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AS3691
4 Precision 400mA Current Sources for
RGB and Single Color LEDs
General Description
The AS3691 (AS3691A and AS3691B) features four high
precision current sinks to drive up to four LED strings. Each of
the current sinks can sustain up to 15V and drive up to 400mA.
Every channel can be controlled independently by PWM inputs.
To ensure best efficiency AS3691 is able to regulate any external
LED power supply (DC-DC converter) to its perfect needs
(patented feedback function).
The full scale current is set by external resistor.
Ordering Information and Content Guide appear at end of
datasheet.
Key Benefits & Features
The benefits and features of the AS3691 4 Precision 400mA
Current Sources for RGB and Single Color LEDs, are listed below:
Figure 1:
Added Value of Using AS3691
Benefits
Features
• Fully flexible current outputs / no SW effort
• 4 × up to 0.4A constant current outputs
• Programmable with external resistors
• 4 independent PWM inputs
• Perfect color uniformity
• Absolute current accuracy ±0.5%
• Unique DC-DC feedback function
• ’Automatic Supply Regulation’ (1) to reduce power
dissipation
• Maximum number of LEDs per channel
• Very wide output voltage current source voltage
compliance
• Down to 0.41V
• Up to 15V (2)
• On-chip safety features
• Integrated overtemperature protection
• Easy integration due to several package
types including thermal enhanced eP-TSSOP
• Package options:
• QFN24 (4 × 4mm)
• eP-TSSOP
Note(s):
1. ams system patent
2. 15V is sufficient for most applications as the AS3691 does not switch off the LED current completely
ams Datasheet
[v2-07] 2016-Jan-21
Page 1
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AS3691 − General Description
Applications
• General Lighting
• Backlighting
• RGB Backlighting for LCD TV/Monitors with White Color
Balancing
Application Diagrams
Figure 2:
Application Diagram of AS3691 for Single Color Lighting
VDD
VDD
Csup
100nF
Rvdd
Cvdd
100nF
UV
UV
VREG
UV1
CURR1
AS3691
UV2
CURR2
Vc
UV3
CURR3
Vc
UV4
CURR4
Vc
Vc
D1
Ref
T1
I1
Overtemp
Pad VSS
T2
R1
ON1
RFB1
T3
I2
R2
RES1 ON2
Ri1
RFB2
T4
I3
R3
RES2 ON3
Ri2
RFB3
I4
R4
RES3 ON4
Ri3
RFB4
RES4
Ri4
VSS
VSS
PWM
PWM
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − General Description
Figure 3:
Application Diagram of AS3691 for RGB Lighting
VDDG
VDDG
VDDB
VDDB
VDDR
VDDR
Rvdd
Cvdd
100nF
UVG
UVG
UVB
UVB
UVR
UVR
UV1
VREG
CURR1
AS3691
UV2
UV3
CURR2
Vc
CURR3
Vc
UV4
CURR4
Vc
Vc
D1
Ref
T1
I1
Overtemp
Pad
R1
VSS
ON1
RFB1
T3
I2
R2
RES1 ON2
Ri1
VSS
T2
RFB2
T4
I3
R3
RES2 ON3
Ri2
RFB3
I4
R4
RES3 ON4
Ri3
RFB4
RES4
Ri4
VSS
PWMG
PWMG
PWMB
PWMB
PWMR
PWMR
ams Datasheet
[v2-07] 2016-Jan-21
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AS3691 − Pin Assignments
Pin Assignments
Figure 4:
Pin Usage
VREG
UV1
CURR1
AS3691
UV2
CURR2
Vc
UV3
CURR3
Vc
UV4
CURR4
Vc
Vc
D1
Ref
T1
I1
Overtemp
Pad
T2
I2
R1
VSS
ON1
RFB1
T3
R2
RES1 ON2
T4
I3
R3
RES2 ON3
RFB2
RFB3
I4
R4
RES3 ON4
RFB4
RES4
Pin Descriptions
Figure 5:
Pin Descriptions
Pin Number
QFN
Package
Pin Number
eP-TSSOP
Package
Pin Name
Type
1
10
CURR1
AI/O
2
11
RFB1
AI
Connect to current set resistor R1 directly at
resistor itself
3
12
nc
nc
Leave open
4
13
RFB4
AI
Connect to current set resistor R4 directly at
resistor itself
5
14
CURR4
AI/O
Current source 4 output
6
15
RES4
AI/O
Connect to current set resistor R4
Page 4
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Description
Current source 1 output
ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Pin Assignments
Pin Number
QFN
Package
Pin Number
eP-TSSOP
Package
Pin Name
Type
Description
7
16
ON4
DI
Current source CURR4 control; internal pullup
resistor to VREG (can be left open, if CURR4 is
always switched ON)
High … 100% current
Low … 5% current
8
17
UV4
AO
Automatic supply regulation for CURR4; if not
used, leave open
9
18
TEST
AI
Digital test input; Leave open or connect to
VSS; internal pulldown to VSS
10
19
UV3
AO
Automatic supply regulation for CURR3; if not
used, leave open
Current source CURR3 control; internal pullup
resistor to VREG (can be left open, if CURR3 is
always switched ON)
High … 100% current
Low … 5% current
11
20
ON3
DI
12
21
RES3
AI/O
Connect to current set resistor R3
13
22
CURR3
AI/O
Current source 3 output
14
23
RFB3
AI
Connect to current set resistor R3 directly at
resistor itself
15
24
VREG
S
Shunt regulator supply; connect to Rvdd and
Cvdd
16
1
RFB2
AI
Connect to current set resistor R2 directly at
resistor itself
17
2
CURR2
AI/O
Current source 2 output
18
3
RES2
AI/O
Connect to current set resistor R2
19
4
ON2
DI
Current source CURR2 control; internal pullup
resistor to VREG (can be left open, if CURR2 is
always switched ON)
High … 100% current
Low … 5% current
20
5
UV2
AO
Automatic supply regulation for CURR2; if not
used, leave open
21
6
VSS
S
22
7
UV1
AO
ams Datasheet
[v2-07] 2016-Jan-21
VSS supply connection
Automatic supply regulation for CURR1; if not
used, leave open
Page 5
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AS3691 − Pin Assignments
Pin Number
QFN
Package
Pin Number
eP-TSSOP
Package
Pin Name
Type
Description
Current source CURR1 control; internal pullup
resistor to VREG (can be left open, if CURR1 is
always switched ON)
High … 100% current
Low … 5% current
23
8
ON1
DI
24
9
RES1
AI/O
Pad
Pad
VSS
S
Connect to current set resistor R1
VSS supply connection; add as many vias to
ground plane as possible
The abbreviations used in Figure 5 are explained below:
AI/O: Analog Input/Output
AI: Analog Input
AO: Analog Output
DI: Digital Input
S: Supply
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Absolute Maximum Ratings
Absolute Maximum Ratings
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. These are stress
ratings only. Functional operation of the device at these or any
other conditions beyond those indicated under Electrical
Characteristics is not implied.
Exposure to absolute maximum rating conditions for extended
periods may affect device reliability.
Figure 6:
Absolute Maximum Ratings
Symbol
Parameter
Min
Max
Unit
Note
VDDMAX
Supply for LEDs
-0.3
> 17
V
See notes (1)
VINVREG
VREG Supply Voltage
-0.3
7.0
V
Applicable for pin VREG
VIN5V
5V Pins
-0.3
VREG + 0.3V
V
Applicable for 5V pins (2)
VIN15V
15V Pins
-0.3
17
V
Applicable for CURR1, CURR2,
CURR3 and CURR4
IIN
Input Pin Current
-25
+25
mA
TSTRG
Storage Temperature Range
-55
125
°C
RHNC
Relative Humidity
(non-condensing)
5
85
%
MSL
Moisture Sensitivity Level
3
ESDHBM
Electrostatic Discharge
±2000
PT
Total Power Dissipation
PDERATE
TBODY
At 25°C, Norm: JEDEC 17
Maximum floor lifetime of
168h
V
Norm: MIL 883 E Method 3015
2.0
W
At 50°C, no airflow for QFN24
on two layer FR4-Cu PCB (3)
PT Derating Factor
23
mW/°C
Body Temperature during
Soldering
260
°C
See notes (3)
According to
IPC/JEDEC J-STD- 020C
Note(s):
1. As the AS3691 is not directly connected to this supply. Only the parameters V INVREG , VIN5V and VIN15V have to be guaranteed by the
application.
