 to 85 oC
Handling Code
TR : Tape & Reel
Assembly Material
G : Halogen and Lead Free Device
APW7008
Assembly Material
Handling Code
Temperature Range
Package Code
APW7008 QA :
APW
7008
XXXXX
XXXXX - Date Code
Note : ANPEC lead-free products contain molding compounds/die attach materials and 100% matte tin plate termination finish;
which are fully compliant with RoHS. ANPEC lead-free products meet or exceed the lead-free requirements of IPC/JEDEC J-STD020C for MSL classification at lead-free peak reflow temperature. ANPEC defines “Green” to mean lead-free (RoHS compliant) and
halogen free (Br or Cl does not exceed 900ppm by weight in homogeneous material and total of Br and Cl does not exceed
1500ppm by weight).
Absolute Maximum Ratings
Symbol
VOUT
VIN
(Note 1, 2)
Parameter
Rating
Unit
VOUT to GND
-0.3 to +6
V
VIN to GND
-0.3 to +6
V
-0.3 to +6
V
ILED1-4 to GND
-0.3 to +6
V
CTRL0/1/2, EN to GND
-0.3 to +6
V
ISET to GND
-0.3 to 2
V
+150
°C
-65 ~ 150
°C
260
°C
VC1+, VC1-, VC2+, VC2- C1+, C1-, C2+, C2- to GND
VILED1-4
VCTRL0/1/2, VEN
VISET
TJ
Maximum Junction Temperature
TSTG
Storage Temperature
TSDR
Maximum Lead Soldering Temperature, 10 Seconds
Note 1: Stresses beyond the absolute maximum rating may damage the device and operating in the absolute maximum rating
conditions for extended periods may affect device reliability.
Note 2: The maximum allowable power dissipation at any TA (ambient temperature) is calculated using: PD(max) = (TJ – TA) /
θJA ;TJ=125°C. Exceeding the maximum allowable power dissipation will result in excessive die temperature.
Thermal Characteristics
Symbol
R θJA
Parameter
Thermal Resistance − Junction to Ambient
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
QFN3x3-16
2
Typical Value
Unit
40
°C/W
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APW7008
Recommended Operating Conditions
Symbol
VIN
Parameter
Input Voltage
Rating
Unit
2.8 to 4.5
V
VOUT
Output Voltage
3 to 4
V
ILED
LED Current
5 to 30
mA
IOUT
TA
Output Current, VIN>3.5V, VF=3.1V, 1x Mode
180
Output Current, 3.5V<VIN>3.1V, VF=3.1V, 1.5x Mode
120
Output Current, 3.1V<VIN>2.8V, VF=3.1V, 2x Mode
90
Ambient Temperature
mA
°C
-40 to 85
Electrical Characteristics
VIN = 2.85 to 5.5V, CIN = COUT = C1 = C2 = 1µF (ESR = 0.03Ω), ILED = 20mA, TA = -40°C to +85°C, unless otherwise noted. Typical
values are at TA = +25°C.
APW7008
Symbol
VIN
VUVLO
Parameter
Test Conditions
Typ.
Max.
2.7
-
5.5
V
2.2
2.4
2.6
V
-
50
-
mV
in 1.5x/2x mode
-
2
4
mA
No switching in 1x mode
-
0.5
1
mA
EN=0
Input Voltage
Under-Voltage Lockout Threshold
VIN falling
Under-Voltage Lockout Hysteresis
IQ
ILED-ERR
Quiescent Current
LED Current Accuracy
Current Matching
IISET
VILED-TH
ROUT
0.1
2
µA
5mA<ILED<30mA
-
±2
±8
%
5mA<ILED<30mA
(Note 4)
-
±1.5
±5
%
5
-
1000
µA
370
400
420
ISET to LED Current Ratio
IILED / (1.2V / REST) 5mA<ILED<30mA, TA
= +25°C
ILED Threshold Voltage
VILED falling
-
100
-
mV
VIN rising, VIN-VOUT
-
300
-
mV
VIN rising, VOUT-VIN
-
300
-
mV
0.8
1
1.2
MHz
1x mode (VIN-VOUT) / IOUT
-
1.6
3
1.5x mode (1.5xVIN-VOUT) / IOUT
-
7
12
2x mode (2xVIN-VOUT) / IOUT
-
16
28
VOUT < 1V
-
40
-
5
5.5
6
1.3
0.7
-
Switching Frequency
Open Loop VOUT Resistance
ISHORT
Short Circuit Current-Limit
VOVP
OVP Threshold
VIH
(Note 3)
ISET Current
1.5x mode to 1x mode Transition
Hysteresis
2x mode to 1.5x mode Transition
Hysteresis
FOSC
Unit
Min.
