ADN8834ACPZ-R7 [ADI]

Ultra compact 1.5 A Thermoelectric Cooler (TEC) Controller ;
ADN8834ACPZ-R7
型号: ADN8834ACPZ-R7
厂家: ADI    ADI
描述:

Ultra compact 1.5 A Thermoelectric Cooler (TEC) Controller 

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Ultracompact, 1.5 A Thermoelectric Cooler  
(TEC) Controller  
Data Sheet  
ADN8834  
FEATURES  
FUNCTIONAL BLOCK DIAGRAM  
VLIM/  
Patented high efficiency single inductor architecture  
Integrated low RDSON MOSFETs for the TEC controller  
TEC voltage and current operation monitoring  
No external sense resistor required  
Independent TEC heating and cooling current limit settings  
Programmable maximum TEC voltage  
2.0 MHz PWM driver switching frequency  
External synchronization  
Two integrated, zero drift, rail-to-rail chopper amplifiers  
Capable of NTC or RTD thermal sensors  
2.50 V reference output with 1% accuracy  
Temperature lock indicator  
VDD  
SD ILIM VTEC ITEC  
PVIN  
ERROR  
AMP  
TEC DRIVER  
IN1P  
IN1N  
TEC CURRENT  
AND VOLTAGE  
SENSE AND LIMIT  
LDR  
LINEAR  
POWER  
STAGE  
OUT1  
COMP  
AMP  
IN2P  
IN2N  
CONTROLLER  
SW  
PWM  
POWER  
STAGE  
SFB  
OUT2  
Available in a 25-ball, 2.5 mm × 2.5 mm WLCSP or in a  
24-lead, 4 mm × 4 mm LFCSP  
VOLTAGE  
REFERENCE  
OSCILLATOR  
APPLICATIONS  
TEC temperature control  
AGND  
VREF  
EN/SY  
PGNDx  
Optical modules  
Optical fiber amplifiers  
Figure 1.  
Optical networking systems  
Instruments requiring TEC temperature control  
GENERAL DESCRIPTION  
The ADN8834 is a monolithic TEC controller with an integrated  
TEC controller. It has a linear power stage, a pulse-width  
modulation (PWM) power stage, and two zero-drift, rail-to-rail  
operational amplifiers. The linear controller works with the PWM  
driver to control the internal power MOSFETs in an H-bridge  
configuration. By measuring the thermal sensor feedback  
voltage and using the integrated operational amplifiers as a  
proportional integral differential (PID) compensator to condition  
the signal, the ADN8834 drives current through a TEC to settle  
the temperature of a laser diode or a passive component attached  
to the TEC module to the programmed target temperature.  
The temperature control loop of the ADN8834 is stabilized by  
PID compensation utilizing the built in, zero drift chopper  
amplifiers. The internal 2.50 V reference voltage provides a 1%  
accurate output that is used to bias a thermistor temperature  
sensing bridge as well as a voltage divider network to program  
the maximum TEC current and voltage limits for both the heating  
and cooling modes. With the zero drift chopper amplifiers,  
extremely good long-term temperature stability is maintained via  
an autonomous analog temperature control loop.  
Table 1. TEC Family Models  
Device No. MOSFET  
Thermal Loop  
Package  
The ADN8834 supports negative temperature coefficient (NTC)  
thermistors as well as positive temperature coefficient (PTC)  
resistive temperature detectors (RTD). The target temperature is  
set as an analog voltage input either from a digital-to-analog  
converter (DAC) or from an external resistor divider.  
ADN8831  
ADN8833  
Discrete  
Integrated Digital  
Digital/analog  
LFCSP (CP-32-7)  
WLCSP (CB-25-7),  
LFCSP (CP-24-15)  
ADN8834  
Integrated Digital/analog  
WLCSP (CB-25-7),  
LFCSP (CP-24-15)  
Rev. A  
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Tel: 781.329.4700  
Technical Support  
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www.analog.com  
 
 
 
 
ADN8834* PRODUCT PAGE QUICK LINKS  
Last Content Update: 02/23/2017  
COMPARABLE PARTS  
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DESIGN RESOURCES  
ADN8834 Material Declaration  
PCN-PDN Information  
EVALUATION KITS  
ADN8834 Evaluation Board  
Quality And Reliability  
Symbols and Footprints  
DOCUMENTATION  
Data Sheet  
DISCUSSIONS  
View all ADN8834 EngineerZone Discussions.  
ADN8834: Ultracompact, 1.5 A Thermoelectric Cooler  
(TEC) Controller  
SAMPLE AND BUY  
Visit the product page to see pricing options.  
User Guides  
UG-858: Evaluating the ADN8834 Ultracompact 1.5 A  
Thermoelectric Cooler (TEC) Controller  
TECHNICAL SUPPORT  
Submit a technical question or find your regional support  
number.  
REFERENCE MATERIALS  
Technical Articles  
Tec Controller Applications In Telecommunication  
Systems  
DOCUMENT FEEDBACK  
Submit feedback for this data sheet.  
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ADN8834  
Data Sheet  
TABLE OF CONTENTS  
Features .............................................................................................. 1  
TEC Voltage/Current Monitor ................................................. 16  
Maximum TEC Voltage Limit .................................................. 16  
Maximum TEC Current Limit ................................................. 17  
Applications Information.............................................................. 18  
Signal Flow .................................................................................. 18  
Thermistor Setup........................................................................ 18  
Thermistor Amplifier (Chopper 1).......................................... 19  
PID Compensation Amplifier (Chopper 2)............................ 19  
MOSFET Driver Amplifiers...................................................... 20  
PWM Output Filter Requirements .......................................... 20  
Input Capacitor Selection.......................................................... 21  
Power Dissipation....................................................................... 21  
PCB Layout Guidelines.................................................................. 23  
Block Diagrams and Signal Flow ............................................. 23  
Guidelines for Reducing Noise and Minimizing Power Loss.....23  
Example PCB Layout Using Two Layers................................. 24  
Outline Dimensions....................................................................... 27  
Ordering Guide .......................................................................... 27  
Applications....................................................................................... 1  
Functional Block Diagram .............................................................. 1  
General Description......................................................................... 1  
Revision History ............................................................................... 2  
Specifications..................................................................................... 3  
Absolute Maximum Ratings............................................................ 6  
Thermal Resistance ...................................................................... 6  
ESD Caution.................................................................................. 6  
Pin Configurations and Function Descriptions ........................... 7  
Typical Performance Characteristics ............................................. 8  
Detailed Functional Block Diagram ............................................ 12  
Theory of Operation ...................................................................... 13  
Analog PID Control................................................................... 14  
Digital PID Control.................................................................... 14  
Powering the Controller ............................................................ 14  
Enable and Shutdown ................................................................ 15  
Oscillator Clock Frequency....................................................... 15  
Temperature Lock Indicator (LFCSP Only) ........................... 15  
Soft Start on Power-Up.............................................................. 15  
REVISION HISTORY  
8/15—Rev. 0 to Rev. A  
Added 24-Lead LFCSP.......................................................Universal  
Changes to Features Section and Table 1 ...................................... 1  
Changes to Table 2............................................................................ 3  
Changes to Table 3............................................................................ 6  
Added Figure 3; Renumbered Sequentially .................................. 7  
Changes to Figure 13........................................................................ 9  
Changes to Figure 23 and Figure 24............................................. 11  
Changes to Figure 25...................................................................... 12  
Changes to Powering the Controller Section and Figure 27  
Caption............................................................................................. 14  
Change to Soft Start on Power-Up Section................................. 15  
Change to Figure 33 ....................................................................... 18  
Changes to Table 7.......................................................................... 21  
Added Table 8; Renumbered Sequentially .................................. 21  
Updated Outline Dimensions....................................................... 27  
Changes to Ordering Guide .......................................................... 27  
4/15—Revision 0: Initial Version  
Rev. A | Page 2 of 27  
 
Data Sheet  
ADN8834  
SPECIFICATIONS  
VIN = 2.7 V to 5.5 V, T J = −40°C to +125°C for minimum/maximum specifications, and TA = 25°C for typical specifications, unless  
otherwise noted.  
Table 2.  
Parameter  
Symbol  
Test Conditions/Comments  
Min  
Typ  
Max  
Unit  
POWER SUPPLY  
Driver Supply Voltage  
Controller Supply Voltage  
Supply Current  
Shutdown Current  
Undervoltage Lockout (UVLO)  
UVLO Hysteresis  
REFERENCE VOLTAGE  
LINEAR OUTPUT  
Output Voltage  
VPVIN  
VVDD  
IVDD  
2.7  
2.7  
5.5  
5.5  
5
700  
2.65  
100  
2.525  
V
V
PWM not switching  
EN/SY = AGND or VLIM/SD = AGND  
VVDD rising  
3.3  
mA  
µA  
V
mV  
V
ISD  
350  
2.55  
90  
VUVLO  
UVLOHYST  
VVREF  
2.45  
80  
IVREF = 0 mA to 10 mA  
ILDR = 0 A  
2.475  
2.50  
VLDR  
Low  
High  
0
VPVIN  
V
V
A
A
A
A
Maximum Source Current  
ILDR_SOURCE  
ILDR_SINK  
TJ = −40°C to +105°C  
TJ = −40°C to +125°C  
TJ = −40°C to +105°C  
TJ = −40°C to +125°C  
ILDR = 0.6 A  
WLCSP, VPVIN = 5.0 V  
WLCSP, VPVIN = 3.3 V  
LFCSP, VPVIN = 5.0 V  
LFCSP, VPVIN = 3.3 V  
WLCSP, VPVIN = 5.0 V  
WLCSP, VPVIN = 3.3 V  
LFCSP, VPVIN = 5.0 V  
LFCSP, VPVIN = 3.3 V  
1.5  
1.2  
Maximum Sink Current  
1.5  
1.2  
On Resistance  
P-MOSFET  
RDS_PL(ON)  
35  
44  
50  
55  
31  
40  
45  
50  
50  
60  
65  
75  
50  
55  
70  
80  
mΩ  
mΩ  
mΩ  
mΩ  
mΩ  
mΩ  
mΩ  
mΩ  
N-MOSFET  
RDS_NL(ON)  
Leakage Current  
P-MOSFET  
N-MOSFET  
Linear Amplifier Gain  
LDR Short-Circuit Threshold  
ILDR_P_LKG  
ILDR_N_LKG  
ALDR  
ILDR_SH_GNDL  
ILDR_SH_PVIN(L)  
THICCUP  
0.1  
0.1  
40  
2.2  
−2.2  
15  
10  
10  
µA  
µA  
V/V  
A
A
ms  
LDR short to PGNDL, enter hiccup  
LDR short to PVIN, enter hiccup  
Hiccup Cycle  
PWM OUTPUT  
Output Voltage  
Low  
VSFB  
ISFB = 0 A  
V
V
V
A
A
A
A
0.06 × VPVIN  
0.93 × VPVIN  
High  
Maximum Source Current  
ISW_SOURCE  
ISW_SINK  
TJ = −40°C to +105°C  
TJ = −40°C to +125°C  
TJ = −40°C to +105°C  
TJ = −40°C to +125°C  
ISW = 0.6 A  
WLCSP, VPVIN = 5.0 V  
WLCSP, VPVIN = 3.3 V  
LFCSP, VPVIN = 5.0 V  
LFCSP, VPVIN = 3.3 V  
1.5  
1.2  
Maximum Sink Current  
1.5  
1.2  
On Resistance  
P-MOSFET  
RDS_PS(ON)  
47  
60  
60  
70  
65  
80  
80  
95  
mΩ  
mΩ  
mΩ  
mΩ  
Rev. A | Page 3 of 27  
 
