UM3304_15 Datasheet, PDF (10/15 Pages) Union Semiconductor, Inc. – 4-Bit Bidirectional Voltage-Level Translator with Auto Direction Sensing and ESD Protection

UM3304/UM3304Q/UM3304QT
Input Driver Requirements
Typical I_IN vs V_IN characteristics of the UM3304/UM3304Q/UM3304QT are shown in Figure 2.
For proper operation, the device driving the data I/Os of the UM3304/UM3304Q/UM3304QT
must have drive strength of at least ±2 mA.
I_IN
V_T/4kΩ
V_IN
-(V_D-V_T)/4kΩ
A: V_T is the input threshold voltage of the UM3304/UM3304Q/UM3304QT (typical V_CCI/2)
B: V_D is the supply voltage of the external driver.
Power Up
Figure 2 Typical I_IN vs V_IN Curve
During operation, ensure that V_CCA≤V_CCB at all times. During power-up sequencing, V_CCA≥ V_CCB
does not damage the device, so any power supply can be ramped up first. The
UM3304/UM3304Q/UM3304QT has circuitry that disables all output ports when either V_CC is
switched off (V_CCA/B = 0 V).
Enable and Disable
The UM3304/UM3304Q/UM3304QT has an OE input that is used to disable the device by setting
OE=low, which places all I/Os in the high-impedance (Hi-Z) state. The disable time (t_dis) indicates
the delay between when OE goes low and when the outputs actually get disabled (Hi-Z). The
enable time (t_en) indicates the amount of time the user must allow for the one-shot circuitry to
become operational after OE is taken high.
Pull-up or Pull-down Resistors on I/O Lines
The UM3304/UM3304Q/UM3304QT is designed to drive capacitive loads of up to 50pF. The
output drivers of the UM3304/UM3304Q/UM3304QT have low dc drive strength. External
pull-up or pull-down resistors need higher than 50kΩ.
For the same reason, the UM3304/UM3304Q/UM3304QT should not be used in open-drain
system, such as I²C or 1-wire system.
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http://www.union-ic.com Rev.15 Aug.2015
10/15