19-2490; Rev 0; 7/02
KIT
ATION
EVALU
BLE
AVAILA
Integrated Temperature
Controllers for Peltier Modules
General Description
Features
o
Smallest, Safest, Most Accurate Complete
Single-Chip Controller
o
On-Chip Power MOSFETS—No External FETs
o
Circuit Footprint < 0.93in
2
o
Circuit Height < 3mm
o
Temperature Stability to 0.001°C
o
Integrated Precision Integrator and Chopper
Stabilized Op Amps
o
Accurate, Independent Heating and Cooling
Current Limits
o
Eliminates Surges By Directly Controlling
TEC Current
o
Adjustable Differential TEC Voltage Limit
o
Low-Ripple and Low-Noise Design
o
TEC Current Monitor
o
Temperature Monitor
o
Over- and Undertemperature Alarm
o
Bipolar ±3A Output Current (MAX1978)
o
Unipolar +6A Output Current (MAX1979)
MAX1978/MAX1979
The MAX1978/MAX1979 are the smallest, safest, most
accurate complete single-chip temperature controllers for
Peltier thermoelectric cooler (TEC) modules. On-chip power
FETs and thermal control-loop circuitry minimize external
components while maintaining high efficiency. Selectable
500kHz/1MHz switching frequency and a unique ripple-can-
cellation scheme optimize component size and efficiency
while reducing noise. Switching speeds of internal
MOSFETs are optimized to reduce noise and EMI. An ultra-
low-drift chopper amplifier maintains ±0.001°C temperature
stability. Output current, rather than voltage, is directly con-
trolled to eliminate current surges. Individual heating and
cooling current and voltage limits provide the highest level of
TEC protection.
The MAX1978 operates from a single supply and provides
bipolar ±3A output by biasing the TEC between the outputs
of two synchronous buck regulators. True bipolar operation
controls temperature without “dead zones” or other nonlin-
earities at low load currents. The control system does not
hunt when the set point is very close to the natural operating
point, where only a small amount of heating or cooling is
needed. An analog control signal precisely sets the TEC
current. The MAX1979 provides unipolar output up to 6A.
A chopper-stabilized instrumentation amplifier and a high-
precision integrator amplifier are supplied to create a pro-
portional-integral (PI) or proportional-integral-derivative (PID)
controller. The instrumentation amplifier can interface to an
external NTC or PTC thermistor, thermocouple, or semicon-
ductor temperature sensor. Analog outputs are provided to
monitor TEC temperature and current. In addition, separate
overtemperature and undertemperature outputs indicate
when the TEC temperature is out of range. An on-chip volt-
age reference provides bias for a thermistor bridge.
The MAX1978/MAX1979 are available in a low-profile
48-lead thin QFN-EP package and is specified over the
-40°C to +85°C temperature range. The thermally
enhanced QFN-EP package with exposed metal pad
minimizes operating junction temperature. An evaluation
kit is available to speed designs.
Ordering Information
PART
MAX1978ETM
MAX1979ETM
*EP
= Exposed pad.
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
48 Thin QFN-EP*
48 Thin QFN-EP
Pin Configuration
MAXV
MAXIN
CTLI
V
DD
GND
GND
48
47
46
CS
REF
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
ITEC
OS1
TOP VIEW
MAXIP
COMP
Applications
Fiber Optic Laser Modules
WDM, DWDM Laser-Diode Temperature Control
Fiber Optic Network Equipment
EDFA Optical Amplifiers
Telecom Fiber Interfaces
ATE
Typical Operating Circuit appears at end of data sheet.
OS2
N.C.
PGND2
LX2
PGND2
LX2
PV
DD
2
N.C.
LX2
PV
DD
2
SHDN
OT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
FREQ
N.C.
PGND1
LX1
PGND1
LX1
PV
DD
1
N.C.
LX1
PV
DD
1
GND
GND
MAX1978
MAX1979
INT-
GND
DIFOUT
FB-
FB+
BFB-
BFB+
INTOUT
QFN-EP
*ELECTRICALLY CONNECTED TO THE UNDERSIDE METAL SLUG.