ADN8834  
Data Sheet  
Parameter  
Symbol  
Test Conditions/Comments  
WLCSP, VPVIN = 5.0 V  
WLCSP, VPVIN = 3.3 V  
LFCSP, VPVIN = 5.0 V  
Min  
Typ  
40  
45  
45  
55  
Max  
60  
65  
75  
85  
Unit  
mΩ  
mΩ  
mΩ  
mΩ  
N-MOSFET  
RDS_NS(ON)  
LFCSP, VPVIN = 3.3 V  
Leakage Current  
P-MOSFET  
N-MOSFET  
SW Node Rise Time1  
PWM Duty Cycle2  
SFB Input Bias Current  
PWM OSCILLATOR  
ISW_P_LKG  
ISW_N_LKG  
tSW_R  
DSW  
ISFB  
0.1  
0.1  
1
10  
10  
µA  
µA  
ns  
%
µA  
CSW = 1 nF  
6
93  
2
1
Internal Oscillator Frequency  
EN/SY Input Voltage  
Low  
fOSC  
EN/SY high  
1.85  
2.0  
2.15  
0.8  
MHz  
VEN/SY_ILOW  
VEN/SY_IHIGH  
fSYNC  
V
V
MHz  
%
ns  
Cycles  
µA  
µA  
High  
2.1  
1.85  
10  
External Synchronization Frequency  
Synchronization Pulse Duty Cycle  
EN/SY Rising to PWM Rising Delay  
EN/SY to PWM Lock Time  
EN/SY Input Current  
Pull-Down Current  
3.25  
90  
DSYNC  
tSYNC_PWM  
tSY_LOCK  
IEN/SY  
50  
Number of SYNC cycles  
10  
0.5  
0.5  
0.3  
0.3  
ERROR/COMPENSATION AMPLIFIERS  
Input Offset Voltage  
VOS1  
VOS2  
VCM1, VCM2  
VCM1 = 1.5 V, VOS1 = VIN1P − VIN1N  
VCM2 = 1.5 V, VOS2 = VIN2P − VIN2N  
10  
10  
100  
100  
VVDD  
µV  
µV  
V
Input Voltage Range  
0
Common-Mode Rejection Ratio (CMRR) CMRR1, CMRR2 VCM1, VCM2 = 0.2 V to VVDD − 0.2 V  
Output Voltage  
120  
dB  
High  
VOH1, VOH2  
VVDD  
0.04  
V
Low  
VOL1, VOL2  
PSRR1, PSRR2  
IOUT1, IOUT2  
10  
mV  
dB  
mA  
MHz  
Power Supply Rejection Ratio (PSRR)  
Output Current  
Gain Bandwidth Product1  
TEC CURRENT LIMIT  
ILIM Input Voltage Range  
Cooling  
120  
2
Sourcing and sinking  
VOUT1,VOUT2 = 0.5 V to VVDD − 1 V  
5
GBW1, GBW2  
VILIMC  
VILIMH  
1.3  
0.2  
VVREF  
0.2  
1.2  
V
V
Heating  
Current-Limit Threshold  
Cooling  
Heating  
VILIMC_TH  
VILIMH_TH  
VITEC = 0.5 V  
VITEC = 2 V  
1.98  
0.48  
2.0  
0.5  
2.02  
0.52  
V
V
ILIM Input Current  
Heating  
Cooling  
Cooling to Heating Current Detection  
Threshold  
IILIMH  
IILIMC  
ICOOL_HEAT_TH  
−0.2  
37.5  
+0.2  
42.5  
µA  
µA  
mA  
Sourcing current  
(VDRL − VSFB)/VVLIM  
40  
40  
TEC VOLTAGE LIMIT  
Voltage Limit Gain  
VLIM/SD Input Voltage Range1  
VLIM/SD Input Current  
Cooling  
AVLIM  
VVLIM  
2
V/V  
V
0.2  
VVDD/2  
IILIMC  
IILIMH  
VOUT2 < VVREF/2  
VOUT2 > VVREF/2, sinking current  
−0.2  
8
+0.2  
12.2  
µA  
µA  
Heating  
10  
Rev. A | Page 4 of 27  
Data Sheet  
ADN8834  
Parameter  
Symbol  
RCS  
Test Conditions/Comments  
Min  
Typ  
Max  
Unit  
TEC CURRENT MEASUREMENT (WLCSP)  
Current Sense Gain  
VPVIN = 3.3 V  
VPVIN = 5 V  
700 mA ≤ ILDR ≤ 1.5 A, VPVIN = 3.3 V  
800 mA ≤ ILDR ≤ 1.5 A, VPVIN = 5 V  
VPVIN = 3.3 V, cooling, VVREF/2 +  
ILDR × RCS  
0.525  
0.535  
V/A  
V/A  
%
%
V
Current Measurement Accuracy  
ITEC Voltage Accuracy  
ILDR_ERROR  
−10  
−10  
1.597  
+10  
+10  
1.649  
VITEC_@_700_mA  
VITEC_@_−700_mA  
1.618  
0.883  
VPVIN = 3.3 V, heating, VVREF/2 −  
0.846  
0.891  
V
I
LDR × RCS  
VITEC_@_800_mA  
VITEC_@_−800_mA  
VPVIN = 5 V, cooling, VVREF/2 + ILDR × RCS  
VPVIN = 5 V, heating, VVREF/2 − ILDR × RCS 0.783  
1.657  
1.678  
0.822  
1.718  
0.836  
V
V
TEC CURRENT MEASUREMENT (LFCSP)  
Current Sense Gain  
RCS  
VPVIN = 3.3 V  
VPVIN = 5 V  
700 mA ≤ ILDR ≤ 1 A, VPVIN = 3.3 V  
800 mA ≤ ILDR ≤ 1 A, VPVIN = 5 V  
VPVIN = 3.3 V, cooling, VVREF/2 + ILDR  
RCS  
VPVIN = 3.3 V, heating, VVREF/2 − ILDR  
RCS  
VPVIN = 5 V, cooling, VVREF/2 + ILDR  
RCS  
VPVIN = 5 V, heating, VVREF/2 − ILDR  
RCS  
0.525  
0.525  
V/A  
V/A  
%
%
V
Current Measurement Accuracy  
ITEC Voltage Accuracy  
ILDR_ERROR  
−15  
−15  
1.374  
+15  
+15  
1.861  
VITEC_@_700_mA  
VITEC_@_−700_mA  
VITEC_@_800_mA  
VITEC_@_−800_mA  
VITEC  
×
1.618  
0.883  
1.678  
0.830  
×
0.750  
1.419  
0.705  
0
1.015  
1.921  
0.955  
V
V
V
V
×
×
ITEC Voltage Output Range  
ITEC = 0 A  
VVREF  
0.05  
ITEC Bias Voltage  
VITEC  
IITEC  
ILDR = 0 A  
1.210  
−2  
1.250  
1.285  
+2  
V
mA  
Maximum ITEC Output Current  
TEC VOLTAGE MEASUREMENT  
Voltage Sense Gain  
AVTEC  
VVTEC_@_1_V  
0.24  
1.475  
0.25  
1.50  
0.26  
1.525  
V/V  
V
Voltage Measurement Accuracy  
VLDR – VSFB = 1 V, VVREF/2 + AVTEC  
×
(VLDR – VSFB  
)
VTEC Output Voltage Range  
VTEC Bias Voltage  
VVTEC  
VVTEC_B  
RVTEC  
0.005  
1.225  
−2  
2.625  
1.285  
+2  
V
V
mA  
VLDR = VSFB  
1.250  
Maximum VTEC Output Current  
TEMPERATURE GOOD (LFCSP Only)  
TMPGD Low Output Voltage  
TMPGD High Output Voltage  
TMPGD Output Low Impedance  
TMPGD Output High Impedance  
High Threshold  
VTMPGD_LO  
VTMPGD_HO  
RTMPGD_LOW  
RTMPGD_LOW  
VOUT1_THH  
VOUT1_THL  
No load  
No load  
0.4  
V
V
V
V
2.0  
25  
50  
1.54  
1.46  
IN2N tied to OUT2, VIN2P = 1.5 V  
IN2N tied to OUT2, VIN2P = 1.5 V  
1.56  
Low Threshold  
1.40  
INTERNAL SOFT START  
Soft Start Time  
tSS  
150  
ms  
V
VLIM/SD SHUTDOWN  
VLIM/SD Low Voltage Threshold  
THERMAL SHUTDOWN  
VVLIM/SD_THL  
0.07  
Thermal Shutdown Threshold  
Thermal Shutdown Hysteresis  
TSHDN_TH  
TSHDN_HYS  
170  
17  
°C  
°C  
1 This specification is guaranteed by design.  
2 This specification is guaranteed by characterization.  
Rev. A | Page 5 of 27  
ADN8834  
Data Sheet  
ABSOLUTE MAXIMUM RATINGS  
Table 3.  
Stresses at or above those listed under Absolute Maximum  
Ratings may cause permanent damage to the product. This is a  
stress rating only; functional operation of the product at these  
or any other conditions above those indicated in the operational  
section of this specification is not implied. Operation beyond  
the maximum operating conditions for extended periods may  
affect product reliability.  
Parameter  
Rating  
PVIN to PGNDL (WLCSP)  
PVIN to PGNDS (WLCSP)  
PVINL to PGNDL (LFCSP)  
PVINS to PGNDS (LFCSP)  
LDR to PGNDL (WLCSP)  
LDR to PGNDL (LFCSP)  
SW to PGNDS  
−0.3 V to +5.75 V  
−0.3 V to +5.75 V  
−0.3 V to +5.75 V  
−0.3 V to +5.75 V  
−0.3 V to VPVIN  
−0.3 V to VPVINL  
−0.3 V to +5.75 V  
−0.3 V to VVDD  
THERMAL RESISTANCE  
θJA is specified for the worst-case conditions, that is, a device  
soldered in a circuit board for surface-mount packages, and is  
based on a 4-layer standard JEDEC board.  
SFB to AGND  
AGND to PGNDL  
AGND to PGNDS  
VLIM/SD to AGND  
ILIM to AGND  
−0.3 V to +0.3 V  
−0.3 V to +0.3 V  
−0.3 V to VVDD  
Table 4.  
Package Type  
25-Ball WLCSP  
24-Lead LFCSP  
θJA  
48  
37  
θJC  
Unit  
°C/W  
°C/W  
−0.3 V to VVDD  
0.6  
1.65  
VREF to AGND  
VDD to AGND  
IN1P to AGND  
−0.3 V to +3 V  
−0.3 V to +5.75 V  
−0.3 V to VVDD  
IN1N to AGND  
OUT1 to AGND  
IN2P to AGND  
−0.3 V to VVDD  
−0.3 V to +5.75 V  
−0.3 V to VVDD  
ESD CAUTION  
IN2N to AGND  
−0.3 V to VVDD  
OUT2 to AGND  
EN/SY to AGND  
−0.3 V to +5.75 V  
−0.3 V to VVDD  
ITEC to AGND  
VTEC to AGND  
−0.3 V to +5.75 V  
−0.3 V to +5.75 V  
Maximum Current  
VREF to AGND  
20 mA  
OUT1 to AGND  
50 mA  
OUT2 to AGND  
50 mA  
ITEC to AGND  
50 mA  
VTEC to AGND  
50 mA  
Junction Temperature  
Storage Temperature Range  
125°C  
−65°C to +150°C  
Lead Temperature (Soldering, 10 sec) 260°C  
Rev. A | Page 6 of 27  
 