Logic Pins High Threshold
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
3
Ω
mA
V
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APW7008
Electrical Characteristics (Cont.)
VIN = 2.85 to 5.5V, CIN = COUT = C1 = C2 = 1µF (ESR = 0.03Ω), ILED = 20mA, TA = -40°C to +85°C, unless otherwise noted. Typical
values are at TA = +25°C.
APW7008
Symbol
Parameter
Test Conditions
Unit
Min.
Typ.
Max.
-
0.6
0.3
V
VIL
Logic Pins Low Threshold
IIH
Logic Pins High Current
VIH = VIN
-
-
1
µA
IIL
Logic Pins Low Current
VIL = GND
-
-
1
µA
Thermal Shutdown
-
150
-
°C
Thermal Shutdown Hysteresis
-
20
-
°C
Note 3: LED current accuracy is defined as: ± (ILED-MEASURED - ILED-SET) / ILED-SET
Note 4: LED current matching is defined as: ± (ILED-MAX - ILED-MIN) / (ILED-MAX + ILED-MIN)
Pin Description
PIN
FUNCTION
NO.
NAME
1
EN
2
CTRL0
3
CTRL1
4
CTRL2
5
ISET
LED Current Set Input. Connect a resistor from ISET to GND to set the LED current. VISET is typically 1.2V.
6
VOUT
Output Voltage Pin. Connect VOUT to the LED anode. Connect a 1µF capacitor from VOUT to GND.
7
VIN
Supply Voltage Input Pin. Connect a 1µF capacitor from VIN to GND.
8
C2+
Bucket Capacitor1 Positive Terminal. Connect a 1µF capacitor from C2+ to C2-.
9
C2-
Bucket Capacitor1 Negative Terminal. Connect a 1µF capacitor from C2+ to C2-.
10
C1+
Bucket Capacitor1 Positive Terminal. Connect a 1µF capacitor from C1+ to C1-.
11
C1-
Bucket Capacitor1 Negative Terminal. Connect a 1µF capacitor from C1+ to C1-.
12
GND
Device Ground Pin.
13
ILED4
14
ILED3
15
ILED2
16
ILED1
Enable Input Pin. The EN pin is an active high Control. Pull EN pin above 1.3V to enable the device; pull EN
pin below 0.3V to disable the device.
LED On/Off Control Pin. Allow disabling or enabling a combination of LEDs.
LEDs Cathode Connection. The LED current flows from VOUT through LED into ILED_ pin. The charge
pump regulates the lowest VILED to 180mV. Connect ILED_ pin to VOUT if the LED is not used.
