1. general description the tea1708 is an automatic discharge ic fo r x capacitors with a low power consumption (typically 1 mw at 230 v (ac). a 500 v clamping circuit is int egrated, protecting the ic during mains surges. in a typical application with only two 200 k ? resistors, the maximum differential mode mains surge voltage allowed exceeds 6 kv. a metal oxide varistor is not required to protect the ic. the x capacitor discharge current is interna lly limited to 2.3 ma. the discharge delay timer is set externally us ing a low voltage capacitor. the very low power consumption in combination with a large discharge current enables the use of a large value x capacitor to reduce emi while retaining the low standby power. 2. features and benefits ? 1 mw power consumption at 230 v (ac) ? integrated 500 v clamp; no metal oxide varistor required to protect the ic ? self supplied, no external bias required ? discharge current internally limited ? adjustable discharge delay ? very high differential surge: 6 kv with two 200 k ? resistors ? easier application design, resolving emi issu es while retaining th e efficiency level 3. applications ? all ac connected power supplies with x ca pacitors > 100 nf requiring a low load standby power. 4. ordering information TEA1708T greenchip x capacitor discharge ic rev. 1 ? 25 september 2013 product data sheet table 1. ordering information type number package name description version TEA1708T so8 plastic small outline package; 8 leads; body width 3.9 mm sot96-1
TEA1708T all information provided in this document is subject to legal disclaimers. ? nxp b.v. 2013. all rights reserved. product data sheet rev. 1 ? 25 september 2013 2 of 11 nxp semiconductors TEA1708T greenchip x capacitor discharge ic 5. block diagram 6. pinning information 6.1 pinning 6.2 pin description fig 1. TEA1708T block diagram d d d 9 7 0 5 + 9 + 9 7 0 5 9 9 9 ? $ fig 2. TEA1708T pinning diagram , & q f + 9 7 0 5 q f q f q f 7 0 5 + 9 d d d table 2. pin description symbol pin description n.c. 1 not connected tmr2 2 timer pin 2 n.c. 3 not connected tmr1 4 timer pin 1 hv2 5 high-voltage mains connection 2 n.c. 6 not connected n.c. 7 not connected hv1 8 high-voltage mains connection 1
TEA1708T all information provided in this document is subject to legal disclaimers. ? nxp b.v. 2013. all rights reserved. product data sheet rev. 1 ? 25 september 2013 3 of 11 nxp semiconductors TEA1708T greenchip x capacitor discharge ic 7. functional description the tea1708 incorporates a timer and a zero-crossing mains voltage detector. if a positive or negative voltage above the threshold zero-crossing mains voltage (20 v) is applied between the high-voltage pins, the timer charges the external capacitor on the tmr1 and tmr2 pins. if the voltage between the tmr1 and tmr2 pins reaches 1.2 v, a discharge current is activated. if the voltage applied between the high-voltage pins, is below the threshold zero-crossing mains voltage, the external capacitor is discharged and the discharging stops. the discharge current is internally limited. when an ac mains voltage is applied, the timer capacitor is charged between the mains zero crossings and discharged during the mains zero crossings. when the ac mains is disconnected and a high voltage remains on the x capacitor, the timer charges the external capacitor above its discharge activati on threshold voltage point (1.2 v), switching on the internally limited discharge current of the external x capacitor. to protect the ic during mains surges, a high voltage clamping circuit is integrated. the clamping circuit is activated for > 500 v posit ive and negative voltages. the high-voltage pins hv1 and hv2 are fully symmetrical. fig 3. functional behavior d d d 0 d l q v g l v f r q q h f w $ & |