 
 
Data Sheet  
ADN8834  
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS  
1
2
3
4
5
A
B
C
D
E
PGNDL  
OUT1  
PGNDL  
IN1P  
IN2P  
1
18 PGNDL  
LDR  
IN2N  
OUT2 2  
17  
ADN8834  
16 PVINL  
15 PVINS  
14 SW  
3
VLIM/SD  
VLIM/  
SD  
LDR  
IN1N  
ITEC  
VTEC  
LDR  
IN2N  
TOP VIEW  
ILIM 4  
(Not to Scale)  
5
VDD  
VREF 6  
PGNDS  
13  
PVIN  
2.54mm  
PVIN  
OUT2  
ILIM  
NOTES  
1. EXPOSED PAD. SOLDER TO THE ANALOG  
GROUND PLANE ON THE BOARD.  
SW  
SW  
EN/SY  
AGND  
VDD  
0.5mm  
PITCH  
PGNDS  
SFB  
PGNDS  
VREF  
2.54mm  
ADN8834  
TOP VIEW  
(BALLS ON THE BOTTOM SIDE)  
Figure 3. LFCSP Pin Configuration (Top View)  
Figure 2. WLCSP Pin Configuration (Top View)  
Table 5. Pin Function Descriptions  
Pin No.  
WLCSP LFCSP  
Mnemonic Description  
A1, A2  
N/A1  
A3  
A4  
A5  
B1, B2  
B3  
B4  
18, 19  
20  
21  
23  
24  
17  
22  
1
PGNDL  
TMPGD  
OUT1  
IN1P  
IN2P  
LDR  
Power Ground of the Linear TEC Controller.  
Temperature Good Output.  
Output of the Error Amplifier.  
Noninverting Input of the Error Amplifier.  
Noninverting Input of the Compensation Amplifier.  
Output of the Linear TEC Controller.  
IN1N  
IN2N  
Inverting Input of the Error Amplifier.  
Inverting Input of the Compensation Amplifier.  
B5  
3
VLIM/SD  
Voltage Limit/Shutdown. This pin sets the cooling and heating TEC voltage limits. When this pin  
is pulled low, the device shuts down.  
C1, C2  
N/A1  
N/A1  
C3  
C4  
C5  
D1, D2  
D3  
D4  
N/A1  
16  
15  
11  
2
4
14  
9
PVIN  
PVINL  
PVINS  
ITEC  
OUT2  
ILIM  
SW  
VTEC  
EN/SY  
Power Input for the TEC Controller.  
Power Input for the Linear TEC Driver.  
Power Input for the PWM TEC Driver.  
TEC Current Output.  
Output of the Compensation Amplifier.  
Current Limit. This pin sets the TEC cooling and heating current limits.  
Switch Node Output of the PWM TEC Controller.  
TEC Voltage Output.  
8
Enable/Synchronization. Set this pin high to enable the device. An external synchronization  
clock input can be applied to this pin.  
D5  
5
VDD  
Power for the Controller Circuits.  
E1, E2  
E3  
E4  
E5  
N/A1  
12, 13  
10  
7
6
0
PGNDS  
SFB  
AGND  
VREF  
EPAD  
Power Ground of the PWM TEC Controller.  
Feedback of the PWM TEC Controller Output.  
Signal Ground.  
2.5 V Reference Output.  
Exposed Pad. Solder to the analog ground plane on the board.  
1 N/A means not applicable.  
Rev. A | Page 7 of 27  
 
ADN8834  
Data Sheet  
TYPICAL PERFORMANCE CHARACTERISTICS  
TA = 25°C, unless otherwise noted.  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
100  
V
V
= 3.3V  
= 5V  
IN  
IN  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
LOAD = 2Ω  
LOAD = 3Ω  
LOAD = 4Ω  
LOAD = 5Ω  
0
0.5  
1.0  
1.5  
0
1.5  
0.5  
1.0  
TEC CURRENT (A)  
TEC CURRENT (A)  
Figure 4. Efficiency vs. TEC Current at VIN = 3.3 V and 5 V in Cooling Mode  
with 2 Ω Load  
Figure 7. Efficiency vs. TEC Current at VIN = 3.3 V with Different Loads in  
Heating Mode  
100  
V
V
= 3.3V  
= 5V  
IN  
IN  
1.4  
1.2  
1.0  
0.8  
0.6  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
0.4  
LOAD = 2Ω  
0.2  
LOAD = 3Ω  
LOAD = 4Ω  
LOAD = 5Ω  
0
2.7  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
0
0.5  
1.0  
1.5  
INPUT VOLTAGE AT PVIN (V)  
TEC CURRENT (A)  
Figure 5. Efficiency vs. TEC Current at VIN = 3.3 V and 5 V in Heating Mode  
with 2 Ω Load  
Figure 8. Maximum TEC Current vs. Input Voltage at PVIN (VIN = 3.3 V),  
Without Voltage and Current Limit in Cooling Mode  
100  
90  
80  
70  
60  
50  
40  
30  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
20  
LOAD = 2Ω  
LOAD = 2Ω  
0.2  
LOAD = 3Ω  
LOAD = 3Ω  
10  
LOAD = 4Ω  
LOAD = 5Ω  
LOAD = 4Ω  
LOAD = 5Ω  
0
0
2.7  
0
0.5  
1.0  
1.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
TEC CURRENT (A)  
INPUT VOLTAGE AT PVIN (V)  
Figure 9. Maximum TEC Current vs. Input Voltage at PVIN (VIN = 3.3 V),  
Without Voltage and Current Limit in Heating Mode  
Figure 6. Efficiency vs. TEC Current at VIN = 3.3 V with Different Loads in  
Cooling Mode  
Rev. A | Page 8 of 27  
 