2. All pins except CURR1, CURR2, CURR3 and CURR4.
3. Depending on actual PCB layout and especially number of vias below the exposed pad – see Layout Recommendations; can be
improved e.g. with Al-PCB or airflow.
ams Datasheet
[v2-07] 2016-Jan-21
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AS3691 − Electrical Characteristics
Electrical Characteristics
Figure 7:
Operating Conditions
Symbol
Parameter
VDD
Main Supply
VDDTOL
Main Supply Voltage
Tolerance
-20
VREGINT
Supply (shunt
regulated by AS3691)
5.0
4.5
VREGEXT
IVREG
Supply Current
TAMB
Ambient Temperature
Min
Typ
Max
Unit
Note
Not
Limited
V
Supply is not directly
connected to the AS3691 –
see Shunt Regulator
+20
%
Applies only for supply
VREG is connected via Rvdd
5.2
5.4
V
If internally
(shunt-)regulated by D1
4.75
5.0
V
If externally supplied
2.5
mA
85
°C
-20
25
Typ
Excluding current through
shunt regulator (D1) – see
Shunt Regulator
Figure 8:
Analog Electrical Characteristics
Symbol
Parameter
Min
VCURR
Current Source CURR1
to CURR4 Voltage
Compliance
ICURR
Current Source Range
Max
Unit
Note
0.9
15.0
V
at 400mA; total power
dissipation limit PT must not be
exceeded
0.41
15.0
V
at 100 mA
10
400
-0.5
ICURR, TOL
(1)
+0.5
mA
%
@25ºC TJUNCTION, excluding
variation of external resistors;
V(CURRx) ≤ 4.0V
%
-20°C to 100°C (2) TJUNCTION,
-20°C to 85°C TAMB, excluding
variation of external resistors;
V(CURRx) ≤ 4.0V
See Automatic Supply
Regulation
Current Source
Tolerance
-1.5
+1.5
VC
Automatic Supply
Regulation Compare
Voltage
1.0
V
VC,GAIN
Automatic Supply
Regulation Gain
2.0
mA/V
Page 8
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ONx = high
ICURRx = 250mV / Rix
(x = 1 to 4)
Voltage to current ratio; output
current range typ 0 to 200μA
ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Electrical Characteristics
Symbol
Parameter
I1-4
Parallel Current
TOVTEMP
Min
Overtemperature Limit
Typ
Max
Unit
1.0
mA
V(CURRx) ≤ 15V
0.1
mA
V(CURRx) ≤ 5.0V
°C
Maximum junction
temperature
140
Note
Note(s):
1. To obtain higher currents connect more than one current source in parallel.
2. Accuracy at 100°C guaranteed by design and verified by laboratory characterization.
Figure 9:
Digital Input Pin Characteristics for Pins ON1, ON2, ON3 and ON4
Symbol
Parameter
Min
VIH
High Level Input
Voltage
VIL
Low Level Input
Voltage
RPU
Pullup Resistor
fON
ams Datasheet
[v2-07] 2016-Jan-21
Input Frequency
Range
Typ
Max
Unit
2.3
VREG
V
0.0
0.9
V
70
0
20
Note
kΩ
Internal pullup resistor R1 to R4
to VREG
kHz
This defines the actual input
frequency seen on the input
ON1 to ON4; the basic
frequency to generate the PWM
signal is not limited by this
parameter
Page 9
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AS3691 − Typical Operating Characteristics
Typical Operating
Characteristics
Figure 10:
Output Current vs. Voltage on Current Source – High Current Range
0,45
0,4
I(CURR1) [A]
0,35
0,3
0,25
0,2
0,15
0,1
0,05
0
0
5
10
15
VCURR1 [V]
Figure 11:
Output Current vs. Voltage on Current Source – Low Current Range
12
I(CURR1) [mA]
10
8
6
4
2
0
0
2
4
6
8
10
12
14
VCURR1 [V]
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Typical Operating Characteristics
Figure 12:
Internal Voltage Reference vs. Temperature, V(CURR1) = 2.0V, Ri1 = 250Ω
253
V(RES1) [mV]
252
251
250
249
248
247
0
20
40
60
80
100
120
140
Temperature [C]
(EQ1)
V ( RES1 )