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
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APW7008
Block Diagram
C1+
C2-
VOUT
1x/1.5x/2x MODE CHARGE PUMP AND
GATE CONTROL LOGIC
VIN
EN
C2+
C1-
POR &
SOFT-START
CURRENT LIMIT
CTRL1
-
+
-
+
-
0.1V
1MHz
OSCILLATOR
LED ON/OFF
CONTROL
-
+
+
0.18V
CTRL0
1.2V
MODE SELECT
AND
MIN ILED SELECT
CTRL2
ILED1
ILED2
CONTROLLED
CURRENT
MIRROR
ILED3
ILED4
+
-
Error
Amp
1.2V
+
+
+
+
-
-
-
-
ISET
GND
Typical Application Circuit
COUT
1µF
Digital
Inputs
16
15
14
13
ILED1 ILED2 ILED3 ILED4
EN
GND 12
1
2
3
4
CTRL0
C1- 11
APW7008
CTRL1
C1+ 10
CTRL2
ISET VOUT VIN
5
6
7
C2C2+
8
9
C2
1µF
C1
1µF
Battery
RSET
CIN
1µF
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
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APW7008
Typical Operating Characteristics
Efficiency vs. Input Voltage
100
100
90
90
80
80
Efficiency (%)
Efficiency (%)
Efficiency vs. Input Voltage
70
60
4 LEDs at 20mA
VF=3.1V
50
70
60
4 LEDs at 15mA
VF=3.1V
50
40
40
30
30
20
20
2.5
3
3.5
4
2.5
4.5
3
3.5
Efficiency vs. Input Voltage
Efficiency vs. Input Voltage
100
100
90
90
80
80
Efficiency (%)
Efficiency (%)
4.5
Input Voltage (V)
Input Voltage (V)
70
60
4 LEDs at 20
15mA
VF=3.3V
50
4
70
60
4 LEDs at 15
20mA
VF=3.3V
50
40
40
30
30
20
20
2.5
3
3.5
4
2.5
4.5
3.5
4
4.5
Input Voltage (V)
Input Voltage (V)
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
3
6
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APW7008
Typical Operating Characteristics (Cont.)
Input Current vs. Input Voltage
Input Current vs. Input Voltage
200
260
240
180
4 LEDs at 30mA
4 LEDs at 20mA
160
Input Current (mA)
Input Current (mA)
220
200
180
160
140
140
120
100
80
120
100
60
2.5
3
3.5
4
4.5
5
2.5
3
Input Voltage (V)
4
4.5
5
Input Voltage (V)
LED Current vs. Input Voltage
LED Current vs. Input Voltage
21
32
31
LED Current (mA)
20
LED Current (mA)
3.5
19
4 LEDs at 20mA
18
30
29
4 LEDs at 30mA
28
27
17
26
16
25
2.5
3
3.5
4
4.5
5
5.5
2.5
Input Voltage (V)
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
3
3.5
4
4.5
5
5.5
Input Voltage (V)
7
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APW7008
Typical Operating Characteristics (Cont.)
Switching Frequency vs. Input Voltage
Logic Threshold Voltage vs. Input Voltage
1.2
1200
in 2x mode
ILED=20mA
1.1
Switching Frequency (kHz)
Logic Threshold Voltage(V)
1150
high threshold
1
0.9
low threshold
0.8
1100
1050
1000
950
900
850
0.7
800
2.5
3
3.5
4
4.5
5
5.5
2.5
3
Input Voltage (V)
4
4.5
Input Voltage (V)
LED Current vs. Temperature
Switching Frequency vs. Temperature
1200
21
4 LEDs at 20mA
VIN=4V
in 2x mode
VIN=4V
1100
20
LED Current (mA)
1000
Switching Frequency (kHz)
3.5
900
800
700
19
18
600
500
17
-40 -20
0
20
40
60
80 100 120 140
-40
Temperature (°C)
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
-20
0
20
40
60
80
100 120 140
Temperature (°C)
8
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APW7008
Typical Operating Characteristics (Cont.)
LED Current vs. Temperature
LED Current vs. Temperature
22
22
4 LEDs at 20mA
VIN=3.3V
4 LEDs at 20mA
VIN=2.7V
21
LED Current (mA)
LED Current (mA)
21
20
19
18
19
18
17
17
-40
-20
0
20
40
60
80
100 120 140
-40
-20
0
20
40
60
80
100 120 140
Temperature (°C)
Temperature (°C)
Quiescent Current vs. Temperature
Quiescent Current vs. Input Voltage
400
3
2.75
in 1x mode
VIN=4V
2.5
Quiescent Current (mA)
Quiescent Current (mA)
20
350
300
250
4 LEDs at 20mA
VF=3.3V
2.25
2
1.75
1.5
1.25
1
0.75
0.5
0.25
0
200
-40 -20
0
20
40
60
80
2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5
100 120 140
Temperature (°C)
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
Input Voltage(V)
9
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APW7008
Typical Opeating Characteristics (Cont.)
