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MAX1979
User Manual
21 pgs640.62 Kb0

MAXIM MAX1978, MAX1979 User Manual

General Description
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-can­cellation scheme optimize component size and efficiency while reducing noise. Switching speeds of internal MOSFETs are optimized to reduce noise and EMI. An ultra­low-drift chopper amplifier maintains ±0.001°C temperature stability. Output current, rather than voltage, is directly con­trolled 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 nonlin­earities 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 high­precision integrator amplifier are supplied to create a pro­portional-integral (PI) or proportional-integral-derivative (PID) controller. The instrumentation amplifier can interface to an external NTC or PTC thermistor, thermocouple, or semicon­ductor 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 volt­age 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.
Applications
Fiber Optic Laser Modules
WDM, DWDM Laser-Diode Temperature Control
Fiber Optic Network Equipment
EDFA Optical Amplifiers
Telecom Fiber Interfaces
ATE
Features
♦ Smallest, Safest, Most Accurate Complete
Single-Chip Controller
♦ On-Chip Power MOSFETS—No External FETs
♦ Circuit Footprint < 0.93in
2
♦ Circuit Height < 3mm
♦ Temperature Stability to 0.001°C
♦ Integrated Precision Integrator and Chopper
Stabilized Op Amps
♦ Accurate, Independent Heating and Cooling
Current Limits
♦ Eliminates Surges By Directly Controlling
TEC Current
♦ Adjustable Differential TEC Voltage Limit
♦ Low-Ripple and Low-Noise Design
♦ TEC Current Monitor
♦ Temperature Monitor
♦ Over- and Undertemperature Alarm
♦ Bipolar ±3A Output Current (MAX1978)
♦ Unipolar +6A Output Current (MAX1979)
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
FREQ N.C.
LX1 PGND1
N.C.
LX1 PVDD1
GND
GND
LX1 PV
DD
1
PGND1
PGND2
LX2
PGND2
LX2
PV
DD
2 N.C. LX2
N.C.
OS2
1
2
3
4
5
6
7
8
9
10
11
12
36
35
34
33
32
31
30
29
28
27
26
25
DIFOUT
FB-
FB+
BFB+
AOUT
AIN-
AIN+
GND
INT-
INTOUT
CS
REF
CTLI
V
DD
GND
GND
MAXV
MAXIN
MAXIP
ITEC
COMP
OS1
QFN-EP
MAX1978 MAX1979
BFB-
TOP VIEW
*ELECTRICALLY CONNECTED TO THE UNDERSIDE METAL SLUG. NOTE: GND IS CONNECTED TO THE UNDERSIDE METAL SLUG.
4847464544434241403938
37
1314151617181920212223
24
OT
PVDD2
SHDN
UT
Pin Configuration
19-2490; Rev 1; 2/07
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.
Typical Operating Circuit appears at end of data sheet.
PART
PK G CO D E
MAX1978ETM
T4877-6
MAX1979ETM
T4877-6
*EP = Exposed paddle.
T EM P R A N G EPIN-PACKAGE
- 40° C to + 85° C 48 Thin QFN-EP*
- 40° C to + 85° C 48 Thin QFN-EP*
MAX1978/MAX1979
Integrated Temperature Controllers for Peltier Modules
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VDD= PVDD1 = PVDD2 = SHDN = 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF, TA= 0°C to +85°C,
unless otherwise noted. Typical values at T
A
= +25°C.)
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.
VDDto 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)
PVDD1, PVDD2 to VDD...........................................-0.3V to +0.3V
PVDD1, PVDD2 to GND...............................-0.3V to (VDD+ 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
PARAMETER
CONDITIONS
UNITS
Input Supply Range V
DD
3.0 5.5 V
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)
4.3
V
DD
= 3V, I
TEC
= 0 to ±3A,
V
OUT
= V
OS1
- V
OS2
(MAX1978)
Output Voltage Range V
OUT
V
DD
= 3V, I
TEC
= 0 to 6A,
V
OUT
= V
OS1
(MAX1979)
2.3
V
MAX1978 ±3
Maximum TEC Current
)
MAX1979 6
A
Reference Voltage V
REF
V
DD
= 3V to 5.5V, I
REF
= 150µA
V
Reference Load Regulation ∆V
REF
V
DD
= 3V to 5.5V, I
REF
= +10µA to -1mA 1.2 5 mV
V
MAXI_
= V
REF
160
V
OS1
< V
CS
V
MAXI_
= V
REF
/3 40 50 60
V
MAXI_
= V
REF
160
Current-Sense Threshold
V
OS1
> V
CS
V
MAXI_
= V
REF
/3 40 50 60
mV
V
DD
= 5V, I = 0.5A
NFET On-Resistance
)
V
DD
= 3V, I = 0.5A
Ω
V
DD
= 5V, I = 0.5A
PFET On-Resistance
)
V
DD
= 3V, I = 0.5A
Ω
V
LX
= V
DD
= 5V, TA = +25°C
10
NFET Leakage
)
VLX = V
DD
= 5V, TA = +85°C1
µA
Note 1: LX has internal clamp diodes to PGND and PVDD. 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.