ICURR 1 = ----------------------Ri 1
Figure 13:
Output Current vs. Temperature, V(CURR1) = 2.0V, Ri1 = 2.5Ω (temperature coefficient of
Ri1 = -200ppm/°C)
I(CURR1) [mA]
102
101
100
99
98
0
10
20
30
40
50
60
70
Temperature [C]
ams Datasheet
[v2-07] 2016-Jan-21
Page 11
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AS3691 − Typical Operating Characteristics
Figure 14:
Cross Coupling of PWM on CURR1 to CURR2; I(CURR1) = 100mA to 4mA, I(CURR2) = 100mA; AS3691A
Figure 15:
PWM Performance of Current Source CURR1, I(CURR1) Changed Between 400mA (ON1=1) and 20mA
(ON1=0); AS3691A
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Typical Operating Characteristics
Figure 16:
Shunt Regulator Voltage VREG vs. Supply VDD with Rfb=1kΩ
6
VREG [V]
5
4
3
2
1
0
0
5
10
15
20
25
30
35
40
VDD [V]
Figure 17:
Automatic Supply Regulation Dynamic Performance Using DC-DC Converter in Regulation Loop
Automatic Supply Regulation Dynamic Performance Using DC-DC Converter in Regulation Loop:
R1 = 47kΩ, R2 = 10kΩ, R3 = 5kΩ, R4 = 500Ω, C1 = 1uF, I(CURR1) = 400mA/20mA (Ri1=0.625Ω)
3 OSRAM Golden Dragon in series as load between CURR1 and VDD
Input signal on pin ON1: PWM signal with f=10kHz, 80% duty cycle
ams Datasheet
[v2-07] 2016-Jan-21
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AS3691 − Typical Operating Characteristics
Figure 18:
Parallel Current I1 to I4 (for measurement of I1 remove current set resistor R1)
0,7
I(CURR1) [mA]
0,6
0,5
0,4
0,3
0,2
0,1
0
0
5
10
15
VCURR1 [V]
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Detailed Description
The AS3691 includes four high precision current sources (sinks).
Each current source is set by an external resistor. For internal
power supply an internal shunt regulator is used. Optionally an
additional 5V device can be supplied as well with this shunt
regulator.
Detailed Description
The current sources are individually controlled by four ON
inputs. If the inputs ON are high or left open, then the current
is set as follows:
(EQ2)
250mV
ICURR 1 – 4 = ----------------Ri 1 – 4
Setting the input ON to low the current is
(EQ3)
10.0mV
ICURR 1 – 4 = ------------------- for part numbers starting with AS3691A
Ri 1 – 4
The current is not zero to avoid high voltage jumps on the LEDs
and supplies and therefore reduce EMI.
(EQ4)
0.0mV
ICURR 1 – 4 = ---------------- + I 1 – 4 = I 1 – 4 for part numbers starting with
Ri 1 – 4
AS3691B; I1-4 is the parallel current (see Figure 17).
Shunt Regulator
The supply of the AS3691 is generated from the high voltage
supply. To obtain a 5V regulated supply, a series resistor Rvdd
is used together with an internal zener diode (shunt regulator
principle). An external capacitor Cvdd is used to filter the supply
on the pin VREG.
The external resistor Rvdd has to be chosen according to the
following formula:
(EQ5)
VDD MIN – VVREGINT MAX
Rvdd = ------------------------------------------------------------------------IVREG MAX
VDD MIN is the minimum voltage of the supply, where Rvdd is
connected.
This ensures enough supply current (IVREG MAX) for the AS3691
under minimum supply voltage VDD MIN.
If a stable 5V supply within the operating conditions limits of
VREG EXT is already existing in the system it is possible to supply
the AS3691 directly. In this case remove the resistor Rvdd and
connected this supply directly to VREG.