NOTE:
GND IS CONNECTED TO THE UNDERSIDE METAL SLUG.
________________________________________________________________
Maxim Integrated Products
AIN+
AIN-
AOUT
UT
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Integrated Temperature
Controllers for Peltier Modules
MAX1978/MAX1979
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND ..............................................................-0.3V to +6V
SHDN,
MAXV, MAXIP, MAXIN,
CTLI,
OT, UT
to GND............................................-0.3V to +6V
FREQ, COMP, OS1, OS2, CS, REF, ITEC, AIN+, AIN-,
AOUT, INT-, INTOUT, BFB+, BFB-, FB+, FB-,
DIFOUT to GND......................................-0.3V to (V
DD
+ 0.3V)
PV
DD
1, PV
DD
2 to V
DD
...........................................-0.3V to +0.3V
PV
DD
1, PV
DD
2 to GND...............................-0.3V to (V
DD
+ 0.3V)
PGND1, PGND2 to GND .......................................-0.3V to +0.3V
COMP, REF, ITEC,
OT, UT,
INTOUT, DIFOUT,
BFB-, BFB+, AOUT Short to GND .............................Indefinite
Peak LX Current (MAX1978) (Note 1).................................±4.5A
Peak LX Current (MAX1979) (Note 1)....................................+9A
Continuous Power Dissipation (T
A
= +70°C)
48-Lead Thin QFN-EP
(derate 26.3mW/°C above +70°C) (Note 2) .................2.105W
Operating Temperature Ranges
MAX1978ETM ..................................................-40°C to +85°C
MAX1979ETM ..................................................-40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1:
LX has internal clamp diodes to PGND and PV
DD
. Applications that forward bias these diodes should not exceed the IC’s
package power dissipation limits.
Note 2:
Solder underside metal slug to PC board ground plane.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
DD
= PV
DD
1 = PV
DD
2 =
SHDN
= 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values at T
A
= +25°C.)
PARAMETER
Input Supply Range
SYMBOL
V
DD
V
DD
= 5V, I
TEC
= 0 to ±3A,
V
OUT
= V
OS1
- V
OS2
(MAX1978)
V
DD
= 5V, I
TEC
= 0 to 6A,
V
OUT
= V
OS1
(MAX1979)
V
DD
= 3V, I
TEC
= 0 to ±3A,
V
OUT
= V
OS1
- V
OS2
(MAX1978)
V
DD
= 3V, I
TEC
= 0 to 6A,
V
OUT
= V
OS1
(MAX1979)
Maximum TEC Current
Reference Voltage
Reference Load Regulation
I
TEC(MAX)
V
REF
∆V
REF
MAX1978
MAX1979
V
DD
= 3V to 5.5V, I
REF
= 150µA
V
DD
= 3V to 5.5V, I
REF
= +10µA to -1mA
V
OS1
< V
CS
Current-Sense Threshold
V
OS1
> V
CS
NFET On-Resistance
PFET On-Resistance
NFET Leakage
R
DS(ON-N)
R
DS(ON-P)
I
LEAK(N)
V
DD
= 5V, I = 0.5A
V
DD
= 3V, I = 0.5A
V
DD
= 5V, I = 0.5A
V
DD
= 3V, I = 0.5A
V
LX
= V
DD
= 5V, T
A
= +25°C
V
LX
= V
DD
= 5V, T
A
= +85°C
V
MAXI_
= V
REF
V
MAXI_
= V
REF
/3
V
MAXI_
= V
REF
V
MAXI_
= V
REF
/3
135
40
135
40
1.485
1.500
1.2
150
50
150
50
0.04
0.06
0.06
0.09
0.02
1
-2.3
CONDITIONS
MIN
3.0
-4.3
TYP
MAX
5.5
+4.3
4.3
V
+2.3
2.3
±3
6
1.515
5
160
60
160
60
0.07
0.08
0.10
0.12
10
Ω
Ω
µA
mV
A
V
mV
UNITS
V
Output Voltage Range
V
OUT
2
_______________________________________________________________________________________
Integrated Temperature
Controllers for Peltier Modules
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
1 = PV
DD
2 =
SHDN
= 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values at T
A
= +25°C.)