SYMBOL
MIN TYP MAX
-4.3 +4.3
-2.3 +2.3
I
TEC(MAX
1.485 1.500 1.515
135 150
135 150
R
DS(ON-N
R
DS(ON-P
I
LEAK(N
0.04 0.07
0.06 0.08
0.06 0.10
0.09 0.12
0.02
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VDD= PVDD1 = PVDD2 = SHDN = 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF, TA= 0°C to +85°C, unless otherwise noted. Typical values at T
A
= +25°C.)
PARAMETER
CONDITIONS
UNITS
VLX = 0, TA = +25°C
10
PFET Leakage I
LEAK(P)
VLX = 0, TA = +85°C1
µA
V
DD
= 5V 30 50
No-Load Supply Current
I
DD(NO LOAD) V
DD
= 3.3V 15 30
mA
Shutdown Supply Current I
DD-SD
SHDN = GND, V
DD
= 5V (Note 3) 2 3 mA
Thermal Shutdown
Hysteresis = 15°C
°C
VDD rising 2.4 2.6 2.8
UVLO Threshold V
UVLO
VDD falling
2.5
V
FREQ = GND 450
650
Switching Frequency Internal Oscillator
f
SW-INT
FREQ=V
DD
800
kHz
OS1, OS2, CS Input Current
I
OS1
, I
OS2
,
I
CS
0 or V
DD
µA
SHDN, FREQ Input Current
I
SHDN
,
I
FREQ
0 or V
DD
-5 +5 µA
SHDN, FREQ Input Low Voltage
V
IL
V
DD
= 3V to 5.5V
0.25 × V
SHDN, FREQ Input High Voltage
V
IH
V
DD
= 3V to 5.5V
0.75 × V
V
MAXV
= V
REF
✕ 0.67,
V
OS1
to V
OS2
= ±4V, V
DD
= 5V
-1 +1
MAXV Threshold Accuracy
V
MAXV
= V
REF
✕ 0.33,
V
OS1
to V
OS2
= ±2V, V
DD
= 3V
-2 +2
%
MAXV, MAXIP, MAXIN Input Bias Current
I
MAXV-BIAS
,
V
MAXV
= V
MAXI_
= 0.1V or 1.5V
µA
CTLI Gain A
CTLI
V
CTLI
= 0.5V to 2.5V (Note 4) 9.5 10
V/V
CTLI Input Resistance R
CTLI
1MΩ terminated at REF 0.5 1.0 2.0 MΩ
Error Amp Transconductance g
m
50
175 µS
ITEC Accuracy V
OS1
to VCS = +100mV or -100mV -10
%
ITEC Load Regulation ∆V
ITEC
V
OS1
to VCS = +100mV or -100mV,
I
ITEC
= ±10µA
%
Instrumentation Amp Input Bias Current
-10 0
nA
Instrumentation Amp Offset Voltage
V
DIF-OS
VDD = 3V to 5.5V
µV
Instrumentation Amp Offset­Voltage Drift with Temperature
V
DD
= 3V to 5.5V 0.1
µV/°C
Instrumentation Amp Preset Gain
A
DIF
R
LOAD
= 10kΩ to REF 45 50 55 V/V
SYMBOL
MIN TYP MAX
0.02
T
S H U TD OWN
2.25
-100 +100
I
MAXI_-BIAS
V
DD
-0.1 +0.1
165
500
1000 1200
2.75
V
DD
10.5
-0.1 +0.1
-200 +20 +200
I
DIF-BIAS
100
+10
+10
MAX1978/MAX1979
Integrated Temperature Controllers for Peltier Modules
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VDD= PVDD1 = PVDD2 = SHDN = 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF, TA= 0°C to +85°C, unless otherwise noted. Typical values at T
A
= +25°C.)