Data Sheet  
ADN8834  
0.10  
0.20  
0.15  
0.10  
0.05  
0
V
V
V
V
V
V
= 3.3V, ITEC = 0A  
T = 15°C  
IN  
IN  
IN  
IN  
IN  
IN  
T = 25°C  
T = 35°C  
T = 45°C  
T = 55°C  
0.08  
0.06  
0.04  
0.02  
0
= 3.3V, ITEC = 0.5A, COOLING  
= 3.3V, ITEC = 0.5A, HEATING  
= 5.0V, ITEC = 0A  
= 5.0V, ITEC = 0.5A, COOLING  
= 5.0V, ITEC = 0.5A, HEATING  
–0.02  
–0.04  
–0.06  
–0.08  
–0.10  
–0.05  
–0.10  
–0.15  
–0.20  
0
1
2
3
4
5
6
7
8
9
10  
0
20  
40  
60  
80  
100 120 140 160 180 200  
LOAD CURRENT AT V  
(mA)  
REF  
TIME (Seconds)  
Figure 10. Thermal Stability over Ambient Temperature at VIN = 3.3 V,  
VTEMPSET = 1 V  
Figure 13. VREF Load Regulation  
0.10  
20  
15  
T = 15°C  
V
V
= 3.3V  
= 5V  
IN  
IN  
T = 25°C  
0.08  
T = 35°C  
T = 45°C  
0.06  
0.04  
T = 55°C  
10  
5
0.02  
0
0
–0.02  
–0.04  
–0.06  
–0.08  
–0.10  
–5  
–10  
–15  
–20  
0
20  
40  
60  
80  
100 120 140 160 180 200  
0
0.5  
1.0  
1.5  
TIME (Seconds)  
TEC CURRENT (A)  
Figure 11. Thermal Stability over Ambient Temperature at VIN = 3.3 V,  
VTEMPSET = 1.5 V  
Figure 14. ITEC Current Reading Error vs. TEC Current in Cooling Mode  
1.0  
20  
V
V
= 3.3V  
= 5V  
V
V
V
V
V
V
= 2.7V AT NO LOAD  
= 3.3V AT NO LOAD  
= 5.5V AT NO LOAD  
= 2.7V AT 5mA LOAD  
= 3.3V AT 5mA LOAD  
= 5.5V AT 5mA LOAD  
IN  
IN  
IN  
IN  
IN  
IN  
IN  
IN  
0.8  
0.6  
15  
10  
5
0.4  
0.2  
0
0
–0.2  
–0.4  
–0.6  
–0.8  
–1.0  
–5  
–10  
–15  
–20  
1.5  
–1.0  
–0.5  
0
–50  
0
50  
100  
150  
AMBIENT TEMPERATURE (°C)  
TEC CURRENT (A)  
Figure 15. ITEC Current Reading Error vs. TEC Current in Heating Mode  
Figure 12. VREF Error vs. Ambient Temperature  
Rev. A | Page 9 of 27  
ADN8834  
Data Sheet  
20  
V
V
= 3.3V  
= 5V  
IN  
IN  
15  
10  
5
TEC CURRENT  
0
4
1
PWM (TEC–)  
–5  
–10  
–15  
–20  
LDO (TEC+)  
0.5  
1.0  
1.5  
2.0  
2.5  
B
B
W
CH1 500mV  
CH3 300mA  
CH2 500mV  
M10ms  
5.4ms  
A CH4  
–8mA  
W
B
TEC VOLTAGE (V)  
T
W
Figure 16. VTEC Voltage Reading Error vs. TEC Voltage in Cooling Mode  
Figure 19. Zero Crossing TEC Current Zoom in from Heating to Cooling  
20  
V
V
= 3.3V  
= 5V  
IN  
IN  
15  
10  
5
TEC CURRENT  
0
4
PWM (TEC–)  
–5  
–10  
–15  
LDO (TEC+)  
1
20  
–2.5  
–2.0  
–1.5  
–1.0  
–0.5  
B
B
W
CH1 500mV  
CH3 200mA Ω  
CH2 500mV  
M10ms  
5.4ms  
A CH4  
12mA  
W
B
TEC VOLTAGE (V)  
T
W
Figure 17. VTEC Voltage Reading Error vs. TEC Voltage in Heating Mode  
Figure 20. Zero Crossing TEC Current Zoom in from Cooling to Heating  
LDO (TEC+)  
EN  
3
PWM (TEC–)  
TEC CURRENT  
TEC CURRENT  
4
4
LDO (TEC–)  
PWM (TEC+)  
1
1
B
B
W
CH1 500mV  
CH4 200mA  
CH2 500mV  
M200ms  
A CH4  
–108mA  
W
B
B
B
W
CH1 1V B CH2 1V  
CH3 2V  
M20.0ms  
A CH3  
800mV  
W
W
T
–28.000ms  
W
B
CH4 500mA  
T
40ms  
W
Figure 18. Cooling to Heating Transition  
Figure 21. Typical Enable Waveforms in Cooling Mode,  
VIN = 3.3 V, Load = 2 Ω, TEC Current = 1 A  
Rev. A | Page 10 of 27  
Data Sheet  
ADN8834  
EN  
SW  
3
3
TEC CURRENT  
4
LDO (TEC+)  
1
2
PWM (TEC–)  
PWM (TEC–)  
LDO (TEC+)  
2
B
B
B
B
M20.0ms  
W
CH1 20mV  
CH3 2.0V  
CH2 20mV  
M400ns  
W
A CH3  
2.50GS/s  
1.00V  
CH1 1V B CH2 1V  
CH3 2V  
A CH3  
800mV  
W
W
W
B
B
T
0.0s  
W
CH4 500mA  
T
40ms  
W
Figure 22. Typical Enable Waveforms in Heating Mode,  
VIN = 3.3 V, Load = 2 Ω, TEC Current = 1 A  
Figure 24. Typical Switch and Voltage Ripple Waveforms in Heating Mode,  
VIN = 3.3 V, Load = 2 Ω, TEC Current = 1 A  
SW  
3
LDO (TEC+)  
PWM (TEC–)  
1
2
B
B
CH1 20mV  
CH3 2.0V  
CH2 20mV  
M400ns  
W
A CH3  
2.50GS/s  
1.00V  
W
B
T
0.0s  
W
Figure 23. Typical Switch and Voltage Ripple Waveforms in Cooling Mode  
VIN = 3.3 V, Load = 2 Ω, TEC Current = 1 A  
Rev. A | Page 11 of 27  
ADN8834  
Data Sheet  
DETAILED FUNCTIONAL BLOCK DIAGRAM  
VTEC  
ITEC  
ADN8834  
TEC DRIVER  
LINEAR POWER  
STAGE  
VDD  
COOLING  
HEATING  
VDD  
5kΩ  
PVIN  
20kΩ  
BAND GAP  
2.5V  
5kΩ  
VOLTAGE  
1.25V  
1.25V  
VREF  
1.25V  
REFERENCE  
TEC CURRENT SENSE  
LDR  
+
20kΩ  
20kΩ  
V
V
= 2.5V AT VDD > 4.0V  
= 1.5V AT VDD < 4.0V  
B
B
TEC  
VOLTAGE  
SENSE  
V
B
SFB  
2kΩ  
80kΩ  
LDR  
V
C
AGND  
IN1P  
+
TEMPERATURE  
ERROR  
AMPLIFIER  
V
B
LINEAR  
AMPLIFIER  
PGNDL  
PGNDL  
V
B
IN1N  
80kΩ  
OUT1  
400kΩ  
SFB  
20kΩ  
20kΩ  
PWM POWER  
STAGE  
1.25V  
PVIN  
100kΩ  
COMPENSATION  
AMPLIFIER  
V
C
IN2P  
IN2N  
20kΩ  
PWM  
MODULATOR  
20kΩ  
20kΩ  
PWM  
MOSFET  
DRIVER  
PWM  
OUT2  
VDD  
SW  
ERROR  
AMPLIFIER  
TEC VOLTAGE  
LIMIT AND INTERNAL  
SOFT START  
40µA  
CLK  
V
B
OSCILLATOR  
CLK  
COOLING  
HEATING  
PGNDS  
PGNDS  
V
V
≥ 2.1V  
≤ 0.8V  
HIGH  
LOW  
SHUTDOWN  
ITEC  
10µA  
DEGLITCH  
TEC  
CURRENT  
LIMIT  
SHUTDOWN  
0.07V  
ILIM  
EN/SY  
VLIM/SD  
Figure 25. Detailed Functional Block Diagram of the ADN8834 for the WLCSP  
Rev. A | Page 12 of 27  
 
Data Sheet  
ADN8834  
THEORY OF OPERATION  
The ADN8834 is a single chip TEC controller that sets and  
stabilizes a TEC temperature. A voltage applied to the input of  
the ADN8834 corresponds to the temperature setpoint of the target  
object attached to the TEC. The ADN8834 controls an internal  
FET H-bridge whereby the direction of the current fed through  
the TEC can be either positive (for cooling mode), to pump  
heat away from the object attached to the TEC, or negative (for  
heating mode), to pump heat into the object attached to the TEC.  
The ADN8834 drives its internal MOSFET transistors to provide  
the TEC current. To provide good power efficiency and zero  
crossing quality, only one side of the H-bridge uses a PWM  
driver. Only one inductor and one capacitor are required to filter  
out the switching frequency. The other side of the H-bridge uses a  
linear output without requiring any additional circuitry. This pro-  
prietary configuration allows the ADN8834 to provide efficiency of  
>90%. For most applications, a 1 µH inductor, a 10 μF capacitor,  
and a switching frequency of 2 MHz maintain less than 1% of the  
worst-case output voltage ripple across a TEC.  
Temperature is measured with a thermal sensor attached to the  
target object and the sensed temperature (voltage) is fed back to  
the ADN8834 to complete a closed thermal control loop of the  
TEC. For the best overall stability, couple the thermal sensor  
close to the TEC. In most laser diode modules, a TEC and a  
NTC thermistor are already mounted in the same package to  
regulate the laser diode temperature.  
The maximum voltage across the TEC and the current flowing  
through the TEC are set by using the VLIM/SD and ILIM pins.  
The maximum cooling and heating currents can be set indepen-  
dently to allow asymmetric heating and cooling limits. For  
additional details, see the Maximum TEC Voltage Limit section  
and the Maximum TEC Current Limit section.  
The TEC is differentially driven in an H-bridge configuration.  
TEC  
CURRENT  
ENABLE/  
SYNC  
TEC  
VOLTAGE  
SHUTDOWN  
C
VDD  
0.1µF  
V
IN  
R
BP  
2.7V TO 5.5V  
EN/SY  
ITEC  
VTEC  
VDD  
VLIM/SD  
TEC  
VOLTAGE  
LIMIT  
PVIN  
C
10µF  
R
R
IN  
V2  
V1  
TEC  
CURRENT  
LIMITS  
ILIM  
R
C1  
R
C2  
LDR  
PGNDL  
SFB  
C
0.1µF  
TEC  
+
L_OUT  
ADN8834  
VREF  
C
0.1µF  
VREF  
R
R
R
A
AGND  
TEMP  
SET  
L = 1µH  
IN2P  
IN1P  
IN1N  
SW  
C
10µF  
SW_OUT  
OUT1  
IN2N  
OUT2 PGNDS  
R
X
B
R
FB  
C
I
R
R
P
I
NTC  
R
TH  
C
C
R
D
F
D
THERMISTER  
Figure 26. Typical Application Circuit with Analog PID Compensation in a Temperature Control Loop  
Rev. A | Page 13 of 27  
 