StartUp in 1x Mode
IIN (100mA/div)
StartUp in 1.5x Mode
4 LEDs at 20mA
VF=3.1V, VIN=4V
4 LEDs at 20mA
VF=3.1V, VIN=3.3V
IIN (100mA/div)
VOUT (2V/div)
VOUT (2V/div)
EN (5V/div)
EN (5V/div)
ILED (10mA/div)
ILED (10mA/div)
TIME (0.1ms/div)
TIME (0.1ms/div)
Dimming in 1x Mode
StartUp in 2x Mode
ILED (10mA/div)
4 LEDs at 20mA
VF=3.1V, VIN=2.7V
IIN (100mA/div)
VOUT (2V/div)
VOUT (1V/div)
EN (5V/div)
4 LEDs at 20mA
VF=3.1V, VIN=4V
f=200Hz
CTRL0 (2V/div)
ILED (10mA/div)
TIME (0.1ms/div)
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
TIME (2ms/div)
10
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APW7008
Typical Operating Characteristics (Cont.)
Dimming in 2x Mode
Dimming in 1.5x Mode
ILED (10mA/div)
ILED (10mA/div)
V OUT (1V/div)
VOUT (1V/div)
CTRL0 (1V/div)
4 LEDs at 20mA, VF=3.1V
VIN=3.3V, f=200Hz
CTRL0 (1V/div)
TIME (2ms/div)
4 LEDs at 20mA, VF=3.1V,
VIN=2.7V, f=200Hz
TIME (2ms/div)
Line Transient Response in 1x to 1.5x Mode
OVP Even with LED Open Circuit
VIN (1V/div)
ILED (10mA/div)
4 LEDs at 20mA, VF=3.1V
VIN=3.2V to 3.8V
V OUT (1V/div)
VOUT (1V/div)
V IN (1V/div)
4 LEDs at 20mA
VF=3.1V, VIN=4V
LED1 is open
ILED (20mA/div)
TIME (0.2ms/div)
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
TIME (0.1ms/div)
11
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APW7008
Typical Operating Characteristics (Cont.)
Line Transient Response in 1.5x to 2x Mode
VIN (1V/div)
4 LEDs at 20mA, VF=3.1V
VIN=2.8V to 3.4V
VOUT (1V/div)
ILED (20mA/div)
TIME (0.1ms/div)
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
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APW7008
Function Description
Soft-Start
Control Logic Pins
The APW7008 provides the soft-start function to limit the
The APW 7008 provides three logic input pins to en-
inrush current during start-up. When the input voltage is
supplied to the device and exceeds the UVLO voltage,
able or disable a combination of LEDs. Table1 shows
the truth table of the logic pins. If the LED channels are
the output capacitor is charged directly from input with a
limited current source. Approximate 100µs after the out-
not used, connecting the ILED pins to VOUT to turn off
the respective LED channels.
put voltage approaches the input voltage, the device starts
to provide the programmed LED current and determines
Control Logic Pin
LED Status
CTRL2
CTRL1
CTRL0
LED4
LED3
LED2
0
0
0
OFF
OFF
OFF
ON
0
0
1
OFF
OFF
ON
OFF
the soft-start is completed and the device operates in 1x
mode. When the programmed LED current cannot be
0
1
0
OFF
ON
OFF
OFF
0
1
1
ON
OFF
OFF
OFF
reached, the charge pump goes into 1.5x mode. If the
1.5x mode charge pump cannot suffice for the LED cur-
1
0
0
OFF
OFF
ON
ON
1
0
1
OFF
ON
ON
ON
rent need, the charge pump will switch to 2x mode.