PARAMETER
PFET Leakage
No-Load Supply Current
Shutdown Supply Current
Thermal Shutdown
UVLO Threshold
Switching Frequency Internal
Oscillator
OS1, OS2, CS Input Current
SHDN,
FREQ Input Current
SHDN,
FREQ Input Low Voltage
SHDN,
FREQ Input High Voltage
SYMBOL
I
LEAK(P)
I
DD(NO
LOAD)
MAX1978/MAX1979
CONDITIONS
V
LX
= 0, T
A
= +25°C
V
LX
= 0, T
A
= +85°C
V
DD
= 5V
V
DD
= 3.3V
SHDN
= GND, V
DD
= 5V (Note 3)
V
DD
rising
V
DD
falling
FREQ = GND
FREQ=V
DD
0 or V
DD
0 or V
DD
V
DD
= 3V to 5.5V
V
DD
= 3V to 5.5V
V
MAXV
= V
REF
✕
0.67,
V
OS1
to V
OS2
= ±4V, V
DD
= 5V
V
MAXV
= V
REF
✕
0.33,
V
OS1
to V
OS2
= ±2V, V
DD
= 3V
MIN
TYP
0.02
1
30
15
2
165
MAX
10
50
30
3
2.8
2.75
650
1200
+100
+5
0.25
×
V
DD
UNITS
µA
mA
mA
°C
V
kHz
µA
µA
V
V
I
DD-SD
T
SHUTDOWN
Hysteresis = 15°C
V
UVLO
f
SW-INT
I
OS1
, I
OS2
,
I
CS
I
SHDN
,
I
FREQ
V
IL
V
IH
2.4
2.25
450
800
-100
-5
2.6
2.5
500
1000
0.75
×
V
DD
-1
-2
-0.1
9.5
0.5
50
-10
-0.1
-10
0
+20
0.1
45
50
55
10
1.0
100
+1
MAXV Threshold Accuracy
%
+2
+0.1
10.5
2.0
175
+10
+0.1
+10
+200
µA
V/V
MΩ
µS
%
%
nA
µV
µV/°C
V/V
MAXV, MAXIP, MAXIN
Input Bias Current
CTLI Gain
CTLI Input Resistance
Error Amp Transconductance
ITEC Accuracy
ITEC Load Regulation
Instrumentation Amp Input Bias
Current
Instrumentation Amp Offset
Voltage
Instrumentation Amp Offset-
Voltage Drift with Temperature
Instrumentation Amp Preset
Gain
I
MAXV-BIAS
,
V
MAXV
= V
MAXI_
= 0.1V or 1.5V
I
MAXI_-BIAS
A
CTLI
R
CTLI
g
m
V
OS1
to V
CS
= +100mV or -100mV
∆V
ITEC
I
DIF-BIAS
V
DIF-OS
V
DD
= 3V to 5.5V
V
DD
= 3V to 5.5V
A
DIF
R
LOAD
= 10kΩ to REF
V
OS1
to V
CS
= +100mV or -100mV,
I
ITEC
= ±10µA
V
CTLI
= 0.5V to 2.5V (Note 4)
1MΩ terminated at REF
-200
_______________________________________________________________________________________
3
Integrated Temperature
Controllers for Peltier Modules
MAX1978/MAX1979
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
1 = PV
DD
2 =
SHDN
= 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values at T
A
= +25°C.)