ADN8834  
Data Sheet  
The Chopper 2 amplifier is used as a buffer for the external  
ANALOG PID CONTROL  
DAC, which controls the temperature setpoint. Connect the  
DAC to IN2P and short the IN2N and OUT2 pins together. See  
Figure 27 for an overview of how to configure the ADN8834  
external circuitry for digital PID control.  
The ADN8834 integrates two self-correcting, auto-zeroing  
amplifiers (Chopper 1 and Chopper 2). The Chopper 1 amplifier  
takes a thermal sensor input and converts or regulates the input  
to a linear voltage output. The OUT1 voltage is proportional to  
the object temperature. The OUT1 voltage is fed into the  
POWERING THE CONTROLLER  
compensation amplifier (Chopper 2) and is compared with a  
temperature setpoint voltage, which creates an error voltage that is  
proportional to the difference. For autonomous analog temperature  
control, Chopper 2 can be used to implement a PID network as  
shown in Figure 27 to set the overall stability and response of the  
thermal loop. Adjusting the PID network optimizes the step  
response of the TEC control loop. A compromised settling time  
and the maximum current ringing become available when this  
adjustment is done. To adjust the compensation network, see  
the PID Compensation Amplifier (Chopper 2) section.  
The ADN8834 operates at an input voltage range of 2.7 V to  
5.5 V that is applied to the VDD pin and the PVIN pin for the  
WLCSP (the PVINS pin and PVINL pin for the LFCSP. The  
VDD pin is the input power for the driver and internal reference.  
The PVIN input power pins are combined for both the linear  
and the switching driver. Apply the same input voltage to all power  
input pins: VDD and PVIN. In some circumstances, an RC low-  
pass filter can be added optionally between the PVIN for the  
WLCSP (PVINS and PVINL for the LFCSP) and VDD pins to  
prevent high frequency noise from entering VDD, as shown in  
Figure 27. The capacitor and resistor values are typically 10 Ω  
and 100 nF, respectively.  
DIGITAL PID CONTROL  
The ADN8834 can also be configured for use in a software  
controlled PID loop. In this scenario, the Chopper 1 amplifier  
can either be left unused or configured as a thermistor input  
amplifier connected to an external temperature measurement  
analog-to-digital converter (ADC). For more information, see  
the Thermistor Amplifier (Chopper 1) section. If Chopper 1 is  
left unused, tie IN1N and IN1P to AGND.  
When configuring power supply to the ADN8834, keep in mind  
that at high current loads, the input voltage may drop substantially  
due to a voltage drop on the wires between the front-end power  
supply and the PVIN for the WLCSP (PVINS and PVINL for  
the LFCSP) pin. Leave a proper voltage margin when designing  
the front-end power supply to maintain the performance.  
Minimize the trace length from the power supply to the PVIN  
for the WLCSP (PVINS and PVINL for the LFCSP) pin to help  
mitigate the voltage drop.  
ENABLE  
COOLING AND HEATING  
TEC CURRENT LIMITS  
2.5V VREF  
R
R
C2  
C1  
R
C
0.1µF  
V1  
TEC  
VOLTAGE  
LIMIT  
VDD  
V
IN  
R
2.7V TO 5.5V  
BP  
EN/SY  
ILIM  
VDD  
2.5V VREF  
VLIM/SD  
PVIN  
C
10µF  
R
IN  
V2  
TEMPERATURE SET  
DAC  
IN2P  
TEC CURRENT READBACK  
ITEC  
VTEC  
VREF  
LDR  
C
0.1µF  
TEC  
+
L_OUT  
TEC VOLTAGE READBACK  
ADN8834  
PGNDL  
2.5V VREF  
C
NTC  
VREF  
R
R
R
0.1uF  
R
SFB  
A
B
TH  
AGND  
L = 1µH  
= 2MHz  
IN1P  
IN1N  
SW  
PGNDS  
C
10µF  
SW_OUT  
THERMISTER  
IN2N OUT2  
OUT1  
F
SW  
R
X
2.5V VREF  
R
FB  
TEMPERATURE  
READBACK  
ADC  
Figure 27. TEC Controller in a Digital Temperature Control Loop (WLCSP)  
Rev. A | Page 14 of 27  
 
 
 
 
Data Sheet  
ADN8834  
Connecting Multiple ADN8834 Devices  
ENABLE AND SHUTDOWN  
Multiple ADN8834 devices can be driven from a single master  
clock signal by connecting the external clock source to the  
EN/SY pin of each slave device. The input ripple can be greatly  
reduced by operating the ADN8834 devices 180° out of phase  
from each other by placing an inverter at one of the EN/SY pins,  
as shown in Figure 29.  
To enable the ADN8834, apply a logic high voltage to the  
EN/SY pin while the voltage at the VLIM/SD pin is above the  
maximum shutdown threshold of 0.07 V. If either the EN/SY  
pin voltage is set to logic low or the VLIM/SD voltage is below  
0.07 V, the controller goes into an ultralow current state. The  
current drawn in shutdown mode is 350 μA typically. Most of  
the current is consumed by the VREF circuit block, which is  
always on even when the device is disabled or shut down. The  
device can also be enabled when an external synchronization  
clock signal is applied to the EN/SY pin, and the voltage at  
VLIM/SD input is above 0.07 V. Table 6 shows the combinations  
of the two input signals that are required to enable the ADN8834.  
ADN8834  
EXTERNAL CLOCK  
EN/SY  
SOURCE  
AGND  
Table 6. Enable Pin Combinations  
EN/SY Input  
VLIM/SD Input  
Controller  
Enabled  
>2.1 V  
>0.07 V  
Switching between high >0.07 V  
>2.1 V and low < 0.8 V  
Enabled  
ADN8834  
<0.8 V  
Floating  
No effect1  
No effect1  
Shutdown  
Shutdown  
Shutdown  
No effect1  
EN/SY  
AGND  
≤0.07 V  
1 No effect means this signal has no effect in shutting down or in enabling the  
device.  
Figure 29. Multiple ADN8834 Devices Driven from a Master Clock  
OSCILLATOR CLOCK FREQUENCY  
TEMPERATURE LOCK INDICATOR (LFCSP ONLY)  
The ADN8834 has an internal oscillator that generates a 2.0 MHz  
switching frequency for the PWM output stage. This oscillator is  
active when the enabled voltage at the EN/SY pin is set to a logic  
level higher than 2.1 V and the VLIM/SD pin voltage is greater  
than the shutdown threshold of 0.07 V.  
The TMPGD outputs logic high when the temperature error  
amplifier output voltage, VOUT1, reaches the IN2P temperature  
setpoint (TEMPSET) voltage. The TMPGD has a detection range  
between 1.46 V and 1.54 V of VOUT1 and hysteresis. The TMPGD  
function allows direct interfacing either to the microcontrollers  
or to the supervisory circuitry.  
External Clock Operation  
The PWM switching frequency of the ADN8834 can be  
synchronized to an external clock from 1.85 MHz to 3.25 MHz,  
applied to the EN/SY input pin as shown on Figure 28.  
SOFT START ON POWER-UP  
The ADN8834 has an internal soft start circuit that generates  
aramp with a typical 150 ms profile to minimize inrush current  
during power-up. The settling time and the final voltage across  
the TEC depends on the TEC voltage required by the control  
voltage of voltage loop. The higher the TEC voltage is, the longer it  
requires to be built up.  
ADN8834  
When the ADN8834 is first powered up, the linear side discharges  
the output of any prebias voltage. As soon as the prebias is  
eliminated, the soft start cycle begins. During the soft start  
cycle, both the PWM and linear outputs track the internal soft  
start ramp until they reach midscale, where the control voltage,  
VC, is equal to the bias voltage, VB. From the midscale voltage,  
the PWM and linear outputs are then controlled by VC and  
diverge from each other until the required differential voltage is  
developed across the TEC or the differential voltage reaches the  
voltage limit. The voltage developed across the TEC depends on  
the control point at that moment in time. Figure 30 shows an  
example of the soft start in cooling mode. Note that, as both the  
LDR and SFB voltages increase with the soft start ramp and  
EXTERNAL CLOCK  
EN/SY  
SOURCE  
AGND  
Figure 28. Synchronize to an External Clock  
Rev. A | Page 15 of 27  
 
 
 
 
 
 
 
ADN8834  
Data Sheet  
approach VB, the ramp slows down to avoid possible current  
Using a Resistor Divider to Set the TEC Voltage Limit  
overshoot at the point where the TEC voltage starts to build up.  
Separate voltage limits are set using a resistor divider. The  
internal current sink circuitry connected to VLIM/SD draws a  
current when the ADN8834 drives the TEC in a heating direction,  
which lowers the voltage at VLIM/SD. The current sink is not  
active when the TEC is driven in a cooling direction; therefore,  
the TEC heating voltage limit is always lower than the cooling  
voltage limit.  
LDR  
REACH  
VOLTAGE LIMIT  
SFB  
TEC VOLTAGE  
BUILDS UP  
V
B
DISCHARGE  
PREBIAS  
SOFT START  
BEGINS  
TIME  
TEC VOLTAGE  
Figure 30. Soft Start Profile in Cooling Mode  
CLK  
LIMIT AND  
INTERNAL  
SOFT START  
TEC VOLTAGE/CURRENT MONITOR  
HEATING  
The TEC real-time voltage and current are detectable at VTEC  
and ITEC, respectively.  
V
REF  
DISABLE  
Voltage Monitor  
R
R
V1  
10µA  
VLIMH  
VTEC is an analog voltage output pin with a voltage proportional  
to the actual voltage across the TEC. A center VTEC voltage of  
1.25 V corresponds to 0 V across the TEC. Convert the voltage  
at VTEC and the voltage across the TEC using the following  
equation:  
VLIM/SD  
SW OPEN = V  
SW CLOSED = V  
VLIMC  
V2  
Figure 31. Using a Resistor Divider to Set the TEC Voltage Limit  
V
VTEC = 1.25 V + 0.25 × (VLDR VSFB  
)
Calculate the cooling and heating limits using the following  
equations:  
Current Monitor  
ITEC is an analog voltage output pin with a voltage proportional  
to the actual current through the TEC. A center ITEC voltage of  
1.25 V corresponds to 0 A through the TEC. Convert the  
voltage at ITEC and the current through the TEC using the  
following equations:  
V
VLIM_COOLING = VREF × RV2/(RV1 +RV2)  
where VREF = 2.5 V.  
V
VLIM_HEATING = VVLIM_COOLING ISINK_VLIM × RV1||RV2  
where ISINK_VLIM = 10 μA.  
V
ITEC_COOLING = 1.25 V + ILDR × RCS  
where the current sense gain (RCS) is 0.525 V/A.  
ITEC_HEATING = 1.25 V − ILDR × RCS  
V
TEC_MAX_COOLING = VVLIM_COOLING × AVLIM  
where AVLIM = 2 V/V.  
V
V
TEC_MAX_HEATING = VVLIM_HEATING × AVLIM  
MAXIMUM TEC VOLTAGE LIMIT  
The maximum TEC voltage is set by applying a voltage divider  
at the VLIM/SD pin to protect the TEC. The voltage limiter  
operates bidirectionally and allows the cooling limit to be  
different from the heating limit.  
Rev. A | Page 16 of 27  
 