1
1
0
ON
ON
ON
ON
1
1
1
OFF
OFF
OFF
OFF
which of 1x and 1.5x, or 2x mode is required. When the
programmed LED current can be reached with 1x mode,
LED1
Mode Transition
Table 1. The Truth Table of Control Logic Pins
The APW7008 operates in 1x, 1.5x, and 2x charge pump
LED Current Setting
modes and automatically switches the charge pump
modes depend on the input voltage to maintain the re-
Connect a resistor from ISET pin to GND to set the LED
quired power for high power efficiency. If the APW7008
operates in 1x mode, the VOUT is pulled up to the VIN.
current. The ISET voltage is typically 1.2V, the LED current is typically 400 times the current through the ISET
When the VIN decreases, the VILED will decease to maintain the regulated LED current. Until the VILED is below
resistor. The LED current is given by:
100mV, the device will switch to 1.5x mode. In 1.5x mode,
the VILED is regulated to 0.18V, and the output voltage is
R SET =
VF+0.18V. If the VIN continues to decrease until the VILED
is below 100mV again, the device will switch to 2x mode.
When the VIN rises and reaches by approximately VOUT300mV, the APW7008 switches back to 1.5x mode. If
400 × 1.2V
ILED
The APW7008 provides up 30mA of LED current per
LED and the device has a max current matching of ±5%
between any two LED currents and a max current accuracy of ±8%. If high accuracy is required, using a 1%
precision surface mount resistor for the need.
the VIN continues to rise and reach by approximately
VOUT+300mV, the APW7008 switches back to 1x mode.
The 2x charge pump is enough to suffice the White LED
for a Li-ion battery application. The APW7008 ensures
ILED (mA)
RSET (kΩ)
that in the 1x mode for as long as possible to increase
the efficiency and extend the operating range by using
5
92
10
47
15
32
20
24
30
16.5
the 2x mode. The transition voltages from 1x to 1.5x and
1.5x to 2x are given by:
VTRANS1X = VF + 0.1V + (IOUT x ROUT1X)
VTRANS1.5X = [VF + 0.1V + (IOUT x ROUT1.5X)] / 1.5
Table 2. RSET Value Selection
where VF is the forward voltage of LED
IOUT is the output current
ROUT1X is the output impedance in 1x mode = 1.6Ω
ROUT1.5X is the output impedance in 1.5x mode = 7Ω
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
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APW7008
Function Description (Cont.)
LED Current Setting (Cont.)
400
350
300
RSET (Ohm)
250
200
150
100
50
0
0
5
10
15
20
25
30
ILED (mA)
Figure 1. RSET Value vs. LED Current
Shutdown/Enable
Pull the EN above 1.3V to enable the device and pull EN
pin below 0.3V to disable the device. In shutdown mode,
all internal control circuits are turned off and the quiescent current is below 2µA. When the device exits shutdown mode, the output has soft-start function as the input voltage startup.
Over-Voltage Protection
If any of LEDs is failed or unused LED channel is not
connected to VOUT, the charge pump mode will go into
2x mode and the output voltage will be pumped to 2
times the input voltage. If the output voltage is over
5.5V, the over-voltage protection circuit will limit the output voltage to approximately 5.5V.
Copyright  ANPEC Electronics Corp.
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APW7008
Application Information
Capacitor Selection
20
For lower input and output voltage ripples, both input and
output capacitors should be larger values and lower
18
LED=20mA
VIN=2.7V, 2x mode
LED Current (mA)
16
ESR capacitors. However, the larger output capacitor
values will increase the soft-start time. The lower charge
pump flying capacitors values and ESR improve the
efficiency, but lower capacitor values may limit the
LED’s currents at low input voltage.
It is recommended that the low ESR and low variation over
14
f=100Hz
12
10
8
f=10kHz
6
4
temperature, such as the ceramic capacitors with X7R
or X5R and the value is 1µF for the input capacitor, out-
f=40kHz
2
f=50kHz
0
put capacitor, and the charge pump flying capacitors.
