ADN8830ACPZ Analog Devices Inc, ADN8830ACPZ Datasheet - Page 7

• Manufacturer Part Number: ADN8830ACPZ
• Description: IC CTRLR THERMO COOLER 32-LFCSP
• Manufacturer: Analog Devices Inc

Specifications of ADN8830ACPZ

• Applications: Thermoelectric Cooler
• Current - Supply: 8mA
• Voltage - Supply: 3.3 V ~ 5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-LFCSP
• Ic Function: Thermoelectric Cooler Controller
• Supply Voltage Range: 3V To 5.5V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: LFCSP
• No. Of Pins: 32
• Msl: MSL 1 - Unlimited
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 015-0070; Q2376189

APPLICATION NOTES
Principle of Operation
The ADN8830 is a controller for a TEC and is used to set and
stabilize the temperature of the TEC. A voltage applied to the
input of the ADN8830 corresponds to a target temperature
setpoint. The appropriate current is then applied to the TEC
to pump heat either to or away from the object whose tem-
perature is being regulated. The temperature of the object is
measured by a thermistor and is fed back to the ADN8830 to
correct the loop and settle the TEC to the appropriate final
temperature. For best stability, the thermistor should be mounted
in close proximity to the object. In most laser diode modules,
the TEC and thermistor are already mounted in the unit and
are used to regulate the temperature of the laser diode.
A complete TEC controller solution requires:
REV. C
THERMFAULT
A precision input amplifier stage to accurately measure the
difference between the target and object temperatures.
A compensation amplifier to optimize the stability and
temperature settling time.
A high output current stage. Because of the high output
currents involved, a TEC controller should operate with
high efficiency to minimize the heat generated from
power dissipation.
TEMPLOCK
TEMPSET
THERMIN
VREF
@25 C
10k
3.3V
3.3V
RTH
10 F
VREF
10k
R4
7.68k
0.1%
C8
0.1%
R3
R2
7.68k
0.1%
32
1
2
3
4
5
6
7
8
9
TEMPOUT
10
31
Figure 1. Typical Application Schematic
30
11
C11
1 F
29
ADN8830
12
205k
1M
R7
R5
SYNCOUT
13
28
100k
10 F
0.1 F
C9
R6
–7–
C1
27
14
In addition, an effective controller should operate down to 3.3 V
and have an indication of when the target temperature has been
reached. The ADN8830 accomplishes all of these requirements
with a minimum of external components. Figure 1 shows a
reference design for a typical application.
Temperature is monitored by connecting the measurement
thermistor to a precision amplifier, called the error amplifier,
with a simple resistor divider. This voltage is compared against
the temperature set input voltage, creating an error voltage that
is proportional to their difference. To maintain accurate wave-
length and power from the laser diode, this difference voltage
must be as accurate as possible. For this reason, self-correction
auto-zero amplifiers are used in the input stage of the ADN8830,
providing a maximum offset voltage of 250 V over time and
temperature. This results in final temperature accuracy within
error source in the temperature control loop. A logic output is
provided at TEMPLOCK to indicate when the target temperature
has been reached.
The output of the error amplifier is then fed into a compensa-
tion amplifier. An external network consisting of a few resistors
and capacitors is connected around the compensation amplifier.
This network can be adjusted by the user to optimize the step
0.01 C in typical applications, eliminating the ADN8830 as an
C10
330pF
26
15
R1
150k
VTEC
25
24
23
22
21
20
19
18
17
16
10 F
C5
10nF
C3
3.3V
2.2nF
C6
FDW2520C-B
CDE ESRD
22 F
C4
3.3V
Q1
Q3
FDW2520C-A
Q4
FDW2520C-B
3.3V
10 F
C7
3.3V
COILCRAFT
DO3316-472
ADN8830
4.7 H
L1
Q2
FDW2520C-A
C12
3.3nF
TEC+
C2
22 F
CDE ESRD
TEC–