Datasheet

Integrated Temperature
Controllers for Peltier Modules
Pin Description (continued)
PIN NAME FUNCTION
23 AIN- Undedicated Chopper-Stabilized Amplifier Inverting Input
24 AOUT Undedicated Chopper-Stabilized Amplifier Output
27, 30 PV
DD
1
Power 1 Inputs. Must be same voltage as V
DD
. Connect all PV
DD
1 inputs together at the V
DD
power plane.
Bypass to PGND1 with a 10µF ceramic capacitor.
28, 31, 33 LX1 Inductor 1 Connection. Connect all LX1 pins together. Connect LX1 to LX2 when using the MAX1979.
32, 34 PGND1
Power Ground 1. Internal synchronous-rectifier ground connections. Connect all PGND pins together at
power ground plane.
36 FREQ Switching-Frequency Select. Low = 500kHz, high = 1MHz.
37 ITEC
TEC Current Monitor Output. The ITEC output voltage is a function of the voltage across the TEC current-
sense resistor. V
ITEC
= 1.50V + (V
OS1
- V
CS
)
✕
8.
38 COMP Current-Control Loop Compensation. For most designs, connect a 10nF capacitor from COMP to GND.
39 MAXIP Maximum Positive TEC Current. Connect MAXIP to REF to set default positive current limit +150mV/R
SENSE
.
40 MAXIN
Maximum Negative TEC Current. Connect MAXIN to REF to set default negative current limit -150mV /
R
SENSE
. Connect MAXIN to MAXIP when using the MAX1979.
41 MAXV
Maximum Bipolar TEC Voltage. Connect an external resistive divider from REF to GND to set the maximum
voltage across the TEC. The maximum TEC voltage is 4
✕
V
MAXV
.
44 V
DD
Analog Supply Voltage Input. Bypass to GND with a 10µF ceramic capacitor.
45 CTLI
TEC Current-Control Input. Sets differential current into the TEC. Center point is 1.50V (no TEC current).
Connect to INTOUT when using the thermal control loop. I
TEC
= (V
OS1
- V
CS
)/R
SENSE
= (V
CTLI
- 1.50)/(10
✕
R
SENSE
). When (V
CLTI
- V
REF
) > 0, V
OS2
> V
OS1
> V
CS
.
46 REF 1.5V Reference Voltage Output. Bypass REF to GND with a 1µF ceramic capacitor.
47 CS
Current-Sense Input. The current through the TEC is monitored between CS and OS1. The maximum TEC
current is given by 150mV/R
SENSE
and is bipolar for the MAX1978. The MAX1979 TEC current is unipolar.
48 OS1
Output Sense 1. OS1 senses one side of the differential TEC voltage. OS1 is a sense point, not a power
output.
— EP Exposed Pad. Solder evenly to the PCB ground plane to maximize thermal performance.
MAX1978/MAX1979
10
Maxim Integrated