0
10
20 30
40
50
60
70 80
90 100
Dimming Duty (%)
Brightness Control
Figure 3. PWM Dimming Frequency vs. LED Current
1. PWM dimming using CTRL0, CTRL1, CTRL2
The first method for dimming the LEDs is to apply a PWM
2. Analog dimming with analog voltage
The second method for dimming the LEDs is to apply a
signal into the CTRL0, CTRL1, and CTRL2 pins. Figure 2
shows the application circuit. The average LED current is
voltage through a resistor into the ISET pin. The variation
of LED current is proportional to the variation of the ana-
proportional to the PWM signal duty cycle. Note that the
frequency of PWM signal will affect the minimum dim-
log voltage. If the resistor values are chosen correctly, the
ming duty. Figure 3 shows the LED current vs. dimming
frequency and dimming duty, the recommend dimming
analog control voltage varies the output current from 0mA
to full LED current. Figure4 shows the application circuit.
frequency is below 10kHz. The average LED current is
calculated by the following equation:
See the table2 and choose the required maximum LED
current and the corresponsive RSET value, using the be-
ILED( avg) =
toff × ILED(max)
low equation to calculate the values of R1 and R2, note
that the VADJ will need to be greater than 1.2V.
ton + toff
VADJ ( VADJ − VISET ) VADJ
=
+
R1
R2
R SET
Where:
ILED(max) is programmed LED current by ISET pin
toff is the off time of the PWM signal
Where:
VISET = 1.2V
ton is the on time of the PWM signal
VIN
VADJ = the analog voltage for dimming the LEDs
RSET = the equivalent RSET resistance (see table 2).
APW7008
APW7008
OFF
ON
PWM
1
ISET
EN
R2
2
3
4
CTRL0
5
VADJ
CTRL1
R1
CTRL2
Figure 4. Analog Voltage Dimming Application Circuit
Figure 2. PWM Dimming Application Circuit
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
15
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APW7008
Application Information (Cont.)
Brightness Control (Cont.)
Layout Consideration
3. Digital dimming with external NMOS transistors
The third method for dimming the LEDs is to change the
The APW7008 is a high frequency charge pump for white
LED driver and requires some care when laying out the
equivalent resistance for RSET with the external NMOS
transistors. The equivalent resistance is the parallel
printed circuit board. The metal GND pad of the bottom
of the package must be soldered to the PCB and con-
combinations of the R1, R2, R3, and R4. R4 is always
connected and selected for the minimum LED current.
nected to the GND plane on the backside through several thermal vias. Place the CIN, COUT, C1, and C2 as
Figure 5 shows the application circuit.
close to IC as possible for reducing the switching noise.
APW7008
ISET
5
R1
R2
R3
R4
Figure 5. Digital Dimming Application Circuit
4. PWM dimming with EN pin
Another method for dimming the LEDs is to apply a
PWM signal into the EN pin. The average LED current
is proportional to the PWM signal duty cycle. Note
that the frequency of PWM signal will affect the minimum dimming duty. The recommend dimming frequency is between 100Hz and 1kHz. The average LED
current is calculated by the following equation:
ILED(avg ) =
ton × ILED(max)
ton + toff
Where:
ILED(max) is programmed LED current by ISET pin
toff is the off time of the PWM signal
ton is the on time of the PWM signal
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
16
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APW7008
Package Information
QFN3x3-16
A
b
E
D
Pin 1
D2
A1
A3
L K
E2
Pin 1
Corner
e
S
Y
M
B
O
L
QFN3x3-16
INCHES
MILLIMETERS
MIN.
MAX.
1.00
0.031
0.039
0.05
0.000
0.002
0.012
MIN.
MAX.
A
0.80
A1
0.00
A3
0.20 REF
0.008 REF
b
0.18
0.30
0.007
D
2.90
3.10
0.114
0.122
D2
1.50
1.80
0.059
0.071
0.122
0.071
E
2.90
3.10
0.114
E2
1.50
1.80
0.059
0.50
0.012
e
0.020 BSC
0.50 BSC
L
0.30
K
0.20
0.020
0.008
Note : 1. Followed from JEDEC MO-220 WEED-4.
