RM6203

4

www.reactor-micro.com

ELECTRICAL CHARACTERISTICS

The specifications are applied at T=25℃, VCC=5.5-7.5V, Ct=680PF, RS=1Ω, unless otherwise noted.(Note 2)(continued)

Re-enabling voltage

3.8

V

Over-Voltage Limiting

Threshold

9.5

10

10.5

V

Note1: Stresses beyond those listed under Absolute Maximum

Ratings may cause permanent damage to the device.

Exposure to any Absolute Maximum Rating condition for

extended periods may affect device reliability and lifetime.

Note2: TheRM6203 is guaranteed to meet performance

specifications from 0℃ to 70℃. Specifications over the -40℃

to 85℃ operating temperature range are assured by design,

characterization and correlation with statistical process

controls.

BLOCK DIAGRAM

In the enabling stage, when power is on, VR is closed; the

pull-up current source FB is closed; OE inputs enabling current

from power tube to VCC; OB controls the base current of the

power tube, limits the collector current of the power tube (i.e.

RM6203 initiates the reception current), so as to ensure the

safety of the power tube; when VCC voltage raises up to 7.8 V,

the enabling stage ends and it goes into the normal stage.

In the normal stage, VCC voltage should be maintained at

4.8V to 9.0V, VR outputs 2.5V reference; FB pull-up current

source is opened; the oscillator output OSC1 decides the

maximum duty ratio, output OSC2 tries to trigger the power

into open period, and the screened power tube turns on the

current peak; if FB is below 1.8V (approximately between 1.2V

and 1.8V), the oscillator period will then be increased, the

smaller the FB is, the wider the oscillator period will be, until

the stop of the oscillator (this feature will lower the stand-by

power consumption of the switch power source); if the external

feedback intends to make VCC higher than 10V, the internal

circuit feedback to FB will stabilize VCC at 9.8V (with this

feature, the internal circuit rather than the external feedback

circuit will be used to stabilize the output voltage, but the

stabilizing accuracy may be low); in the open period, OB

supplies base current to power tube, OE pulls down the emitter

of the power tube to IS, and the OB uses the slope current

driving (i.e. the OB open current is the function of IS, when IS

= 0V, OB open current is approximately 40mA, then the OB