PARAMETER
Integrator Amp Open-Loop Gain
Integrator Amp CMRR
Integrator Amp Input Bias Current
Integrator Amp Voltage Offset
Integrator Amp Gain Bandwidth
Undedicated Chopper Amp
Open-Loop Gain
Undedicated Chopper Amp
CMRR
Undedicated Chopper Amp Input
Bias Current
Undedicated Chopper Amp
Offset Voltage
Undedicated Chopper Amp Gain
Bandwidth
Undedicated Chopper Amp
Output Ripple
BFB_ Buffer Error
UT
and
OT
Leakage Current
UT
and
OT
Output Low Voltage
UT
Trip Threshold
OT
Trip Threshold
I
LEAK
V
OL
SYMBOL
A
OL-INT
CMRR
INT
I
INT-BIAS
V
INT-OS
GBW
INT
A
OL-AIN
CMRR
AIN
I
AIN-BIAS
V
AIN-OS
GBW
AIN
V
RIPPLE
A=5
C
LOAD
< 100pF
V
UT
= V
OT
= 5.5V
Sinking 4mA
FB+ - FB- (see
Typical Application Circuit)
FB+ - FB- (see
Typical Application Circuit)
50
-20
20
-200
V
DD
= 3V to 5.5V
V
DD
= 3V to 5.5V
-10
-200
R
LOAD
= 10kΩ to REF
V
DD
= 3V to 5.5V
V
DD
= 3V to 5.5V
-3
+0.1
100
120
85
0
+10
100
20
0
+200
1
150
+10
+200
CONDITIONS
R
LOAD
= 10kΩ to REF
MIN
TYP
120
100
1
+3
MAX
UNITS
dB
dB
nA
mV
kHz
dB
dB
nA
µV
kHz
mV
µV
µA
mV
mV
mV
4
_______________________________________________________________________________________
Integrated Temperature
Controllers for Peltier Modules
ELECTRICAL CHARACTERISTICS
(V
DD
= PV
DD
1 = PV
DD
2 =
SHDN
= 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 5)
PARAMETER
Input Supply Range
SYMBOL
V
DD
V
DD
= 5V, I
TEC
= 0 to ±3A,
V
OUT
= V
OS1
-V
OS2
(MAX1978)
V
DD
= 5V, I
TEC
= 0 to 6A,
V
OUT
= V
OS1
(MAX1979)
V
DD
= 3V, I
TEC
= 0 to ±3A,
V
OUT
= V
OS1
- V
OS2
(MAX1978)
V
DD
= 3V, I
TEC
= 0 to 6A,
V
OUT
= V
OS1
(MAX1979)
Maximum TEC Current
Reference Voltage
Reference Load Regulation
I
TEC(MAX)
V
REF
∆V
REF
MAX1978
MAX1979
V
DD
= 3V to 5.5V, I
REF
= 150µA
V
DD
= 3V to 5.5V,
I
REF
= 10µA to -1mA
V
OS1
< V
CS
Current-Sense Threshold
V
OS1
> V
CS
No-Load Supply Current
Shutdown Supply Current
UVLO Threshold
Switching Frequency Internal
Oscillator
OS1, OS2, CS Input Current
SHDN,
FREQ Input Current
SHDN,
FREQ Input Low Voltage
SHDN,
FREQ Input High Voltage
I
DD(NO
LOAD)
MAX1978/MAX1979
CONDITIONS
MIN
3
-4.3
MAX
5.5
+4.3
4.3
UNITS
V
Output Voltage Range
V
OUT
V
-2.3
+2.3
2.3
±3
6
1.475
1.515
5
A
V
mV
V
MAXI_
= V
REF
V
MAXI_
= V
REF
/3
V
MAXI_
= V
REF
V
MAXI_
= V
REF
/3
135
40
135
40
160
60
160
60
50
30
3
mA
mA
V
kHz
µA
µA
V
V
mV
V
DD
= 5V
V
DD
= 3.3V
SHDN
= GND, V
DD
= 5V (Note 3)
V
DD
rising
V
DD
falling
FREQ = GND
FREQ = V
DD
2.4
2.25
450
800
-100
-5
I
DD-SD
V
UVLO
f
SW-INT
2.8
2.75
650
1200
+100
+5
0.25
✕
V
DD
I
OS1
, I
OS2
,
0 or V
DD
I
CS
I
SHDN
,
I
FREQ
V
IL
V
IH
0 or V
DD
V
DD
= 3V to 5.5V
V
DD
= 3V to 5.5V
0.75
✕
V
DD
_______________________________________________________________________________________
5
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