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
17
www.anpec.com.tw
APW7008
Carrier Tape & Reel Dimensions
P0
P2
P1
A
B0
W
F
E1
OD0
K0
A0
A
OD1 B
B
T
SECTION A-A
SECTION B-B
H
A
d
T1
Application
QFN3x3-16
A
H
T1
C
d
D
12.4+2.00 13.0+0.50
-0.00
-0.20 1.5 MIN.
330±2.00
50 MIN.
P0
P1
P2
D0
D1
4.0±0.10
8.0±0.10
2.0±0.05
1.5+0.10
-0.00
1.5 MIN.
W
E1
20.2 MIN. 12.0±0.30 1.75±0.10
T
A0
B0
F
5.5±0.05
K0
0.6+0.00
-0.40 3.30±0.20 3.30±0.20 1.30±0.20
(mm)
Devices Per Unit
Package Type
Unit
Quantity
QFN3x3-16
Tape & Reel
3000
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
18
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APW7008
Taping Direction Information
QFN3x3-16
USER DIRECTION OF FEED
Classification Profile
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
19
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APW7008
Classification Reflow Profiles
Profile Feature
Sn-Pb Eutectic Assembly
Pb-Free Assembly
100 °C
150 °C
60-120 seconds
150 °C
200 °C
60-120 seconds
3 °C/second max.
3°C/second max.
183 °C
60-150 seconds
217 °C
60-150 seconds
See Classification Temp in table 1
See Classification Temp in table 2
Time (tP)** within 5°C of the specified
classification temperature (Tc)
20** seconds
30** seconds
Average ramp-down rate (Tp to Tsmax)
6 °C/second max.
6 °C/second max.
6 minutes max.
8 minutes max.
Preheat & Soak
Temperature min (Tsmin)
Temperature max (Tsmax)
Time (Tsmin to Tsmax) (ts)
Average ramp-up rate
(Tsmax to TP)
Liquidous temperature (TL)
Time at liquidous (tL)
Peak package body Temperature
(Tp)*
Time 25°C to peak temperature
* Tolerance for peak profile Temperature (Tp) is defined as a supplier minimum and a user maximum.
** Tolerance for time at peak profile temperature (tp) is defined as a supplier minimum and a user maximum.
Table 1. SnPb Eutectic Process – Classification Temperatures (Tc)
Package
Thickness
<2.5 mm
≥2.5 mm
Volume mm
<350
235 °C
220 °C
3
Volume mm
≥350
220 °C
220 °C
3
Table 2. Pb-free Process – Classification Temperatures (Tc)
Package
Thickness
<1.6 mm
1.6 mm – 2.5 mm
≥2.5 mm
Volume mm
<350
260 °C
260 °C
250 °C
3
Volume mm
350-2000
260 °C
250 °C
245 °C
3
Volume mm
>2000
260 °C
245 °C
245 °C
3
Reliability Test Program
Test item
SOLDERABILITY
HOLT
PCT
TCT
ESD
Latch-Up
Method
JESD-22, B102
JESD-22, A108
JESD-22, A102
JESD-22, A104
MIL-STD-883-3015.7
JESD 78
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
20
Description
5 Sec, 245°C
1000 Hrs, Bias @ 125°C
168 Hrs, 100%RH, 2atm, 121°C
500 Cycles, -65°C~150°C
VHBM≧2KV, VMM≧200V
10ms, 1tr≧100mA
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APW7008
Customer Service
Anpec Electronics Corp.
Head Office :
No.6, Dusing 1st Road, SBIP,
Hsin-Chu, Taiwan, R.O.C.
Tel : 886-3-5642000
Fax : 886-3-5642050
Taipei Branch :
2F, No. 11, Lane 218, Sec 2 Jhongsing Rd.,
Sindian City, Taipei County 23146, Taiwan
Tel : 886-2-2910-3838
Fax : 886-2-2917-3838
Copyright  ANPEC Electronics Corp.
Rev. A.3 - Feb., 2009
21
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