Overtemperature Protection
If the junction temperature inside the AS3691 rises above
TOVTEMP, the current sources are switched OFF.
ams Datasheet
[v2-07] 2016-Jan-21
Page 15
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AS3691 − Detailed Description
Automatic Supply Regulation
The purpose of the automatic supply regulation is to minimize
the voltage supply to reduce the voltage across the current
sources of the AS3691 (CURR1-CURR4 to VSS) and therefore
reduce the power dissipation of the AS3691 and the complete
system. The AS3691 automatically controls the minimum
required supply voltage for the different led strings to support
very power efficient systems for lighting using the following
circuit (any off-the-shelf DC-DC converter or ldo with adjustable
output voltage can be used):
Figure 19:
Automatic Supply Regulation Circuit
From main
supply
VDDx
DCDC Converter
for VDD
R1
Voltage Feedback Vfb
input for DCDC
R2
R3
R4
Csup
100nF
UVx
C1
UV1
CURR1
UV2
CURR2
Feedback resistor divider
(part of DCDC converter circuit)
Vc
Vc
AS3691
The function of this circuit is as follows:
All channels, which are connected to the supply VDDx should
have their respective UV pin connected together to UVx
(see Figure 19 and Typical Application Schematic). If any of
these current sources has a too low voltage, it gradually pulls
the wire UVx low. (The analog gain between the current source
CURRx and output UVx is defined by the parameter V C,GAIN.)
Therefore the feedback pin Vfb of the DC-DC converter is pulled
low and the DC-DC converter compensates this by increasing
the voltage on VDDx to obtain the same feedback voltage as
before.
To stabilize this regulation loop, the low pass filter build by C1
and R4 is used (this should be the dominant pole for the
regulation loop).
Page 16
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Detailed Description
The minimum output voltage VDDx min can be set accurately by
the resistors R1 and R2. The maximum output voltage VDDx max
is set by R1, R2, R3 and R4 (Vref is the internal voltage reference
of the DC-DC converter; usually Vref = Vfb):
(EQ6)
R1 + R2
VDDx MIN = Vref ⋅ -----------------R2
(EQ7)
R 1 + R 2 || ( R 3 + R 4 )
VDDx MAX = Vref ⋅ -----------------------------------------------R 2 || ( R 3 + R 4 )
Therefore even if a led string is broken (then UVx is forced to
0V) or some LEDs are shorted, the supply always stays within
the limits VDDx MIN and VDDx MAX.
ams Datasheet
[v2-07] 2016-Jan-21
Page 17
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AS3691 − Application Information
Application Information
Typical Application Schematic
For RGB LEDs (and a white color balancing circuit) use the
following application schematic including automatic supply
regulation (feedback paths UVR, UVG, UVB):
Figure 20:
Typical AS3691 System for RGB (Back-Lighting); Several AS3691 Can Be Cascaded
Main
supply
DCDC Converter
for VDDR
VDDR
Voltage Feedback
input for DCDC
UVR
Feedback resistor divider
(part of DCDC converter circuit)
DCDC Converter
for VDDG
VDDG
Voltage Feedback
input for DCDC
UVG
Feedback resistor divider
(part of DCDC converter circuit)
DCDC Converter
for VDDB
VDDB
Voltage Feedback
input for DCDC
UVB
Feedback resistor divider
(part of DCDC converter circuit)
VDDG
VDDB
VDDR
...
...
UVG
UVB
UVR
Vc
...
Vc
Vc
Vc
Vc
Vc
Vc
Vc
...
D1
D1
D1
Overtemp
Overtemp
Overtemp
AS3691
AS3691
AS3691
VSS
PWMG
PWMB
PWMR
5V Supply
5V powered
system
(optional)
PWMG
PWMB
PWMR
Page 18
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Application Information
A typical AS3691 for single color LEDs can be done as follows
using automatic supply regulation (feedback path UV):
Figure 21:
Typical AS3691 System for Single Color LEDs and Supply Regulation Loop; Several AS3691 Can Be
Cascaded
VDD
Main
supply
Csup
100nF
DCDC Converter
for VDD
...
...
Voltage Feedback
input for DCDC
UV
Vc
...
5V powered
system
(optional)
Vc
Vc
Vc
...
