TMS37157 Datasheet, PDF (6/47 Pages) Texas Instruments – PASSIVE LOW FREQUENCY INTERFACE DEVICE WITH EEPROM AND 134.2 kHz TRANSPONDER INTERFACE

TMS37157
SWRS083A – SEPTEMBER 2009 – REVISED NOVEMBER 2009
Transponder Charge
Tx
Vcl
5.75
www.ti.com
0V
Figure 1. Activation limit of TMS37157
MEMORY
PARAMETER
P/E-C
Program/erase cycles
25°C
X_DRET
Data retention
T_s = 25°C
MIN
TYP
200000
10
MAX
UNIT
Cycles
Years
TEST INTERFACE
PARAMETER
R_TCLK
R_TDAT
R_TEN
V_OL
V_OH
Pull-down resistor, TCLK
Pull-down resistor, TDAT
Pull-down resistor, TEN
Low level output voltage, TDAT
High level output voltage, TDAT
V_CL = 5V, R_L = 2.5 kΩ
V_CL = 5V, R_L = 2.5 kΩ
MIN
TYP
MAX UNIT
7
10
25
kΩ
20
150
375
kΩ
5
10
25
kΩ
0.25
V
4.75
V
TRANSPONDER MODE
TRANSPONDER TIMING USING PPM
PARAMETER
MIN
TYP
MAX UNIT
PPM - Pulse Position Modulation
t_offtrp
t_ontrpL
t_ontrpH
t_bittrpL
t_bittrpH
Write pulse pause (PPM)⁽¹⁾
Write pulse activation/ low bit (PPM)⁽¹⁾
Write pulse activation/ high bit (PPM)⁽¹⁾
Write low bit period⁽¹⁾
Write high bit period^{(1) (2) (3)}
170
μs
230
μs
350
μs
400
μs
510
520
1730
μs
(1) This timing is measured at the transponder using a pickup coil. This timing is with Low Bit Frequency = 134.7kHz and is influenced by
various factors e.g. detuning and coupling to the reader antenna and. Out of this timing the low and high bit are detected by the
transponder logic.
(2) Except the last bit this limitation of the duration is valid for all downlink bits.
(3) To detect a High bit the absolute minimum of t_bittrpH = 510 μs must be met.
READER RECOMMENDATIONS
PARAMETER
QTX,
QRX
Reader operating quality factor
f_TX
t_TX
t_TXoff
t_prog
t_RD
Transmitter frequency
Charge time
Transmitter off time
Programming time
Read time
MIN
134.16
20
3
15
14.9
TYP
134.2
25
15
MAX
10
UNIT
134.24 kHz
ms
ms
ms
ms
6
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