 
 
Data Sheet  
ADN8834  
1.25 V VILIM _ HEATING  
MAXIMUM TEC CURRENT LIMIT  
ITEC _ MAX _ HEATING  
RCS  
To protect the TEC, separate maximum TEC current limits in  
cooling and heating directions are set by applying a voltage  
combination at the ILIM pin.  
VILIM_HEATING must not exceed 1.2 V and VILIM_COOLING must be  
more than 1.3 V to leave proper margins between the heating  
and the cooling modes.  
Using a Resistor Divider to Set the TEC Current Limit  
The internal current sink circuitry connected to ILIM draws a  
40 μA current when the ADN8834 drives the TEC in a cooling  
direction, which allows a high cooling current. Use the following  
equations to calculate the maximum TEC currents:  
VDD  
40µA  
V
REF  
COOLING  
V
ILIM_HEATING = VREF × RC2/(RC1 +RC2)  
R
R
C1  
+
ITEC  
where VREF = 2.5 V.  
ILIM  
TEC  
CURRENT  
LIMIT  
V
ILIM_COOLING= VILIM_HEATING + ISINK_ILIM × RC1||RC2  
C2  
SW OPEN = V  
SW CLOSED = V  
ILIMH  
where ISINK_ILIM = 40 μA.  
ILIMC  
V
ILIM _COOLING 1.25 V  
ITEC _ MAX _COOLING  
Figure 32. Using a Resistor Divider to Set the TEC Current Limit  
RCS  
where RCS = 0.525 V/A.  
Rev. A | Page 17 of 27  
 
ADN8834  
Data Sheet  
APPLICATIONS INFORMATION  
TEC DRIVER  
LINEAR POWER  
STAGE  
V
IN  
PVIN  
+
TEC CURRENT SENSE  
LDR  
LDR  
+
TEMPERATURE ERROR  
AMPLIFIER  
PID COMPENSATION  
AMPLIFIER  
LINEAR  
AMPLIFIER  
PGNDL  
PGNDL  
TEC  
+
A
= R /(R + R ) – R /R  
FB TH FB  
A = Z2/Z1  
V
V
X
CHOPPER 1  
CHOPPER 2  
IN2P  
IN1P  
SFB  
OUT2  
OUT1  
CONTROL  
IN1N  
IN2N  
V
IN  
PWM POWER  
STAGE  
PVIN  
PWM  
MODULATOR  
PWM  
MOSFET  
DRIVER  
SW  
OSCILLATOR  
PGNDS  
PGNDS  
V
R
REF  
V
V
/2  
TEMPSET  
REF  
Z
1
Z
2
R
FB  
R
X
V
V
OUT2  
OUT1  
R
TH  
Figure 33. Signal Flow Block Diagram  
SIGNAL FLOW  
THERMISTOR SETUP  
The ADN8834 integrates two auto-zero amplifiers, defined as  
the Chopper 1 amplifier and the Chopper 2 amplifier. Both of the  
amplifiers can be used as standalone amplifiers; therefore, the  
implementation of temperature control can vary. Figure 33  
shows the signal flow through the ADN8834, and a typical  
implementation of the temperature control loop using the  
Chopper 1 amplifier and the Chopper 2 amplifier.  
The thermistor has a nonlinear relationship to temperature; near  
optimal linearity over a specified temperature range can be achieved  
with the proper value of RX placed in series with the thermistor.  
First, the resistance of the thermistor must be known, where  
RLOW = RTH at TLOW  
RMID = RTH at TMID  
RHIGH = RTH at THIGH  
In Figure 33, the Chopper 1 and Chopper 2 amplifiers are config-  
ured as the thermistor input amplifier and the PID compensation  
amplifier, respectively. The thermistor input amplifier gains the  
thermistor voltage, then outputs to the PID compensation amplifier.  
The PID compensation amplifier then compensates a loop  
response over the frequency domain.  
TLOW and THIGH are the endpoints of the temperature range and  
MID is the average. In some cases, with only the β constant  
available, calculate RTH using the following equation:  
T
1
T
1
TR  
RTH = R exp β  
R
The output from the compensation loop at OUT2 is fed to the linear  
MOSFET gate driver. The voltage at LDR is fed with OUT2 into  
the PWM MOSFET gate driver. Including the internal transistors,  
the gain of the differential output section is fixed at 5. For details  
on the output drivers, see the MOSFET Driver Amplifier section.  
where:  
TH is a resistance at T (K).  
RR is a resistance at TR (K).  
R
Rev. A | Page 18 of 27  
 
 
 
 
Data Sheet  
ADN8834  
Calculate RX using the following equation:  
values is to input a step function to IN2P; thus changing the target  
temperature, and adjust the compensation network to minimize  
the settling time of the TEC temperature.  
RLOW RMID RMID RHIGH 2RLOW RHIGH  
RLOW RHIGH 2RMID  
RX  
A typical compensation network for temperature control of a laser  
module is a PID loop consisting of a very low frequency pole and  
two separate zeros at higher frequencies. Figure 35 shows a simple  
network for implementing PID compensation. To reduce the noise  
sensitivity of the control loop, an additional pole is added at a higher  
frequency than that of the zeros. The bode plot of the magnitude is  
shown in Figure 36. Use the following equation to calculate the  
unity-gain crossover frequency of the feed-forward amplifier:  
THERMISTOR AMPLIFIER (CHOPPER 1)  
The Chopper 1 amplifier can be used as a thermistor input  
amplifier. In Figure 33, the output voltage is a function of the  
thermistor temperature. The voltage at OUT1 is expressed as:  
RFB  
RTH RX  
RFB  
R
VREF  
2
VOUT1  
1   
where:  
TH is a thermistor.  
RX is a compensation resistor.  
FB   
RFB  
TH RX  
R
R
1
f
0dB   
TECGAIN  
R
RICI  
R
To ensure stability, the unity-gain crossover frequency must be  
lower than the thermal time constant of the TEC and thermistor.  
However, this thermal time constant is sometimes unspecified,  
making it difficult to characterize. There are many texts written  
on loop stabilization, and it is beyond the scope of this data sheet to  
discuss all methods and trade-offs for optimizing compensation  
networks.  
Calculate R using the following equation:  
R = RX + RTH_@_25°C  
VOUT1 is centered around VREF/2 at 25°C. An average temperature-  
to-voltage coefficient is −25 mV/°C at a range of 5°C to 45°C.  
2.5  
V
OUT1 is a convenient measure to gauge the thermal instability of  
2.0  
1.5  
1.0  
0.5  
0
the system, which is also known as TEMPOUT. If the thermal loop  
is in steady state, the TEMPOUT voltage equals the TEMPSET  
voltage, meaning that the temperature of the controlled object  
equals the target temperature.  
ADN8834  
CHOPPER 2  
–15  
5
25  
45  
65  
TEMPERATURE (°C)  
IN2P  
OUT1  
IN2N  
OUT2  
Figure 34. VOUT1 vs. Temperature  
C
C
I
R
R
P
I
PID COMPENSATION AMPLIFIER (CHOPPER 2)  
V
TEMPSET  
C
R
D
F
D
Use the Chopper 2 amplifier as the PID compensation amplifier.  
The voltage at OUT1 feeds into the PID compensation amplifier.  
The frequency response of the PID compensation amplifier is  
dictated by the compensation network. Apply the temperature  
set voltage at IN2P. In Figure 39, the voltage at OUT2 is  
calculated using the following equation:  
PID COMPENSATOR  
Figure 35. Implementing a PID Compensation Loop  
Z2  
Z1  
0dB  
VOUT2 VTEMPSET  
(VOUT1 VTEMPSET )  
where:  
TEMPSET is the control voltage input to the IN2P pin.  
R
P
R
|| R  
V
D
I
Z1 is the combination of RI, RD, and CD (see Figure 35).  
Z2 is the combination of RP, CI, and CF (see Figure 35).  
R
P
R
I
The user sets the exact compensation network. This network  
varies from a simple integrator to proportional-integral (PI), PID  
(proportional-integral-derivative), or any other type of network.  
The user also determines the type of compensation and component  
values because they are dependent on the thermal response of the  
object and the TEC. One method to empirically determine these  
1
1
1
1
2π × R C  
2π × R  
C
2π × C (R + R ) 2π × R C  
I
I
P
I
D D I I D  
FREQUENCY (Hz Log Scale)  
Figure 36. Bode Plot for PID Compensation  
Rev. A | Page 19 of 27  
 
 
 