D1
D1
Overtemp
Overtemp
AS3691
AS3691
VSS
PWM
(optional)
PWM
Note(s): Csup (100nF) is only required, if there are long wires
(>0.3m) between the DC-DC converter and the AS3691. The
wire length between the Csup capacitor and the CURRx pin on
AS3691 should not exceed 0.3m. If this cannot be guaranteed,
add additional capacitors of 100nF to the pins CURRx.
ams Datasheet
[v2-07] 2016-Jan-21
Page 19
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AS3691 − Application Information
Design Example
Assume a single color LEDs application (4 times 3 LEDs in series,
each 100mA with Uf ranging from Uf min = 3.2V to Uf max = 3.8V)
with a fixed supply. First choose the external current set resistor
with the following formula:
(EQ8)
250mV
Ri 1 – 4 = ---------------------------ICURR 1 – 4
So for a current of 100mA, use a resistor of 2.5Ω; 1/8W rated
resistors are suitable (even up to 400mA).
Then calculate the required voltage of the power supply. The
minimum voltage on the current sink for guaranteed operation
is 0.41V (V CURR @100mA) and the maximum forward voltage of
the LEDs is assumed to be Uf max = 3.8V. Therefore
3 * 3.8V + 0.41V = 11.81V.
As this is the required minimum voltage of the power supply,
add all the tolerances on top. Assumed ±10% supply tolerance
results in a power supply with nominal 13V (to have at least
11.81V in worst case).
Using the following formula to calculate the external shunt
resistor:
(EQ9)
VDD MIN – VREGINT MAX VDD MIN – 5.4V
Rvdd = ----------------------------------------------------------------- = ---------------------------------------IVREG MAX
2.5mA
VDD MIN is the minimum voltage of the power supply, where
Rvdd is connected obtains 2564Ω. The nearest lower(!) available
value is 2.4kΩ. For Cvdd use:
(EQ10)
Cvdd = 100nF
Csup (100nF) is only required, if there are long connections
between the DC-DC converter and the AS3691 (>0.3m). The
wire length between the Csup capacitor and the CURRx pin on
AS3691 should not exceed 0.3m. If this cannot be guaranteed,
add additional capacitors of 100nF to the pins CURRx.
Then calculate the maximum power dissipation inside the
AS3691. The worst case is maximum voltage supply (13V + 10%)
together with LEDs with minimum forward voltage Uf min :
For these conditions the maximum voltage on any current
source (CURR1 to CURR4) is:
(EQ11)
VCURR MAX = ( 1 + VDD TOL )VDD – nU fmin
Not using automatic supply regulation
In our example 14.3V – 9.6V = 4.7V. The maximum power
dissipation inside the AS3691 is now (assuming 4 identical
strings):
(EQ12)
P MAX = 4VCURRMAX ICURR
In our example 1.88W. As
Page 20
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Application Information
(EQ13)
PT – P MAX
T MAX = --------------------------- + 50°C
P DERATE
Note(s):
For PT and PDERATE see Absolute Maximum Ratings.
• The system can be operated safely up to an ambient
temperature of 55°C assuming worst case power supplies
and worst case LEDs.
• If the internal junction temperature of the AS3691 rises
too high, the AS3691 will switch OFF the current sources
for protection (it will never damage the AS3691).
Using Automatic Supply Regulation
For the identical system using the automatic supply regulation,
the supply is regulated to minimize the power dissipation of
the system. Therefore the tolerance of the VDD supply and also
the variation in forward voltages of the LEDs can be ignored
(only the difference in one lot of LEDs is still important, as the
four strings are connected in parallel to the power supply).
Assume a difference of ΔUf = 0.2V of forward voltage of the LEDs
in one lot, then calculate the maximum voltage on the current
source of the AS3691 (CURR1 to CURR4) with
(EQ14)
VCURR MAX = nΔU f + V C
Using automatic supply regulation ΔUf variation of LED forward
voltage in one lot (for one application) V C is internal set voltage
(1.0V) to be 1.6V. Using the identical formulas as above, P MAX
now is 0.64W and T MAX is 110°C.
Therefore using automatic supply regulation, the ambient
temperature can be up to 110°C under identical conditions.
ams Datasheet
[v2-07] 2016-Jan-21
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AS3691 − Application Information
Layout Recommendations
See ams ‘AN3691_TECH_Module Description’1 as a layout
example for the AS3691.
Layout Checklist
1. Use the bottom layer as ground plane and minimize the
number and the length of connections within this layer.
2. Do as many vias as possible on the exposed pad (for
thermal performance) to the ground plane.
3. Connect RFBx and RESx together at the current set
resistor Rix (see above recommended layout).
4. The ground connections of the current set resistors
should be as close to the AS3691 as possible.