PARAMETER
CONDITIONS
UNITS
R
LOAD
= 10kΩ to REF
dB
Integrator Amp CMRR
dB
VDD = 3V to 5.5V 1 nA
Integrator Amp Voltage Offset
VDD = 3V to 5.5V -3
+3 mV
Integrator Amp Gain Bandwidth
kHz
Undedicated Chopper Amp Open-Loop Gain
R
LOAD
= 10kΩ to REF
dB
Undedicated Chopper Amp CMRR
85 dB
Undedicated Chopper Amp Input Bias Current
VDD = 3V to 5.5V -10 0
nA
Undedicated Chopper Amp Offset Voltage
VDD = 3V to 5.5V
µV
Undedicated Chopper Amp Gain Bandwidth
kHz
Undedicated Chopper Amp Output Ripple
A = 5 20 mV
BFB_ Buffer Error C
L OA D
< 100p F
0
µV
UT and OT Leakage Current I
LEAK
V UT = V OT = 5.5V 1 µA
UT and OT Output Low Voltage V
OL
Sinking 4mA 50 150 mV
UT Trip Threshold FB+ - FB- (see Typical Application Circuit) -20 mV OT Trip Threshold FB+ - FB- (see Typical Application Circuit)20 mV
Integrator Amp Open-Loop Gain A
Integrator Amp Input Bias Current I
SYMBOL
OL-INT
CMRR
INT
INT-BIAS
V
INT-OS
GBW
INT
MIN TYP MAX
120
100
+0.1
100
A
OL-AIN
CMRR
AIN
I
AIN-BIAS
V
AIN-OS
GBW
AIN
V
RIPPLE
-200 +10 +200
-200
120
+10
100
+200
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS
(VDD= PVDD1 = PVDD2 = SHDN = 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF, TA= -40°C to +85°C, unless otherwise noted.) (Note 5)
PARAMETER
SYMBOL
CONDITIONS
MIN
MAX
UNITS
Input Supply Range V
DD
3 5.5 V
V
DD
= 5V, I
TEC
= 0 to ±3A,
V
OUT
= V
OS1 -VOS2
(MAX1978)
V
DD
= 5V, I
TEC
= 0 to 6A,
V
OUT
= V
OS1
(MAX1979)
4.3
V
DD
= 3V, I
TEC
= 0 to ±3A,
V
OUT
= V
OS1
- V
OS2
(MAX1978)
Output Voltage Range V
OUT
V
DD
= 3V, I
TEC
= 0 to 6A,
V
OUT
= V
OS1
(MAX1979)
2.3
V
MAX1978 ±3
Maximum TEC Current
)
MAX1979 6
A
Reference Voltage V
REF
V
DD
= 3V to 5.5V, I
REF
= 150µA
V
Reference Load Regulation ∆V
REF
V
DD
= 3V to 5.5V,
I
REF
= 10µA to -1mA
5mV
V
MAXI_
= V
REF
160
V
OS1
< V
CS
V
MAXI_
= V
REF
/3 40 60
V
MAXI_
= V
REF
160
Current-Sense Threshold
V
OS1
> V
CS
V
MAXI_
= V
REF
/3 40 60
mV
V
DD
= 5V 50
No-Load Supply Current
I
DD(NO LOAD) V
DD
= 3.3V 30
mA
Shutdown Supply Current I
DD-SD
SHDN = GND, V
DD
= 5V (Note 3) 3 mA
VDD rising 2.4 2.8
UVLO Threshold V
UVLO
VDD falling
V
FREQ = GND
650
Switching Frequency Internal Oscillator
f
SW-INT
FREQ = V
DD
kHz
OS1, OS2, CS Input Current
I
OS1
, I
OS2
,
I
CS
0 or V
DD
µA
SHDN, FREQ Input Current
I
SHDN
,
I
F REQ
0 or V
DD
-5 +5 µA
SHDN, FREQ Input Low Voltage V
IL
V
DD
= 3V to 5.5V
0.25
✕
V
SHDN, FREQ Input High Voltage
V
IH
V
DD
= 3V to 5.5V
0.75
✕
V
I
TEC(MAX
-4.3 +4.3
-2.3 +2.3
1.475 1.515
135
135
2.25 2.75
450
800 1200
-100 +100
V
DD
V
DD
Note 3: Includes power FET leakage. Note 4: CTLI gain is defined as:
Note 5: Specifications to -40°C are guaranteed by design, not production tested.