 
ADN8834  
Data Sheet  
5.0  
2.5  
MOSFET DRIVER AMPLIFIERS  
V
V
= 5.0V  
= 3.3V  
SYS  
SYS  
The ADN8834 has two separate MOSFET drivers: a switched  
output or pulse-width modulated (PWM) amplifier, and a high  
gain linear amplifier. Each amplifier has a pair of outputs that drive  
the gates of the internal MOSFETs, which, in turn, drive the TEC as  
shown in Figure 33. A voltage across the TEC is monitored via  
the SFB and LDR pins. Although both MOSFET drivers achieve  
the same result, to provide constant voltage and high current,  
their operation is different. The exact equations for the two  
outputs are  
0
–2.5  
–5.0  
V
LDR = VB − 40(VOUT2 − 1.25 V)  
SFB = VLDR + 5(VOUT2 − 1.25 V)  
0
0.25  
0.75  
1.25  
1.75  
2.25  
2.75  
V
OUT2 (V)  
where:  
Figure 39. TEC Voltage vs. OUT2 Voltage  
V
OUT2 is the voltage at OUT2.  
PWM OUTPUT FILTER REQUIREMENTS  
VB is determined by VVDD as  
VB = 1.5 V for VVDD < 4.0 V  
VB = 2.5 V for VVDD > 4.0 V  
A type three compensator internally compensates the PWM  
amplifier. As the poles and zeros of the compensator are designed  
and fixed by assuming the resonance frequency of the output  
LC tank being 50 kHz, the selection of the inductor and the  
capacitor must follow this guideline to ensure system stability.  
The compensation network that receives the temperature set voltage  
and the thermistor voltage fed by the input amplifier determines  
the voltage at OUT2. VLDR and VSFB have a low limit of 0 V and  
an upper limit of VVDD. Figure 37, Figure 38, and Figure 39 show  
the graphs of these equations.  
Inductor Selection  
The inductor selection determines the inductor current ripple and  
loop dynamic response. Larger inductance results in smaller  
current ripple and slower transient response as smaller inductance  
results in the opposite performance. To optimize the performance,  
the trade-off must be made between transient response speed,  
efficiency, and component size. Calculate the inductor value  
with the following equation:  
7.5  
V
V
= 5.0V  
= 3.3V  
SYS  
SYS  
5.0  
2.5  
0
VSW _OUT  
×
(
VIN VSW _OUT  
)
L =  
VIN × fSW × ∆IL  
where:  
SW_OUT is the PWM amplifier output.  
SW is the switching frequency (2 MHz by default).  
V
f
–2.5  
∆IL is the inductor current ripple.  
0
0.25  
0.75  
1.25  
1.75  
2.25  
2.75  
OUT2 (V)  
A 1 µH inductor is typically recommended to allow reasonable  
output capacitor selection while maintaining a low inductor current  
ripple. If lower inductance is required, a minimum inductor value  
of 0.68 µH is suggested to ensure that the current ripple is set to  
a value between 30% and 40% of the maximum load current,  
which is 1.5 A.  
Figure 37. LDR Voltage vs. OUT2 Voltage  
7.5  
5.0  
2.5  
0
V
V
= 5.0V  
= 3.3V  
SYS  
SYS  
Except for the inductor value, the equivalent dc resistance (DCR)  
inherent in the metal conductor is also a critical factor for  
inductor selection. The DCR accounts for most of the power loss  
on the inductor by DCR × IOUT2. Using an inductor with high  
DCR degrades the overall efficiency significantly. In addition,  
there is a conduct voltage drop across the inductor because of  
the DCR. When the PWM amplifier is sinking current in cooling  
mode, this voltage drives the minimum voltage of the amplifier  
higher than 0.06 × VIN by at least tenth of millivolts. Similarly, the  
maximum PWM amplifier output voltage is lower than 0.93 × VIN.  
–2.5  
0
0.25  
0.75  
1.25  
1.75  
2.25  
2.75  
OUT2 (V)  
Figure 38. SFB Voltage vs. OUT2 Voltage  
Rev. A | Page 20 of 27  
 
 
 
 
 
Data Sheet  
ADN8834  
This voltage drop is proportional to the value of the DCR and it  
reduces the output voltage range at the TEC.  
POWER DISSIPATION  
This section provides guidelines to calculate the power  
dissipation of the ADN8834. Approximate the total power  
dissipation in the device by  
When selecting an inductor, ensure that the saturation current  
rating is higher than the maximum current peak to prevent sat-  
uration. In general, ceramic multilayer inductors are suitable for low  
current applications due to small size and low DCR. When the  
noise level is critical, use a shielded ferrite inductor to reduce the  
electromagnetic interference (EMI).  
P
LOSS = PPWM + PLINEAR  
where:  
P
P
LOSS is the total power dissipation in the ADN8834.  
LINEAR is the power dissipation in the linear regulator.  
Table 7. Recommended Inductors  
PWM Regulator Power Dissipation  
Vendor Value  
Device No.  
Footprint  
The PWM power stage is configured as a buck regulator and  
its dominant power dissipation (PPWM) includes power switch  
conduction losses (PCOND), switching losses (PSW), and transition  
losses (PTRAN). Other sources of power dissipation are usually  
less significant at the high output currents of the application  
thermal limit and can be neglected in approximation.  
Toko  
1.0 µH 20%,  
2.6 A (typical)  
1.0 µH 20%,  
2.2 A (typical)  
1.0 µH 20%,  
2.3 A (typical)  
DFE201612R-H-1R0M  
2.0 × 1.6  
Taiyo  
Yuden  
Murata  
MAKK2016T1R0M  
LQM2MPN1R0MGH  
2.0 × 1.6  
2.0 × 1.6  
Use the following equation to estimate the power dissipation of  
the buck regulator:  
Capacitor Selection  
The output capacitor selection determines the output voltage  
ripple, transient response, as well as the loop dynamic response  
of the PWM amplifier output. Use the following equation to  
select the capacitor:  
P
LOSS = PCOND + PSW + PTRAN  
Conduction Loss (PCOND  
)
The conduction loss consists of two parts: inductor conduction  
loss (PCOND_L) and power switch conduction loss (PCOND_S).  
VSW _ OUT  
×
(
VIN VSW _ OUT  
)
C =  
V
IN ×8× L ×( fSW )2 × ∆VOUT  
PCOND = PCOND_L + PCOND_S  
Note that the voltage caused by the product of current ripple,  
ΔIL, and the capacitor equivalent series resistance (ESR) also  
add up to the total output voltage ripple. Selecting a capacitor  
with low ESR can increase overall regulation and efficiency  
performance.  
Inductor conduction loss is proportional to the DCR of the output  
inductor, L. Using an inductor with low DCR enhances the overall  
efficiency performance. Estimate inductor conduction loss by  
2
P
COND_L = DCR × IOUT  
Power switch conduction losses are caused by the flow of the  
output current through both the high-side and low-side power  
switches, each of which has its own internal on resistance (RDSON).  
Table 8. Recommended Capacitors  
Footprint  
(mm)  
Vendor Value  
Device No.  
Use the following equation to estimate the amount of power  
switch conduction loss:  
Murata 10 µF  
ZRB18AD71A106KE01L  
1.6 × 0.8  
10%, 10 V  
Murata 10 µF  
20%, 10 V  
10 µF  
20%, 10 V  
2
P
COND_S = (RDSON_HS × D + RDSON_LS × (1 − D)) × IOUT  
where:  
DSON_HS is the on resistance of the high-side MOSFET.  
D is the duty cycle (D = VOUT/VIN).  
DSON_LS is the on resistance of the low-side MOSFET.  
GRM188D71A106MA73 1.6 × 0.8  
LMK107BC6106MA-T 1.6 × 0.8  
Taiyo  
Yuden  
R
R
INPUT CAPACITOR SELECTION  
On the PVIN pin, the amplifiers require an input capacitor  
to decouple the noise and to provide the transient current to  
maintain a stable input and output voltage. A 10 µF ceramic  
capacitor rated at 10 V is the minimum recommended value.  
Increasing the capacitance reduces the switching ripple that  
couples into the power supply but increases the capacitor size.  
Because the current at the input terminal of the PWM amplifier  
is discontinuous, a capacitor with low effective series inductance  
(ESL) is preferred to reduce voltage spikes.  
In most applications, a decoupling capacitor is used in parallel  
with the input capacitor. The decoupling capacitor is usually a  
100 nF ceramic capacitor with very low ESR and ESL, which  
provides better noise rejection at high frequency bands.  
Rev. A | Page 21 of 27  
 