5. The ground connection of the capacitor Cvdd should be
as close as possible to the AS3691.
6. Minimize Area build by ‘Csup VSS connection – Csup
Supply Connection – LEDs – CURRx – Csup VSS
connection’ (to minimize inductance in this path).
1. Please contact ams for more information.
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Package Drawings & Markings
Package Drawings & Markings
QFN Package
Figure 22:
QFN 24 – 4 × 4mm Package Drawings
RoHS
Green
Note(s):
1. Dimensioning and tolerancing conform to ASME Y14. 5M-1994.
2. All dimensions are in millimeters. Angles are in degrees.
3. Dimension b applies to metallized terminal and is measured between 0.25mm and 0.30mm from terminal tip. Dimension L1
represents terminal full back from package edge up to 0.15mm is acceptable.
4. Coplanarity applies to the exposed heat slug as well as the terminal.
5. Radius on terminal is optional.
6. N is the total number of terminals.
ams Datasheet
[v2-07] 2016-Jan-21
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AS3691 − Package Drawings & Mark ings
Figure 23:
QFN Marking Diagram
AS3691B
YYWWXZZ
@
Figure 24:
QFN Package Code
YY
WW
X
ZZ
@
Manufacturing year
Manufacturing week
Plant’s identifier
Letters of free choice
Sublot Identifier
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Package Drawings & Markings
eP-TSSOP Package
Figure 25:
eP-TSSOP Package Drawings
RoHS
Green
Note(s):
1. Dimensioning and tolerancing conform to ASME Y14. 5M-1994.
2. All dimensions are in millimeters. Angles are in degrees.
3. N is the total number of terminals.
ams Datasheet
[v2-07] 2016-Jan-21
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AS3691 − Package Drawings & Mark ings
Figure 26:
eP-TSSOP Marking
AS3691B @
YYWWMZZ
Figure 27:
eP-TSSOP Package Code
YY
WW
M
ZZ
@
Manufacturing year
Manufacturing week
Plant’s identifier
Letters of free choice
Sublot Identifier
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Ordering & Contact Information
Ordering & Contact Information
Figure 28:
Ordering Information
Ordering Code
Marking
Package
Delivery Form
Delivery Quantity
AS3691A-ZQFT
AS3691A
QFN24
Trays in Dry Pack
4900 pcs/tray
AS3691B-ZQFT
AS3691B
QFN24
Trays in Dry Pack
4900 pcs/tray
AS3691B-ZQFP
AS3691B
QFN24
Tape and Reel in Dry Pack
6000 pcs/reel
AS3691B-ZTSP
AS3691B
eP-TSSOP24
Tape and Reel in Dry Pack
4500 pcs/reel
Description:
AS3691V-ZPPD
V … AS3691 version, either A or B
AS3691A: 10mV on VRESx (x = 1 to 4) if ONx = 0
(see Detailed Description)
AS3691B: 0mV on VRESx (x = 1 to 4) if ONx = 0
(see Detailed Description)
Z … Temperature range -20°C to 85°C
PP … Package;
QF for QFN, TS for enhanced Power TSSOP
D … Delivery form;
P for Tape & Reel in Dry Pack,
T for Trays in Dry Pack
Buy our products or get free samples online at:
www.ams.com/ICdirect
Technical Support is available at:
www.ams.com/Technical-Support
Provide feedback about this document at:
www.ams.com/Document-Feedback
For further information and requests, e-mail us at:
[email protected]
For sales offices, distributors and representatives, please visit:
www.ams.com/contact
Headquarters
ams AG
Tobelbaderstrasse 30
8141 Unterpremstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
ams Datasheet
[v2-07] 2016-Jan-21
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AS3691 − RoHS Compliant & ams Green Statement
RoHS Compliant & ams Green
Statement
RoHS: The term RoHS compliant means that ams AG products
fully comply with current RoHS directives. Our semiconductor
products do not contain any chemicals for all 6 substance
categories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed to
be soldered at high temperatures, RoHS compliant products are
suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br): ams Green
defines that in addition to RoHS compliance, our products are
free of Bromine (Br) and Antimony (Sb) based flame retardants
(Br or Sb do not exceed 0.1% by weight in homogeneous
material).