A
CTLI
VV
VV
CTLI REF
OSI CS
=
−
()
−
()
MAX1978/MAX1979
Integrated Temperature Controllers for Peltier Modules
6 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VDD= PVDD1 = PVDD2 = SHDN = 5V, FREQ = GND, CTLI = FB+ = FB- = MAXV = MAXIP = MAXIN = REF, TA= -40°C to +85°C, unless otherwise noted.) (Note 5)
PARAMETER
CONDITIONS
UNITS
V
MAXV
= V
REF
✕ 0.67,
V
OS1
to V
OS2
= ±4V, V
DD
= 5V
-1 +1
MAXV Threshold Accuracy
V
MAXV
= V
REF
✕ 0.33, V
OS1
to V
OS2
= ±2V,
V
DD
= 3V
-2 +2
%
MAXV, MAXIP, MAXIN Input Bias Current
I
MAXV-BIAS
,
V
MAXV
= V
MAXI_
= 0.1V or 1.5V
µA
CTLI Gain A
CTLI
V
CTLI
= 0.5V to 2.5V (Note 4) 9.5
V/V
CTLI Input Resistance R
CTLI
1MΩ terminated at REF 0.5 2.0 MΩ
Error Amp Transconductance g
m
50 175 µS
ITEC Accuracy V
OS1
to VCS = +100mV or -100mV -10
%
ITEC Load Regulation ∆V
ITEC
V
OS1
to VCS = +100mV or
-100mV, I
ITEC
= ±10µA
%
Instrumentation Amp Input Bias Current
-10
nA
Instrumentation Amp Offset Voltage
VDD = 3V to 5.5V
µV
Instrumentation Amp Preset Gain
A
DIF
R
LOAD
= 10kΩ to REF 45 55 V/V
VDD = 3V to 5.5V 1 nA
Integrator Amp Voltage Offset
VDD = 3V to 5.5V -3 +3 mV
Undedicated Chopper Amp Input Bias Current
VDD = 3V to 5.5V -10
nA
Undedicated Chopper Amp Offset Voltage
VDD = 3V to 5.5V
µV
BFB_ Buffer Error C
LOAD
< 100pF
µV
UT and OT Leakage Current I
LEAK
V UT = V OT = 5.5V 1 µA
UT and OT Output Low Voltage V
OL
Sinking 4mA 150 mV
SYMBOL
MIN MAX
Integrator Amp Input Bias Current I
I
MAXI_-BIAS
I
DIF-BIAS
V
DIF-OS
INT-BIAS
V
INT-OS
I
AIN-BIAS
V
AIN-OS
-0.1 +0.1
-0.125 +0.125
-200 +200
-200 +200
-200 +200
10.5
+10
+10
+10
MAX1978/MAX1979
Integrated Temperature
Controllers for Peltier Modules
_______________________________________________________________________________________ 7
EFFICIENCY vs. TEC CURRENT
V
DD
= 5V
MAX1978 toc01
TEC CURRENT (A)
EFFICIENCY (%)
2.01.51.00.5
10
20
30
40
50
60
70
80
90
0
0 2.5
R
TEC
= 1.1
Ω
EFFICIENCY vs. TEC CURRENT
V
DD
= 3.3V
MAX1978 toc02
TEC CURRENT (A)
2.0
1.50.5 1.0
10
20
30
40
50
60
70
80
0
0 2.5
R
TEC
= 0.855Ω
EFFICIENCY (%)
OUTPUT-VOLTAGE
RIPPLE WAVEFORMS
MAX1978 toc03
400ns/div
V
OS2
100mV/div
AC-COUPLED
V
OS1
100mV/div
AC-COUPLED
V
OS1
- V
OS1
50mV/div
INPUT SUPPLY RIPPLE
MAX1978 toc04
200ns/div
V
DD
20mV/div AC-COUPLED
TEC CURRENT vs. CTLI VOLTAGE
MAX1978 toc05
20ms/div
V
CTLI
1V/div
I
TEC
2A/div
-0V
-0A
ZERO-CROSSING TEC CURRENT
MAX1978 toc06
1ms/div
V
CTLI
200mV/div
I
TEC
500mA/div
1.5V
0A
V
ITEC
vs. TEC CURRENT
MAX1978 toc07
TEC CURRENT (A)
V
ITEC
(V)
210-1-2
0.5
1.0
1.5
2.0
2.5
3.0
0
-3 3
TEC CURRENT vs. TEMPERATURE
MAX1978 toc08
TEMPERATURE (°C)
I
TEC
(A)
806040200-20
0.995
1.000
1.005
1.010
0.990
-40
I
TEC
= 1A
R
SENSE
= 0.68Ω
SWITCHING FREQUENCY
vs. TEMPERATURE
SWITCHING FREQUENCY (kHz)
494
496
498
500
502
504
506
508
492
MAX1978 toc09
TEMPERATURE (°C)
806040200-20-40
V
CTLI
= 1.5V
R
TEC
= 1Ω
Typical Operating Characteristics
(VDD= 5V, V
CTLI
= 1V, V
FREQ
= GND, RTEC = 1Ω, circuit of Figure 1, TA= +25°C, unless otherwise noted.)
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