 
ADN8834  
Data Sheet  
Use the following equation to estimate the transition loss:  
TRAN = 0.5 × VIN × IOUT × (tR + tF) × fSW  
Switching Loss (PSW)  
P
Switching losses are associated with the current drawn by the  
controller to turn the power devices on and off at the switching  
frequency. Each time a power device gate is turned on or off,  
the controller transfers a charge from the input supply to the  
gate, and then from the gate to ground. Use the following  
equation to estimate the switching loss:  
where:  
tR is the rise time of the switch node.  
tF is the fall time of the switch node.  
For the ADN8834, tR and tF are both approximately 1 ns.  
Linear Regulator Power Dissipation  
P
SW = (CGATE_HS + CGATE_LS) × VIN2 × fSW  
The power dissipation of the linear regulator is given by the  
following equation:  
where:  
C
C
GATE_HS is the gate capacitance of the high-side MOSFET.  
GATE_LS is the gate capacitance of the low-side MOSFET.  
P
LINEAR = [(VIN VOUT) × IOUT] + (VIN × IGND  
where:  
IN and VOUT are the input and output voltages of the linear  
regulator.  
)
f
SW is the switching frequency.  
V
For the ADN8834, the total of (CGATE_HS + CGATE_LS) is  
approximately 1 nF.  
IOUT is the load current of the linear regulator.  
Transition Loss (PTRAN  
)
IGND is the ground current of the linear regulator.  
Transition losses occur because the high-side MOSFET cannot  
turn on or off instantaneously. During a switch node transition,  
the MOSFET provides all the inductor current. The source-to-  
drain voltage of the MOSFET is half the input voltage, resulting  
in power loss. Transition losses increase with both load and input  
voltage and occur twice for each switching cycle.  
Power dissipation due to the ground current is generally small  
and can be ignored for the purposes of this calculation.  
Rev. A | Page 22 of 27  
Data Sheet  
ADN8834  
PCB LAYOUT GUIDELINES  
SOURCE OF  
ELECTRICAL  
POWER  
TEC  
VOLTAGE  
LIMITING  
TEC  
VOLTAGE  
SENSING  
OBJECT  
TEMPERATURE  
ERROR  
COMPENSATION  
THERMOELECTRIC  
COOLER  
TARGET  
TEMPERATURE  
TEC  
DRIVER  
TEMPERATURE  
SENSOR  
(TEC)  
TEC  
CURRENT  
LIMITING  
TEC  
CURRENT  
SENSING  
TEMPERATURE  
SIGNAL  
CONDITIONING  
Figure 40. System Block Diagram  
To prevent noise signal from circulating through ground plates,  
reference all of the sensitive analog signals to AGND and connect  
AGND to PGNDS using only a single point connection. This  
ensures that the switching currents of the power stage do not  
flow into the sensitive AGND node.  
BLOCK DIAGRAMS AND SIGNAL FLOW  
The ADN8834 integrates analog signal conditioning blocks, a  
load protection block, and a TEC controller power stage all in a  
single IC. To achieve the best possible circuit performance,  
attention must be paid to keep noise of the power stage from  
contaminating the sensitive analog conditioning and protection  
circuits. In addition, the layout of the power stage must be  
performed such that the IR losses are minimized to obtain the  
best possible electrical efficiency.  
PWM Power Stage Layout Guidelines  
The PWM power stage consists of a MOSFET pair that forms a  
switch mode output that switches current from PVIN to the load  
via an LC filter. The ripple voltage on the PVIN pin is caused by  
the discontinuous current switched by the PWM side MOSFETs.  
This rapid switching causes voltage ripple to form at the PVIN  
input, which must be filtered using a bypass capacitor. Place a 10 μF  
capacitor as close as possible to the PVIN pin to connect PVIN to  
PGNDS. Because the 10 μF capacitor is sometimes bulky and has  
higher ESR and ESL, a 100 nF decoupling capacitor is usually  
used in parallel with it, placed between PVIN and PGNDS.  
The system block diagram of the ADN8834 is shown in Figure 40.  
GUIDELINES FOR REDUCING NOISE AND  
MINIMIZING POWER LOSS  
Each printed circuit board (PCB) layout is unique because of  
the physical constraints defined by the mechanical aspects of a  
given design. In addition, several other circuits work in conjunction  
with the TEC controller; these circuits have their own layout  
requirements, so there are always compromises that must be  
made for a given system. However, to minimize noise and keep  
power losses to a minimum during the PCB layout process,  
observe the following guidelines.  
Because the decoupling is part of the pulsating current loop,  
which carries high di/dt signals, the traces must be short and  
wide to minimize the parasitic inductance. As a result, this  
capacitor is usually placed on the same side of the board as the  
ADN8834 to ensure short connections. If the layout requires  
that a 10 μF capacitor be on the opposite side of the PCB, use  
multiple vias to reduce via impedance.  
General PCB Layout Guidelines  
Switching noise can interfere with other signals in the system;  
therefore, the switching signal traces must be placed away from  
the power stage to minimize the effect. If possible, place the  
ground plate between the small signal layer and power stage  
layer as a shield.  
The layout around the SW node is also critical because it switches  
between PVIN and ground rapidly, which makes this node a  
strong EMI source. Keep the copper area that connects the SW  
node to the inductor small to minimize parasitic capacitance  
between the SW node and other signal traces. This helps minimize  
noise on the SW node due to excessive charge injection. However,  
in high current applications, the copper area may be increased  
reasonably to provide heat sink and to sustain high current flow.  
Supply voltage drop on traces is also an important consideration  
because it determines the voltage headroom of the TEC controller  
at high currents. For example, if the supply voltage from the front-  
end system is 3.3 V, and the voltage drop on the traces is 0.5 V,  
PVIN sees only 2.8 V, which limits the maximum voltage of the  
linear regulator as well as the maximum voltage across the TEC. To  
mitigate the voltage waste on traces and impedance interconnec-  
tion, place the ADN8834 and the input decoupling components  
close to the supply voltage terminal. This placement not only  
improves the system efficiency but also provides better regulation  
performance at the output.  
Connect the ground side of the capacitor in the LC filter as close as  
possible to PGNDS to minimize the ESL in the return path.  
Rev. A | Page 23 of 27  
 
 
 
 
ADN8834  
Data Sheet  
Linear Power Stage Layout Guidelines  
Place the thermistor conditioning and PID circuit components  
close to each other near the inputs of Chopper 1 and Chopper 2.  
Avoid crossing paths between the amplifier circuits and the  
power stages to prevent noise pickup on the sensitive nodes.  
Always reference the thermistor to AGND to have the cleanest  
connection to the amplifier input and to avoid any noise or  
offset build up.  
The linear power stage consists of a MOSFET pair that forms a  
linear amplifier, which operates in linear mode for very low output  
currents, and changes to fully enhanced mode for greater  
output currents.  
Because the linear power stage does not switch currents rapidly  
like the PWM power stage, it does not generate noise currents.  
However, the linear power stage still requires a minimum  
amount of bypass capacitance to decouple its input.  
EXAMPLE PCB LAYOUT USING TWO LAYERS  
Figure 41, Figure 42, and Figure 43 show an example ADN8834  
PCB layout that uses two layers. This layout example achieves a  
small solution size of approximately 20 mm2 with all of the  
conditioning circuitry and PID included. Using more layers and  
blinds via allows the solution size to be reduced even further  
because more of the discrete components can relocate to the  
bottom side of the PCB.  
Place a 100 nF capacitor that connects from PVIN to PGNDL as  
close as possible to the PVIN pin.  
Placing the Thermistor Amplifier and PID Components  
The thermistor conditioning and PID compensation amplifiers  
work with very small signals and have gain; therefore, attention  
must be paid when placing the external components with these  
circuits.  
0
RX  
CD  
CF  
NTC  
0201  
0201  
0201  
CI  
AGND  
0.5  
1.0  
1.5  
0402  
RI  
0201  
RP  
0201  
R
0201  
PGND  
TEMPSET  
ITEC  
CONNECT TO GROUND PLANE  
RA  
0201  
PGNDL  
PGNDL  
OUT 1  
IN1N  
ITEC  
VTEC  
SFB  
IN1P  
IN2N  
IN2P  
RB  
0201  
VLIM /  
SD  
TEC+  
LR  
LDR  
RV1  
0201  
TEC–  
CINL  
2.0  
2.5  
3.0  
3.5  
4.0  
PVIN  
PVIN  
OUT 2  
EN/SY  
AGND  
ILIM  
RV2  
0201  
VIN  
RC1  
0201  
VDD  
VTEC  
CINS  
RC2  
0201  
CVDD  
PGNDS  
PGNDS  
VREF  
CONNECT AGND  
RBP  
TO PGNDS ONLY AT A  
SINGLE POINT AS A  
STAR CONNECTION  
CVREF  
0201  
CSW_OUT  
0402  
CONNECT TO GROUND PLANE  
Figure 41. Example PCB Layout Using Two Layers (Top and Bottom Layers)  
Rev. A | Page 24 of 27  
 
 
Data Sheet  
ADN8834  
Figure 42. Example PCB Layout Using Two Layers (Top Layer Only)  
Rev. A | Page 25 of 27  
 
ADN8834  
Data Sheet  
0
NTC  
AGND  
0.5  
1.0  
1.5  
2.0  
2.5  
3.0  
3.5  
4.0  
PGND  
TEMPSET  
ITEC  
CONNECT TO GROUND PLANE  
TEC+  
CIN_L  
TEC–  
VIN  
VTEC  
CIN_S  
CVDD  
RBP  
CONNECT TO GROUND PLANE  
Figure 43. Example PCB Layout Using Two Layers (Bottom Layer Only)  
Rev. A | Page 26 of 27  
 
Data Sheet  
ADN8834  
OUTLINE DIMENSIONS  
2.58  
2.54 SQ  
2.50  
BOTTOM VIEW  
(BALL SIDE UP)  
5
4
3
2
1
A
B
C
D
E
BALL A1  
IDENTIFIER  
2.00  
REF  
0.50  
BSC  
TOP VIEW  
(BALL SIDE DOWN)  
0.390  
0.360  
0.330  
0.660  
0.600  
0.540  
END VIEW  
COPLANARITY  
0.05  
0.270  
0.240  
0.210  
SEATING  
PLANE  
0.360  
0.320  
0.280  
Figure 44. 25-Ball Wafer Level Chip Scale Package [WLCSP]  
(CB-25-7)  
Dimensions shown in millimeters  
4.10  
0.30  
4.00 SQ  
0.25  
3.90  
PIN 1  
INDICATOR  
0.18  
PIN 1  
INDICATOR  
24  
19  
1
18  
0.50  
BSC  
2.70  
2.60 SQ  
2.50  
EXPOSED  
PAD  
13  
6
12  
7
0.50  
0.40  
0.30  
0.20 MIN  
TOP VIEW  
BOTTOM VIEW  
FOR PROPER CONNECTION OF  
THE EXPOSED PAD, REFER TO  
THE PIN CONFIGURATION AND  
FUNCTION DESCRIPTIONS  
0.80  
0.75  
0.70  
0.05 MAX  
0.02 NOM  
SECTION OF THIS DATA SHEET.  
COPLANARITY  
0.08  
0.20 REF  
SEATING  
PLANE  
COMPLIANT TO JEDEC STANDARDS MO-220-WGGD-8.  
Figure 45. 24-Lead Lead-frame Chip Scale Package [LFCSP_WQ]  
(CP-24-15)  
Dimensions shown in millimeters  
ORDERING GUIDE  
Package  
Option  
Model1  
Temperature Range2 Package Description  
ADN8834ACBZ-R7  
ADN8834CB-EVALZ  
ADN8834ACPZ-R2  
ADN8834ACPZ-R7  
ADN8834CP-EVALZ  
ADN8834MB-EVALZ  
−40°C to +125°C  
25-Ball Wafer Level Chip Scale Package [WLCSP]  
25-Ball WLCSP Evaluation Board: 1.5 A TEC Current Limit, 3 V TEC Voltage Limit  
24-Lead Lead Frame Chip Scale Package [LFCSP_WQ]  
24-Lead Lead Frame Chip Scale Package [LFCSP_WQ]  
24-Lead LFCSP Evaluation Board: 1.5 A TEC Current Limit, 3 V TEC Voltage Limit  
Mother Evaluation Board of the ADN8834 for PID tuning  
CB-25-7  
−40°C to +125°C  
−40°C to +125°C  
CP-24-15  
CP-24-15  
1 Z = RoHS Compliant Part.  
2 Operating junction temperature range. The ambient operating temperature range is −40°C to +85°C.  
©2015 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D12954-0-8/15(A)  
Rev. A | Page 27 of 27  
 
 

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