Important Information: The information provided in this
statement represents ams AG knowledge and belief as of the
date that it is provided. ams AG bases its knowledge and belief
on information provided by third parties, and makes no
representation or warranty as to the accuracy of such
information. Efforts are underway to better integrate
information from third parties. ams AG has taken and continues
to take reasonable steps to provide representative and accurate
information but may not have conducted destructive testing or
chemical analysis on incoming materials and chemicals. ams AG
and ams AG suppliers consider certain information to be
proprietary, and thus CAS numbers and other limited
information may not be available for release.
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ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Copyrights & Disclaimer
Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141
Unterpremstaetten, Austria-Europe. Trademarks Registered. All
rights reserved. The material herein may not be reproduced,
adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner.
Devices sold by ams AG are covered by the warranty and patent
indemnification provisions appearing in its General Terms of
Trade. ams AG makes no warranty, express, statutory, implied,
or by description regarding the information set forth herein.
ams AG reserves the right to change specifications and prices
at any time and without notice. Therefore, prior to designing
this product into a system, it is necessary to check with ams AG
for current information. This product is intended for use in
commercial applications. Applications requiring extended
temperature range, unusual environmental requirements, or
high reliability applications, such as military, medical
life-support or life-sustaining equipment are specifically not
recommended without additional processing by ams AG for
each application. This product is provided by ams AG “AS IS”
and any express or implied warranties, including, but not
limited to the implied warranties of merchantability and fitness
for a particular purpose are disclaimed.
ams AG shall not be liable to recipient or any third party for any
damages, including but not limited to personal injury, property
damage, loss of profits, loss of use, interruption of business or
indirect, special, incidental or consequential damages, of any
kind, in connection with or arising out of the furnishing,
performance or use of the technical data herein. No obligation
or liability to recipient or any third party shall arise or flow out
of ams AG rendering of technical or other services.
ams Datasheet
[v2-07] 2016-Jan-21
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AS3691 − Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
Page 30
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Product Status
Definition
Pre-Development
Information in this datasheet is based on product ideas in
the planning phase of development. All specifications are
design goals without any warranty and are subject to
change without notice
Pre-Production
Information in this datasheet is based on products in the
design, validation or qualification phase of development.
The performance and parameters shown in this document
are preliminary without any warranty and are subject to
change without notice
Production
Information in this datasheet is based on products in
ramp-up to full production or full production which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade
Discontinued
Information in this datasheet is based on products which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade, but these products have been superseded and
should not be used for new designs
ams Datasheet
[v2-07] 2016-Jan-21
AS3691 − Revision Information
Revision Information
Changes from 2.3 (2007-Oct-30) to current revision 2-07 (2016-Jan-21)
Page
2.3 (2007-Oct-30) to 2-04 (2015-Dec-18)
Content of austriamicrosystems datasheet was converted to latest ams design
Added benefits to Figure 1
1
Updated Figure Absolute Maximum Ratings
7
Updated Ordering & Contact Information
29
2-04 (2015-Dec-18) to 2-05 (2015-Dec-22)
Updated QFN Package section
23
Updated eP-TSSOP Package section
25
2-05 (2015-Dec-22) to 2-06 (2016-Jan-18)
Updated Ordering & Contact Information
27
2-06 (2016-Jan-18) to 2-07 (2016-Jan-21)
Updated Figure 1
1
Note(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.
ams Datasheet
[v2-07] 2016-Jan-21
Page 31
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AS3691 − Content Guide
Content Guide
Page 32
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1
1
2
2
General Description
Key Benefits & Features
Applications
Application Diagrams
4
4
Pin Assignments
Pin Descriptions
7
8
10
Absolute Maximum Ratings
Electrical Characteristics
Typical Operating Characteristics
15
15
15
16
Detailed Functional Description
Shunt Regulator
Overtemperature Protection
Automatic Supply Regulation
18
18
20
21
22
Application Information
Typical Application Schematic
Design Example
Using Automatic Supply Regulation
Layout Recommendations
23
23
25
Package Drawings & Markings
QFN Package
ePTSSOP Package
27
28
29
30
31
Ordering & Contact Information
RoHS Compliant & ams Green Statement
Copyrights & Disclaimer
Document Status
Revision Information
ams Datasheet
[v2-07] 2016-Jan-21