UAA2016P

Product Summary

CONTROLLERThe UAA2016 is designed to drive triacs with the Zero Voltage technique
which allows RFI–free power regulation of resistive loads. Operating directly
on the AC power line, its main application is the precision regulation of
electrical heating systems such as panel heaters or irons.
A built–in digital sawtooth waveform permits proportional temperature
regulation action over a ±1°C band around the set point. For energy savings
there is a programmable temperature reduction function, and for security a
sensor failsafe inhibits output pulses when the sensor connection is broken.
Preset temperature (i.e. defrost) application is also possible. In applications
where high hysteresis is needed, its value can be adjusted up to 5°C around
the set point. All these features are implemented with a very low external
component count.

Parametrics

? Zero Voltage Switch for Triacs, up to 2.0 kW (MAC212A8)
? Direct AC Line Operation
? Proportional Regulation of Temperature over a 1°C Band
? Programmable Temperature Reduction
? Preset Temperature (i.e. Defrost)
? Sensor Failsafe
? Adjustable Hysteresis
? Low External Component Count

Features

APPLICATION INFORMATION
(For simplicity, the LED in series with Rout
 is omitted in the
following calculations.)
Triac Choice and Rout
 Determination
Depending on the power in the load, choose the triac that
has the lowest peak gate trigger current. This will limit the
output current of the UAA2016 and thus its power
consumption. Use Figure 4 to determine Rout
 according to
the triac maximum gate current (IGT) and the application low
temperature limit. For a 2.0 kW load at 220 Vrms, a good triac
choice is the Motorola MAC212A8. Its maximum peak gate
trigger current at 25°C is 50 mA.
For an application to work down to – 20°C, Rout
 should be
60 ?. It is assumed that: IGT(T) = IGT(25°C)
exp (–T/125)
with T in °C, which applies to the MAC212A8.
Output Pulse Width, Rsync
The pulse with TP is determined by the triac’s IHold, ILatch
together with the load value and working conditions
(frequency and voltage):
Given the RMS AC voltage and the load power, the load
value is:
RL = V2rms/POWER
The load current is then:
I
Load
 (Vrms
2

sin(2
ft)–V
TM
)R
L
where VTM is the maximum on state voltage of the triac, f is
the line frequency.
Set ILoad = ILatch for t = TP/2 to calculate TP.
Figures 6 and 7 give the value of TP which corresponds to
the higher of the values of IHold and ILatch, assuming that
VTM = 1.6 V. Figure 8 gives the Rsync that produces the
corresponding TP.
RSupply and Filter Capacitor
With the output current and the pulse width determined as
above, use Figures 9 and 10 to determine RSupply, assuming
that the sinking current at Vref
 pin (including NTC bridge
current) is less than 0.5 mA. Then use Figure 11 and 12 to
determine the filter capacitor (CF) according to the ripple
desired on supply voltage. The maximum ripple allowed is
1.0 V.
Temperature Reduction Determined by R1
(Refer to Figures 13 and 14.)

Diagrams

MAXIMUM RATINGS (Voltages referenced to Pin 7)
Rating Symbol Value Unit
Supply Current (IPin 5) ICC 15 mA
Non–Repetitive Supply Current
(Pulse Width = 1.0 μs)
ICCP 200 mA
AC Synchronization Current Isync 3.0 mA
Pin Voltages VPin 2
VPin 3
VPin 4
VPin 6
0; Vref
0; Vref
0; Vref
0; VEE
V
Vref
 Current Sink IPin 1 1.0 mA
Output Current (Pin 6)
(Pulse Width < 400 μs)
IO 150 mA
Power Dissipation PD 625 mW
Thermal Resistance, Junction–to–Air RθJA 100 °C/W
Operating Temperature Range TA – 20 to + 85 °C
ELECTRICAL CHARACTERISTICS (TA = 25°C, VEE = –7.0 V, voltages referred to Pin 7, unless otherwise noted.)
Characteristic Symbol Min Typ Max Unit
Supply Current (Pins 6, 8 not connected)
(TA = – 20° to + 85°C)
ICC
— 0.9 1.5
mA
Stabilized Supply Voltage (Pin 5)    (ICC = 2.0 mA) VEE –10 – 9.0 – 8.0 V
Reference Voltage (Pin 1) Vref – 6.5 – 5.5 – 4.5 V
Output Pulse Current (TA = – 20° to + 85°C)
(Rout
 = 60 W, VEE = – 8.0 V)
IO
90 100 130
mA
Output Leakage Current (Vout
 = 0 V) IOL — — 10 μA
Output Pulse Width (TA = – 20° to + 85°C) (Note 1)
(Mains = 220 Vrms, Rsync = 220 k?)
TP
50 — 100
μs
Comparator Offset (Note 5) Voff –10 — +10 mV
Sensor Input Bias Current I
IB — — 0.1 μA
Sawtooth Period (Note 2) TS — 40.96 — sec
Sawtooth Amplitude (Note 6) AS 50 70 90 mV
Temperature Reduction Voltage (Note 3)
(Pin 4 Connected to VCC)
VTR
280 350 420
mV
Internal Hysteresis Voltage
(Pin 2 Not Connected)
VIH
— 10 —
mV
Additional Hysteresis (Note 4)
(Pin 2 Connected to VCC)
VH
280 350 420
mV
Failsafe Threshold (TA = – 20° to + 85°C) (Note 7) VFSth 180 — 300 mV
NOTES: 1. Output pulses are centered with respect to zero crossing point. Pulse width is adjusted by the value of Rsync
. Refer to application curves.
2. The actual sawtooth period depends on the AC power line frequency. It is exactly 2048 times the corresponding period. For the 50 Hz case it is 40.96
sec. For the 60 Hz case it is 34.13 sec. This is to comply with the European standard, namely that 2.0 kW loads cannot be connected or removed
from the line more than once every 30 sec.
3. 350 mV corresponds to 5°C temperature reduction. This is tested at probe using internal test pad. Smaller temperature reduction can be obtained by
adding an external resistor between Pin 4 and VCC. Refer to application curves.
4. 350 mV corresponds to a hysteresis of 5°C. This is tested at probe using internal test pad. Smaller additional hysteresis can be obtained by adding
an external resistor between Pin 2 and VCC. Refer to application curves.
5. Parameter guaranteed but not tested. Worst case 10 mV corresponds to 0.15°C shift on set point.
6. Measured at probe by internal test pad. 70 mV corresponds to 1°C. Note that the proportional band is independent of the NTC value.
7. At very low temperature the NTC resistor increases quickly. This can cause the sensor input voltage to reach the failsafe threshold, thus inhibiting
output pulses; refer to application schematics. The corresponding temperature is the limit at which the circuit works in the typical application. By
setting this threshold at 0.05 Vref
, the NTC value can increase up to 20 times its nominal value, thus the application works below – 20°C.